0001564590-21-012639 | 10-K | XBRL Viewer | Seacor Marine Holdings INC

^[1]

1,012,873

899,024

(291,538)

(308,917)

Net property and equipment

721,335

590,107

Construction in progress

32,327

70,806

753,662

660,913

Right-of-Use Asset - Operating Leases

7,134

16,537

Right-of-Use Asset - Finance Leases

129

Investments, at Equity, and Advances to 50% or Less Owned Companies

75,308

120,831

Construction Reserve Funds

12,893

Other Assets

2,734

3,358

Total assets

1,017,663

1,009,193

Current Liabilities:

Current portion of operating lease liabilities

7,030

14,896

Current portion of finance lease liabilities

Current portion of long-term debt

Recourse

26,734

17,802

Non Recourse

5,643

Accounts payable and accrued expenses

29,967

24,598

Due to SEACOR Holdings

Accrued wages and benefits

1,744

1,545

Accrued interest

1,664

729

Accrued capital, repair and maintenance expenditures

11,328

15,978

Deferred and Unearned revenues

4,452

5,296

Accrued insurance deductibles and premiums

2,274

3,564

Accrued professional fees

975

871

Derivatives

4,591

2,925

Other current liabilities

4,439

4,479

Liabilities associated with assets held for sale

30,927

27,540

Total current liabilities

131,804

120,297

Long-Term Operating Lease Liabilities

4,345

9,255

Long-Term Finance Lease Liabilities

105

Long-Term Debt

Recourse

328,690

239,939

Non Recourse

111,820

115,775

Conversion Option Liability on Convertible Senior Notes

5,205

Deferred Income Taxes

35,822

33,564

Deferred Gains and Other Liabilities

3,239

6,234

Total liabilities

615,827

530,269

SEACOR Marine Holdings Inc. stockholders' equity:

Preferred stock, $.01 par value, 10,000,000 shares authorized; none issued nor outstanding

Common stock, $.01 par value, 60,000,000 shares authorized; 23,504,050 and 21,928,674 shares issued in 2020 and 2019, respectively

235

219

Additional paid-in capital

451,179

429,318

Retained earnings

(51,839)

27,076

Shares held in treasury of 73,284 and 47,185 in 2020 and 2019, respectively, at cost

(848)

(669)

Accumulated other comprehensive loss, net of tax

2,790

1,548

Total stockholders equity

401,517

457,492

Noncontrolling interests in subsidiaries

319

21,432

Total equity

401,836

478,924

Total liabilities and equity

$ 1,017,663

$ 1,009,193

[1]	Includes property and equipment acquired in business acquisitions at acquisition date fair value, and net of the impact of recognized impairment charges.

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Trade receivables, allowance for credit loss	$ 582	$ 455
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	60,000,000	60,000,000
Common stock, shares issued (in shares)	23,504,050	21,928,674
Shares held in treasury (in shares)	73,284	47,185

Consolidated Statements of Loss - USD ($) $ in Thousands	12 Months Ended
Consolidated Statements of Loss - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Operating Revenues	$ 141,837	$ 174,453	$ 179,161
Costs and Expenses:
Operating	91,145	109,523	119,587
Administrative and general	40,051	39,791	41,616
Lease expense	7,525	15,840	12,964
Depreciation and amortization	57,167	57,166	61,419
Costs and expenses	195,888	222,320	235,586
Losses on Asset Dispositions and Impairments, Net	(17,588)	(6,461)	(11,989)
Operating Loss	(71,639)	(54,328)	(68,414)
Other Income (Expense):
Interest income	1,273	1,389	1,171
Interest expense	(30,691)	(28,956)	(26,726)
SEACOR Holdings guarantee fees	(47)	(108)	(29)
Loss on Debt Extinguishment			(638)
Derivative gains, net	4,310	71	2,854
Foreign currency losses, net	(1,294)	(2,541)	(1,328)
Other, net	(19)	(1)	677
Nonoperating income expense	(26,468)	(30,146)	(24,019)
Loss from Continuing Operations Before Tax Benefit and Equity in Losses of 50% or Less Owned Companies	(98,107)	(84,474)	(92,433)
Income Tax (Benefit) Expense:
Current	(25,182)	4,921	9,297
Deferred	2,258	(12,890)	(22,760)
Income Tax (Benefit) Expense	(22,924)	(7,969)	(13,463)
Loss Before Equity in Losses of 50% or Less Owned Companies	(75,183)	(76,505)	(78,970)
Equity in Losses of 50% or Less Owned Companies, Net of Tax	(8,163)	(14,459)	(4,009)
Loss from Continuing Operations	(83,346)	(90,964)	(82,979)
Income (Loss) on Discontinued Operations, Net of Tax	364	(7,731)	927
Net Loss	(82,982)	(98,695)	(82,052)
Net Loss attributable to Noncontrolling Interests in Subsidiaries	(4,067)	(5,858)	(4,444)
Net Loss attributable to SEACOR Marine Holdings Inc.	$ (78,915)	$ (92,837)	$ (77,608)
Basic and Diluted (Loss) Income Per Common Share and Warrants of SEACOR Marine Holdings Inc.
Continuing operations	$ (3.20)	$ (3.62)	$ (3.74)
Discontinued operations	0.02	(0.33)	0.04
Basic and Diluted Income (Loss) Per Common Share and Warrants	$ (3.18)	$ (3.95)	$ (3.70)
Weighted Average Common Shares and Warrants Outstanding:
Basic and diluted shares	24,785,744	23,513,925	20,926,307

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net Loss	$ (82,982)	$ (98,695)	$ (82,052)
Other Comprehensive Income (Loss):
Foreign currency translation gains (losses), net	2,112	20,157	(2,365)
Derivative losses on cash flow hedges	(2,139)	(1,901)	(1,939)
Other comprehensive income	1,242	18,163	(4,349)
Income tax benefit (expense)		173	(46)
Other comprehensive income, net	1,242	18,336	(4,395)
Comprehensive Loss	(81,740)	(80,359)	(86,447)
Comprehensive Loss attributable to Noncontrolling Interests in Subsidiaries	(4,067)	(5,858)	(4,544)
Comprehensive Loss attributable to SEACOR Marine Holdings Inc.	(77,673)	(74,501)	(81,903)
Interest Expense
Other Comprehensive Income (Loss):
Reclassification of derivative losses on cash flow hedges	1,425	552	31
Equity Method Investments
Other Comprehensive Income (Loss):
Reclassification of derivative losses on cash flow hedges	$ (156)	$ (645)	$ (76)

Consolidated Statements of Comprehensive Loss (Parenthetical)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Reclassification of derivative losses on cash flow hedges to equity in losses	50.00%	50.00%	50.00%

Consolidated Statements of Changes In Equity - USD ($)	Total	Previously Reported [Member]	Revision of Prior Period, Accounting Standards Update, Adjustment [Member]	Common Stock [Member]	Common Stock [Member] Previously Reported [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member] Previously Reported [Member]	Treasury Stock [Member]	Treasury Stock [Member] Previously Reported [Member]	Retained Earnings [Member]	Retained Earnings [Member] Previously Reported [Member]	Retained Earnings [Member] Revision of Prior Period, Accounting Standards Update, Adjustment [Member]	Accumulated Other Comprehensive Loss [Member]	Accumulated Other Comprehensive Loss [Member] Previously Reported [Member]	Non-Controlling Interests In Subsidiaries [Member]	Non-Controlling Interests In Subsidiaries [Member] Previously Reported [Member]
Balance at Dec. 31, 2017	$ 511,097,000			$ 177,000		$ 303,996,000				$ 204,442,000			$ (12,493,000)		$ 14,975,000
Balance (in shares) at Dec. 31, 2017				17,675,356
Issuance of Common Stock	42,996,000			$ 23,000		42,973,000
Issuance of Common Stock (in shares)				2,291,084
Issuance of Warrants	62,809,000					62,809,000
Amortization of employee share awards	3,494,000					3,494,000
Exercise of options	833,000			$ 1,000		832,000
Exercise of options (in shares)				66,625
Exercise of Warrants				$ 3,000				$ (3,000)
Exercise of Warrants (in shares)				289,442				108
Restricted stock vesting	(88,000)							$ (88,000)
Restricted stock vesting (in shares)				116,701				3,899
Director share awards	893,000					893,000
Acquisition of consolidated joint venture	(12,037.000)														(12,037,000)
Issuance of noncontrolling interests	31,010,000					375,000									31,010,000
Net Loss	(82,052,000)									(77,608,000)					(4,444,000)
Other comprehensive (income) loss	(4,395,000)												(4,295,000)		(100,000)
Balance at Dec. 31, 2018	565,351,000	$ 554,935,000	$ 10,416,000	$ 204,000	$ 204,000	415,372,000	$ 415,372,000	$ (91,000)	$ (91,000)	137,250,000	$ 126,834,000	$ 10,416,000	(16,788,000)	$ (16,788,000)	29,404,000	$ 29,404,000
Balance (in shares) at Dec. 31, 2018				20,439,208	20,439,208			4,007	4,007
Issuance of Common Stock	6,596,000			$ 7,000		6,589,000
Issuance of Common Stock (in shares)				653,872
Restricted stock grants	2,000			$ 2,000
Restricted stock grants (in shares)				245,400
Cancellation of restricted stock grants (in shares)				(2,200)
Amortization of employee share awards	5,046,000					5,046,000
Exercise of options	$ 1,421,000			$ 1,000		1,420,000
Exercise of options (in shares)	113,750			113,750
Exercise of Warrants	$ 3,000			$ 4,000				$ (1,000)
Exercise of Warrants (in shares)				444,391
Restricted stock vesting	(579,000)					(2,000)		$ (577,000)
Restricted stock vesting (in shares)				(43,129)				43,129
Director share awards	894,000			$ 1,000		893,000
Director share awards (in shares)				30,197				49
Acquisition of consolidated joint venture	(2,114,000)														(2,114,000)
Sale of Standby Safety Fleet	(17,399,000)									(17,399,000)
Dissolution of an entity	62,000									62,000
Net Loss	(98,695,000)									(92,837,000)					(5,858,000)
Other comprehensive (income) loss	18,336,000												18,336,000
Balance at Dec. 31, 2019	$ 478,924,000			$ 219,000		429,318,000		$ (669,000)		27,076,000			1,548,000		21,432,000
Balance (in shares) at Dec. 31, 2019	21,928,674			21,881,489				47,185
Restricted stock grants	$ 3,000			$ 3,000
Restricted stock grants (in shares)				289,452
Cancellation of grants and options	101,000					101,000
Cancellation of grants and options (in shares)				(12,650)
Amortization of employee share awards	$ 3,969,000					3,969,000
Exercise of options (in shares)	0
Exercise of Warrants	$ 2,000			$ 3,000				$ (1,000)
Exercise of Warrants (in shares)				338,320				354
Restricted stock vesting	(178,000)							$ (178,000)
Restricted stock vesting (in shares)				(25,745)				25,745
Director share awards	755,000			$ 1,000		754,000
Director share awards (in shares)				59,900
Acquisition of consolidated joint venture				$ 9,000		17,037,000									(17,046,000)
Acquisition of consolidated joint venture (in shares)				900,000
Net Loss	(82,982,000)									(78,915,000)					(4,067,000)
Other comprehensive (income) loss	1,242,000												1,242,000
Balance at Dec. 31, 2020	$ 401,836,000			$ 235,000		$ 451,179,000		$ (848,000)		$ (51,839,000)			$ 2,790,000		$ 319,000
Balance (in shares) at Dec. 31, 2020	23,504,050			23,430,766				73,284

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash Flows from Continuing Operating Activities:
Net Loss	$ (83,346)	$ (100,070)	$ (82,979)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Depreciation and amortization	57,167	57,166	61,419
Deferred financing cost amortization	1,107	1,055	1,886
Amortization of deferred gains against charter expense			(8,037)
Amortization of employee share awards	4,069	5,046	3,494
Restricted stock vesting	(178)	(577)	(88)
Director share awards	755	894	893
Debt discount amortization	6,672	5,662	5,348
Provision for expected credit losses	230	(404)	(880)
Losses from equipment sales, retirements or impairments	17,588	6,461	11,989
Loss from sale of Boston Putford Offshore Safety		9,106
Gain from other sales			(428)
Derivative gains	(4,310)	(71)	(2,854)
Cash settlement payments on derivative transactions, net	(1,331)	(482)	1,407
Currency losses	1,294	2,541	1,328
Deferred	2,258	(12,890)	(22,760)
Equity losses	8,163	14,459	4,009
Dividends received from equity investees	2,117	2,073	1,724
Changes in operating assets and liabilities:
Accounts Receivables	(30,165)	10,182	(18,734)
Other Assets	6,530	554	925
Accounts payable and accrued liabilities	(18,343)	957	(21,253)
Net cash (used in) provided by operating activities	(29,723)	1,662	(63,591)
Cash Flows from Investing Activities:
Purchases of property and equipment	(20,808)	(44,775)	(35,645)
Proceeds from disposition of property and equipment	20,674	55,321	10,655
Cash impact of sale of ERRV fleet		(5,140)
Purchase of subsidiary from joint venture	(8,445)		8,017
Investments in and advances to 50% or less owned companies	(2,206)	(17,395)	(43,386)
Return of investments and advances from 50% or less owned companies		461	16,263
Construction reserve funds transferred to short-term cash	3,745
Construction reserve funds utilized	9,148	15,168	17,300
Principal payments on notes due from equity investees	1,715
Net cash provided by (used in) investing activities	3,823	31,030	(26,796)
Cash Flows from Financing Activities:
Payments on long-term debt	(22,601)	(23,974)	(41,932)
Proceeds from issuance of long-term debt			53,546
Proceeds from exercise of stock options and warrants	2	1,424	833
Interest on Finance Leases	1
Issuance of stock			42,996
Issuance of warrants			12,809
Purchase of subsidiary shares from noncontrolling interests		(3,392)
Net cash (used in) provided by financing activities	(22,598)	(25,942)	68,252
Effects of Exchange Rate Changes on Cash, Cash Equivalents and Restricted Cash	30	(16,619)	299
Net Decrease in Cash, Cash Equivalents and Restricted Cash, Continuing Operations	(48,468)	(9,869)	(21,836)
Cash Flows from Discontinued Operations:
Operating Activities	8,217	13,778	10,566
Investing Activities	(8,318)	(15,388)	(4,353)
Financing Activities	941	0	998
Effects of Exchange Rate Changes on Cash, Restricted Cash and Cash Equivalents	119	1,674	(1,074)
Net Increase in Cash, Restricted Cash and Cash Equivalents on Discontinued Operations	959	64	6,137
Net Decrease in Cash, Cash Equivalents and Restricted Cash	(47,509)	(9,805)	(15,699)
Cash, Cash Equivalents and Restricted Cash, Beginning of Year	87,047	96,852	112,551
Cash, Cash Equivalents and Restricted Cash, End of Year	39,538	87,047	96,852
Supplemental disclosures:
Cash paid for interest, excluding capitalized interest	21,977	21,479	20,014
Income taxes refunded, net	1,094	1,999	321
Noncash Investing and Financing Activities:
Increase in property, plant and equipment related to an acquisition	142,282		140,257
Decrease in joint venture investments related to an acquisition	22,222
Increase in long-term debt related to an acquisition	75,569		$ 106,640
Increase in long-term debt related to asset purchases	21,252	10,626
Increase in capital expenditures in accounts payable and accrued liabilities	$ 3,193	2,409
ERRV Fleet Business
Cash Flows from Investing Activities:
Proceeds from disposition of property and equipment		$ 27,390

Nature of Operations and Accounting Policies

12 Months Ended

Dec. 31, 2020

Nature Of Operation And Accounting Policies [Abstract]

Nature of Operations and Accounting Policies

1.	NATURE OF OPERATIONS AND ACCOUNTING POLICIES

Nature of Operations and Segmentation. The consolidated financial statements include the accounts of SEACOR Marine and its consolidated subsidiaries (collectively referred to as the “Company”). The Company provides global marine and support transportation services to offshore oil, natural gas and windfarm facilities worldwide. The Company and its joint ventures operate a diverse fleet of offshore support and specialty vessels that (i) deliver cargo and personnel to offshore installations, (ii) handle anchors and mooring equipment required to tether rigs to the seabed, (iii) tow rigs and assist in placing them on location and moving them between regions, (iv) provide construction, well work-over and decommissioning support and (v) carry and launch equipment used underwater in drilling and well installation, maintenance, inspection and repair. Additionally, the Company’s vessels provide accommodations for technicians and specialists, safety support and emergency response services. The Company’s fleet also includes crew transfer vessels (“CTVs”) used primarily in windfarm operations.

Accounting standards require public business enterprises to report information about each of their operating business segments that exceed certain quantitative thresholds or meet certain other reporting requirements. Operating business segments have been defined as a component of an enterprise about which separate financial information is available and is evaluated regularly by the chief operating decision maker in assessing performance.

As a result of the announced sale of Windcat Workboats Holdings Ltd (“Windcat Workboats”), the Company’s indirect wholly owned subsidiary, and the CTV business of Windcat Workboats (the “Windcat Workboats CTV Business”) on December 18, 2020, the Company classified the CTV assets of the Windcat Workboats CTV Business as Assets held for sale as of December 31, 2020. Unless the context indicates otherwise, all of the results presented exclude the CTV operations of the Windcat Workboats CTV Business which are classified as Assets held for sale. The Company has identified the following five principal geographic regions as its reporting segments:

United States, primarily Gulf of Mexico. As of December 31, 2020, 23 vessels were located in the U.S. Gulf of Mexico, including 17 owned, three leased-in, two joint-ventured and one managed-in. The Company’s vessels in this market support deep-water anchor handling, fast cargo transport, general cargo transport, well intervention, work-over, decommissioning and diving support operations.

Africa, primarily West Africa. As of December 31, 2020, 15 vessels were located in West Africa, including 13 owned, one leased-in and one joint-ventured. The Company’s vessels in this area generally support projects for major oil companies, primarily in Angola and Nigeria.

Middle East and Asia. As of December 31, 2020, 23 vessels were located in the Middle East and Asia, including 20 owned, two joint-ventured and one managed. The Company’s vessels in this area generally support exploration, personnel transport and seasonal construction activities in Egypt, Israel and Malaysia and countries along the Arabian Gulf and Arabian Sea, such as Saudi Arabia, the United Arab Emirates and Qatar.

Latin America. As of December 31, 2020, 38 vessels were located in this region, including eight owned and 30 joint ventured. Of these joint-ventured vessels, (i) 16 are owned by Mantenimiento Express Maritimo, S.A.P.I. de C.V. (“MexMar”), a joint venture company that is 49% owned by SEACOR Marine International LLC (“SMI”), a wholly owned subsidiary of SEACOR Marine, and 51% owned by subsidiaries of Proyectos Globales de Energía y Servicios CME, S.A. de C.V. (“CME”), and (ii) 13 are owned by MEXMAR Offshore International LLC (“MEXMAR Offshore”), a joint venture company that is 49% owned by SMI and 51% owned by a subsidiary of CME. These vessels, consisting of a fleet of FSVs, supply, specialty and liftboat vessels, provide support for exploration and production activities in Mexico, Brazil and Guyana. From time to time, the Company’s vessels also work in Trinidad and Tobago, and Colombia.

Europe, primarily North Sea. As of December 31, 2020, the Company had two owned vessels that are were classified in our continuing operations, located in this region, supporting the construction and maintenance of offshore wind turbines as well as supporting oil and gas explorations and production operations in the North Sea. On December 18, 2020, the Company announced the sale of its Windcat Workboats CTV Business (“Windcat Sale”), comprised of 46 CTVs located in Europe providing crew transfer to offshore wind platforms, which closed on January 12, 2021. As a result of the announced sale of the Windcat Workboats CTV Business on December 18, 2020, the Company classified the CTV assets of the Windcat Workboats CTV Business as Assets held for sale as of December 31, 2020.

Basis of Consolidation. The consolidated financial statements include the accounts of SEACOR Marine and its controlled subsidiaries. Control is generally deemed to exist if the Company has greater than 50% of the voting rights of a subsidiary. All significant intercompany accounts and transactions are eliminated in the combination and consolidation.

Noncontrolling interests in consolidated subsidiaries are included in the consolidated balance sheets as a separate component of equity. The Company reports consolidated net income (loss) inclusive of both the Company’s and the noncontrolling interests' share, as well as the amounts of consolidated net income (loss) attributable to each of the Company and the noncontrolling interests. If a subsidiary is deconsolidated upon a change in control, any retained noncontrolled equity investment in the former controlled subsidiary is measured at fair value and a gain or loss is recognized in net income (loss) based on such fair value. If a subsidiary is consolidated upon a change in control, any previous noncontrolled equity investment in the subsidiary is measured at fair value and a gain or loss is recognized in net income (loss) based on such fair value.

The Company employs the equity method of accounting for investments in 50% or less owned companies that it does not control but has the ability to exercise significant influence over the operating and financial policies of the business venture. Significant influence is generally deemed to exist if the Company has between 20% and 50% of the voting rights of a business venture, but may exist when the Company’s ownership percentage is less than 20%. In certain circumstances, the Company may have an economic interest in excess of 50% but may not control and consolidate the business venture. Conversely, the Company may have an economic interest less than 50% but may control and consolidate the business venture. The Company reports its investments in and advances to these business ventures in the accompanying consolidated balance sheets as investments, at equity, and advances to 50% or less owned companies. The Company reports its share of earnings from investments in 50% or less owned companies in the accompanying consolidated statements of loss as equity in earnings (losses) of 50% or less owned companies, net of tax.

The Company reports its qualifying investments at cost, less impairment if any, plus or minus observable price changes in orderly transactions for an identical or similar investment of the same issuer for its investments in 50% or less owned companies it does not control or exercise significant influence. These investments in private companies are adjusted for capital distributions and other-than-temporary declines in fair value.

Certain reclassifications were made to previously reported amounts in the consolidated financial statements and notes thereto to make them consistent with the current period presentation.

Use of Estimates. The preparation of financial statements in conformity with accounting principles generally accepted in the U.S. requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Such estimates include those related to deferred revenues, allowance for credit losses, useful lives of property and equipment, impairments, income tax provisions and certain accrued liabilities. Actual results could differ from estimates and those differences may be material.

Revenue Recognition. The Company contracts with various customers to carry out management services for vessels as agents for and on behalf of ship owners. These services include crew management, technical management, commercial management, insurance arrangements, sale and purchase of vessels, provisions and bunkering. As the manager of the vessels, the Company undertakes to use its best endeavors to provide the agreed management services as agents for and on behalf of the owners in accordance with sound ship management practice and to protect and promote the interest of the owners in all matters relating to the provision of services hereunder. The Company also contracts with various customers to carry out management services regarding engineering for vessel construction and vessel conversions. The vast majority of the ship management agreements span over the length of one to three years and are typically billed on a monthly basis. The Company transfers control of the service to the customer and satisfies its performance obligation over the term of the contract, and therefore recognized revenue over the term of the contract while related costs are expensed as incurred.

Revenue that does not meet these criteria is deferred until the criteria is met and such revenue is considered a contract liability. Contract liabilities, which are included in other current liabilities from continuing operations in the accompanying consolidated balance sheets, for the years ended December 31 were as follows (in thousands):

	2020			2019			2018
Balance at beginning of year	$	4,755		$	1,327		$	10,104
Revenues deferred during the year		2,042			8,134			3,518
Revenues recognized during the year		(3,490	)		(4,706	)		(12,295	)
Balance at end of year	$	3,307		$	4,755		$	1,327

As of December 31, 2020 the Company deferred revenues of $3.3 million primarily related to $2.0 million of prepaid vessel management fees, $0.8 million related to the time charter of offshore support vessels to customers from which collections were not reasonably assured and $0.5 million of prepaid charter modification and reservation fees.

The Company earns revenue primarily from the time charter and bareboat charter of vessels to customers. Since the Company charges customers based upon daily rates of hire, vessel revenues are recognized on a daily basis throughout the contract period. Under a time charter, the Company provides a vessel to a customer and is responsible for all operating expenses, typically excluding fuel. Under a bareboat charter, the Company provides a vessel to a customer and the customer assumes responsibility for all operating expenses and assumes all risks of operation. In the U.S. Gulf of Mexico, time charter durations and rates are typically established in the context of master service agreements that govern the terms and conditions of the charter. From time to time, the Company may also participate in pooling arrangements. In a pooling arrangement, the time charter revenues of certain of the Company’s vessels are shared with the time charter revenues of certain vessels of similar type owned by non-affiliated vessel owners based upon an agreed formula. On January 9, 2019, the only active pooling arrangement was terminated, and three FSV’s were purchased by the Company.

Contract or charter durations may range from several days to several years. Charters vary in length from short-term to multi-year periods, many with cancellation clauses and without early termination penalties. As a result of options and frequent renewals, the stated duration of charters may have little correlation with the length of time the vessel is contracted to provide services to a particular customer.

Cash Equivalents. The Company considers all highly liquid investments with an original maturity of three months or less, when purchased, to be cash equivalents. Cash equivalents consist of U.S. treasury securities, money market instruments, time deposits and overnight investments.

Restricted Cash. Restricted cash primarily relates to banking facility requirements.

For the year ended December 31, cash, cash equivalents and restricted cash from continuing operations consists of:

	2020		2019
Cash	$	32,666	$	81,382
Restricted cash		3,352		3,104
Total	$	36,018	$	84,486

Trade and Other Receivables. Customers are primarily major integrated national and international oil companies, large independent oil and natural gas exploration and production companies, and offshore windfarm operations. Customers are granted credit on a short-term basis and the related credit risks are minimal. Other receivables consist primarily of operating expenses the Company incurs in relation to vessels it manages for other entities, as well as insurance and income tax receivables. The Company routinely reviews its receivables and makes provisions for credit losses; however, those provisions are estimates and actual results may materially differ from those estimates. Trade receivables are deemed uncollectible and are removed from accounts receivable and the allowance for credit losses when collection efforts have been exhausted.

Derivative Instruments. The Company accounts for derivatives through the use of a fair value concept whereby all of the Company’s derivative positions are stated at fair value in the accompanying consolidated balance sheets. Realized and unrealized gains and losses on derivatives not designated as hedges are reported in the accompanying consolidated statements of loss as Derivative gains (losses), net. Realized and unrealized gains and losses on derivatives designated as fair value hedges are recognized as corresponding increases or decreases in the fair value of the underlying hedged item to the extent they are effective, with any ineffective portion reported in the accompanying consolidated statements of loss as Derivative gains (losses), net. Realized and unrealized gains and losses on derivatives designated as cash flow hedges are reported as a component of other comprehensive loss in the accompanying consolidated statements of comprehensive loss to the extent they are effective and reclassified into earnings on the same line item associated with the hedged transaction and in the same period the hedged transaction affects earnings. Any ineffective portions of cash flow hedges are reported in the accompanying consolidated statements of loss as Derivative gains (losses), net. Realized and unrealized gains and losses on derivatives designated as cash flow hedges that are entered into by the Company’s 50% or less owned companies are also reported as a component of the Company’s other comprehensive loss in proportion to the Company’s ownership percentage, with reclassifications and ineffective portions being included in Equity in earnings (losses) of 50% or less owned companies, net of tax, in the accompanying consolidated statements of loss.

Concentrations of Credit Risk. The Company is exposed to concentrations of credit risk associated with its cash and cash equivalents, restricted cash, construction reserve funds and derivative instruments. The Company minimizes its credit risk relating to these positions by monitoring the financial condition of the financial institutions and counterparties involved and by primarily conducting business with large, well-established financial institutions and diversifying its counterparties. The Company does not currently anticipate nonperformance by any of its significant counterparties. The Company is also exposed to concentrations of credit risk relating to its receivables due from customers described above. The Company does not generally require collateral or other security to support its outstanding receivables. The Company minimizes its credit risk relating to receivables by performing ongoing credit evaluations and, to date, credit losses have not been material.

Inventories.

Inventories, which consist of fuel and supplies, are stated at the lower of cost (using the first-in, first-out method) or market. The Company records write-downs, as needed, to adjust the carrying amount of inventories to the lower of cost or market. In the year ended December 31, 2020, 2019 and 2018, there were no inventory reserves.

Property and Equipment. Equipment, stated at cost, is depreciated using the straight-line method over the estimated useful life of the asset to an estimated salvage value. With respect to offshore support vessels, the estimated useful life is typically based upon a newly built vessel being placed into service and represents the point at which it is typically not justifiable for the Company to continue to operate the vessel in the same or similar manner. From time to time, the Company may acquire older vessels that have already exceeded the Company’s useful life policy, in which case the Company depreciates such vessels based on its best estimate of remaining useful life, typically the next regulatory survey or certification date.

As of December 31, 2020, the estimated useful life (in years) of each of the Company’s major categories of new offshore support vessels was as follows:

Offshore Support Vessels:
CTVs		10
All other offshore support vessels (excluding crew transfer)		20

The Company’s property and equipment from continuing operations as of December 31 was as follows (in thousands):

	Historical Cost ⁽¹⁾		Accumulated Depreciation			Net Book Value
2020
Offshore support vessels:
AHTS⁽²⁾	$	50,189	$	(31,779	)	$	18,410
FSV⁽³⁾		375,747		(104,739	)		271,008
Supply		238,624		(15,991	)		222,633
Liftboats		321,751		(117,364	)		204,387
Crew transfer		3,163		(3,138	)		25
General machinery and spares		7,746		(7,733	)		13
Other ⁽⁴⁾		15,653		(10,794	)		4,859
	$	1,012,873	$	(291,538	)	$	721,335
2019
Offshore support vessels:
AHTS⁽²⁾	$	94,078	$	(73,095	)	$	20,983
FSV⁽³⁾		388,460		(101,295	)		287,165
Supply		44,958		(8,471	)		36,487
Specialty		14,805		(10,466	)		4,339
Liftboats		327,028		(93,166	)		233,862
Crew transfer		5,032		(4,518	)		514
General machinery and spares		7,650		(7,648	)		2
Other ⁽⁴⁾		17,013		(10,258	)		6,755
	$	899,024	$	(308,917	)	$	590,107

(1)	Includes property and equipment acquired in business acquisitions at acquisition date fair value, and net of the impact of recognized impairment charges.

(2)	Anchor Handling Towing Supply (“AHTS”).

(3)	Fast support vessels (“FSVs”).

(4)	Includes land, buildings, leasehold improvements, vehicles and other property and equipment.

Depreciation and amortization expense from continuing operations totaled $57.2 million, $57.2 million and $61.4 million in 2020, 2019 and 2018, respectively. Depreciation and amortization from discontinued operations totaled $6.2 million, $6.8 million and $7.4 million in 2020, 2019 and 2018.

On December 2, 2019, the Company completed the sale of its North Sea standby business, comprised of 18 emergency response and rescue vehicles (“ERRVs”) with a net book value of $24.3 million. Depreciation and amortization expense totaled $3.5 million and $3.4 million in 2019 and 2018, respectively.

Equipment maintenance and repair costs and the costs of routine overhauls, drydockings and inspections performed on vessels and equipment are charged to operating expense as incurred. Expenditures that extend the useful life or improve the marketing and commercial characteristics of vessels, as well as major renewals and improvements to other properties, are capitalized.

Certain interest costs incurred during the construction of vessels are capitalized as part of the vessels’ carrying values and are amortized over such vessels estimated useful lives. Capitalized interest totaled $0.7 million, $1.5 million and $2.4 million in 2020, 2019 and 2018, respectively.

Impairment of Long-Lived Assets. The Company performs an impairment analysis of long-lived assets used in operations, including intangible assets, when indicators of impairment are present. These indicators may include a significant decrease in the market price of a long-lived asset or asset group, a significant adverse change in the extent or manner in which a long-lived asset or asset group is being used or in its physical condition, or a current period operating or cash flow loss combined with a history of operating or cash flow losses or a forecast that demonstrates continuing losses associated with the use of a long-lived asset or asset group. If the carrying values of the assets are not recoverable, as determined by their estimated future undiscounted cash flows, the estimated fair value of the assets or asset groups are compared to their current carrying values and impairment charges are recorded if the carrying value exceeds fair value.

As a result of the difficult conditions experienced in the offshore oil and natural gas markets beginning in the second half of 2014 and the corresponding reductions in utilization and rates per day worked of its fleet, the Company identified indicators of impairment and recognized impairment charges primarily associated with its AHTS fleet, its liftboat fleet, certain specialty vessels, vessels removed from service and goodwill. When reviewing its fleet for impairment, the Company groups vessels with similar operating and marketing characteristics, including cold-stacked vessels expected to return to active service, into vessel classes. All other vessels, including vessels retired and removed from service, are evaluated for impairment on a vessel by vessel basis.

During the year ended December 31, 2020, the Company recorded non-cash impairment charges totaling $18.8 million. The Company recorded partial impairments ($5.3 million) on the five-company owned liftboat vessels based on outside valuations of its remaining fleet. Estimated fair values for the Company owned vessels were established by independent appraisers based on researched market information, replacement cost information and other data. If market conditions further decline from the depressed utilization and rates per day worked experienced over the last three years, fair values based on future appraisals could decline significantly. In addition, the Company impaired ($7.0 million) on two leased-in liftboat vessels that based on current market environment, were determined that neither of these two leased-in vessels would return to active service during their remaining lease terms. Additionally, one leased-in anchor-handling towing supply (“AHTS”) was impaired ($0.5 million), one specialty vessel was impaired ($1.2 million) and one hull that was included in construction in progress was impaired ($4.8 million).

During the year ended December 31, 2019, the Company recorded non-cash impairment charges of $12.0 million, primarily related to four AHTS vessels previously removed from service and adjusted to scrap value, and four fast support vessels (“FSV”), each of which has been adjusted to indicative sales price, and two leased-in vessels (one AHTS and one platform supply vessel “PSV”), adjusted for indicative future cash flows. During the year ended December 31, 2018, the Company recorded non-cash impairment charges of $14.6 million primarily associated with its AHTS fleet (four owned vessels and three leased-in vessels) and one specialty vessel.

The Company’s other vessel classes and other individual vessels in active service and cold-stacked status, for which no impairment was deemed necessary, have generally experienced a less severe decline in utilization and rates per day worked based on specific market factors. The market factors include vessels with more general utility to a broad range of customers (e.g., FSVs), vessels required for customers to meet regulatory mandates and operating under multiple year contracts or vessels that service customers outside of the offshore oil and natural gas market (e.g., CTVs).

For vessel classes and individual vessels with indicators of impairment but not recently impaired as of December 31, 2020 the Company has estimated that their future undiscounted cash flows exceed their current carrying values. The Company’s estimates of future undiscounted cash flows are highly subjective as utilization and rates per day worked are uncertain, including the timing of an estimated market recovery in the offshore oil and natural gas markets and the timing and cost of reactivating cold-stacked vessels. If market conditions decline further, changes in the Company’s expectations on future cash flows may result in recognizing additional impairment charges related to its long-lived assets in future periods.

Impairment of 50% or Less Owned Companies. Investments in 50% or less owned companies are reviewed periodically to assess whether there is an other-than-temporary decline in the carrying value of the investment. In its evaluation, the Company considers, among other items, recent and expected financial performance and returns, impairments recorded by the investee and the capital structure of the investee. When the Company determines the estimated fair value of an investment is below carrying value and the decline is other-than-temporary, the investment is written down to its estimated fair value. Actual results may vary from the Company’s estimates due to the uncertainty regarding projected financial performance, the severity and expected duration of declines in value, and the available liquidity in the capital markets to support the continuing operations of the investee, among other factors. Although the Company believes its assumptions and estimates are reasonable, the investee’s actual performance compared with the estimates could produce different results and lead to additional impairment charges in future periods. No impairment charges of investments in 50% or less owned companies were incurred for the years ended December 31, 2020 and 2019. During the year ended December 31, 2018 the Company recognized impairment charges of $1.2 million net of tax, related to its 50% or less owned companies (see “Note 5. Investments, at Equity, and Advances to 50% or Less Owned Companies”).

Business Combinations. The Company recognizes 100% of the fair value of assets acquired, liabilities assumed, and noncontrolling interests when the acquisition constitutes a change in control of the acquired entity. Shares issued in consideration for a business combination, contingent consideration arrangements and pre-acquisition loss and gain contingencies are all measured and recorded at their acquisition-date fair value. Subsequent changes to fair value of contingent consideration arrangements are generally reflected in earnings. Acquisition-related transaction costs are expensed as incurred and any changes in an acquirer’s existing income tax valuation allowances and tax uncertainty accruals are recorded as an adjustment to income tax expense. The operating results of entities acquired are included in the accompanying consolidated statements of loss from the date of acquisition (see “Note 3 Business Acquisitions”).

Debt Discount and Issue Costs. Debt discounts and costs incurred in connection with the issuance of debt are amortized over the life of the related debt using the effective interest rate method for term loans and straight-line method for revolving credit facilities and are included in interest expense in the accompanying consolidated statements of loss.

Self-insurance Liabilities. The Company maintains marine hull, liability and war risk, general liability, workers compensation and other insurance customary in the industry in which it operates. Both the marine hull and liability policies have annual aggregate deductibles. Marine hull annual aggregate deductibles are accrued as claims are incurred while marine liability annual aggregate deductibles are accrued based on historical loss experience. Exposure to the health benefit plans are limited by maintaining stop-loss and aggregate liability coverage. To the extent that estimated self-insurance losses, including the accrual of annual aggregate deductibles, differ from actual losses realized, the Company’s insurance reserves could differ significantly and may result in either higher or lower insurance expense in future periods.

Income Taxes. Deferred income tax assets and liabilities have been provided in recognition of the income tax effect attributable to the book and tax basis differences of assets and liabilities reported in the accompanying consolidated financial statements. Deferred tax assets or liabilities are provided using the enacted tax rates expected to apply to taxable income in the periods in which they are expected to be settled or realized. Interest and penalties relating to uncertain tax positions are recognized in interest expense and administrative and general, respectively, in the accompanying consolidated statements of loss. The Company records a valuation allowance to reduce its deferred tax assets if it is more likely than not that some portion or all of the deferred tax assets will not be realized.

The Global Intangible Low Taxed Income (“GILTI”) regime effectively imposes a minimum tax on worldwide foreign earnings and subjects U.S. shareholders of controlled foreign corporations (“CFCs”) to current taxation on certain income earned through a CFC. The Company has made the policy election to record any liability, associated with GILTI in the period in which it is incurred.

SEACOR Marine was included in the consolidated U.S. federal income tax return of SEACOR Holdings Inc. (“SEACOR Holdings”) through 2016. SEACOR Holdings’ policy for allocation of U.S. federal income taxes required its domestic subsidiaries included in the consolidated U.S. federal income tax return to compute their provision for U.S. federal income taxes on a separate company basis and settle with SEACOR Holdings.

In the normal course of business, the Company or SEACOR Holdings may be subject to challenges from tax authorities regarding the amount of taxes due for the Company. These challenges may alter the timing or amount of taxable income or deductions. As part of the calculation of income tax expense, the Company determines whether the benefits of its tax positions are at least more likely than not of being sustained based on the technical merits of the tax position. For tax positions that are more likely than not of being sustained, the Company accrues the largest amount of the tax benefit that is more likely than not of being sustained. Such accruals require management to make estimates and judgments with respect to the ultimate outcome of its tax benefits and actual results could vary materially from these estimates.

On June 26, 2020, the Company entered into the Tax Refund Agreement with SEACOR Holdings (see “Note 17. Related Party Transactions”).

Deferred Gains - Vessel Sale-Leaseback Transactions and Financed Vessel Sales. Prior to the implementation of ASC 842, the Company entered into vessel sale-leaseback transactions with finance companies or provided seller financing on sales of its vessels to third-parties or to 50% or less owned companies. A portion of the gains realized from these transactions was not immediately recognized in income but rather was recorded in the accompanying consolidated balance sheets in deferred gains and other liabilities. In sale-leaseback transactions, gains were deferred to the extent of the present value of future minimum lease payments and were amortized as reductions to rental expense over the applicable lease terms (see “Note 7. Leases”). When the Company determines that future cash inflows do not support future lease cash obligations, the Company records an impairment expense for the amount of the cash flow shortage of all future lease costs, costs to maintain the vessel to the end of the lease term, and costs to return the vessel to its owner, less the amount of any unamortized deferred gains. In financed vessel sales, gains were deferred to the extent that the repayment of purchase notes were dependent on the future operations of the sold vessels and were amortized based on cash received from the buyers. Unamortized deferred gains for four vessels under sale-leaseback agreements were fully recognized in 2019 as an adjustment to the opening balance of Retained Earnings with the implementation of the new leasing standard (see “Note 7. Leases”). Deferred gain activity related to these transactions for the years ended December 31 was as follows (in thousands):

	2019			2018
Balance at beginning of year	$	11,026		$	23,553
Amortization of deferred gains included in operating expenses as reduction to rental expense		—			(8,037	)
Reclass of gain to Retained Earnings		(11,026	)		—
Recognition of deferred gains included in losses on asset dispositions and impairments, net		—			(4,490	)
Balance at end of year	$	—		$	11,026

Deferred Gains - Vessel Sales to the Company’s 50% or Less Owned Companies. A portion of the gains realized from non-financed sales of the Company’s vessels to its 50% or less owned companies has been deferred and recorded in the accompanying consolidated balance sheets in deferred gains and other liabilities. In most instances, the sale of a Company vessel to a 50% or less owned company is considered a sale of a business in which the Company relinquishes control to its 50% or less owned company resulting in gain recognition; however, the Company defers gains to the extent of any uncalled capital commitment it has with the 50% or less owned company. The Company no longer had any deferred gains as of the end of 2019. Activity related to these transactions for the years ended December 31 was as follows (in thousands):

	2019			2018
Balance at beginning of year	$	793		$	1,453
Amortization of deferred gains included in losses on asset dispositions and impairments, net		—			(25	)
Other		(793	)		(635	)
Balance at end of year	$	—		$	793

Foreign Currency Translation. The assets, liabilities and results of operations of certain consolidated subsidiaries are measured using their functional currency, which is the currency of the primary foreign economic environment in which they operate. Upon consolidating these subsidiaries with the Company, their assets and liabilities are translated to U.S. dollars at currency exchange rates as of the consolidated balance sheet dates and their revenues and expenses are translated at the weighted average currency exchange rates during the applicable reporting periods. Translation adjustments resulting from the process of translating these subsidiaries’ financial statements are reported in other comprehensive loss in the accompanying consolidated statements of comprehensive loss.

Foreign Currency Transactions. Certain consolidated subsidiaries enter into transactions denominated in currencies other than their functional currency. Gains and losses resulting from changes in currency exchange rates between the functional currency and the currency in which a transaction is denominated are included in foreign currency losses, net in the accompanying consolidated statements of loss in the period in which the currency exchange rates change.

Accumulated Other Comprehensive (Loss) Income. The components of accumulated other comprehensive loss were as follows (in thousands):

	SEACOR Marine Holdings Inc. Stockholders' Equity									Noncontrolling Interests
	Foreign Currency Translation Adjustments			Derivative Gains (Losses) on Cash Flow Hedges, net			Total			Foreign Currency Translation Adjustments			Derivative Gains (Losses) on Cash Flow Hedges, net			Other Comprehensive (Loss) Income
Year Ended December 31, 2017	$	(13,195	)	$	702		$	(12,493	)	$	(1,357	)	$	1		$	(881	)
Other comprehensive loss		(2,277	)		(1,972	)		(4,249	)		(88	)		(12	)	$	(4,349	)
Income tax (expense)		—			(46	)		(46	)		—			—			(46	)
Year Ended December 31, 2018		(15,472	)		(1,316	)		(16,788	)		(1,445	)		(11	)	$	(4,395	)
Other comprehensive income		20,157			(1,994	)		18,163			—			—		$	18,163
Income tax benefi		—			173			173			—			—			173
Year Ended December 31, 2019		4,685			(3,137	)		1,548			(1,445	)		(11	)	$	18,336
Other comprehensive income		2,112			(870)			1,242			—			—		$	1,242
Income tax benefit (expense)		—			—			—			—			—			—
Year Ended December 31, 2020	$	6,797		$	(4,007	)	$	2,790		$	(1,445	)	$	(11	)	$	1,242

Loss Per Share. Basic loss per common share of the Company is computed based on the weighted average number of common shares issued and outstanding during the relevant periods. Diluted loss per common share of the Company is computed based on the weighted average number of common shares issued and outstanding plus the effect of potentially dilutive securities through the application of the treasury stock and if-converted methods. Dilutive securities for this purpose assume restricted stock grants have vested, common shares have been issued pursuant to the exercise of outstanding stock options and common shares have been issued pursuant to the conversion of the Convertible Senior Notes. For the years ended December 31, 2020, 2019 and 2018, diluted loss per common share of the Company excluded 1,488,292 shares, 1,826,966 shares, and 2,183,708 shares, respectively, issuable upon the conversion of the Convertible Senior Notes as the effect of their inclusion in the computation would be anti-dilutive. In addition, for the years ended December 31, 2020, 2019 and 2018, diluted loss per common share of the Company excluded 436,714 shares, 303,609 shares and 192,346 shares, respectively, of restricted stock and 1,120,541, 913,569 and 805,566 outstanding stock options as the effect of their inclusion in the computation would be anti-dilutive. In 2020 and 2019, the Company issued 149,200 and 109,600 performance share awards, of which 240,800 were still outstanding as of December 31, 2020. These performance share awards are not considered outstanding until such time as they would be probable of being exercised, therefore they were not included in the computation of earnings (loss) per share.

Recently Adopted Accounting Standards. On May 28, 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, “Revenue from Contracts with Customers (Topic 606)” to clarify the principles for recognizing revenue and to develop a common revenue standard and disclosure requirements. The standard supersedes previous revenue recognition requirements and industry-specific guidance. Under the standard, revenue is recognized when a customer obtains control of promised goods or services in an amount that reflects the consideration the entity expects to receive in exchange for those goods or services. The Company adopted this standard on January 1, 2018 using the modified retrospective approach by recognizing the cumulative effect of initially applying the standard as an adjustment to the opening balance of retained earnings. The Company implemented the necessary changes to its business processes, systems and controls to support recognition and disclosure of this ASU upon adoption. The Company’s revenues are primarily based on leases or rental agreements with customers which are not addressed in the standard. As a result, the adoption of the accounting standard did not have a material effect on the Company’s consolidated financial position, results of operations or cash flows, but did result in increased disclosures related to revenue recognition policies.

On February 25, 2016, the FASB issued a comprehensive new leasing standard meant to improve transparency and comparability among companies by requiring lessees to recognize a lease liability and a corresponding lease asset for virtually all lease contracts. It also requires additional disclosures about leasing arrangements. The Company adopted the new standard on January 1, 2019 and applied the transition provisions of the new standard at its adoption date with recognition of a cumulative-effect adjustment to the opening balance of retained earnings. The adoption of the new standard had a material impact on the Company’s consolidated financial position, results of operations and cash flows. The adjustment to the Company’s balance sheet on January 1, 2019 included the addition of $33.7 million of right-of-use assets, $31.9 million in lease liability, and a cumulative-effect adjustment to the opening balance of retained earnings of $1.7 million for certain of its equipment, office and land leases. In addition, unamortized deferred gains for four vessels leased under sale-leaseback arrangements were fully recognized as an adjustment to the opening balance of retained earnings of $8.7 million, net of tax, ($11.0 million deferred gains net of $2.3 million deferred taxes).

On October 24, 2016, the FASB issued a new accounting standard, which requires companies to account for the income tax effects of intercompany sales and transfers of assets other than inventory. The Company adopted the new standard on January 1, 2018, resulting in a reduction of $12.1 million to the Company’s opening retained earnings.

On August 28, 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820). This new guidance modifies the disclosure requirements related to fair value measurement. The new guidance is effective for fiscal years beginning after December 15, 2019. The effects of this standard on our financial position or reporting was not material.

On August 29, 2018, the FASB issued ASU No. 2018-15, Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40). The new guidance reduces complexity for the accounting for costs of implementing a cloud computing service arrangement and aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal use software license). For public companies, the amendments in this ASU are effective for fiscal years, and interim periods within those fiscal years beginning after December 15, 2019. The effects of this standard on our financial position, results of operations or cash flows was not material.

On June 30, 2016, the FASB issued ASU No. 2016-13, Financial Instruments-Credit Losses (Topic 326). This ASU represents a significant change in the Accounting for Credit Losses. The ASU introduced a new accounting model, the Current Expected Credit Losses model (CECL), which required earlier recognition of credit losses and additional disclosures related to credit risk. The CECL model utilizes a lifetime expected credit loss measurement objective for the recognition of credit losses for loans and other receivables at the time the financial asset is originated or acquired. The expected credit losses are adjusted each period for changes in expected lifetime credit losses. This model replaced the multiple existing impairment models in prior U.S. GAAP, which generally required that a loss be incurred before it is recognized. The standard applies to financial assets arising from revenue transactions such as contract assets and accounts receivables. Management implemented the new standard in 2020 and it did not have a material impact on the consolidated financial statements.

Transformation, Facility Restructuring and Severance Charges

12 Months Ended

Dec. 31, 2020

Restructuring And Related Activities [Abstract]

Transformation, Facility Restructuring and Severance Charges

2.	TRANSFORMATION, FACILITY RESTRUCTURING AND SEVERANCE CHARGES

Due to the highly competitive nature of the Company’s business and the continuing losses incurred over the last few years, the Company reduced its overall cost structure and workforce to better align the Company with current activity levels. The transformation plan, which began in the third quarter of 2019 and extended through the third quarter of 2020 (the “Transformation Plan”), included a workforce reduction, organization restructuring, facility consolidations and other cost reduction measures and efficiency initiatives across the Company’s geographic regions. These initiatives impacted all of the Company’s reportable segments and are expected to result in annualized recurring savings of at least $8.0 million. The Company continues to evaluate additional opportunities for further cost reductions to adapt to changing conditions caused by COVID-19 and other market conditions.

In connection with the Transformation Plan, for the twelve months ended December 31, 2020, the Company recognized year-to-date restructuring and transformation charges of $1.2 million, which includes severance charges of $1.1 million and other restructuring charges of $0.1 million. Other restructuring charges included contract termination costs, relocation and other associated costs. The restructuring and transformation charges are reflected in the Company’s general and administrative expense.

The components of restructuring charges for the years ended December 31, 2020 and 2019, were as follows (in thousands):

December 31, 2020

	United States (primarily Gulf of Mexico)		Africa (primarily West Africa)		Middle East and Asia		Latin America		Europe (primarily North Sea)		Total
Transformation Plan
Severance Charges	$	275	$	—	$	665	$	—	$	185	$	1,125
Other Charges		31		—		31		—		—		62
Total Charges	$	306		—	$	696		—	$	185	$	1,187

December 31, 2019

	United States (primarily Gulf of Mexico)		Africa (primarily West Africa)		Middle East and Asia		Latin America		Europe (primarily North Sea)		Total
Transformation Plan
Severance Charges	$	2,995	$	—	$	184	$	—	$	200	$	3,379
Other Charges		307		—		31		—		—		339
Total Charges	$	3,302		—	$	215		—	$	200	$	3,718

The severance and other restructuring charges gave rise to certain liabilities primarily related to liabilities accrued as part of the Transformation Plan. As of December 31, 2020, all related liabilities associated with the Transformation Plan have been recognized.

The Transformation Plan was completed during the third quarter of 2020. No material future costs related to these efforts are expected, but to the extent the Company identifies additional opportunities for further costs reductions beyond the Transformation Plan, these opportunities may give rise to restructuring charges. On a cumulative basis, the Company recognized $4.9 million in restructuring charges.

Seacosco Acquisition

12 Months Ended

Dec. 31, 2020

Business Combinations [Abstract]

Business Acquisitions

3.	BUSINESS ACQUISITIONS

On May 31, 2020, SEACOR Offshore Asia LLC (“SEACOR Offshore Asia”), an indirect wholly-owned subsidiary of SEACOR Marine, entered into a Sale and Purchase Agreement (“SEACOSCO SPA”) with China Shipping Fan Tai Limited, a company incorporated under the laws of the British Virgin Islands, and China Shipping Industry (Hong Kong) Co., Limited, a company incorporated under the laws of the Hong Kong Special Administrative Region (together, the “SEACOSCO Sellers”), pursuant to which SEACOR Offshore Asia agreed to acquire the 50% membership interest in SEACOSCO Offshore LLC (such remaining interest, the “SEACOSCO Interests”) held by the SEACOSCO Sellers that the Company did not already own.

On June 30, 2020, SEACOR Offshore Asia completed the acquisition of the SEACOSCO Interests from the SEACOSCO Sellers (the “SEACOSCO Acquisition”). As a result of the completion of the acquisition, the Company owns 100% of the membership interests in SEACOSCO Offshore LLC. On July 14, 2020, the name of SEACOSCO Offshore LLC was changed to SEACOR Offshore Delta LLC (“SEACOR Offshore Delta”).

The price payable by SEACOR Offshore Asia for the membership interests was $28.2 million (the “SEACOSCO Purchase Price”), $8.4 million of which was paid to the Sellers at the closing of the transaction, with annual installment payments of $1.0 million, $2.5 million and $2.5 million payable in the first, second and third year after the signing date (the “SEACOSCO SPA Signing Date”), respectively, and the remaining $13.7 million due four years after such signing date. The deferred portion of the SEACOSCO

Purchase Price accrues interest at a fixed rate of 1.5%, 7.0%, 7.5% and 8.0% for the first through fourth years after the SEACOSCO SPA Signing Date, respectively.

SEACOR Offshore Delta is the owner of eight PSVs built by COSCO Shipping Heavy Industry (Guangdong) Co., Ltd. (the “COSCO (Guangdong) Shipyard” and such PSVs, the “SEACOR Delta PSVs”). The SEACOSCO Sellers obtained a second lien mortgage on the SEACOR Delta PSVs to secure the payment of the deferred portion of the SEACOSCO Purchase Price, and SEACOR Marine provided a limited deficiency guarantee solely with respect to the short-fall in vessel collateral value, if any, in the event the SEACOSCO Sellers exercise their remedies under the mortgages.

The SEACOR Delta PSVs were initially acquired by vessel owning subsidiaries (“SEACOR Delta SPVs”) of SEACOR Offshore Delta pursuant to existing deferred purchase agreements with the COSCO (Guangdong) Shipyard (“Guangdong DPAs”) under which an aggregate of approximately $100.8 million was outstanding as of June 30, 2020 (the “SEACOR Delta Shipyard Financing”). As of December 31, 2020, $95.3 million was outstanding. The Guangdong DPAs provide for amortization of the purchase price for each vessel over a period of 10 years from delivery bearing floating interest rate of three-month LIBOR plus 4.0%. SEACOR Offshore Delta has taken delivery of all eight SEACOR Delta PSVs, seven with a 2018 or 2019 year of build, and one with a 2020 year of build. The payment obligations of the SEACOR Delta SPVs under the Guangdong DPAs for each vessel is secured by a first lien mortgage on the vessel and a pledge of the SEACOR Delta SPV’s equity, and SEACOR Marine provided a limited deficiency guarantee solely with respect to the short-fall in vessel collateral value, if any, in the event the COSCO (Guangdong) Shipyard exercises its remedies under the mortgages.

Purchase Price Allocation. The eight SEACOR Delta PSVs are all based on plans from the same designer, have a similar age of construction (2018-2020) and were constructed at the same shipyard. Two of the vessels are high specification diesel/electric powered PSVs. The other six vessels are all “sister” vessels with identical specifications. These six vessels are high specification diesel/electric/hybrid powered vessels. In accordance with ASU No. 2017-01-Business Combinations (Topic 805): Clarifying the Definition of a Business, due to the fact that the assets acquired have substantially all of their fair value concentrated as a group of similar assets, this acquisition qualified as an asset purchase. The allocation of the purchase price for the Company’s acquired assets for the six months ended June 30 was as follows (in thousands):

Assets Acquired (In Thousands):			June 30, 2020
Current Assets				7,700
Fixed Assets				142,282
Current Liabilities				(23,929	)
Book Value of Debt Acquired	(100,759	)
Discount on Debt Acquired	25,190
Fair Value of Debt Acquired				(75,569	)
Total Cost Basis for Purchase				50,484
Purchase Price			$	(28,150	)
Acquisition costs				(112	)
Equity Investment In SEACOR Offshore Delta (f/k/a SEACOSCO)				(22,222	)
				(50,484	)

Equipment Acquisitions and Dispositions

12 Months Ended

Dec. 31, 2020

Property Plant And Equipment [Abstract]

Equipment Acquisitions and Dispositions

4.	EQUIPMENT ACQUISITIONS AND DISPOSITIONS

Equipment Additions. The Company’s capital expenditures and payments on equipment were $20.8 million, $44.8 million, and $35.6 million in 2020, 2019 and 2018, respectively. Deliveries of offshore support vessels for the years ended December 31 were as follows:

	2020 ⁽¹⁾		2019 ⁽²⁾		2018 ⁽³⁾
FSV		—		2		6
Supply		4		2		5
Liftboat		—		—		—
		4		4		11

(1)	Excludes three CTVs as assets held for sale and seven PSVs acquired as part of the SEACOSCO Acquisition (See “Note 3. Business Acquisitions”).

(2)	Excludes two CTVs as assets held for sale.

(3)	Excludes two CTVs as assets held for sale.

Equipment Dispositions.

On January 12, 2021, a wholly-owned subsidiary of SEACOR Marine Holdings Inc. (the “Company”), completed the sale of the Company’s Windcat Workboats CTV business through the sale of 100% of the equity of Windcat Workboats, a wholly-owned subsidiary of the Company (“Windcat” and together with its subsidiaries, the “Windcat Group”), to CMB N.V. (the “Windcat Buyer”) pursuant to a Sale and Purchase Agreement entered into on December 18, 2020. At closing, the Windcat Buyer paid to the Company an aggregate purchase price of £32.8 million. After deducting transaction costs and expenses and giving effect to foreign exchange rate hedges, the Company received net cash proceeds of approximately US$42.6 million. The Windcat Buyer also assumed all of the approximately £20.4 million of debt outstanding under Windcat Workboat’s existing revolving credit facility. As of December 31, 2020, the Windcat Group owned a total of 41 CTVs and held interests in an additional five CTVs through its joint ventures, all of which were included in the sale. These vessels have been classified as and included as Assets held for sale as of December 31, 2020. The Company recognized a gain on the sale of Windcat Workboats in January 2021 of approximately $22.8 million.

During the year ended December 31, 2020, the Company sold two anchor handling towing supply (“AHTS”) vessels and one specialty vessel previously removed from service, four FSVs, one specialty vessels, one vessel under construction and other equipment for $21.6 million ($20.7 million cash and $0.9 million in previously received deposits) and gains of $1.2 million.

For the year ended December 31, 2019, the Company completed the sale of its ERRV fleet business, which consisted of 18 vessels with a net book value of $23.4 million. The net proceeds from the sale of the ERRV fleet, including property and equipment, were approximately $27.4 million resulting in a net loss on dispositions of $9.1 million. Additional consideration of up to £4 million (equivalent to approximately $5.2 million based on the exchange rate at the time of the sale) may be payable to the Company based on revenue targets being achieved in 2021. The revenue targets were not achieved in 2020 and as such no additional consideration payments were made.

In addition to the sale of the North Sea ERRV fleet, for the year ended December 31, 2019, the Company sold one AHTS vessels, five FSVs, five PSVs, three liftboats, and other equipment for net proceeds of $55.3 million ($54.2 million in cash and $1.1 million in cash deposits previously received) and gains of $5.5 million.

During the year ended December 31, 2018, the Company sold property and equipment for net proceeds of $12.3 million ($12.2 million in cash and $0.1 million in cash deposits previously received) and recorded gains of $5.7 million, all of which were recognized at the time of sale.

Major equipment dispositions for the years ended December 31 were as follows:

	2020 ⁽¹⁾		2019		2018 ⁽²⁾
AHTS		2		1		1
FSV		4		5		9
Supply		1		5		—
CTV		—		—		—
Liftboats		1		3		2
Specialty		2		—		—
		10		14		12

(1)	Excludes three vessels that were previously removed from service (two AHTS vessels and one specialty vessel).

(2)	Excludes one CTV from assets held for sale.

Investments, at Equity, and Advances to 50% or Less Owned Companies

12 Months Ended

Dec. 31, 2020

Schedule Of Investments [Abstract]

Investments, at Equity, and Advances to 50% or Less Owned Companies

5.	INVESTMENTS, AT EQUITY, AND ADVANCES TO 50% OR LESS OWNED COMPANIES

Investments, at equity, and advances to 50% or less owned companies as of December 31 were as follows (in thousands):

	Ownership			2020		2019
MexMar		49.0	%	$	50,037	$	54,249
SEACOSCO⁽¹⁾		50.0	%		—		37,480
OSV Partners⁽²⁾		30.4	%		9,094		10,668
SEACOR Marlin		49.0	%		7,979		7,929
MEXMAR Offshore⁽³⁾		49.0	%		1,960		—
Offshore Vessel Holdings		49.0	%		2,388		7,905
Other	20.0% — 50.0%				3,850		2,600
				$	75,308	$	120,831

⁽¹⁾	^{^{The Company acquired the}^remaining^50%^{of the SEACOSCO Joint Venture that it did not own on June 30, 2020.}}

⁽²⁾^{The Company owns}^66.7^{% of the General Partner and}^29.7^{% of the limited Partner}^.

⁽³⁾^{This Joint Venture holds the investment in UP Offshore}^.

Combined Condensed Financial Information of Other Investees. Summarized financial information of the Company’s other investees, at equity, as of and for the years ended December 31 was as follows (in thousands):

	2020		2019
Current assets	$	109,687	$	106,051
Noncurrent assets		259,424		607,541
Current liabilities		109,074		104,423
Noncurrent liabilities		115,626		331,357

	2020			2019			2018
Operating Revenues	$	160,781		$	136,690		$	105,163
Costs and Expenses:
Operating and administrative		142,228			116,517			75,529
Depreciation		27,044			27,412			25,359
		169,272			143,929			100,888
Loss on Asset Dispositions and Impairments, Net		—			(166	)		(262	)
Operating (Loss) Income	$	(8,491	)	$	(7,405	)	$	4,013
Net Loss	$	(18,229	)	$	(36,816	)	$	(14,861	)

As of December 31, 2020 and 2019, cumulative undistributed net earnings of all 50% or less owned companies included in the Company’s consolidated retained earnings were $20.7 million and $14.7 million, respectively.

MexMar. MexMar owns and operates 16 offshore support vessels in Mexico and manages four PSV’s and one FSV on behalf of OVH in Mexico. During the years ended December 31, 2020 and 2019, there were no returns of capital advances or distributions to shareholders. During the year ended December 31, 2018, MexMar returned previously provided capital advances of $9.8 million. During the years ended December 31, 2020, 2019 and 2018 the Company charged $0.3 million of vessel management fees to MexMar.

SEACOSCO. On May 31, 2020, SEACOR Offshore Asia, entered into the SEACOSCO SPA, pursuant to which SEACOR Offshore Asia agreed to acquire the SEACOSCO Interests held by the SEACOSCO Sellers that the Company did not already own.

On June 30, 2020, SEACOR Offshore Asia completed the SEACOSCO Acquisition (see “Note 3. Business Acquisitions).

OSV Partners. SEACOR OSV Partners GP LLC and SEACOR OSV Partners I LP (collectively “OSV Partners”) own and operate five offshore support vessels. On September 28, 2018, OSV Partners amended its term loan facility to, among other things, extend its maturity to September 28, 2021, and in connection therewith, the Company participated in a $5.0 million preferred equity offering by OSV Partners and subordinated loan in the amount of $5.0 million issued by OSV Partners, investing $1.1 million in such preferred equity (and committing to invest an additional $1.1 million in such preferred equity if called by the general partner of OSV Partners prior to September 30, 2020) and providing $2.1 million of such loan. On December 18, 2019, the general partner of OSV Partners called the remaining commitments of the Company and other limited partners and the Company satisfied its commitment with an additional $1.1 million investment in such preferred equity. The Company has no further commitments to OSV Partners. On December 23, 2019, OSV Partners further amended its term loan facility to, among other things, provide for interest-only payments during 2020 with the next principal payment due March 31, 2021. The lenders to OSV Partners have no recourse to the Company for outstanding amounts under the facility, and the Company is not obligated to participate in any future investment in or loan any money to OSV Partners. For the years ended December 31, 2020 and 2019, vessel management fees were abated and not charged. For the year ended December 31, 2018, the Company received $0.6 million, of vessel management fees from OSV Partners.

SEACOR Marlin. SEACOR Marlin LLC (“SEACOR Marlin”) own and operate Seacor Marlin supply vessel. On September 13, 2018, the Company sold 51% of SEACOR Marlin to MEXMAR Offshore (MI) LLC, a wholly owned subsidiary of MexMar, for $8.0 million in cash, which generated a gain of $0.4 million. The Seacor Marlin supply vessel was pledged as collateral under the MexMar credit facility, for which the Company receives an annual collateral fee.

MEXMAR Offshore. On December 20, 2018, UP Offshore (Bahamas) Ltds (“UP Offshore”), a provider of offshore support vessel services to the energy industry in Brazil, was acquired by MEXMAR Offshore, a new joint venture company that is 49% owned by the Company, and 51% owned by a subsidiary of CME. MEXMAR Offshore acquired UP Offshore for nominal consideration, re-financed its existing debt to fund capital expenditures on two vessels and a $10.0 million loan to fund new working capital requirements. During the year ended December 31, 2019, UP Offshore sold one PSV to a third party and repositioned three PSV’s to Mexico.

Offshore Vessel Holdings (“OVH”). On December 28, 2018, the Company invested $4.9 million for a 49% interest in OVH, the remaining 51% is owned by a subsidiary of CME. OVH invests in offshore assets and charters marine equipment. During the year ended December 31, 2019 OVH loaned $10.0 million to Operadora Productura Mexsicana, a drilling company in Mexico which owns and operates two jackup drilling rigs (“OPM”), chartered in three PSV’s from UP Offshore and purchased one FSV from the Company for $2.4 million through a seller’s finance agreement.

Other. The Company’s other 50% or less owned companies own and operate no vessels. During the year ended December 31, 2020, the Company received dividends of $2.1 million from these 50% or less owned companies. During the year ended December 31, 2019, the Company received dividends of $2.1 million and $0.5 million of return capital from these 50% or less owned companies. During the year ended December 31, 2018, the Company recognized impairment charges of $1.2 million, net of tax, to reduce its investment carrying value in a certain 50% or less owned company to zero. During the year ended December 31, 2020, no vessel management fees were received from these 50% or less owned companies. In the years ended December 31, 2019 and 2018, the Company received less than $0.1 million and $0.3 million, respectively.

Construction Reserve Funds

12 Months Ended

Dec. 31, 2020

Restricted Cash And Investments [Abstract]

Construction Reserve Funds

6.	CONSTRUCTION RESERVE FUNDS

The Company has established, pursuant to Section 511 of the Merchant Marine Act, 1936, as amended, construction reserve fund accounts subject to agreements with the Maritime Administration (“MARAD”). In accordance with this statute, the Company is permitted to deposit proceeds from the sale of certain vessels into the construction reserve fund accounts and defer the taxable gains realized from the sale of those vessels. Qualified withdrawals from the construction reserve fund accounts are only permitted for the purpose of acquiring qualified U.S.-flag vessels as defined in the statute and approved by MARAD. To the extent that sales proceeds are reinvested in replacement vessels, the carryover depreciable tax basis of the vessels originally sold is attributed to the U.S.-flag vessels acquired using such qualified withdrawals. The construction reserve funds must be committed for expenditure within three years of the date of sale of the equipment, subject to two one-year extensions that can be granted at the discretion of MARAD or be released for the Company’s general use as nonqualified withdrawals. For nonqualified withdrawals, the Company is obligated to pay taxes on the previously deferred gains at the prevailing statutory tax rate plus penalties and interest thereon for the period such taxes were deferred.

As of December 31, 2020, the Company had $4.2 million in short-term construction reserve funds included in cash and cash equivalents. During the years ended December 31, 2020, 2019 and 2018, construction reserve fund withdrawals totaled $9.1 million, $15.2 million and $17.3 million, respectively.

Leases

12 Months Ended

Dec. 31, 2020

Leases [Abstract]

Leases

LEASES

On February 25, 2016, the FASB issued a comprehensive new leasing standard, ASC 842, Leases, meant to improve transparency and comparability among companies by requiring lessees to recognize a lease liability and a corresponding lease asset for virtually all lease contracts. It also requires additional disclosures about leasing arrangements. The Company adopted the standard on January 1, 2019 and applied the transition provisions of the standard with recognition of a cumulative-effect adjustment to the opening balance of retained earnings. The adoption of the standard had a material impact on the Company’s consolidated financial position, results of operations and cash flows. The adjustment to the Company’s balance sheet on January 1, 2019 included the addition of $33.7 million of right-of-use assets, $31.9 million in lease liability, and a cumulative-effect adjustment to the opening balance of retained earnings of $1.7 million for certain of its equipment, office and land leases. In addition, unamortized deferred gains for four vessels previously accounted for under sale-leaseback arrangements of $8.7 million, ($11.0 million deferred gains net of $2.3 million deferred taxes), were fully recognized as an adjustment to the opening balance of retained earnings.

As of December 31, 2020, the Company leases two AHTS vessels, one liftboat, one FSV and certain facilities and other equipment. The leases typically contain purchase and renewal options or rights of first refusal with respect to the sale or lease of the equipment. As of December 31, 2020, the remaining lease terms of the vessels have remaining durations from eight to 12 months. The lease terms of the other equipment range in duration from 11 to 312 months.

As of December 31, 2020, future minimum payments for leases for the years ended December 31 were as follows (in thousands):

	Operating Leases			Finance Leases
2021	$	7,855		$	42
2022		639			39
2023		628			39
2024		559			36
2025		539			—
Years subsequent to 2025		4,215			—
		14,435			156
Interest component		(3,060	)		(15	)
		11,375			141
Current portion of long-term operating lease liabilities		(7,030	)		(36	)
Long-term operating lease liabilities	$	4,345		$	105

For the years ended December 31, the components of lease expense were as follows (in thousands):

	2020		2019
Operating lease expense ⁽¹⁾	$	6,205	$	13,442
Finance lease cost:
Amortization of finance lease asset ⁽¹⁾		11		—
Interest on lease liabilities ⁽²⁾		1		—
Short-term lease costs ⁽¹⁾		1,320		2,398
	$	7,537	$	15,840

⁽¹⁾	Included in selling, general and administrative expenses and amortization costs in the consolidated statements of loss.

⁽²⁾	Included in interest expense in the consolidated statements of loss.

For the year ended December 31, 2020, supplemental cashflow information related to leases were as follows (in thousands):

	2020
Operating cash flows from operating leases	$	14,785
Right-of-use assets obtained for operating lease liabilities		1,706
Right-of-use assets obtained for finance lease liabilities		140

For the year ended December 31, 2020, other information related to leases were as follows:

	2020
Weighted average remaining lease term, in years - operating leases		7.6
Weighted average remaining lease term, in years - finance leases		4.2
Weighted average discount rate - operating leases		4.7	%
Weighted average discount - finance leases		5.3	%

The Company performed an impairment analysis and determined that some of the leased offshore support vessels are impaired due to an operating or cash flow loss currently and in the forecasted future. The Company recorded impairment losses of $5.9 million for two such leases for the year ended December 31, 2020 and $5.3 million for one such lease for the year ended December 31, 2019.

Long Term Debt

12 Months Ended

Dec. 31, 2020

Debt Disclosure [Abstract]

Long Term Debt

8.	LONG-TERM DEBT

The Company’s long-term debt obligations as of December 31 were as follows (in thousands):

	December 31,2020			December 31, 2019
Recourse Long-term debt⁽¹⁾:
Convertible Senior Notes	$	125,000		$	125,000
SEACOR Marine Foreign Holdings Credit Facility		100,750			113,750
Sea-Cat Crewzer III Term Loan Facility		21,653			24,128
SEACOR Offshore Delta (f/k/a SEACOSCO) Acquisition Debt		19,705			—
SEACOR Delta (f/k/a SEACOSCO) Shipyard Financing⁽²⁾		95,317			—
SEACOR Alpine Shipyard Financing⁽³⁾		31,103			10,534
SEACOR 88/888 Term Loan		5,500			5,500
BNDES Equipment Construction Finance Notes		-			3,332
Total recourse Long-term debt		399,028			282,244
Non-recourse Long-term debt⁽⁴⁾:
Falcon Global USA Term Loan Facility		102,349			102,349
Falcon Global USA Revolver		15,000			15,000
SEACOR 88/888 Term Loan		5,500			5,500
Total non-recourse Long-term debt		122,849			122,849
Total principal due for long-term debt		521,877			405,093
Current portion due within one year		(32,377	)		(17,802	)
Unamortized debt discount		(44,864	)		(26,343	)
Deferred financing costs		(4,126	)		(5,234	)
Long-term debt, less current portion	$	440,510		$	355,714
Long-Term Debt included in current liabilities associated with assets held for sale - Windcat Workboats Facilities	$	27,626		$	24,537

⁽¹⁾	^{Recourse debt represents debt issued by SEACOR Marine and/or its subsidiaries and guaranteed by SEACOR Marine as defined in the relevant debt agreements.}
⁽²⁾	^{SEACOR Delta Shipyard Financing includes vessel financing on the}^eight^{vessels acquired in the SEACOSCO Acquisition (see “Note 3.}^{Business Acquisitions}^”).
⁽³⁾	^{SEACOR Alpine Shipyard Financing includes vessel financing on the SEACOR Alps, the SEACOR Andes and the SEACOR Atlas vessels.}
⁽⁴⁾	^{Non-recourse debt represents debt issued by the Company’s Consolidated Subsidiaries with no recourse to SEACOR Marine or its other non-debtor subsidiaries, other than certain limited support obligations as defined in the respective debt agreements, which in aggregate are not considered to be material to the Company’s business and financial condition.}

The Company’s contractual long-term debt maturities from continuing operations for the years ended December 31 were as follows (in thousands):

2021	$	32,377
2022		38,484
2023		244,983
2024		134,523
2025		11,365
Years subsequent to 2025		60,145
	$	521,877

As of December 31, 2020, the Company is in compliance with all debt covenants and lender requirements.

Falcon Global. On February 24, 2021, SEACOR Marine, Falcon Global USA LLC, an indirect wholly owned subsidiary of SEACOR Marine (“FGUSA”), and certain subsidiaries of FGUSA, entered into a Seventh Consent, Agreement and Omnibus Amendments (the “Seventh FGUSA Credit Facility Amendment”) to that certain (i) $131.1 million term and revolving loan facility, dated as of February 8, 2018, with a syndicate of lenders administered by JP Morgan Chase Bank, N.A. (as amended, the “FGUSA Credit Facility”) and (ii) obligation guaranty issued by SEACOR Marine, dated February 8, 2018, pursuant to which SEACOR Marine provides a guarantee of certain limited obligations of FGUSA under the Credit Facility (as amended, the “FGUSA Guaranty”).

The Seventh FGUSA Credit Facility Amendment provides for, among other things, (i) the extension from March 2021 to June 2021 of the commencement of monthly repayment of the term loan, with payments being the lesser of (a) $0.8 million and (b) the amount outstanding under the term loan, (ii) the extension of the FGUSA Guaranty for an additional three months from February 8, 2021 to May 8, 2021, (iii) that the audited financial statements of FGUSA and its consolidated subsidiaries for the fiscal year ended December 31, 2020 are not required to be without a “going concern” or like qualification, commentary or exception, and (iv) the

extension of the deadline for delivery of certain physical vessel appraisals from April 30, 2021 to December 31, 2021. Except as provided in the Guaranty, the FGUSA Credit Facility, is non-recourse to SEACOR Marine and its subsidiaries other than FGUSA.

SEACOR Alpine. In 2019, the Company committed to take possession of three Rolls Royce UT1771 CDL designed diesel electric powered PSVs of 3,800 tons delivered deadweight capacity with dynamic position class 2 and firefighting class 1 notations. As part of this transaction, the shipbuilder, COSCO Shipping Heavy Industry (Zhoushan) Co. Ltd., agreed to finance 70% of the cost of each of these vessels pursuant to a deferred payment agreement. The deferred payment agreement calls for increasing quarterly payments of principal and interest payments that bear interest at an annual rate of 5% over a four-year term from delivery. The Company took delivery of the SEACOR Alps, the SEACOR Andes and the SEACOR Atlas on September 30, 2019, April 20, 2020 and August 10, 2020, respectively.

Windcat Workboats. On March 3, 2020, Windcat Workboats, together with certain other obligors that are its subsidiaries entered into an agreement (the “RCF Amendment”) with Coöperatieve Rabobank U.A. to amend the €25 million revolving credit facility agreement, originally dated as of May 24, 2016, as amended and restated from time to time. Amended provisions included, among other things, the extension of the maturity date from December 31, 2021 to December 31, 2022. Applicable fees in the amount of €0.1 million were paid in conjunction with the RCF Amendment and will be amortized over the credit facility term. During the year ended December 31, 2020, the Company borrowed an additional €1.0 million under the Windcat Workboats credit facilities, resulting in a net increase in USD borrowings of $1.1 million. On December 18, 2020, the Company announced the sale of Windcat Workboats, which was completed on January 12, 2021. Upon completion of the sale, the Windcat Buyer assumed all financial obligations related to Windcat Workboats. The long-term debt obligations as of December 31, 2020 are classified as liabilities associated with assets held for sale.

SEACOR Offshore Delta (f/k/a SEACOSCO). On June 30, 2020, the Company completed the acquisition of the SEACOSCO Interests that it did not already own. The deferred portion of the SEACOSCO Purchase Price is payable in annual installment payments of $1.0 million, $2.5 million and $2.5 million in the first, second and third year after the SEACOSCO SPA Signing Date, respectively, with the remaining $13.7 million due four years after such date. The deferred portion of the SEACOSCO Purchase Price accrues interest at a fixed rate of 1.5%, 7.0%, 7.5% and 8.0% for the first through fourth years after the signing date, respectively. The Guangdong DPAs comprising the SEACOR Delta Shipyard Financing provide for amortization of the purchase price for each vessel over a period of 10 years from delivery with the unpaid amount bearing floating interest rate of three-month LIBOR plus 4.0% (see “Note 3. Business Acquisitions”).

SEACOR Marine Foreign Holdings. On September 26, 2018, SEACOR Marine Foreign Holdings Inc. (“SMFH”), a wholly-owned subsidiary of the Company, entered into a $130.0 million loan facility with a syndicate of lenders administered by DNB Bank ASA (as amended from time to time, the “SMFH Loan Facility”). Subject to Amendment No. 1, Amendment No. 2, Amendment No. 3 and the Letter Agreement described below, SMFH’s obligations pursuant to the SMFH Loan Facility were initially secured by mortgages on 20 vessels owned by the Company’s vessel owning subsidiaries as well as an assignment of earnings from those subsidiaries. The loan matures in 2023 and bears interest at a variable rate based on LIBOR (currently 4%). The obligations of SMFH under the SMFH Loan Facility are guaranteed by SEACOR Marine (the “SMFH Loan Facility Guaranty”). The proceeds from the SMFH Loan Facility were used to pay off all obligations under other credit facilities of subsidiaries of the Company (Falcon Global International Term Loan Facility, Sea-Cat Crewzer II Term Loan Facility, Sea-Cat Crewzer Term Loan Facility and C-Lift Acquisition Notes totaling $101.3 million, consisting of $99.9 million principal and $1.4 million accrued interest), resulting in a net increase in term debt of $30.1 million. Principal payments of $3.3 million per quarter under the SMFH Loan Facility began in December 2018. As a result of this transaction, the Company recognized a loss of $0.6 million upon the extinguishment of debt. In October 2018, the Company entered into an interest rate swap agreement on the notional value at inception of $65.0 million related to this debt. The SMFH Loan Facility provides for customary events of default and has customary affirmative and negative covenants for transactions of this type that are applicable to SEACOR Marine, SMFH and its subsidiaries.

On August 6, 2019, SEACOR Marine, SMFH, and certain vessel-owning subsidiaries of SEACOR Marine, entered into Amendment No. 1 to the SMFH Loan Facility and SMFH Loan Facility Guaranty (the “Amendment No. 1”), which provided for, among other things, (i) the release of one vessel from a mortgage securing the SMFH Loan Facility and the substitution of mortgages over two other vessels owned by vessel-owning subsidiaries of SEACOR Marine, and (ii) the modification of certain financial maintenance and restrictive covenants contained in the SMFH Loan Facility or the SMFH Loan Facility Guaranty, including with respect to asset maintenance, vessel collateral releases, EBTIDA coverage ratios and the payment of dividends and distributions. On November 26, 2019, SEACOR Marine, SMFH, and certain vessel-owning subsidiaries of SEACOR Marine, entered into Amendment No. 2 to the SMFH Loan Facility, as amended (the “Amendment No. 2”), which provided for, among other things, (i) the release of six vessels from mortgages securing the SMFH Loan Facility and the substitution of mortgages over three other vessels owned by vessel-owning subsidiaries of SEACOR Marine and (ii) the bareboat registration in Nigeria of a vessel subject to a mortgage securing the SMFH Loan Facility.

On June 29, 2020, SEACOR Marine, SMFH, and certain vessel-owning subsidiaries of SEACOR Marine, entered into Amendment No. 3 to the SMFH Loan Facility, as amended (the “Amendment No. 3”), which provides for, among other things, (i) the modification of certain financial maintenance and restrictive covenants contained in the SMFH Loan Facility or the guaranty provided

by SEACOR Marine with respect thereto, including with respect to EBITDA coverage ratios, mandatory prepayment events, and the exclusion of certain indebtedness associated with the acquisition of the SEACOSCO Interests, and (ii) the placement of mortgages on two additional vessels owned by vessel-owning subsidiaries of SEACOR Marine as security for the indebtedness under the SMFH Loan Facility.

On December 18, 2020, SEACOR Marine, SMFH and DNB Bank ASA, New York Branch, as facility agent on behalf of the lenders under the SMFH Loan Facility, and SMFH Loan Facility Guaranty, entered into a letter agreement (the “Letter Agreement”) pursuant to which an estimated $31,200,000 tax refund receivable from the IRS under the Coronavirus Aid, Relief, and Economic Security Act (“CARES Act”) will be treated as cash or cash equivalents, for the period up to and including January 31, 2021, for purposes of calculating the Company’s cash or cash equivalent balances required under the SMFH Loan Facility Guaranty.

BNDES. In October 2019, Oceanpact purchased from the Company the two vessels securing the BNDES Equipment Construction Finance Notes, but the transfer of title of the vessels from the Company to Oceanpact was subject to the assignment of the BNDES Equipment Construction Finance Notes to Oceanpact. On June 9, 2020, Banco Nacional de Desenvolvimento Economico e Social (“BNDES”), a Brazilian government-owned entity, provided a suspension for a period of six months, from May 11, 2020 to October 10, 2020, on the payment of principal and compensatory interest under the BNDES Equipment Construction Finance Notes, without changing the final term of the debt amortization period nor the interest rate thereunder. Collection on the receivable balance from Oceanpact was also deferred. Oceanpact continued to work with BNDES to follow through with the assignment of the loan or accept another form of guarantee provided by Oceanpact in order to obtain a debt release from BNDES. On October 15, 2020, the Company’s outstanding debt balance to BNDES was paid in full and the receivable from OceanPact was paid in full. In addition, on October 23, 2020, the Company received a notification that the guarantor letter of credit had been released. The Company has no further obligations under the BNDES Equipment Construction Finance Notes.

Convertible Senior Notes. On December 1, 2015, the Company issued $175.0 million in aggregate principal amount of its Convertible Senior Notes (the “Convertible Senior Notes”), at an interest rate of 3.75%, initially due December 1, 2022, (subsequently amended to December 2, 2023 as described below) to investment funds managed and controlled by the Carlyle Group (collectively “Carlyle”). The Convertible Senior Notes are convertible into shares of Common Stock at a conversion rate of 23.26 shares per $1,000 in principal amount of such notes, subject to certain conditions, or, into warrants to purchase an equal number of shares of Common Stock at an exercise price of $0.01 per share in order to facilitate the Company’s compliance with the provisions of the Jones Act. The indenture governing the Convertible Senior Notes contains customary events of default with respect to the Convertible Senior Notes.

Upon completion of the Spin-off, the Company bifurcated the embedded conversion option liability of $27.3 million from the Convertible Senior Notes and recorded an additional debt discount (see “Note 10. Derivative Instruments and Hedging Strategies” and “Note 11. Fair Value Measurements”). The adjusted unamortized debt discount and issue costs are being amortized as additional non-cash interest expense over the remaining maturity of the debt for an overall effective interest rate of 7.95% and the changes in the fair value of the bifurcated derivative are recorded as derivative income or loss.

On May 2, 2018, the Company and Carlyle entered into an exchange transaction (the “Exchange”) pursuant to which Carlyle exchanged $50 million in principal amount of the Convertible Senior Notes for Warrants to purchase 1,886,792 shares of Common Stock (to facilitate compliance with the provisions of the Jones Act) at an exercise price of $0.01 per share, subject to adjustments (the “Carlyle Warrants”), representing an implied exchange rate of approximately 37.73 shares per $1,000 in principal amount of the Convertible Senior Notes (equivalent to an exchange price of $26.50 per share). The Carlyle Warrants have a 25-year term, which commenced May 2, 2018. The Company and Carlyle also amended the $125.0 million in principal amount of Convertible Senior Notes that remained outstanding following the Exchange to (i) increase the interest rate from 3.75% per annum to 4.25% per annum and (ii) extend the maturity date of the Convertible Senior Notes by 12 months to December 1, 2023. Interest on the Convertible Senior Notes is payable semi-annually on June 15 and December 15 of each year.

Sea-Cat Crewzer III Term Loan Facility. On April 21, 2016, Sea-Cat Crewzer III LLC (“Sea-Cat Crewzer III”) entered into a €27.6 million term loan facility (payable in U.S. dollars) secured by the vessel owned by Sea-Cat Crewzer III and fully guaranteed by SEACOR Marine (the “Sea-Cat Crewzer III Loan Facility”). Borrowings under the facility bear interest at a Commercial Interest Reference Rate, currently 2.76%. During the years ended December 31, 2017 and 2016, Sea-Cat Crewzer III drew $7.1 million and $22.8 million, respectively, under the facility and incurred issue costs of $2.7 million in 2016 related to this facility. During the years ended December 31, 2018 Sea-Cat Crewzer III made scheduled payments of $3.1 million, related to this facility. On December 26, 2019, Sea-Cat Crewzer III, SEACOR Marine, Banco Santander S.A. (as mandated lead arranger and agent), and Santander Bank, N.A. (as lender) entered into Amendment No. 1 to the Sea-Cat Crewzer III Loan Facility, which provided for, among other things, an increase to the maximum debt to capitalization ratio required to be maintained thereunder. On December 24, 2020, Sea-Cat Crewzer III, SEACOR Marine, Banco Santander S.A. (as mandated lead arranger and agent), and Santander Bank, N.A. (as lender) entered into Amendment No. 2 to the Sea-Cat Crewzer III Loan Facility, which provided for, among other things, a waiver of the covenant breaches related to maximum debt to capitalization ratio and the exclusion of certain obligations of the guarantor from the guarantor’s net financial debt for purposes of calculating the guarantor’s permitted net financial debt to equity. The original loan agreement did not expressly exclude certain obligation of the guarantor, including but not limited to non-recourse obligations. This amendment allows Sea-Cat Crewzer III to be in compliance with its debt agreements.

SEACOR 88/888. On July 5, 2018, a wholly owned subsidiary of SEACOR Marine entered into a new term loan of $11.0 million and used the funds to acquire two vessels, the SEACOR 88 and SEACOR 888, that were previously managed (but not owned) by the Company. The term loan matures in 2023, bears interest at a variable rate (currently 3.75%) and is secured by the two vessels. SEACOR Marine provided a limited guaranty of such loan under which claims recoverable from SEACOR Marine shall not exceed the lesser of (x) $5.5 million and (y) 50% of the obligations outstanding at the time a claim is made thereunder. In October 2018, the Company entered into an interest rate swap agreement on the notional value at inception of $5.5 million related to this loan.

Letters of Credit. As of December 31, 2020, the Company had outstanding letters of credit totaling $0.5 million for one lease obligation and labor and performance guarantees.

Income Taxes

12 Months Ended

Dec. 31, 2020

Income Tax Disclosure [Abstract]

Income Taxes

9.	INCOME TAXES

In late 2017, the U.S. Tax Cuts and Jobs Act (the “Tax Act”) was enacted into law. This law significantly impacted our corporate income taxes commencing in 2018 and will continue to do so in future years. The most significant provisions included reducing the corporate tax rate from 35% to 21%; eliminating U.S. federal tax on dividends from foreign subsidiaries, creating a limitation on deductible interest expense, further restricting the compensation deduction, and changing the utilization of Net Operating Losses (“NOL’s”).

In arriving at the 2020 results the Company took into account the impacts of the Tax Act based on our interpretation of the provisions enacted and the regulations issued as of this date

On March 27, 2020 the Coronavirus Aid, Relief, and Economic Security Act (“CARES Act”) was enacted into law in response to the COVID-19 pandemic. The CARES Act lifts certain deduction limitations originally imposed by the 2017 Tax Act. Under the CARES Act, corporate taxpayers may carry back NOLs realized during 2018 through 2020 for up to five years. The CARES Act also eliminates the 80% of taxable income limitations by allowing corporate entities to fully utilize NOL carryforwards to offset taxable income in 2018 through 2020, and increased the deductible interest expense limit, as discussed in further detail below.

As a result of the CARES Act, On June 26, 2020 the Company entered into a Tax Refund and Indemnification Agreement (the “Tax Refund Agreement”) with SEACOR Holdings, the Company’s former parent company (see “Note 17. Related Party Transactions”). The Tax Refund Agreement will enable the Company to utilize net operating losses (“NOLs”) generated in 2018 and 2019 to claim refunds for tax years prior to the Company’s spin-off from SEACOR Holdings in 2017 (at which time the Company was included in SEACOR Holdings consolidated tax returns) that are now permitted to be carried back pursuant to the provisions of the CARES Act and for which SEACOR Holdings needs to claim the refund on behalf of the Company. As a result, the Company expects to receive cash tax refunds of approximately $31.2 million within the next 12 months, subject to the refund schedule of the Internal Revenue Service. The Internal Revenue Service has been recently experiencing delays in processing refund claims due in part to the COVID-19 pandemic.

SEACOR Holdings will retain certain of the funds to facilitate tax savings realized by SEACOR Holdings of no less than 35% of the amount of its own 2019 NOLs. Additionally, a $3.0 million transaction fee was paid to SEACOR Holdings concurrently with the signing of the agreement as consideration for its cooperation in connection with the filing of the applicable tax refund returns. As of December 31, 2020, the Tax Refund Agreement does not restrict the use of approximately $23.1 million of the refund, with the remaining approximately $8.1 million required to be deposited into an account to be used solely to satisfy certain of the Company’s obligations that remain guaranteed by SEACOR Holdings.

Loss before income tax benefit and equity in earnings (losses) of 50% or less owned companies derived from U.S. and foreign companies for the years ended December 31 were as follows (in thousands):

	2020			2019			2018
United States	$	(83,560	)	$	(71,833	)	$	(72,540	)
Foreign		(17,748	)		(23,663	)		(28,675	)
Eliminations		3,201			11,022			8,782
	$	(98,107	)	$	(84,474	)	$	(92,433	)

The components of income tax expense (benefit) for the years ended December 31 were as follows (in thousands):

	2020			2019			2018
Current:
Federal	$	(30,838	)	$	(6	)	$	5,987
State		123			(78	)		3
Foreign		5,533			5,005			3,307
		(25,182	)		4,921			9,297
Deferred:
Federal		2,435			(12,594	)		(21,466	)
State		(139	)		(224	)		(1,404	)
Foreign		(38	)		(72	)		110
		2,258			(12,890	)		(22,760	)
	$	(22,924	)	$	(7,969	)	$	(13,463	)

For the year ending December 31, 2020 the Company received a $1.6 million tax refund that had been withheld by the State of Qatar from vessel revenues between 2010 and 2016. Of this amount, approximately $0.3 million will be claimed as foreign tax credits by SEACOR Holdings on its U.S. tax return prior to the spin-off of SEACOR Marine in 2017. Subject to final resolution of taxes with the State of Qatar, these amounts are expected to be remitted to SEACOR Holdings Inc. The remaining amount relates to foreign taxes that were considered in computing earnings and profits and available foreign taxes of foreign subsidiaries of the Company and will require the Company to recompute its 2017 tax liability under Internal Revenue Code Section 965. The additional U.S. tax liability of the Company under Section 965 due to these refunds is expected to be approximately $0.4 million.

For the year ending December 31, 2019, the Company recorded a return to provision adjustment related to losses from a consolidated joint venture for the 2018 tax year. The resulting additional liability of $2.3 million was recorded in the Company’s financial statements during the third quarter of 2019.

For 2018, the Company incurred a current tax liability of $1.4 million related to the non-qualified withdrawal of funds from a Capital Construction Fund (“CCF”) by a partnership in which the Company held a 50% interest. The Company had previously recorded a deferred tax liability in connection with this CCF fund.

The following table reconciles the difference between the statutory federal income tax rate for the Company and the effective income tax rate for the years ended December 31:

	2020			2019			2018
Statutory rate		(21.0	)%		(21.0	)%		(21.0	)%
U.S. federal income tax law changes		(11.8	)%		—	%		—	%
SEACOR Holdings share awards to Company personnel		0.3	%		—	%		0.2	%
Non-deductible expenses		—	%		—	%		—	%
Exclusion of foreign subsidiaries with accumulated losses and withholding tax		7.7	%		7.4	%		9.3	%
Noncontrolling interests		1.3	%		1.7	%		(1.6	)%
State taxes		—	%		(0.3	)%		(1.5	)%
Return to provision		(0.4	)%		2.8	%		(0.5	)%
Other		0.5	%		—	%		0.5	%
Effective Tax Rate		(23.4	)%		(9.4	)%		(14.6	)%

For the year ending December 31, 2020, the Company’s effective income tax rate of 23.4% was primarily due to the effect of the NOL carrybacks pursuant to the CARES Act, foreign subsidiaries with current losses for which there is no federal income tax benefit, foreign taxes not creditable against U.S. income taxes, and taxes on income attributable to noncontrolling interests.

For the year ending December 31, 2019, the Company’s effective income tax rate of 9.4% was lower than the statutory tax rate of 21% primarily due to foreign subsidiaries with current losses for which there is no federal income tax benefit, foreign taxes not creditable against U.S. income taxes, and noncontrolling interests.

For the year ending December 31, 2018, the Company’s effective income tax rate of 14.6% was lower than the Company’s statutory tax rate of 21% primarily due to foreign subsidiaries with current losses for which there is no federal income tax benefit, foreign taxes not creditable against U.S. income taxes, and noncontrolling interests.

The components of net deferred income tax liabilities as of December 31 were as follows (in thousands):

	2020			2019
Deferred tax liabilities:
Property and equipment	$	58,676		$	63,827
Investments in 50% or Less Owned Companies		2,925			3,039
Other		4,819			10,612
Total deferred tax liabilities		66,420			77,478
Deferred tax assets:
Federal Net Operating Loss Carryforwards		23,061			28,664
Other		10,073			16,561
		33,134			45,225
Valuation Allowance		(2,536	)		(1,311	)
Total deferred tax assets		30,598			43,914
Net deferred tax liabilities	$	35,822		$	33,564

The Section 163(j) interest deduction limitations were amended to limit the ability of the Company to deduct net interest expense to thirty percent of adjusted taxable income. The CARES Act modified the computation for 2020 to increase the limit to fifty percent of adjusted taxable income and to allow a deduction for fifty percent of partnership excess business interest from 2019. For the year ended December 31, 2020, $4.4 million of interest expense was suspended and $3.3 million of 2019 suspended interest was deductible, and for the year ended December 31, 2019, $6.6 million of interest expense was suspended. In addition to the $3.6 million of interest suspended in 2018 this results in a total interest expense amount available for carry forward of $11.3 million. This amount will be available to be deducted in future years subject to the 30% limitation.

Future utilization of NOL’s arising in tax years after December 31, 2017 are limited to eighty percent of taxable income and are allowed to be carried forward indefinitely. The CARES Act allowed a five-year carryback of NOL’s generated in 2018, 2019 and 2020. The 2018 and 2019 NOLs were eligible to be carried back pursuant to the CARES Act. As of December 31, 2020, the Company has $42.2 million of net operating losses generated prior to December 31, 2017 and $67.6 million of net operating losses generated after 2017. Net operating losses generated in 2017 may carry forward 20 years (expiring in 2037). The 2020 NOL will carry forward indefinitely with no expiration period but its utilization will be subject to an annual 80 percent of taxable income limitation.

As of December 31, 2020, the Company's valuation allowance of $2.5 million related primarily to foreign tax credit carryforwards which the Company expects to expire unutilized and Louisiana state net operating loss carryforwards.

Derivative Instruments And Hedging Activities Disclosure [Abstract]

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References + Details

Derivative Instruments and Hedging Strategies

12 Months Ended

Dec. 31, 2020

Derivative Instruments and Hedging Strategies

10.	DERIVATIVE INSTRUMENTS AND HEDGING STRATEGIES

Derivative instruments are classified as either assets or liabilities based on their individual fair values. The fair values of the Company’s derivative instruments from continuing operations as of December 31 were as follows (in thousands):

		2020				2019
	Balance Sheet Classification	Derivative Asset		Derivative Liability		Derivative Asset		Derivative Liability
Derivatives designated as hedging instruments:
Interest rate swap agreements (cash flow hedges)	Current	$	—	$	3,698	$	—	$	2,925
			—		3,698		—		2,925
Derivatives not designated as hedging instruments:
Forward Exchange Contract	Current		—		893		—		—
Conversion option liability on Convertible Senior Notes	Long-Term		—		2		—		5,205
		$	—	$	895	$	—	$	5,205

Economic Hedges. The Company enters and settles forward currency exchange, option and future contracts with respect to various foreign currencies. These contracts enable the Company to buy currencies in the future at fixed exchange rates, which could offset possible consequences of changes in currency exchange rates with respect to the Company’s business conducted outside of the U.S. The Company generally does not enter into contracts with forward settlement dates beyond twelve to eighteen months. During the year ended December 31, 2020, the Company recognized losses of $0.9 million on these contracts which were recognized concurrently in earnings and included in derivative liabilities in the accompanying consolidated balance sheets.

Cash Flow Hedges. The Company and certain of its 50% or less owned companies have interest rate swap agreements designated as cash flow hedges at their inception. By entering into these interest rate swap agreements, the Company and its 50% or less owned companies have converted the variable LIBOR or EURIBOR component of certain of their outstanding borrowings to a fixed interest rate. The Company recognized losses on derivative instruments designated as cash flow hedges of $0.7 million for the year ended December 31, 2020, losses of $1.3 million for the year ended December 31, 2019 and gains of $1.6 million for the year ended December 31, 2018 as a component of other comprehensive loss. As of December 31, 2020, the interest rate swaps held by the Company and certain of the Company’s 50% or less owned companies were as follows:

•

Windcat Workboats had two interest rate swap agreements maturing in 2021 that call for the Company to pay a fixed rate of interest of (0.03%) plus margin on the aggregate notional value of €15.0 million ($20.4 million) and receive a variable interest rate based on EURIBOR on the aggregate notional value. The swap agreements are classified in liabilities associated with assets held for sale;

•

SEACOR Marine Foreign Holdings had an interest rate swap agreement maturing in 2023 that calls for SMFH to pay a fixed rate of interest of 3.32% plus margin on the amortized notional value of $7.8 million and receive a variable interest rate based on LIBOR on the amortized notional value;

•

SEACOR Marine Foreign Holdings had an interest rate swap agreement maturing in 2023 that calls for SMFH to pay a fixed rate of interest of 3.195% plus margin on the amortized notional value of $43.0 million and receive a variable interest rate based on LIBOR on the amortized notional value;

•

SEACOR 88/888 had an interest rate swap agreement maturing in 2023 that calls for Seacor 88/888 to pay a fixed rate of interest of 3.175% plus margin on the amortized notional value of $5.5 million and receive a variable interest rate based on LIBOR on the amortized notional value; and

•

MexMar, in which the Company has a 49% noncontrolling interest, had five interest rate swap agreements with maturities in 2023 that call for MexMar to pay a fixed rate of interest ranging from 1.71% to 2.10% per annum on the aggregate amortized notional value of plus margin on the aggregate amortized notional value of $69.4 million and receive a variable interest rate based on LIBOR on the aggregate amortized notional value.

Derivative Instruments. The Company utilizes derivative instruments to manage the volatility of cash flows due to fluctuating interest rates. All derivative instruments not qualifying for the normal purchase and normal sale exception are recorded on the balance sheets at fair value. The treatment of the periodic changes in fair value will depend on whether the derivative is designated and effective as a hedge for accounting purposes.

If a derivative qualifies for hedge accounting and is designated as a cash flow hedge, the effective portion of the change in fair value of the derivative is deferred in Accumulated Other Comprehensive Income (“AOCI”), a component of owners’ equity, and reclassified to earnings when the forecasted transaction occurs. Cash flows from a derivative instrument designated as a hedge are classified in the same category as the cash flows from the item being hedged. As such, we include the cash flows from interest rate derivative instruments in interest expense.

If a derivative does not qualify as a hedge or is not designated as a hedge, the gain or loss resulting from the change in fair value on the derivative is recognized currently in earnings as a component of other income (expense).

We formally document all relationships between hedging instruments and hedged items, as well as its risk management objectives and strategy for undertaking the hedge. This documentation includes the specific identification of the hedging instrument and the hedged item, the nature of the risk being hedged and the manner in which the hedging instrument’s effectiveness will be assessed. At the inception of the hedge, and on an ongoing basis, we assess whether the derivatives used in hedging transactions are highly effective in offsetting changes in cash flows of hedged items.

The relationship between the hedging instrument and the hedged item must be highly effective in achieving the offset of changes in cash flows attributable to the hedged risk both at the inception of the contract and on an ongoing basis. We measure hedge ineffectiveness on a quarterly basis and reclassify any ineffective portion of the gain or loss related to the change in fair value to earnings in the current period.

We will discontinue hedge accounting on a prospective basis when a hedge instrument is terminated or ceases to be highly effective. Gains and losses deferred in AOCI related to cash flow hedges for which hedge accounting has been discontinued remain deferred until the forecasted transaction occurs. If it is no longer probable that a hedged forecasted transaction will occur, deferred gains or losses on the hedging instrument are reclassified to earnings immediately.

For balance sheet classification purposes, we analyze the fair values of the derivative instruments on a contract by contract basis and report the related fair values and any related collateral by counterparty on a gross basis. Realized and unrealized gains and losses on derivatives designated as cash flow hedges that are entered into by the Company’s 50% or less owned companies are also reported as a component of the Company’s other comprehensive loss in proportion to the Company’s ownership percentage, with reclassifications and ineffective portions being included in equity in earnings (losses) of 50% or less owned companies, net of tax, in the accompanying consolidated statements of loss.

The fair value of our derivative instruments, depending on the type of instrument, was determined by the use of present value methods or standard option valuation models with assumptions about commodity prices based on those observed in underlying markets. The estimated fair value of our derivative instruments from continuing operations was a net liability of $4.6 million as of December 31, 2020. The estimated fair value is net of an adjustment for credit risk based on the default probabilities by year as indicated by market quotes for the counterparties’ credit default swap rates. The credit risk adjustment was $0.3 million at December 31, 2020.

The following tables reflect amounts recorded in Other Comprehensive Income (Loss) (“OCI”) and amounts reclassified from OCI to revenue and expense for the periods indicated:

	Losses Recognized in OCI on Derivatives (Effective Portion)
Derivatives in Cash Flow Hedging Relationships	2020			2019			2018
Interest rate swap contracts	$	(2,139	)	$	(1,901	)	$	(1,939	)
Joint venture interest rate swap contracts		(156	)		(645	)		(76	)
	Losses Reclassified from OCI into Income (Effective Portion)
Location of Loss	2020			2019			2018
Interest expense	$	1,425		$	552		$	31

Our consolidated earnings are also affected by the use of the mark-to-market method of accounting for derivative instruments that do not qualify for hedge accounting or that have not been designated as hedges. The changes in fair value of these instruments are recorded on the balance sheet and through earnings rather than being deferred until the anticipated transaction settles. The use of mark-to-market accounting for financial instruments can cause non-cash earnings volatility due to changes in the underlying commodity price indices.

Other Derivative Instruments. The Company recognized gains (losses) on derivative instruments not designated as hedging instruments for the years ended December 31 as follows (in thousands):

	Derivative gains (losses), net
	2020			2019		2018
Conversion option liability on Convertible Senior Notes	$	5,203		$	71	$	1,556
Interest rate swap agreements		—			—		1,298
Forward currency exchange, option and future contracts		(893	)		—		—
	$	4,310		$	71	$	2,854

The conversion option liability relates to the bifurcated embedded conversion option in the Convertible Senior Notes (See “Note 8. Long-Term Debt”). The forward currency exchange contract relates to £31.5 million swap related to the proceeds to be received from the sale of Windcat Workboats (see “Note 4. Equipment Acquisitions and Dispositions”).

Fair Value Measurements

12 Months Ended

Dec. 31, 2020

Fair Value Disclosures [Abstract]

Fair Value Measurements

11.	FAIR VALUE MEASUREMENTS

The fair value of an asset or liability is the price that would be received to sell an asset or transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The Company utilizes a fair value hierarchy that maximizes the use of observable inputs and minimizes the use of unobservable inputs when measuring fair value and defines three levels of inputs that may be used to measure fair value. Level 1 inputs are quoted prices in active markets for identical assets or liabilities. Level 2 inputs are observable inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly, including quoted prices for similar assets or liabilities in active markets, quoted prices in markets that are not active, inputs other than quoted prices that are observable for the asset or liability, or inputs derived from observable market data. Level 3 inputs are unobservable inputs that are supported by little or no market activity and are significant to the fair value of the assets or liabilities.

The Company’s financial assets and liabilities as of December 31 that are measured at fair value on a recurring basis were as follows (in thousands):

	Level 1		Level 2		Level 3⁽¹⁾
2020
LIABILITIES
Derivative instruments (included in other current liabilities)	$	—	$	4,591	$	—
Conversion Option Liability on Convertible Senior Notes		—		—		2
2019
ASSETS
Construction reserve funds		12,893		—		—
LIABILITIES
Derivative instruments (included in other current liabilities)		—		2,925		—
Conversion Option Liability on Convertible Senior Notes		—		—		5,205

(1)	For the year ended December 31, 2020, the Company recognized a $5.2 million gain in the fair market valuation of the Conversion Option on the Convertible Senior Notes, as valued by an independent third-party.

Level 3 Measurement. The fair value of the conversion option liability on the Convertible Senior Notes is estimated with significant inputs that are both observable and unobservable in the market and therefore is considered a Level 3 fair value measurement. The Company used a binomial lattice model that assumes the holders will maximize their value by finding the optimal decision between redeeming at the redemption price or converting into shares of Common Stock. This model estimates the fair value of the conversion option as the differential in the fair value of the notes including the conversion option compared with the fair value of the notes excluding the conversion option. The significant observable inputs used in the fair value measurement include the price of Common Stock and the risk-free interest rate. The significant unobservable inputs are the estimated Company credit spread and Common Stock volatility, which were based on comparable companies in the marine transportation and energy industries.

The estimated fair value of the Company’s other financial assets and liabilities as of December 31 were as follows (in thousands):

			Estimated Fair Value
	Carrying Amount		Level 1		Level 2		Level 3
2020
ASSETS
Cash, cash equivalents and restricted cash	$	36,018	$	36,018	$	—	$	—
Investments, at cost, in 50% or less owned companies (included in other assets)		132	see below
LIABILITIES
Long-term debt, including current portion		472,887		—		470,561		—
2019
ASSETS
Cash, cash equivalents and restricted cash	$	84,486	$	84,486	$	—	$	—
Investments, at cost, in 50% or less owned companies (included in other assets)		132	see below
LIABILITIES
Long-term debt, including current portion		373,516		—		356,086		—

The carrying value of cash, cash equivalents and restricted cash approximates fair value. The fair value of the Company’s long-term debt was estimated by using discounted cash flow analysis based on estimated current rates for similar types of arrangements. It was not practicable to estimate the fair value of the Company’s investments, at cost, in 50% or less owned companies because of the lack of a quoted market price and the inability to estimate fair value without incurring excessive costs. Considerable judgment was required in developing certain of the estimates of fair value and, accordingly, the estimates presented herein are not necessarily indicative of the amounts that the Company could realize in a current market exchange.

The Company’s non-financial assets and liabilities that were measured at fair value during the years ended December 31 were as follows (in thousands):

	Level 1		Level 2		Level 3
2020
ASSETS
Property and equipment:
Liftboats	$	—	$	43,005	$	—
2019
ASSETS
Property and equipment:
AHTS	$	—	$	520	$	—
FSVs		—		1,858		—

Property and equipment. During the years ended December 31, 2020, 2019 and 2018 the Company recognized impairment charges of $18.8 million, $12.0 million, and $14.6 million, respectively, associated with certain offshore support vessels. The Level 2 fair values were determined based on the contracted sales prices of the property and equipment, sales prices of similar property and equipment or scrap value, as applicable. The Level 3 fair values were determined based on third-party valuations using significant inputs that are unobservable in the market. Due to limited market transactions, the primary valuation methodology applied by the appraisers was an estimated cost approach less estimated economic depreciation for comparably aged and conditioned assets less estimated economic obsolescence based on market data or utilization and rates per day worked trending of the vessels since 2014.

Investments, at equity, in 50% or less owned companies. During the year ended December 31, 2020, the Company marked two of its investments in 50% or less owned companies, Seabulk Tims I and Offshore Vessel Holdings, to zero due to a return of funds that exceeded the carrying value of the investment and continued losses, respectively. The Company did not make any further adjustments to any of its investments in 50% or less owned companies.

Warrants And Rights Note Disclosure [Abstract]

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Warrants

12 Months Ended

Dec. 31, 2020

Warrants

12.

WARRANTS

In connection with various transactions, the Company issued 2,560,456 warrants to purchase shares of Common Stock at an exercise price of $0.01 per share (“Warrants”), of which 1,488,292 remain outstanding as of December 31, 2020.

On September 1, 2020 and September 18, 2020, 255,307 and 83,367 Warrants were exercised, respectively, for a penny per share, resulting in 1,488,292 Warrants outstanding as of December 31, 2020. In connection with the exercise of Warrants on September 18, 2020, 354 shares of Common Stock were withheld as payment for the exercise price of the exercised Warrants.

On May 28, 2019 and June 14, 2019, 380,000 and 64,440 Warrants were exercised, respectively, for a penny per share, resulting in 1,826,966 Warrants outstanding as of December 31, 2019. In connection with the exercise of Warrants on June 14, 2019, 49 shares of Common Stock were withheld as payment for the exercise price of the exercised Warrants.

Stockholders' Equity

12 Months Ended

Dec. 31, 2020

Equity [Abstract]

Stockholders' Equity

13.	STOCKHOLDERS' EQUITY

The Company has previously registered 2,174,000 shares of Common Stock for issuance under the SEACOR Marine Holdings Inc. 2017 Equity Incentive Plan (the “2017 Plan”). The Company’s shareholders approved the SEACOR Marine Holdings Inc. 2020 Equity Incentive Plan (the “2020 Plan”) at the annual meeting of shareholders held on June 9, 2020 (the “Approval Date”), which authorized the issuance of 2,080,000 shares of Common Stock under the 2020 Plan. On June 9, 2020 the Company filed a registration statement on Form S-8 with the Securities and Exchange Commission (“SEC”) with respect to the registration of 2,114,821 shares of Common Stock, representing the 2,080,000 shares of Common Stock approved by the Company’s shareholders for issuance under the 2020 Plan, plus 24,821 shares of Common Stock remaining available for issuance under the 2017 Equity Incentive Plan as of the Approval Date that will be available for issuance under the 2020 Plan, plus Common Stock subject to awards outstanding under the 2017 Plan, that pursuant to the terms of the 2017 Plan and the 2020 Plan, may be available for future issuance under the 2020 Plan.

On March 20, 2020, SEACOR LB Holdings LLC, an indirect wholly-owned subsidiary of SEACOR Marine (“SEACOR LB Holdings”), entered into a membership interest purchase agreement with SEACOR Marine, Montco Offshore, LLC (“Montco”) and Lee Orgeron, the principal of Montco, pursuant to which SEACOR LB Holdings purchased the 28% minority equity interest in Falcon Global Holdings held by Montco in exchange for 900,000 shares of Common Stock issued to Montco as consideration in a private placement. The purchase resulted in the Company owning 100% of Falcon Global Holdings.

On May 28, 2019 and June 8, 2019, 380,000 and 64,440 Warrants were exercised, respectively, for a penny per share. In connection with the exercise of Warrants on June 14, 2019, 49 shares of Common Stock were withheld as payment for the exercise price of the exercised Warrants.

On January 25, 2019, Seabulk Overseas Transport, Inc., a wholly owned subsidiary of SEACOR Marine (“Seabulk Overseas”), acquired a 6.25% minority interest in Windcat Workboats that it did not previously own upon the exercise of certain put options by one of the two minority owners pursuant to the terms of a subscription and shareholders agreement, as amended (the “Subscription and Shareholders Agreement”), in exchange for consideration of £1.6 million (approximately $2.0 million) in cash. The Company acquired the other 6.25% minority interest in Windcat Workboats that the Company did not already own on March 15, 2019 in exchange for consideration of 50,000 shares of Common Stock and €1.2 million (approximately $1.4 million) in cash. The Common Stock was issued in a private placement in reliance upon the exemption from registration provided by Section 4(a)(2) of the Securities Act. The two acquisitions resulted in Seabulk Overseas owning (and SEACOR Marine indirectly owning) 100% of Windcat Workboats.

On January 9, 2019, certain indirect wholly owned subsidiaries of SEACOR Marine acquired three FSVs in exchange for the private placement of 603,872 shares of Common Stock to domestic U.S. holders affiliated with the McCall family of Louisiana. The value of the vessels and the Common Stock was $7.8 million based on the closing price of a share of Common Stock on the NYSE on the day of the exchange. The Common Stock was issued in reliance upon the exemption from registration provided by Section 4(a)(2) of the Securities Act. The Company has operated the acquired vessels for the past ten years under a revenue sharing pooling agreement that included four of its owned FSVs of similar specification. In accordance with its terms, this pooling agreement was terminated.

On January 1, 2019, the Company adopted ASC 842 regarding the recording of lease on the balance sheet. This adoption resulted in an increase of $10.4 million, net of tax, to the Company’s opening retained earnings for the current period.

Noncontrolling Interests in Subsidiaries

12 Months Ended

Dec. 31, 2020

Noncontrolling Interest [Abstract]

Noncontrolling Interests in Subsidiaries

14.	NONCONTROLLING INTERESTS IN SUBSIDIARIES

Noncontrolling interests in the Company’s consolidated subsidiaries as of December 31 were as follows (in thousands):

	Noncontrolling Interests				2020		2019
Falcon Global Holdings		—	%	⁽¹⁾	$	—	$	21,119
Other		1.8	%			319		313
					$	319	$	21,432

⁽¹⁾	^{Before March 20, 2020, noncontrolling interest was}²⁸^%^.

Falcon Global Holdings. Prior to March 20, 2020, the Company held 72% of the equity interest in Falcon Global Holdings. On March 20, 2020, the Company completed the acquisition of the remaining 28% minority interest in Falcon Global Holdings, resulting in the Company’s 100% ownership of Falcon Global Holdings. Consideration paid by the Company was 900,000 shares of Common Stock issued in a private placement to the seller of the minority interest, Montco. Prior to the acquisition of the remaining noncontrolling interest in Falcon Global Holdings the net loss attributable to Falcon Global Holdings was $16.6 million, of which $4.6 million was attributable to noncontrolling interest.

Savings and Multi-employer Pension Plans

12 Months Ended

Dec. 31, 2020

Compensation And Retirement Disclosure [Abstract]

Savings and Multi-employer Pension Plans

15.	SAVINGS AND MULTI-EMPLOYER PENSION PLANS

SEACOR Marine Savings Plan. On January 1, 2016, the Company’s eligible U.S. based employees were transferred from the SEACOR Holdings sponsored defined contribution plan to the “SEACOR Marine 401(k) Plan,” a new Company sponsored defined contribution plan (the “Savings Plan”). Effective upon the June 1, 2017 Spin-off, the Company discontinued its contribution to the Savings Plan up until January 1, 2019, at which time the Company’s contribution were limited to 1% of an employee’s wages. In 2020, the Company increased its contributions to 2% of an employee’s wages. The Savings Plan costs for the year ended December 31, 2020 and 2019 were $0.3 million and $0.2 million, respectively.

MNOPF and MNRPF. Certain of the Company’s subsidiaries are participating employers in two industry-wide, multi-employer, defined benefit pension funds in the United Kingdom: the U.K Merchant Navy Officers Pension Fund (“MNOPF”) and the U.K. Merchant Navy Ratings Pension Fund (“MNRPF”). The Company’s participation in the MNOPF began with the acquisition of the Stirling group of companies (the “Stirling Group”) in 2001 and relates to certain officers employed between 1978 and 2002 by the Stirling Group and/or its predecessors. The Company’s participation in the MNRPF also began with the acquisition of the Stirling Group in 2001 and relates to ratings employed by the Stirling Group and/or its predecessors through today. Both of these plans are in deficit positions and, depending upon the results of future actuarial valuations, it is possible that the plans could experience funding deficits that will require the Company to recognize payroll related operating expenses in the periods invoices are received.

Under the direction of a court order, any funding deficit of the MNOPF is to be remedied through funding contributions from all participating current and former employers. Prior to 2015, the Company was invoiced and expensed $19.4 million for its allocated share of the then cumulative funding deficits, including portions deemed uncollectible due to the non-existence or liquidation of certain former employers. The invoiced amounts were re-paid in full, other than with respect to $2.6 million invoiced in 2013, for which the Company had a repayment plan with the trustees of the MNOPF to repay such invoice in full by December 31, 2023. As of December 31, 2020, the remaining liability due to the MNOPF had been settled in full.

On November 7, 2018, the Company received notice from MNOPF that a deficit of £9.0 million existed but noted that the trustee did not propose to collect any additional funds in respect of such deficit. Depending on the results of future valuations, it is possible that the MNOPF will experience further funding deficits requiring the Company to recognize payroll related expenses in the periods the notice is received.

The cumulative funding deficits of the MNRPF were being recovered by additional annual contributions from current employers that were subject to adjustment following the results of future tri-annual actuarial valuations. In 2015, the Company was invoiced and expensed $6.9 million for its share of a funding deficit in the MNRPF. The Company had a repayment plan with the trustees of the MNRPF for the amount to be repaid in full by October 30, 2018 and the amounts were settled by that date. On July 20, 2018, the Company was notified of additional contributions due and recognized in the second quarter of 2018 payroll related expenses of $1.2 million (£0.9 million) for its allocated share of the cumulative funding deficit including portions deemed uncollectible due to the non-existence or liquidation of certain former employers. As of December 31, 2020, all invoices related to the MNRPF have been settled in full. Depending upon the results of future actuarial valuations it is possible that the plan could experience further funding deficits that will require the Company to recognize payroll related operating expenses for those periods.

Other Plans. Certain employees participate in other defined contribution plans in various international regions. During the years ended December 31, 2020, 2019 and 2018, the Company incurred costs, primarily from employer matching contributions of $0.4 million, $0.3 million and $0.2 million, respectively.

The entire disclosure for retirement benefits.

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Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Share Based Compensation

12 Months Ended

Dec. 31, 2020

Share Based Compensation

16.	SHARE BASED COMPENSATION

Equity Incentive Plan. During 2017, the Company adopted the SEACOR Marine Holdings Inc. 2017 Equity Incentive Plan (the “2017 Plan”). The 2017 Plan authorizes the Compensation Committee, or another committee designated by the Board and made up of two or more non-employee directors and outside directors, to provide equity-based or other incentive-based compensation for the purpose of attracting and retaining the Company and its affiliates’ directors, employees and certain consultants, and providing those directors, employees and consultants incentive opportunities and rewards for superior performance. The Board has authorized the issuance of 2,174,000 shares of Common Stock in connection with awards pursuant to the 2017 Plan, which was equal to 10% of the total number shares of Common Stock outstanding at the time of authorization. The types of awards under the 2017 Plan may include stock options, stock appreciation rights, restricted stock and restricted stock units, performance awards and other stock-based awards. The Company’s shareholders approved the SEACOR Marine Holdings Inc. 2020 Equity Incentive Plan (the “2020 Plan”) at the annual meeting of shareholders held on June 9, 2020 (the “Approval Date”), which authorized the issuance of 2,080,000 shares of Common Stock under the 2020 Plan. On June 9, 2020 the Company filed a registration statement on Form S-8 with the SEC with respect to the registration of 2,114,821 shares of Common Stock, representing the 2,080,000 shares of Common Stock approved by the Company’s shareholders for issuance under the 2020 Plan, plus 24,821 shares of Common Stock remaining available for issuance under the 2017 Plan as of the Approval Date that will be available for issuance under the 2020 Plan, plus shares of Common Stock subject to awards outstanding under the 2017 Plan, that pursuant to the terms of the 2017 Plan and the 2020 Plan, may be available for future issuance under the 2020 Plan. As of December 31, 2020, a total of 1,928,832 shares of Common Stock remained available for issuance under the 2020 Plan.

Restricted stock typically vests from one to four years after the date of grant and options to purchase shares of Common Stock typically vest and become exercisable from one to four years after date of grant. Options to purchase shares of Common Stock granted under the 2017 Plan and the 2020 Plan expire no later than the tenth anniversary of the date of grant. In the event of a participant’s death, retirement, termination by the Company without cause or a change in control of the Company, as defined in the 2017 Plan, restricted stock vests immediately and in the event of participant’s death or retirement, options to purchase shares of Common Stock vest and become immediately exercisable.

Distribution of SEACOR Marine Restricted Stock by SEACOR Holdings. Certain officers and employees of the Company previously received compensation through participation in SEACOR Holdings share award plans. Pursuant to the Employee Matters Agreement with SEACOR Holdings, participating Company personnel vested in all outstanding SEACOR Holdings share awards upon the Spin-off in 2017 and received SEACOR Marine restricted stock from the Spin-off distribution in connection with outstanding SEACOR Holdings restricted stock held. Therefore, the Company paid SEACOR Holdings $2.7 million upon completion of the Spin-off for the distribution of 120,693 shares of SEACOR Marine restricted stock, which is being amortized over the participants’ remaining original vesting periods.

Employee Stock Purchase Plan. During 2017, the Company adopted the SEACOR Marine Holdings Inc. 2017 Employee Stock Purchase Plan (the “Marine ESPP”). The Marine ESPP, if implemented by the Company’s Board of Directors, will permit the Company to offer shares of its Common Stock for purchase by eligible employees at a price equal to 85% of the lesser of (i) the fair market value of a share of its Common Stock on the first day of the offering period or (ii) the fair market value of a share of its Common Stock on the last day of the offering period. There are 300,000 shares of the Company’s Common Stock reserved for issuance under the Marine ESPP during the ten years following its adoption.

Share Award Transactions. The following transactions have occurred in connection with the Company’s share-based compensation under the 2017 Plan and the 2020 Plan during the years ended December 31:

	2020			2019
Director Stock Awards Granted		59,900			30,197

Restricted Stock Activity:
Outstanding as of the beginning of year		303,609			192,346
Granted		289,452	⁽¹⁾		245,400
Vested		143,697			131,937
Forfeited		12,650			2,200
Outstanding as of the end of year		436,714			303,609

Stock Option Activity:
Outstanding as of the beginning of year		913,569			805,566
Granted		261,972			230,503
Exercised		—			113,750
Forfeited		55,000			8,750
Outstanding as of the end of year		1,120,541			913,569

(1)	Excludes 240,800 grants of performance-based stock units that are not considered outstanding until such time that they become probable to vest.

During the year ended December 31, 2020, the Company recognized $4.8 million of compensation expense related to stock awards, restricted stock and stock options granted to employees and directors under the 2017 Plan and the 2020 Plan. As of December 31, 2020, the Company had approximately $4.7 million in total unrecognized compensation costs. The weighted average period over which the compensation cost of non-vested awards will be recognized is approximately 1.24 and 0.89 years for restricted stock and stock options, respectively.

During the year ended December 31, 2019, the Company recognized $5.3 million of compensation expense related to stock awards, restricted stock and stock options granted to employees and Directors under the 2017 Plan. As of December 31, 2018, the Company had approximately $6.5 million in total unrecognized compensation costs.

During the year ended December 31, 2018, the Company recognized $4.4 million of compensation expense related to stock awards, restricted stock and stock options granted to employees and Directors under the 2017 Plan. As of December 31, 2018, the Company had approximately $6.8 million in total unrecognized compensation costs.

The weighted average fair value of restricted stock granted under the 2017 Plan and the 2020 Plan were $6.40 and $13.28 for the year ended December 31, 2020 and 2019, respectively. The fair value was based the closing price of the Company’s stock on the day of the grant. The weighted average fair value of stock options granted under the 2017 Plan and the 2020 Plan was $3.60 and $8.73 for the year ended December 31, 2020 and 2019, respectively. The fair value of each option granted during the years ended December 31, 2020 and 2019, was estimated on the date of grant using the Black-Scholes option pricing model with the following assumptions: (a) no dividend yield; (b) weighted average expected volatility of 76.1 and 51.1, respectively; (c) weighted average discount rate of 0.52% and 2.1%, respectively; and (d) expected life of 9.92 and 9.75 years, respectively. The intrinsic value of stock options exercised during 2019 was $1.6 million. There were no stock options exercised in 2020.

During the year ended December 31, 2020, the number of shares and the weighted average grant price of restricted stock transactions were as follows:

	Restricted Stock
	Number of Shares		Weight Average Grant Price
Non-Vested as of December 31, 2019		303,609	$	20.46
Granted		289,452		6.81
Vested		143,697		13.43
Forfeited		12,650		12.30
Non-Vested as of December 31, 2020		436,714		11.60

During the year ended December 31, 2020, the number of shares and the weighted average exercise price on stock option transactions were as follows:

	Stock Options
	Number of Shares		Weight Average Grant Price
Non-Vested as of December 31, 2019		913,569	$	14.81
Granted		261,972		3.68
Exercised		—		—
Forfeited		55,000		13.43
Non-Vested as of December 31, 2020		1,120,541		12.49
Exercisable as of December 31, 2020⁽¹⁾		716,965		13.03

(1)	The weighted average remaining contractual term is 8.18 years.

As of December 31, 2020, there was no aggregate intrinsic value for options outstanding.

Related Party Transactions

12 Months Ended

Dec. 31, 2020

Related Party Transactions

17.	RELATED PARTY TRANSACTIONS

Transactions with SEACOR Holdings. In connection with the Spin-off, SEACOR Marine entered into certain agreements with SEACOR Holdings that govern SEACOR Marine’s relationship with SEACOR Holdings following the Spin-off, including a Distribution Agreement, two Transition Services Agreements, an Employee Matters Agreement and a Tax Matters Agreement.

As of December 31, 2020, SEACOR Holdings had guaranteed $8.1 million for various obligations of the Company, including performance obligations under sale-leaseback arrangements (see “Note 7. Leases”). As of December 31, 2019 and 2018, SEACOR Holdings had guaranteed $22.8 million and $40.6 million, respectively, for various obligations of the Company, including performance obligations under sale-leaseback arrangements and invoiced amounts for funding deficits under the MNOPF (see “Note 15. Savings and Multi-Employer Pension Plans”). Pursuant to the Transition Services Agreement with SEACOR Holdings, SEACOR Holdings charges the Company a fee of 0.5% on outstanding guaranteed amounts, which declines as the guaranteed obligations are settled by the Company. The Company recognized guarantee fees in connection with sale-leaseback arrangements of $0.1 million, $0.2 million and $0.3 million during 2020, 2019 and 2018, respectively. in the accompanying consolidated statements of loss. Guarantee fees paid to SEACOR Holdings for all other obligations are recognized as SEACOR Holdings guarantee fees in the accompanying consolidated statements of loss.

On June 26, 2020, the Company entered into a Tax Refund and Indemnification Agreement (the “Tax Refund Agreement”) with SEACOR Holdings Inc. (“SEACOR Holdings”), the Company’s former parent company. The Tax Refund Agreement will enable the Company to utilize net operating losses (“NOLs”) generated in 2018 and 2019 to claim refunds for tax years prior to the Company’s spin-off from SEACOR Holdings in 2017 (at which time the Company was included in SEACOR Holdings consolidated tax returns) that are now permitted to be carried back pursuant to the provisions of the CARES Act and for which SEACOR Holdings needs to claim the refund on behalf of the Company. As a result, the Company expects to receive cash tax refunds of approximately $31.2 million within the next 12 months, subject to the refund schedule of the IRS. The IRS has been recently experiencing delays in processing refund claims due in part to the COVID-19 pandemic. SEACOR Holdings will retain certain of the funds to facilitate tax savings realized by SEACOR Holdings of no less than 35% of the amount of its own 2019 NOLs. Additionally, a $3.0 million transaction fee was paid to SEACOR Holdings concurrently with the signing of the Tax Refund Agreement as consideration for its cooperation in connection with the filing of the applicable tax refund returns. As of December 31, 2020, the Tax Refund Agreement does not restrict the use of approximately $23.1 million of the refund, with the remaining approximately $8.1 million required to be deposited into an account to be used solely to satisfy certain of the Company’s obligations that remain guaranteed by SEACOR Holdings which primarily relate to vessel operating leases. Two of these vessel operating leases expired in the fourth quarter of 2020, reducing the remaining guarantee on the three remaining vessels to $7.0 million. The remaining three vessel operating leases that SEACOR Holdings guarantees expire in 2021 and the Company will apply the amount deposited to satisfy these obligations.

Following the completion of the Spin-off, the Company is no longer charged for management fees or shared services allocation (see below) for administrative support by SEACOR Holdings; however, the Company continued to be supported by SEACOR Holdings for corporate services pursuant to the Transition Services Agreements with SEACOR Holdings under which it was initially charged $6.3 million annually for these services. The fees incurred have declined as the services and functions provided by SEACOR Holdings are terminated and replicated within the Company. For the year ended December 31, 2019 and 2018 the Company incurred fees of $0.6 million, and $4.5 million, respectively, for these services that were recognized as additional administrative and general expenses in the accompanying consolidated statements of loss. There were no services provided or any fees during 2020.

Transactions regarding OSV Partners. Charles Fabrikant (Non-Executive Chairman of SEACOR Marine), John Gellert (President, Chief Executive Officer and Director of SEACOR Marine), Jesús Llorca (Executive Vice President and Chief Financial Officer of SEACOR Marine), other members of the Company’s management and Board of Directors and other unaffiliated individuals indirectly invested in OSV Partners by purchasing interests from three unaffiliated limited partners of OSV Partners who wished to dispose of their interests. During 2018, OSV Partners (i) raised $7.5 million of cash: $5.0 million in the form of second lien debt and $2.5 million in the form of class A preferred interests and (ii) obtained commitments from the limited partners of OSV Partners for an additional $2.5 million in the form of Class A preferred interests. On December 18, 2019, the general partner of OSV Partners called these remaining commitments. As of December 31, 2020, limited liability companies controlled by management and Directors of the Company had invested $1.5 million, or 3.9%, in the limited partner interests; $0.3 million, or 5.0%, in preferred interests; $0.2 million, or 3.9%, in the form of second lien debt; and $0.2 million, or 3.9%, in the Class A preferred interests of OSV Partners. As of December 31, 2020, the investments of Messrs. Fabrikant, Gellert and Llorca in such limited liability companies were $0.3 million, $0.4 million and $0.2 million, respectively, representing 39.6% of such limited liability companies’ membership interests. The general partner of OSV Partners is a joint venture managed by the Company and an unaffiliated third-party. The Company owns 30.4% in the limited partner interests, 38.6% in the preferred interests, 43.0% of the second lien debt, and 43.0% in the Class A preferred interest of OSV Partners. The Company agreed to not charge OSV Partners the management fee it is contractually entitled to through December 31, 2020.

Transactions regarding Windcat Workboats. On January 25, 2019, Seabulk Overseas acquired a 6.25% minority interest in Windcat Workboats that it did not previously own upon the exercise of a put option by one of the two minority owners, each of whom was a member (or an affiliate of a member) of management of Windcat Workboats at the time of acquisition, pursuant to the terms of a certain Subscription and Shareholders Agreement, as amended, for consideration of £1.6 ($2.0 million). On March 15, 2019, Seabulk Overseas acquired the other 6.25% minority interest in Windcat Workboats that it did not previously own for consideration of 50,000 shares of Common Stock and €1.2 million (approximately $1.4 million) in cash. The two acquisitions resulted in Seabulk Overseas owning 100% of Windcat Workboats, a consolidated subsidiary which owns and operates the Company’s CTV business that is primarily used to move personnel and supplies in Europe’s offshore wind markets.

On January 12, 2021, a wholly owned subsidiary of SEACOR Marine, completed the sale of the Windcat Workboats CTV business through the sale of 100% of the equity of Windcat Workboats to CMB N.V. pursuant to a Sale and Purchase Agreement entered into on December 18, 2020 (see “Note 1. Nature of Operations and Accounting Policies” and “Note 4. Equipment Acquisitions and Dispositions”).

Transactions with Carlyle. On December 1, 2015, the Company issued $175.0 million aggregate principal amount of its Convertible Notes to investment funds managed and controlled by Carlyle. Interest on the Convertible Notes is payable semi-annually on June 15 and December 15 of each year, commencing June 15, 2016 (see “Note 8. Long-Term Debt”).

Pursuant to the note purchase agreement for the Convertible Notes and the Investment Agreement, the Company must use reasonable best efforts, subject to its directors’ fiduciary duties, to cause a person designated by Carlyle to be appointed as a director on the Board of Directors, if Carlyle, solely as a result of the conversion of the Convertible Notes, collectively owns, continues to own, or would (upon conversion) own 10.0% or more of the Company’s outstanding shares of Common Stock. During 2017, Ferris Hussein served on the Board of Directors as the director designated by Carlyle until his resignation on April 17, 2018. Carlyle has not exercised this right subsequent to Mr. Hussein’s resignation but retains the right to appoint a member to the Board of Directors. Mr. Hussein has been designated by Carlyle to observe meetings of the Board of Directors pursuant to Carlyle’s observer rights under the Convertible Notes. This observation right will terminate at the time Carlyle owns less than $50.0 million in aggregate principal amount of the Convertible Notes or a combination of the Convertible Notes and our Common Stock representing less than 5.0% of the Company’s Common Stock outstanding on a fully diluted basis, assuming the conversion of all of the Convertible Notes and Warrants to purchase Common Stock held by Carlyle.

In April 2018, the Company entered into the following Exchange and other transactions with Carlyle pursuant to which:

•

the Company exchanged $50.0 million in principal amount of the Convertible Notes for Common Stock (or warrants to purchase an equivalent number of shares of Common Stock at an exercise price of $0.01 per share) at an exchange rate of 37.73 per $1,000 principal amount of the Notes (equivalent to an exchange price of $26.50) for a total of approximately 1.9 million shares of Common Stock including Common Stock issuable upon exercise of the Exchange Warrants (the “Exchange”);

•

the Company and Carlyle amended the $125.0 million in principal amount of Convertible Notes that remains outstanding after the Exchange to (i) increase the interest rate from 3.75% per annum to 4.25% per annum and (ii) extend the maturity of the Convertible Notes by 12 months to December 1, 2023;

•

Carlyle purchased 750,000 shares of Common Stock in a private placement whereby the Company issued an aggregate of 2,168,586 shares of Common Stock and warrants to purchase 674,164 shares of Common Stock at an exercise price of $0.01 per share in a private placement exempt from registration under the Securities Act (the “PIPE Issuance”) for aggregate consideration of $15.0 million; and

•

During 2020 and 2019, Carlyle exercised 83,367 and 64,440 warrants, respectively. As of December 31, 2020, Carlyle still has 1,488,292 outstanding warrants.

Transactions with CME. Mr. Alfredo Miguel Bejos, a Director of SEACOR Marine, currently serves as President and Chief Executive Officer of CME.

During 2020 and 2019, CME exercised 255,307 and 380,000 warrants, respectively. As of December 31, 2020, all of CME’s outstanding warrants have been exercised.

On December 20, 2018, MEXMAR Offshore, a joint venture that is 49.0% owned by a subsidiary of the Company and 51.0% owned by a subsidiary of CME, acquired UP Offshore. UP Offshore was acquired for nominal consideration. In connection with the acquisition, UP Offshore’s existing debt was refinanced with $95.0 million of new indebtedness composed of (i) a $70.0 million six-year debt facility provided by UP Offshore’s existing lenders that is non-recourse to the Company, CME or any of their respective subsidiaries, (ii) a $15.0 million loan from MexMar, a joint venture between CME and the Company, to fund capital expenditures on two vessels and (iii) a $10.0 million loan from MEXMAR Offshore to fund working capital requirements funded by an approximate $5.0 million capital contribution to MEXMAR Offshore by each of the Company and CME. Due to losses from equity earnings, the Company’s investment in MEXMAR Offshore was written down to $0 in 2019. In July 2020, MEXMAR Offshore purchased from a consortium of banks in Brazil, $70 million of UP Offshore’s debt for $5.5 million, of which the Company’s commitment was $2.7 million to fund this purchase. As of December 31, 2020, the Company had loaned its proportional share of this commitment to MEXMAR Offshore of $1.96 million. The Company funded its remaining commitment in February 2021.

The Company also participates in a variety of other joint ventures with CME, including MexMar, SEACOR Marlin and OVH. These agreements with MexMar were negotiated at arms-length in the ordinary course of business.

In 2019, the Company sold an FSV to OVH for $2.4 million through a seller’s finance agreement.

Transaction with Talos Energy Inc. Mr. Robert D. Abendschein, a Director of SEACOR Marine, currently serves as Executive Vice President and Head of Operations of Talos Energy Inc. (together with its subsidiaries and affiliates, “Talos Energy”). Talos Energy is a customer of the Company and its subsidiaries, primarily with respect to the chartering of liftboats and other vessels. The Company recognized $1.5 million, $3.2 million and $2.9 million in revenue with Talos Energy in 2020, 2019 and 2018, respectively.

Commitments and Contingencies

12 Months Ended

Dec. 31, 2020

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

18.	COMMITMENTS AND CONTINGENCIES

As of December 31, 2020, the Company’s unfunded capital commitments from continuing operations were $11.7 million for one PSV and miscellaneous vessel equipment. Of the unfunded capital commitments, $10.7 million is payable during 2021 and $1.0 million is payable during 2022. As of December 31, 2020, the Company had indefinitely deferred an additional $9.6 million of orders with respect to one FSV that the Company had previously reported as an unfunded capital commitments.

In December 2015, the Brazilian Federal Revenue Office issued a tax-deficiency notice to Seabulk Offshore do Brasil Ltda, an indirect wholly-owned subsidiary of SEACOR Marine (“Seabulk Offshore do Brasil”), with respect to certain profit participation contributions (also known as “PIS”) and social security financing contributions (also known as “COFINS”) requirements alleged to be due from Seabulk Offshore do Brasil (“Deficiency Notice”) in respect of the period of January 2011 until December 2012. In January 2016, the Company administratively appealed the Deficiency Notice on the basis that, among other arguments, (i) such contributions were not applicable in the circumstances of a 70%/30% cost allocation structure, and (ii) the tax inspector had incorrectly determined that values received from outside of Brazil could not be classified as expense refunds. The initial appeal was dismissed by the Brazilian Federal Revenue Office and the Company appealed such dismissal and is currently awaiting an administrative trial. Recently, a local Brazilian law was enacted that supports the Company’s position that such contribution requirements are not applicable, but it is uncertain whether such law will be taken into consideration with respect to administrative proceedings commenced prior to the enactment of the law. Accordingly, the success of Seabulk Offshore do Brasil in the administrative proceedings cannot be assured and the matter may need to be addressed through judicial court proceedings. The potential levy arising from the Deficiency Notice is R$18.12 million based on a historical potential levy of R$12.87 million (USD $3.5 million and USD $2.5 million, respectively, based on the exchange rate as of December 31, 2020).

For a discussion of the Company’s potential obligations with respect to the MNOPF and MNRPF, see “Note 15. Savings and Multi-Employer Pension Plan.”

In the normal course of its business, the Company becomes involved in various other litigation matters including, among other things, claims by third parties for alleged property damages and personal injuries. Management has used estimates in determining the Company’s potential exposure to these matters and has recorded reserves in its financial statements related thereto where appropriate. It is possible that a change in the Company’s estimates of that exposure could occur, but the Company does not expect such changes in estimated costs could have a material adverse effect on the Company’s business, financial position, results of operations, cash flows and prospects.

Major Customers and Segment Information

12 Months Ended

Dec. 31, 2020

Notes To Financial Statements [Abstract]

Major Customers and Segment Information

19.	MAJOR CUSTOMERS AND SEGMENT INFORMATION

During the year ended December 31, 2020, two customers, SEACOR Marine Arabia LLC, a joint venture through which vessels are in service to Saudi Aramco, and Exxon Mobil were each responsible for $30.7 million or 21% and $24.8 million or 17%, respectively, of the Company’s total consolidated operating revenues from continuing operations. During the year ended December 31, 2019, SEACOR Marine Arabia LLC was responsible for $30.8 million or 17% ($20.3 million or 11% from Zamil Offshore and $10.5 million or 6% from Saudi Aramco) of the Company’s total consolidated operating revenues from continuing operations. During the year ended December 31, 2018, SEACOR Marine Arabia LLC was responsible for $21.4 million or 12% ($12.2 million or 7% from Zamil Offshore and $9.2 million or 5% from Saudi Aramco) of the Company’s total consolidated operating revenues from continuing operations. Additionally, Exxon Mobil was responsible for revenues of $16.5 million or 9% and $3.1 million or 2% in 2019 and 2018, respectively.

For the years ended December 31, 2020, 2019 and 2018, the ten largest customers of the Company accounted for approximately 76%, 61%, and 57%, respectively, of the Company’s operating revenues from continuing operations. The loss of one or more of these customers could have a material adverse effect on the Company’s results of operations and cash flows.

For the years ended December 31, 2020, 2019 and 2018, approximately 89%, 75%, and 71%, respectively, of the Company’s operating revenues and ($6.6) million, ($13.0) million, and ($1.9) million, respectively, of equity in losses from 50% or less owned companies, net of tax, were derived from its continuing foreign operations.

The Company’s offshore support vessels are highly mobile and regularly and routinely move between countries within a geographic region of the world. In addition, these vessels may be redeployed among the geographic regions, subject to flag restrictions, as changes in market conditions dictate. Because of this asset mobility, operating revenues and long-lived assets in any one country and capital expenditures for long-lived assets and gains or losses on asset dispositions and impairments in any one geographic region are not considered meaningful.

The following tables summarize (in thousands) the operating results and property and equipment of the Company’s reportable segments. Direct vessel profit is the Company’s measure of segment profitability, a key metric in assessing the performance of its fleet. Direct vessel profit is defined as operating revenues less direct operating expenses excluding leased-in equipment expense. The Company utilizes direct vessel profit as its primary financial measure to analyze and compare the operating performance of its individual vessels, fleet categories, regions and combined fleet.

	United States (primarily Gulf of Mexico)			Africa (primarily West Africa)			Middle East and Asia			Latin America			Europe Continuing Operations			Total
For the year ended December 31, 2020
Operating Revenues:
Time charter	$	9,873		$	35,876		$	52,052		$	23,806		$	11,847		$	133,454
Bareboat charter		2,910			—			—			—			(55	)		2,855
Other		2,422			(465	)		2,157			1,084			330			5,528
		15,205			35,411			54,209			24,890			12,122			141,837
Direct Costs and Expenses:
Operating:
Personnel		10,065			10,552			18,188			6,698			2,845			48,348
Repairs and maintenance		1,655			5,175			5,232			2,131			468			14,661
Drydocking		1,167			2,014			759			329			—			4,269
Insurance and loss reserves		1,774			1,026			1,721			462			780			5,763
Fuel, lubes and supplies		1,172			2,940			2,706			990			320			8,128
Other		373			984			6,891			1,369			359			9,976
		16,206			22,691			35,497			11,979			4,772			91,145
Direct Vessel (Loss) Profit	$	(1,001	)	$	12,720		$	18,712		$	12,911		$	7,350			50,692
Other Costs and Expenses:
Operating:
Leased-in equipment	$	4,272		$	3,029		$	170		$	45		$	9			7,525
Administrative and general																	40,051
Depreciation and amortization	$	21,427		$	10,833		$	16,595		$	5,481		$	2,831			57,167
																	104,743
Losses on Asset Dispositions and Impairments, Net																	(17,588	)
Operating Loss																$	(71,639	)
As of December 31, 2020
Property and Equipment:
Historical cost	$	257,592		$	204,079		$	361,514		$	130,769		$	58,919		$	1,012,873
Accumulated depreciation		(134,391	)		(60,535	)		(75,349	)		(13,312	)		(7,951	)		(291,538	)
	$	123,201		$	143,544		$	286,165		$	117,457		$	50,968		$	721,335
Total Assets⁽¹⁾	$	164,656		$	153,399		$	289,314		$	179,942		$	74,495		$	861,806

(1)	Total assets exclude $105.6 million of corporate assets, and $50.2 million of assets held for sale.

	United States (primarily Gulf of Mexico)			Africa (primarily West Africa)			Middle East and Asia			Latin America			Europe Continuing Operations			Total
For the year ended December 31, 2019
Operating Revenues:
Time charter	$	38,955		$	44,160		$	54,312		$	11,460		$	8,165		$	157,052
Bareboat charter		1,562			—			—			3,569			—			5,131
Other		3,806			1,461			1,669			1,390			3,944			12,270
		44,323			45,621			55,981			16,419			12,109			174,453
Direct Costs and Expenses:
Operating:
Personnel		17,491			13,833			16,698			4,459			3,494			55,975
Repairs and maintenance		7,583			4,701			7,182			1,348			587			21,401
Drydocking		4,594			490			600			161			3			5,848
Insurance and loss reserves		2,370			1,051			1,449			311			441			5,622
Fuel, lubes and supplies		2,936			3,471			2,904			1,056			255			10,622
Other		393			4,354			3,095			1,182			1,031			10,055
		35,367			27,900			31,928			8,517			5,811			109,523
Direct Vessel Profit	$	8,956		$	17,721		$	24,053		$	7,902		$	6,298			64,930
Other Costs and Expenses:
Operating:
Leased-in equipment	$	10,894		$	3,090		$	173		$	10		$	1,673			15,840
Administrative and general																	39,791
Depreciation and amortization	$	21,947		$	10,404		$	16,400		$	6,205		$	2,210			57,166
																	112,797
Losses on Asset Dispositions and Impairments, Net																	(6,461	)
Operating Loss																$	(54,328	)
As of December 31, 2019
Property and Equipment:
Historical cost	$	297,392		$	207,107		$	292,446		$	57,534		$	44,545		$	899,024
Accumulated depreciation		(157,514	)		(57,136	)		(73,039	)		(16,239	)		(4,989	)		(308,917	)
	$	139,878		$	149,971		$	219,407		$	41,295		$	39,556		$	590,107
Total Assets⁽¹⁾	$	224,229		$	161,915		$	250,890		$	116,736		$	64,156		$	817,926

(1)	Total assets exclude $145.5 million of corporate assets, and $45.7 million of assets held-for-sale.

	United States (primarily Gulf of Mexico)			Africa (primarily West Africa)			Middle East and Asia			Latin America			Europe Continuing Operations			Total
For the year ended December 31, 2018
Operating Revenues:
Time charter	$	38,802		$	43,847		$	50,072		$	17,343		$	—		$	150,064
Bareboat charter		—			—			—			4,635			—			4,635
Other		14,762			7,661			(887	)		1,554			1,372			24,462
		53,564			51,508			49,185			23,532			1,372			179,161
Direct Costs and Expenses:
Operating:
Personnel		18,708			16,538			16,806			4,399			2,081			58,532
Repairs and maintenance		5,152			6,330			11,172			1,011			720			24,385
Drydocking		1,957			2,085			1,362			128			2,260			7,792
Insurance and loss reserves		2,922			1,096			1,371			495			86			5,970
Fuel, lubes and supplies		3,568			3,826			4,027			1,225			258			12,904
Other		393			4,313			3,980			1,130			188			10,004
		32,700			34,188			38,718			8,388			5,593			119,587
Direct Vessel Profit (Loss)	$	20,864		$	17,320		$	10,467		$	15,144		$	(4,221	)		59,574
Other Costs and Expenses:
Operating:
Leased-in equipment	$	8,240		$	4,281		$	224		$	5		$	214			12,964
Administrative and general																	41,616
Depreciation and amortization	$	23,227		$	10,453		$	18,762		$	7,908		$	1,069			61,419
																	115,999
Losses on Asset Dispositions and Impairments, Net																	(11,989	)
Operating Loss																$	(68,414	)
As of December 31, 2018
Property and Equipment:
Historical cost	$	432,336		$	184,361		$	306,897		$	124,177		$	26		$	1,047,797
Accumulated depreciation		(224,737	)		(55,206	)		(81,378	)		(57,002	)		(17	)		(418,340	)
	$	207,599		$	129,155		$	225,519		$	67,175		$	9		$	629,457
Total Assets⁽¹⁾	$	351,748		$	140,335		$	260,002		$	137,983		$	(28,450	)		861,618

(1)	Total assets exclude $153.1 million of corporate assets, and $88.2 million of assets held-for-sale.

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

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Discontinued Operations And Disposal Groups [Abstract]

Discontinued Operations

12 Months Ended

Dec. 31, 2020

Discontinued Operations

20.	DISCONTINUED OPERATIONS

On January 12, 2021, the Company completed the sale of Windcat Workboats, which on December 31, 2020 was classified as current assets held for sale. The Company’s discontinued operations as of December 31, 2019, consisted of both Windcat Workboats and Boston Putford Offshore Safety. The Company has no continuing involvement in either of these businesses, which is considered a strategic shift in the Company’s operations. Summarized selected operating result of the Company’s assets held for sale and discontinued operations were as follows for the years ended December 31, (in thousands):

	2020		2019
Assets from Discontinued Operations:
Current assets	$	10,138	$	9,603
Net property and equipment		34,580		31,447
Non-current assets		5,517		4,668
		50,235		45,718
Liability from Discontinued Operations:
Current liabilities	$	2,418	$	2,060
Long-term liabilities		28,509		25,480
	$	30,927	$	27,540

	Windcat Workboats						Boston Putford Offshore Safety
	2020			2019			2020		2019
Operating Revenues:
Time charter	$	29,383		$	25,249		$	—	$	41,214
Other revenue		2,305			1,790			—		45
		31,688			27,039			—		41,259
Costs and Expenses:
Operating		17,334			14,202			—		33,836
Direct Vessel Profit		14,354			12,837			—		7,423

General and Administrative Expenses		5,516			4,935			—		4,207
Lease Expense		628			318			—		60
Depreciation		6,166			6,846			—		3,504
Gains on Asset Dispositions and Impairments, Net		—			1,064			—		91
Operating Income (Loss)		2,044			1,802			—		(257	)
Other Income (Expense)
Interest income		59			56			—		11
Interest expense		(1,115	)		(1,100	)		—		(210	)
Foreign currency translation (loss) gain		(750	)		880			—		(75	)
Other, net		19			—			—		—
		(1,787	)		(164	)		—		(274	)
Operating Income (Loss) Before Equity Earnings of 50% or Less Owned Companies, Net of Tax		257			1,638			—		(531	)
Income Tax (Benefit) Expense		(86	)		57			—		(2	)
Operating Income (Loss) Before Equity Earnings of 50% or Less Owned Companies		343			1,581			—		(529	)
Equity in Earnings of 50% or Less Owned Companies, Net of Tax		21			155			—		168
Net Income (Loss) from Discontinued Operations	$	364		$	1,736		$	—	$	(361	)

Quarterly Financial Information (Unaudited)

12 Months Ended

Dec. 31, 2020

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Information

21.QUARTERLY FINANCIAL INFORMATION (UNAUDITED)

Selected financial information for interim quarterly periods is presented below (in thousands, except share data). Earnings (loss) per common share of SEACOR Marine Holdings Inc. are computed independently for each of the quarters presented and the sum of the quarterly earnings per share may not necessarily equal the total for the year.

	Three Months Ended
	Dec. 31,			Sept. 30,			June 30,			March 31,
2020
Operating Revenues	$	36,044		$	36,201		$	33,925		$	35,667
Operating Loss		(16,915	)		(13,179	)		(17,824	)		(23,721	)
Net (Loss) Income:
Continuing Operations		(38,898	)		(19,842	)		(6,668	)		(17,938	)
Discontinued Operations		51			1,765			602			(2,054	)
	$	(38,847	)	$	(18,077	)	$	(6,066	)	$	(19,992	)
Net Loss attributable to SEACOR Marine Holdings Inc:	$	(38,816	)	$	(18,081	)	$	(6,073	)	$	(15,945	)
Basic and Diluted (Loss) Income Per Common Share of SEACOR Marine Holdings Inc.
Continuing Operations	$	(1.54	)	$	(0.79	)	$	(0.26	)	$	(0.58	)
Discontinued Operations	$	—		$	0.07		$	0.02		$	(0.08	)
	$	(1.54	)	$	(0.72	)	$	(0.24	)	$	(0.66	)
2019
Operating Revenues	$	42,478		$	46,996		$	45,014		$	39,965
Operating Loss		(10,555	)		(5,566	)		(18,591	)		(19,616	)
Net (Loss) Income:
Continuing Operations		(19,439	)		(12,586	)		(31,632	)		(27,307	)
Discontinued Operations		(2,479	)		(5,654	)		1,368			(966	)
	$	(21,918	)	$	(18,240	)	$	(30,264	)	$	(28,273	)
Net Loss attributable to SEACOR Marine Holdings Inc:	$	(20,455	)	$	(18,444	)	$	(28,389	)	$	(25,549	)
Basic and Diluted (Loss) Income Per Common Share of SEACOR Marine Holdings Inc.
Continuing Operations	$	(0.76	)	$	(0.54	)	$	(1.27	)	$	(1.07	)
Discontinued Operations	$	(0.10	)	$	(0.24	)	$	0.06		$	(0.04	)
	$	(0.86	)	$	(0.78	)	$	(1.21	)	$	(1.11	)

121

Schedule II - Valuation and Qualifying Accounts

12 Months Ended

Dec. 31, 2020

Valuation And Qualifying Accounts [Abstract]

Schedule II - Valuation and Qualifying Accounts

SEACOR MARINE HOLDINGS INC.

SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS

For the Years Ended December 31, 2020, 2019 and 2018

(in thousands)

Description	Balance Beginning of Year		Reserves Acquired		Charges (Recoveries) to Cost and Expenses			Deductions			Balance End of Year
Year Ended December 31, 2020
Allowance for credit loss reserves (deducted from trade and notes receivable)	$	455	$	18	$	230		$	(121	)	$	582
Year Ended December 31, 2019
Allowance for credit loss reserves (deducted from trade and notes receivable)	$	860	$	—	$	(405	)	$	—		$	455
Year Ended December 31, 2018
Allowance for credit loss reserves (deducted from trade and notes receivable)	$	4,039	$	—	$	(928	)	$	(2,251	)	$	860

Nature of Operations and Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2020

Accounting Policies [Abstract]

Nature of Operations and Segmentation

Basis of Consolidation

Certain reclassifications were made to previously reported amounts in the consolidated financial statements and notes thereto to make them consistent with the current period presentation.

Use of Estimates

Revenue Recognition

	2020			2019			2018
Balance at beginning of year	$	4,755		$	1,327		$	10,104
Revenues deferred during the year		2,042			8,134			3,518
Revenues recognized during the year		(3,490	)		(4,706	)		(12,295	)
Balance at end of year	$	3,307		$	4,755		$	1,327

Cash Equivalents

Restricted Cash

Restricted Cash. Restricted cash primarily relates to banking facility requirements.

For the year ended December 31, cash, cash equivalents and restricted cash from continuing operations consists of:

	2020		2019
Cash	$	32,666	$	81,382
Restricted cash		3,352		3,104
Total	$	36,018	$	84,486

Trade and Other Receivables

Derivative Instruments

Concentrations of Credit Risk

Inventories

Inventories.

Property and Equipment

As of December 31, 2020, the estimated useful life (in years) of each of the Company’s major categories of new offshore support vessels was as follows:

Offshore Support Vessels:
CTVs		10
All other offshore support vessels (excluding crew transfer)		20

The Company’s property and equipment from continuing operations as of December 31 was as follows (in thousands):

	Historical Cost ⁽¹⁾		Accumulated Depreciation			Net Book Value
2020
Offshore support vessels:
AHTS⁽²⁾	$	50,189	$	(31,779	)	$	18,410
FSV⁽³⁾		375,747		(104,739	)		271,008
Supply		238,624		(15,991	)		222,633
Liftboats		321,751		(117,364	)		204,387
Crew transfer		3,163		(3,138	)		25
General machinery and spares		7,746		(7,733	)		13
Other ⁽⁴⁾		15,653		(10,794	)		4,859
	$	1,012,873	$	(291,538	)	$	721,335
2019
Offshore support vessels:
AHTS⁽²⁾	$	94,078	$	(73,095	)	$	20,983
FSV⁽³⁾		388,460		(101,295	)		287,165
Supply		44,958		(8,471	)		36,487
Specialty		14,805		(10,466	)		4,339
Liftboats		327,028		(93,166	)		233,862
Crew transfer		5,032		(4,518	)		514
General machinery and spares		7,650		(7,648	)		2
Other ⁽⁴⁾		17,013		(10,258	)		6,755
	$	899,024	$	(308,917	)	$	590,107

(1)	Includes property and equipment acquired in business acquisitions at acquisition date fair value, and net of the impact of recognized impairment charges.

(2)	Anchor Handling Towing Supply (“AHTS”).

(3)	Fast support vessels (“FSVs”).

(4)	Includes land, buildings, leasehold improvements, vehicles and other property and equipment.

Impairment of Long-Lived Assets and Impairment of 50% or Less Owned Companies

Business Combinations

Debt Discount and Issue Costs

Self-insurance Liabilities

Income Taxes

On June 26, 2020, the Company entered into the Tax Refund Agreement with SEACOR Holdings (see “Note 17. Related Party Transactions”).

Deferred Gains - Vessel Sale-Leaseback Transactions and Financed Vessel Sales

	2019			2018
Balance at beginning of year	$	11,026		$	23,553
Amortization of deferred gains included in operating expenses as reduction to rental expense		—			(8,037	)
Reclass of gain to Retained Earnings		(11,026	)		—
Recognition of deferred gains included in losses on asset dispositions and impairments, net		—			(4,490	)
Balance at end of year	$	—		$	11,026

	2019			2018
Balance at beginning of year	$	793		$	1,453
Amortization of deferred gains included in losses on asset dispositions and impairments, net		—			(25	)
Other		(793	)		(635	)
Balance at end of year	$	—		$	793

Foreign Currency Translation

Accumulated Other Comprehensive (Loss) Income

Accumulated Other Comprehensive (Loss) Income. The components of accumulated other comprehensive loss were as follows (in thousands):

	SEACOR Marine Holdings Inc. Stockholders' Equity									Noncontrolling Interests
	Foreign Currency Translation Adjustments			Derivative Gains (Losses) on Cash Flow Hedges, net			Total			Foreign Currency Translation Adjustments			Derivative Gains (Losses) on Cash Flow Hedges, net			Other Comprehensive (Loss) Income
Year Ended December 31, 2017	$	(13,195	)	$	702		$	(12,493	)	$	(1,357	)	$	1		$	(881	)
Other comprehensive loss		(2,277	)		(1,972	)		(4,249	)		(88	)		(12	)	$	(4,349	)
Income tax (expense)		—			(46	)		(46	)		—			—			(46	)
Year Ended December 31, 2018		(15,472	)		(1,316	)		(16,788	)		(1,445	)		(11	)	$	(4,395	)
Other comprehensive income		20,157			(1,994	)		18,163			—			—		$	18,163
Income tax benefi		—			173			173			—			—			173
Year Ended December 31, 2019		4,685			(3,137	)		1,548			(1,445	)		(11	)	$	18,336
Other comprehensive income		2,112			(870)			1,242			—			—		$	1,242
Income tax benefit (expense)		—			—			—			—			—			—
Year Ended December 31, 2020	$	6,797		$	(4,007	)	$	2,790		$	(1,445	)	$	(11	)	$	1,242

Loss Per Share

Recently Adopted Accounting Standards

Nature of Operations and Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2020

Nature Of Operation And Accounting Policies [Abstract]

Schedule of Deferred Revenues

	2020			2019			2018
Balance at beginning of year	$	4,755		$	1,327		$	10,104
Revenues deferred during the year		2,042			8,134			3,518
Revenues recognized during the year		(3,490	)		(4,706	)		(12,295	)
Balance at end of year	$	3,307		$	4,755		$	1,327

Schedule Of Cash Cash Equivalents And Restricted Cash From Continuing Operations

For the year ended December 31, cash, cash equivalents and restricted cash from continuing operations consists of:

	2020		2019
Cash	$	32,666	$	81,382
Restricted cash		3,352		3,104
Total	$	36,018	$	84,486

Schedule of Property and Equipment Useful Life

As of December 31, 2020, the estimated useful life (in years) of each of the Company’s major categories of new offshore support vessels was as follows:

Offshore Support Vessels:
CTVs		10
All other offshore support vessels (excluding crew transfer)		20

Summary of Property and Equipment from Continuing Operations

The Company’s property and equipment from continuing operations as of December 31 was as follows (in thousands):

	Historical Cost ⁽¹⁾		Accumulated Depreciation			Net Book Value
2020
Offshore support vessels:
AHTS⁽²⁾	$	50,189	$	(31,779	)	$	18,410
FSV⁽³⁾		375,747		(104,739	)		271,008
Supply		238,624		(15,991	)		222,633
Liftboats		321,751		(117,364	)		204,387
Crew transfer		3,163		(3,138	)		25
General machinery and spares		7,746		(7,733	)		13
Other ⁽⁴⁾		15,653		(10,794	)		4,859
	$	1,012,873	$	(291,538	)	$	721,335
2019
Offshore support vessels:
AHTS⁽²⁾	$	94,078	$	(73,095	)	$	20,983
FSV⁽³⁾		388,460		(101,295	)		287,165
Supply		44,958		(8,471	)		36,487
Specialty		14,805		(10,466	)		4,339
Liftboats		327,028		(93,166	)		233,862
Crew transfer		5,032		(4,518	)		514
General machinery and spares		7,650		(7,648	)		2
Other ⁽⁴⁾		17,013		(10,258	)		6,755
	$	899,024	$	(308,917	)	$	590,107

(1)	Includes property and equipment acquired in business acquisitions at acquisition date fair value, and net of the impact of recognized impairment charges.

(2)	Anchor Handling Towing Supply (“AHTS”).

(3)	Fast support vessels (“FSVs”).

(4)	Includes land, buildings, leasehold improvements, vehicles and other property and equipment.

Schedule Of Deferred Gain Activity

Deferred gain activity related to these transactions for the years ended December 31 was as follows (in thousands):

	2019			2018
Balance at beginning of year	$	11,026		$	23,553
Amortization of deferred gains included in operating expenses as reduction to rental expense		—			(8,037	)
Reclass of gain to Retained Earnings		(11,026	)		—
Recognition of deferred gains included in losses on asset dispositions and impairments, net		—			(4,490	)
Balance at end of year	$	—		$	11,026

Activity related to these transactions for the years ended December 31 was as follows (in thousands):

	2019			2018
Balance at beginning of year	$	793		$	1,453
Amortization of deferred gains included in losses on asset dispositions and impairments, net		—			(25	)
Other		(793	)		(635	)
Balance at end of year	$	—		$	793

Schedule of Accumulated Other Comprehensive (Loss) Income

Accumulated Other Comprehensive (Loss) Income. The components of accumulated other comprehensive loss were as follows (in thousands):

	SEACOR Marine Holdings Inc. Stockholders' Equity									Noncontrolling Interests
	Foreign Currency Translation Adjustments			Derivative Gains (Losses) on Cash Flow Hedges, net			Total			Foreign Currency Translation Adjustments			Derivative Gains (Losses) on Cash Flow Hedges, net			Other Comprehensive (Loss) Income
Year Ended December 31, 2017	$	(13,195	)	$	702		$	(12,493	)	$	(1,357	)	$	1		$	(881	)
Other comprehensive loss		(2,277	)		(1,972	)		(4,249	)		(88	)		(12	)	$	(4,349	)
Income tax (expense)		—			(46	)		(46	)		—			—			(46	)
Year Ended December 31, 2018		(15,472	)		(1,316	)		(16,788	)		(1,445	)		(11	)	$	(4,395	)
Other comprehensive income		20,157			(1,994	)		18,163			—			—		$	18,163
Income tax benefi		—			173			173			—			—			173
Year Ended December 31, 2019		4,685			(3,137	)		1,548			(1,445	)		(11	)	$	18,336
Other comprehensive income		2,112			(870)			1,242			—			—		$	1,242
Income tax benefit (expense)		—			—			—			—			—			—
Year Ended December 31, 2020	$	6,797		$	(4,007	)	$	2,790		$	(1,445	)	$	(11	)	$	1,242

Transformation, Facility Restructuring and Severance Charges (Tables)

12 Months Ended

Dec. 31, 2020

Restructuring And Related Activities [Abstract]

Schedule of Components of Restructuring Charges

The components of restructuring charges for the years ended December 31, 2020 and 2019, were as follows (in thousands):

December 31, 2020

	United States (primarily Gulf of Mexico)		Africa (primarily West Africa)		Middle East and Asia		Latin America		Europe (primarily North Sea)		Total
Transformation Plan
Severance Charges	$	275	$	—	$	665	$	—	$	185	$	1,125
Other Charges		31		—		31		—		—		62
Total Charges	$	306		—	$	696		—	$	185	$	1,187

December 31, 2019

	United States (primarily Gulf of Mexico)		Africa (primarily West Africa)		Middle East and Asia		Latin America		Europe (primarily North Sea)		Total
Transformation Plan
Severance Charges	$	2,995	$	—	$	184	$	—	$	200	$	3,379
Other Charges		307		—		31		—		—		339
Total Charges	$	3,302		—	$	215		—	$	200	$	3,718

Business Acquisitions (Tables)

12 Months Ended

Dec. 31, 2020

Business Combinations [Abstract]

Summary of Purchase Price Allocation of Acquired Assets

The allocation of the purchase price for the Company’s acquired assets for the six months ended June 30 was as follows (in thousands):

Assets Acquired (In Thousands):			June 30, 2020
Current Assets				7,700
Fixed Assets				142,282
Current Liabilities				(23,929	)
Book Value of Debt Acquired	(100,759	)
Discount on Debt Acquired	25,190
Fair Value of Debt Acquired				(75,569	)
Total Cost Basis for Purchase				50,484
Purchase Price			$	(28,150	)
Acquisition costs				(112	)
Equity Investment In SEACOR Offshore Delta (f/k/a SEACOSCO)				(22,222	)
				(50,484	)

Equipment Acquisitions and Dispositions (Tables)

12 Months Ended

Dec. 31, 2020

Property Plant And Equipment [Abstract]

Schedule of Vessel Acquired and Disposed

	2020 ⁽¹⁾		2019 ⁽²⁾		2018 ⁽³⁾
FSV		—		2		6
Supply		4		2		5
Liftboat		—		—		—
		4		4		11

(1)	Excludes three CTVs as assets held for sale and seven PSVs acquired as part of the SEACOSCO Acquisition (See “Note 3. Business Acquisitions”).

(2)	Excludes two CTVs as assets held for sale.

(3)	Excludes two CTVs as assets held for sale.

	2020 ⁽¹⁾		2019		2018 ⁽²⁾
AHTS		2		1		1
FSV		4		5		9
Supply		1		5		—
CTV		—		—		—
Liftboats		1		3		2
Specialty		2		—		—
		10		14		12

(1)	Excludes three vessels that were previously removed from service (two AHTS vessels and one specialty vessel).

(2)	Excludes one CTV from assets held for sale.

Investments, at Equity, and Advances to 50% or Less Owned Companies (Tables)

12 Months Ended

Dec. 31, 2020

Schedule Of Investments [Abstract]

Equity Method Investments

Investments, at equity, and advances to 50% or less owned companies as of December 31 were as follows (in thousands):

	Ownership			2020		2019
MexMar		49.0	%	$	50,037	$	54,249
SEACOSCO⁽¹⁾		50.0	%		—		37,480
OSV Partners⁽²⁾		30.4	%		9,094		10,668
SEACOR Marlin		49.0	%		7,979		7,929
MEXMAR Offshore⁽³⁾		49.0	%		1,960		—
Offshore Vessel Holdings		49.0	%		2,388		7,905
Other	20.0% — 50.0%				3,850		2,600
				$	75,308	$	120,831

⁽¹⁾	^{^{The Company acquired the}^remaining^50%^{of the SEACOSCO Joint Venture that it did not own on June 30, 2020.}}

⁽²⁾^{The Company owns}^66.7^{% of the General Partner and}^29.7^{% of the limited Partner}^.

⁽³⁾^{This Joint Venture holds the investment in UP Offshore}^.

	2020		2019
Current assets	$	109,687	$	106,051
Noncurrent assets		259,424		607,541
Current liabilities		109,074		104,423
Noncurrent liabilities		115,626		331,357

	2020			2019			2018
Operating Revenues	$	160,781		$	136,690		$	105,163
Costs and Expenses:
Operating and administrative		142,228			116,517			75,529
Depreciation		27,044			27,412			25,359
		169,272			143,929			100,888
Loss on Asset Dispositions and Impairments, Net		—			(166	)		(262	)
Operating (Loss) Income	$	(8,491	)	$	(7,405	)	$	4,013
Net Loss	$	(18,229	)	$	(36,816	)	$	(14,861	)

Leases (Tables)

12 Months Ended

Dec. 31, 2020

Leases [Abstract]

Summary of Future Minimum Payments For Leases

As of December 31, 2020, future minimum payments for leases for the years ended December 31 were as follows (in thousands):

	Operating Leases			Finance Leases
2021	$	7,855		$	42
2022		639			39
2023		628			39
2024		559			36
2025		539			—
Years subsequent to 2025		4,215			—
		14,435			156
Interest component		(3,060	)		(15	)
		11,375			141
Current portion of long-term operating lease liabilities		(7,030	)		(36	)
Long-term operating lease liabilities	$	4,345		$	105

Summary of Components of Leases Expense

For the years ended December 31, the components of lease expense were as follows (in thousands):

	2020		2019
Operating lease expense ⁽¹⁾	$	6,205	$	13,442
Finance lease cost:
Amortization of finance lease asset ⁽¹⁾		11		—
Interest on lease liabilities ⁽²⁾		1		—
Short-term lease costs ⁽¹⁾		1,320		2,398
	$	7,537	$	15,840

⁽¹⁾	Included in selling, general and administrative expenses and amortization costs in the consolidated statements of loss.

⁽²⁾	Included in interest expense in the consolidated statements of loss.

Summary of Supplemental Cash Flow Information Related to Leases

For the year ended December 31, 2020, supplemental cashflow information related to leases were as follows (in thousands):

	2020
Operating cash flows from operating leases	$	14,785
Right-of-use assets obtained for operating lease liabilities		1,706
Right-of-use assets obtained for finance lease liabilities		140

Summary of Other Information Related to Leases

For the year ended December 31, 2020, other information related to leases were as follows:

	2020
Weighted average remaining lease term, in years - operating leases		7.6
Weighted average remaining lease term, in years - finance leases		4.2
Weighted average discount rate - operating leases		4.7	%
Weighted average discount - finance leases		5.3	%

Long-term Debt (Tables)

12 Months Ended

Dec. 31, 2020

Debt Disclosure [Abstract]

Schedule of Long-term Debt Obligations

The Company’s long-term debt obligations as of December 31 were as follows (in thousands):

	December 31,2020			December 31, 2019
Recourse Long-term debt⁽¹⁾:
Convertible Senior Notes	$	125,000		$	125,000
SEACOR Marine Foreign Holdings Credit Facility		100,750			113,750
Sea-Cat Crewzer III Term Loan Facility		21,653			24,128
SEACOR Offshore Delta (f/k/a SEACOSCO) Acquisition Debt		19,705			—
SEACOR Delta (f/k/a SEACOSCO) Shipyard Financing⁽²⁾		95,317			—
SEACOR Alpine Shipyard Financing⁽³⁾		31,103			10,534
SEACOR 88/888 Term Loan		5,500			5,500
BNDES Equipment Construction Finance Notes		-			3,332
Total recourse Long-term debt		399,028			282,244
Non-recourse Long-term debt⁽⁴⁾:
Falcon Global USA Term Loan Facility		102,349			102,349
Falcon Global USA Revolver		15,000			15,000
SEACOR 88/888 Term Loan		5,500			5,500
Total non-recourse Long-term debt		122,849			122,849
Total principal due for long-term debt		521,877			405,093
Current portion due within one year		(32,377	)		(17,802	)
Unamortized debt discount		(44,864	)		(26,343	)
Deferred financing costs		(4,126	)		(5,234	)
Long-term debt, less current portion	$	440,510		$	355,714
Long-Term Debt included in current liabilities associated with assets held for sale - Windcat Workboats Facilities	$	27,626		$	24,537

⁽¹⁾	^{Recourse debt represents debt issued by SEACOR Marine and/or its subsidiaries and guaranteed by SEACOR Marine as defined in the relevant debt agreements.}
⁽²⁾	^{SEACOR Delta Shipyard Financing includes vessel financing on the}^eight^{vessels acquired in the SEACOSCO Acquisition (see “Note 3.}^{Business Acquisitions}^”).
⁽³⁾	^{SEACOR Alpine Shipyard Financing includes vessel financing on the SEACOR Alps, the SEACOR Andes and the SEACOR Atlas vessels.}
⁽⁴⁾	^{Non-recourse debt represents debt issued by the Company’s Consolidated Subsidiaries with no recourse to SEACOR Marine or its other non-debtor subsidiaries, other than certain limited support obligations as defined in the respective debt agreements, which in aggregate are not considered to be material to the Company’s business and financial condition.}

Schedule of Long-term Debt Maturities

The Company’s contractual long-term debt maturities from continuing operations for the years ended December 31 were as follows (in thousands):

2021	$	32,377
2022		38,484
2023		244,983
2024		134,523
2025		11,365
Years subsequent to 2025		60,145
	$	521,877

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

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Schedule of Income before Income Tax, Domestic and Foreign

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2020

Income Tax Disclosure [Abstract]

Loss before income tax benefit and equity in earnings (losses) of 50% or less owned companies derived from U.S. and foreign companies for the years ended December 31 were as follows (in thousands):

	2020			2019			2018
United States	$	(83,560	)	$	(71,833	)	$	(72,540	)
Foreign		(17,748	)		(23,663	)		(28,675	)
Eliminations		3,201			11,022			8,782
	$	(98,107	)	$	(84,474	)	$	(92,433	)

Schedule of Components of Income Tax Expense (Benefit)

The components of income tax expense (benefit) for the years ended December 31 were as follows (in thousands):

	2020			2019			2018
Current:
Federal	$	(30,838	)	$	(6	)	$	5,987
State		123			(78	)		3
Foreign		5,533			5,005			3,307
		(25,182	)		4,921			9,297
Deferred:
Federal		2,435			(12,594	)		(21,466	)
State		(139	)		(224	)		(1,404	)
Foreign		(38	)		(72	)		110
		2,258			(12,890	)		(22,760	)
	$	(22,924	)	$	(7,969	)	$	(13,463	)

Schedule of Effective Income Tax Rate Reconciliation

The following table reconciles the difference between the statutory federal income tax rate for the Company and the effective income tax rate for the years ended December 31:

	2020			2019			2018
Statutory rate		(21.0	)%		(21.0	)%		(21.0	)%
U.S. federal income tax law changes		(11.8	)%		—	%		—	%
SEACOR Holdings share awards to Company personnel		0.3	%		—	%		0.2	%
Non-deductible expenses		—	%		—	%		—	%
Exclusion of foreign subsidiaries with accumulated losses and withholding tax		7.7	%		7.4	%		9.3	%
Noncontrolling interests		1.3	%		1.7	%		(1.6	)%
State taxes		—	%		(0.3	)%		(1.5	)%
Return to provision		(0.4	)%		2.8	%		(0.5	)%
Other		0.5	%		—	%		0.5	%
Effective Tax Rate		(23.4	)%		(9.4	)%		(14.6	)%

Schedule of Deferred Tax Assets and Liabilities

The components of net deferred income tax liabilities as of December 31 were as follows (in thousands):

	2020			2019
Deferred tax liabilities:
Property and equipment	$	58,676		$	63,827
Investments in 50% or Less Owned Companies		2,925			3,039
Other		4,819			10,612
Total deferred tax liabilities		66,420			77,478
Deferred tax assets:
Federal Net Operating Loss Carryforwards		23,061			28,664
Other		10,073			16,561
		33,134			45,225
Valuation Allowance		(2,536	)		(1,311	)
Total deferred tax assets		30,598			43,914
Net deferred tax liabilities	$	35,822		$	33,564

Derivative Instruments and Hedging Strategies (Tables)

12 Months Ended

Dec. 31, 2020

Derivative Instruments And Hedging Activities Disclosure [Abstract]

Schedule of Fair Value of Derivative Assets and Liabilities From Continuing Operations

The fair values of the Company’s derivative instruments from continuing operations as of December 31 were as follows (in thousands):

		2020				2019
	Balance Sheet Classification	Derivative Asset		Derivative Liability		Derivative Asset		Derivative Liability
Derivatives designated as hedging instruments:
Interest rate swap agreements (cash flow hedges)	Current	$	—	$	3,698	$	—	$	2,925
			—		3,698		—		2,925
Derivatives not designated as hedging instruments:
Forward Exchange Contract	Current		—		893		—		—
Conversion option liability on Convertible Senior Notes	Long-Term		—		2		—		5,205
		$	—	$	895	$	—	$	5,205

Effect of Derivative Instruments on Other Comprehensive Income (Loss)

The following tables reflect amounts recorded in Other Comprehensive Income (Loss) (“OCI”) and amounts reclassified from OCI to revenue and expense for the periods indicated:

	Losses Recognized in OCI on Derivatives (Effective Portion)
Derivatives in Cash Flow Hedging Relationships	2020			2019			2018
Interest rate swap contracts	$	(2,139	)	$	(1,901	)	$	(1,939	)
Joint venture interest rate swap contracts		(156	)		(645	)		(76	)
	Losses Reclassified from OCI into Income (Effective Portion)
Location of Loss	2020			2019			2018
Interest expense	$	1,425		$	552		$	31

Schedule of Gains (Losses) on Derivative Instruments not Designated as Hedging Instruments

The Company recognized gains (losses) on derivative instruments not designated as hedging instruments for the years ended December 31 as follows (in thousands):

	Derivative gains (losses), net
	2020			2019		2018
Conversion option liability on Convertible Senior Notes	$	5,203		$	71	$	1,556
Interest rate swap agreements		—			—		1,298
Forward currency exchange, option and future contracts		(893	)		—		—
	$	4,310		$	71	$	2,854

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2020

Fair Value Disclosures [Abstract]

Schedule of Fair Value of Assets and Liabilities Measured on Recurring Basis

The Company’s financial assets and liabilities as of December 31 that are measured at fair value on a recurring basis were as follows (in thousands):

	Level 1		Level 2		Level 3⁽¹⁾
2020
LIABILITIES
Derivative instruments (included in other current liabilities)	$	—	$	4,591	$	—
Conversion Option Liability on Convertible Senior Notes		—		—		2
2019
ASSETS
Construction reserve funds		12,893		—		—
LIABILITIES
Derivative instruments (included in other current liabilities)		—		2,925		—
Conversion Option Liability on Convertible Senior Notes		—		—		5,205

(1)	For the year ended December 31, 2020, the Company recognized a $5.2 million gain in the fair market valuation of the Conversion Option on the Convertible Senior Notes, as valued by an independent third-party.

Schedule of Estimated Fair Values of Financial Assets and Liabilities

The estimated fair value of the Company’s other financial assets and liabilities as of December 31 were as follows (in thousands):

			Estimated Fair Value
	Carrying Amount		Level 1		Level 2		Level 3
2020
ASSETS
Cash, cash equivalents and restricted cash	$	36,018	$	36,018	$	—	$	—
Investments, at cost, in 50% or less owned companies (included in other assets)		132	see below
LIABILITIES
Long-term debt, including current portion		472,887		—		470,561		—
2019
ASSETS
Cash, cash equivalents and restricted cash	$	84,486	$	84,486	$	—	$	—
Investments, at cost, in 50% or less owned companies (included in other assets)		132	see below
LIABILITIES
Long-term debt, including current portion		373,516		—		356,086		—

Schedule of Other Assets and Liabilities Measured at Fair Value

The Company’s non-financial assets and liabilities that were measured at fair value during the years ended December 31 were as follows (in thousands):

	Level 1		Level 2		Level 3
2020
ASSETS
Property and equipment:
Liftboats	$	—	$	43,005	$	—
2019
ASSETS
Property and equipment:
AHTS	$	—	$	520	$	—
FSVs		—		1,858		—

Noncontrolling Interests in Subsidiaries (Tables)

12 Months Ended

Dec. 31, 2020

Noncontrolling Interest [Abstract]

Schedule of Noncontrolling Interests in the Company's Consolidated Subsidiaries

Noncontrolling interests in the Company’s consolidated subsidiaries as of December 31 were as follows (in thousands):

	Noncontrolling Interests				2020		2019
Falcon Global Holdings		—	%	⁽¹⁾	$	—	$	21,119
Other		1.8	%			319		313
					$	319	$	21,432

⁽¹⁾	^{Before March 20, 2020, noncontrolling interest was}²⁸^%^.

Share Based Compensation (Tables)

12 Months Ended

Dec. 31, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Equity Incentive Plan Transactions

The following transactions have occurred in connection with the Company’s share-based compensation under the 2017 Plan and the 2020 Plan during the years ended December 31:

	2020			2019
Director Stock Awards Granted		59,900			30,197

Restricted Stock Activity:
Outstanding as of the beginning of year		303,609			192,346
Granted		289,452	⁽¹⁾		245,400
Vested		143,697			131,937
Forfeited		12,650			2,200
Outstanding as of the end of year		436,714			303,609

Stock Option Activity:
Outstanding as of the beginning of year		913,569			805,566
Granted		261,972			230,503
Exercised		—			113,750
Forfeited		55,000			8,750
Outstanding as of the end of year		1,120,541			913,569

(1)	Excludes 240,800 grants of performance-based stock units that are not considered outstanding until such time that they become probable to vest.

Schedule of Restricted Stock Transactions

During the year ended December 31, 2020, the number of shares and the weighted average grant price of restricted stock transactions were as follows:

	Restricted Stock
	Number of Shares		Weight Average Grant Price
Non-Vested as of December 31, 2019		303,609	$	20.46
Granted		289,452		6.81
Vested		143,697		13.43
Forfeited		12,650		12.30
Non-Vested as of December 31, 2020		436,714		11.60

Schedule of Stock Option Transactions

During the year ended December 31, 2020, the number of shares and the weighted average exercise price on stock option transactions were as follows:

	Stock Options
	Number of Shares		Weight Average Grant Price
Non-Vested as of December 31, 2019		913,569	$	14.81
Granted		261,972		3.68
Exercised		—		—
Forfeited		55,000		13.43
Non-Vested as of December 31, 2020		1,120,541		12.49
Exercisable as of December 31, 2020⁽¹⁾		716,965		13.03

(1)	The weighted average remaining contractual term is 8.18 years.

Major Customers and Segment Information (Tables)

12 Months Ended

Dec. 31, 2020

Segment Reporting [Abstract]

Schedule of Segment Reporting Information, by Segment

	United States (primarily Gulf of Mexico)			Africa (primarily West Africa)			Middle East and Asia			Latin America			Europe Continuing Operations			Total
For the year ended December 31, 2020
Operating Revenues:
Time charter	$	9,873		$	35,876		$	52,052		$	23,806		$	11,847		$	133,454
Bareboat charter		2,910			—			—			—			(55	)		2,855
Other		2,422			(465	)		2,157			1,084			330			5,528
		15,205			35,411			54,209			24,890			12,122			141,837
Direct Costs and Expenses:
Operating:
Personnel		10,065			10,552			18,188			6,698			2,845			48,348
Repairs and maintenance		1,655			5,175			5,232			2,131			468			14,661
Drydocking		1,167			2,014			759			329			—			4,269
Insurance and loss reserves		1,774			1,026			1,721			462			780			5,763
Fuel, lubes and supplies		1,172			2,940			2,706			990			320			8,128
Other		373			984			6,891			1,369			359			9,976
		16,206			22,691			35,497			11,979			4,772			91,145
Direct Vessel (Loss) Profit	$	(1,001	)	$	12,720		$	18,712		$	12,911		$	7,350			50,692
Other Costs and Expenses:
Operating:
Leased-in equipment	$	4,272		$	3,029		$	170		$	45		$	9			7,525
Administrative and general																	40,051
Depreciation and amortization	$	21,427		$	10,833		$	16,595		$	5,481		$	2,831			57,167
																	104,743
Losses on Asset Dispositions and Impairments, Net																	(17,588	)
Operating Loss																$	(71,639	)
As of December 31, 2020
Property and Equipment:
Historical cost	$	257,592		$	204,079		$	361,514		$	130,769		$	58,919		$	1,012,873
Accumulated depreciation		(134,391	)		(60,535	)		(75,349	)		(13,312	)		(7,951	)		(291,538	)
	$	123,201		$	143,544		$	286,165		$	117,457		$	50,968		$	721,335
Total Assets⁽¹⁾	$	164,656		$	153,399		$	289,314		$	179,942		$	74,495		$	861,806

(1)	Total assets exclude $105.6 million of corporate assets, and $50.2 million of assets held for sale.

	United States (primarily Gulf of Mexico)			Africa (primarily West Africa)			Middle East and Asia			Latin America			Europe Continuing Operations			Total
For the year ended December 31, 2019
Operating Revenues:
Time charter	$	38,955		$	44,160		$	54,312		$	11,460		$	8,165		$	157,052
Bareboat charter		1,562			—			—			3,569			—			5,131
Other		3,806			1,461			1,669			1,390			3,944			12,270
		44,323			45,621			55,981			16,419			12,109			174,453
Direct Costs and Expenses:
Operating:
Personnel		17,491			13,833			16,698			4,459			3,494			55,975
Repairs and maintenance		7,583			4,701			7,182			1,348			587			21,401
Drydocking		4,594			490			600			161			3			5,848
Insurance and loss reserves		2,370			1,051			1,449			311			441			5,622
Fuel, lubes and supplies		2,936			3,471			2,904			1,056			255			10,622
Other		393			4,354			3,095			1,182			1,031			10,055
		35,367			27,900			31,928			8,517			5,811			109,523
Direct Vessel Profit	$	8,956		$	17,721		$	24,053		$	7,902		$	6,298			64,930
Other Costs and Expenses:
Operating:
Leased-in equipment	$	10,894		$	3,090		$	173		$	10		$	1,673			15,840
Administrative and general																	39,791
Depreciation and amortization	$	21,947		$	10,404		$	16,400		$	6,205		$	2,210			57,166
																	112,797
Losses on Asset Dispositions and Impairments, Net																	(6,461	)
Operating Loss																$	(54,328	)
As of December 31, 2019
Property and Equipment:
Historical cost	$	297,392		$	207,107		$	292,446		$	57,534		$	44,545		$	899,024
Accumulated depreciation		(157,514	)		(57,136	)		(73,039	)		(16,239	)		(4,989	)		(308,917	)
	$	139,878		$	149,971		$	219,407		$	41,295		$	39,556		$	590,107
Total Assets⁽¹⁾	$	224,229		$	161,915		$	250,890		$	116,736		$	64,156		$	817,926

(1)	Total assets exclude $145.5 million of corporate assets, and $45.7 million of assets held-for-sale.

	United States (primarily Gulf of Mexico)			Africa (primarily West Africa)			Middle East and Asia			Latin America			Europe Continuing Operations			Total
For the year ended December 31, 2018
Operating Revenues:
Time charter	$	38,802		$	43,847		$	50,072		$	17,343		$	—		$	150,064
Bareboat charter		—			—			—			4,635			—			4,635
Other		14,762			7,661			(887	)		1,554			1,372			24,462
		53,564			51,508			49,185			23,532			1,372			179,161
Direct Costs and Expenses:
Operating:
Personnel		18,708			16,538			16,806			4,399			2,081			58,532
Repairs and maintenance		5,152			6,330			11,172			1,011			720			24,385
Drydocking		1,957			2,085			1,362			128			2,260			7,792
Insurance and loss reserves		2,922			1,096			1,371			495			86			5,970
Fuel, lubes and supplies		3,568			3,826			4,027			1,225			258			12,904
Other		393			4,313			3,980			1,130			188			10,004
		32,700			34,188			38,718			8,388			5,593			119,587
Direct Vessel Profit (Loss)	$	20,864		$	17,320		$	10,467		$	15,144		$	(4,221	)		59,574
Other Costs and Expenses:
Operating:
Leased-in equipment	$	8,240		$	4,281		$	224		$	5		$	214			12,964
Administrative and general																	41,616
Depreciation and amortization	$	23,227		$	10,453		$	18,762		$	7,908		$	1,069			61,419
																	115,999
Losses on Asset Dispositions and Impairments, Net																	(11,989	)
Operating Loss																$	(68,414	)
As of December 31, 2018
Property and Equipment:
Historical cost	$	432,336		$	184,361		$	306,897		$	124,177		$	26		$	1,047,797
Accumulated depreciation		(224,737	)		(55,206	)		(81,378	)		(57,002	)		(17	)		(418,340	)
	$	207,599		$	129,155		$	225,519		$	67,175		$	9		$	629,457
Total Assets⁽¹⁾	$	351,748		$	140,335		$	260,002		$	137,983		$	(28,450	)		861,618

(1)	Total assets exclude $153.1 million of corporate assets, and $88.2 million of assets held-for-sale.

Discontinued Operations (Tables)

12 Months Ended

Dec. 31, 2020

Discontinued Operations And Disposal Groups [Abstract]

Schedule of Assets Held for Sale

Summarized selected operating result of the Company’s assets held for sale and discontinued operations were as follows for the years ended December 31, (in thousands):

	2020		2019
Assets from Discontinued Operations:
Current assets	$	10,138	$	9,603
Net property and equipment		34,580		31,447
Non-current assets		5,517		4,668
		50,235		45,718
Liability from Discontinued Operations:
Current liabilities	$	2,418	$	2,060
Long-term liabilities		28,509		25,480
	$	30,927	$	27,540

	Windcat Workboats						Boston Putford Offshore Safety
	2020			2019			2020		2019
Operating Revenues:
Time charter	$	29,383		$	25,249		$	—	$	41,214
Other revenue		2,305			1,790			—		45
		31,688			27,039			—		41,259
Costs and Expenses:
Operating		17,334			14,202			—		33,836
Direct Vessel Profit		14,354			12,837			—		7,423

General and Administrative Expenses		5,516			4,935			—		4,207
Lease Expense		628			318			—		60
Depreciation		6,166			6,846			—		3,504
Gains on Asset Dispositions and Impairments, Net		—			1,064			—		91
Operating Income (Loss)		2,044			1,802			—		(257	)
Other Income (Expense)
Interest income		59			56			—		11
Interest expense		(1,115	)		(1,100	)		—		(210	)
Foreign currency translation (loss) gain		(750	)		880			—		(75	)
Other, net		19			—			—		—
		(1,787	)		(164	)		—		(274	)
Operating Income (Loss) Before Equity Earnings of 50% or Less Owned Companies, Net of Tax		257			1,638			—		(531	)
Income Tax (Benefit) Expense		(86	)		57			—		(2	)
Operating Income (Loss) Before Equity Earnings of 50% or Less Owned Companies		343			1,581			—		(529	)
Equity in Earnings of 50% or Less Owned Companies, Net of Tax		21			155			—		168
Net Income (Loss) from Discontinued Operations	$	364		$	1,736		$	—	$	(361	)

Tabular disclosure of information related to a disposal group. Includes, but is not limited to, a discontinued operation, disposal classified as held-for-sale or disposed of by means other than sale or disposal of an individually significant component.

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Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Information (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2020

Selected Financial Information for Interim Quarterly Periods

	Three Months Ended
	Dec. 31,			Sept. 30,			June 30,			March 31,
2020
Operating Revenues	$	36,044		$	36,201		$	33,925		$	35,667
Operating Loss		(16,915	)		(13,179	)		(17,824	)		(23,721	)
Net (Loss) Income:
Continuing Operations		(38,898	)		(19,842	)		(6,668	)		(17,938	)
Discontinued Operations		51			1,765			602			(2,054	)
	$	(38,847	)	$	(18,077	)	$	(6,066	)	$	(19,992	)
Net Loss attributable to SEACOR Marine Holdings Inc:	$	(38,816	)	$	(18,081	)	$	(6,073	)	$	(15,945	)
Basic and Diluted (Loss) Income Per Common Share of SEACOR Marine Holdings Inc.
Continuing Operations	$	(1.54	)	$	(0.79	)	$	(0.26	)	$	(0.58	)
Discontinued Operations	$	—		$	0.07		$	0.02		$	(0.08	)
	$	(1.54	)	$	(0.72	)	$	(0.24	)	$	(0.66	)
2019
Operating Revenues	$	42,478		$	46,996		$	45,014		$	39,965
Operating Loss		(10,555	)		(5,566	)		(18,591	)		(19,616	)
Net (Loss) Income:
Continuing Operations		(19,439	)		(12,586	)		(31,632	)		(27,307	)
Discontinued Operations		(2,479	)		(5,654	)		1,368			(966	)
	$	(21,918	)	$	(18,240	)	$	(30,264	)	$	(28,273	)
Net Loss attributable to SEACOR Marine Holdings Inc:	$	(20,455	)	$	(18,444	)	$	(28,389	)	$	(25,549	)
Basic and Diluted (Loss) Income Per Common Share of SEACOR Marine Holdings Inc.
Continuing Operations	$	(0.76	)	$	(0.54	)	$	(1.27	)	$	(1.07	)
Discontinued Operations	$	(0.10	)	$	(0.24	)	$	0.06		$	(0.04	)
	$	(0.86	)	$	(0.78	)	$	(1.21	)	$	(1.11	)

121

Schedule II - Valuation and Qualifying Accounts (Tables)

12 Months Ended

Dec. 31, 2020

Valuation And Qualifying Accounts [Abstract]

Schedule of Valuation and Qualifying Accounts

Description	Balance Beginning of Year		Reserves Acquired		Charges (Recoveries) to Cost and Expenses			Deductions			Balance End of Year
Year Ended December 31, 2020
Allowance for credit loss reserves (deducted from trade and notes receivable)	$	455	$	18	$	230		$	(121	)	$	582
Year Ended December 31, 2019
Allowance for credit loss reserves (deducted from trade and notes receivable)	$	860	$	—	$	(405	)	$	—		$	455
Year Ended December 31, 2018
Allowance for credit loss reserves (deducted from trade and notes receivable)	$	4,039	$	—	$	(928	)	$	(2,251	)	$	860

Nature of Operations and Accounting Policies - Additional Information (Details)

12 Months Ended

Dec. 31, 2020

USD ($)

Segment

Vessel

Dec. 31, 2019

USD ($)

Dec. 31, 2018

USD ($)

Dec. 02, 2019

USD ($)

Jan. 01, 2019

USD ($)

Dec. 20, 2018

Jan. 01, 2018

USD ($)

Dec. 31, 2017

USD ($)

Nature Of Operations And Accounting Policies [Line Items]

Number of reportable segments | Segment

Contract with customer, liability

49.00%

$ 3,307,000

$ 4,755,000

$ 1,327,000

$ 10,104,000

Contract with customer liability current

4,452,000

5,296,000

Inventory reserves

Capitalized interest costs, including allowance for funds used during construction, total

721,335,000

590,107,000

629,457,000

700,000

1,500,000

2,400,000

Impairment of long-lived assets held-for-use

18,800,000

12,000,000.0

14,600,000

Partial impairment of right to use assets

5,300,000

Equity method investment, other than temporary impairment

$ 0

$ 1,200,000

Deferred gain net

$ 0

Incremental common shares attributable to conversion of debt securities, total | shares

1,488,292

1,826,966

2,183,708

Right-of-Use Asset - Operating Leases

$ 7,134,000

$ 16,537,000

Operating Lease, Liability

11,375,000

Change in Accounting Principle for Unamortized Deferred Gains

(51,839,000)

27,076,000

Deferred taxes

$ 66,420,000

$ 77,478,000

Nature Of Operations And Accounting Policies [Line Items]

Deferred gain net

$ 11,000.0

Deferred taxes

2,300

Accounting Standards Update 2014-09

Nature Of Operations And Accounting Policies [Line Items]

Change in accounting principle, accounting standards update, adopted [true false]

true

Change in accounting principle, accounting standards update, adoption date

Jan. 01, 2018

Change in accounting principle, accounting standards update, immaterial effect [true false]

true

Accounting Standards Update 2016-02

Nature Of Operations And Accounting Policies [Line Items]

Change in accounting principle, accounting standards update, adopted [true false]

true

Change in accounting principle, accounting standards update, adoption date

Jan. 01, 2019

Change in accounting principle, accounting standards update, immaterial effect [true false]

false

Right-of-Use Asset - Operating Leases

33,700,000

Operating Lease, Liability

31,900,000

Accounting Standards Update 2016-02 | Cumulative Effect, Period of Adoption, Adjustment | Change in Accounting Principle for Equipment, Office and Land Leases

Nature Of Operations And Accounting Policies [Line Items]

Accounting Standards Update 2016-02 | Cumulative Effect, Period of Adoption, Adjustment | Change in Accounting Principle for Unamortized Deferred Gains

1,700,000

Nature Of Operations And Accounting Policies [Line Items]

Accounting Standards Update 2019-12

$ 8,700,000

Nature Of Operations And Accounting Policies [Line Items]

Change in accounting principle, accounting standards update, adopted [true false]

true

Change in accounting principle, accounting standards update, adoption date

Jan. 01, 2018

Accounting Standards Update 2019-12 | Cumulative Effect, Period of Adoption, Adjustment

Nature Of Operations And Accounting Policies [Line Items]

Nature Of Operations And Accounting Policies [Line Items]

$ 12,100,000

Performance Share Awards

Number of shares issued | shares

149,200

109,600

Number of shares outstanding | shares

240,800

Restricted Stock

Nature Of Operations And Accounting Policies [Line Items]

Antidilutive securities excluded from computation of earnings per share, amount | shares

436,714

303,609

192,346

Employee Stock Option

Nature Of Operations And Accounting Policies [Line Items]

Antidilutive securities excluded from computation of earnings per share, amount | shares

1,120,541

913,569

805,566

Continuing Operations

Nature Of Operations And Accounting Policies [Line Items]

Depreciation, total

$ 57,200,000

$ 61,400,000

Discontinued Operations

Nature Of Operations And Accounting Policies [Line Items]

Depreciation, total

6,200,000

$ 6,800,000

7,400,000

Prepaid Vessel Management Fees

$ 24,300,000

Nature Of Operations And Accounting Policies [Line Items]

Contract with customer liability current

2,000,000.0

Prepaid Charter Modification and Reservation Fees [Member]

Nature Of Operations And Accounting Policies [Line Items]

Contract with customer liability current

500,000

Geographic Distribution, Domestic

Nature Of Operations And Accounting Policies [Line Items]

Contract with customer, liability

3,300,000

Geographic Distribution, Foreign

Nature Of Operations And Accounting Policies [Line Items]

Contract with customer, liability

$ 800,000

Nature Of Operations And Accounting Policies [Line Items]

Minimum | SEACOR Marine Foreign Holdings

20.00%

Nature Of Operations And Accounting Policies [Line Items]

50.00%

Nature Of Operations And Accounting Policies [Line Items]

50.00%

Nature Of Operations And Accounting Policies [Line Items]

ERRVs | Discontinued Operations

$ 25,000

$ 514,000

Nature Of Operations And Accounting Policies [Line Items]

Depreciation, total

3,500,000

3,400,000

Liftboat Vessels

Nature Of Operations And Accounting Policies [Line Items]

Anchor Handling Towing Supply

7,000,000.0

Nature Of Operations And Accounting Policies [Line Items]

Nature Of Operations And Accounting Policies [Line Items]

500,000

Specialty Vessel

Vessel Under Construction

1,200,000

Nature Of Operations And Accounting Policies [Line Items]

Nature Of Operations And Accounting Policies [Line Items]

$ 4,800,000

CME

Noncontrolling interest, ownership percentage by noncontrolling owners

51.00%

Nature Of Operations And Accounting Policies [Line Items]

Nature Of Operations And Accounting Policies [Line Items]

49.00%

SMI

Nature Of Operations And Accounting Policies [Line Items]

49.00%

MEXMAR Offshore

Nature Of Operations And Accounting Policies [Line Items]

^[1]

49.00%

UNITED STATES

Number of vessels leased-in | Vessel

Number of vessels managed-in | Vessel

Nature Of Operations And Accounting Policies [Line Items]

$ 123,201,000

139,878,000

207,599,000

Africa

Number of vessels leased-in | Vessel

Nature Of Operations And Accounting Policies [Line Items]

$ 143,544,000

149,971,000

129,155,000

Middle East and Asia

Number of vessels managed-in | Vessel

Nature Of Operations And Accounting Policies [Line Items]

$ 286,165,000

219,407,000

225,519,000

Latin America

Nature Of Operations And Accounting Policies [Line Items]

$ 117,457,000

41,295,000

67,175,000

Europe

Europe | Crew Transfer Vessels

$ 50,968,000

$ 39,556,000

$ 9,000

Nature Of Operations And Accounting Policies [Line Items]

Number of equipment sold upon completion | Vessel

[1]	^{This Joint Venture holds the investment in UP Offshore}^.

Nature of Operations and Accounting Policies - Schedule Of Deferred Revenues (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Nature Of Operation And Accounting Policies [Abstract]
Balance at beginning of year	$ 4,755	$ 1,327	$ 10,104
Revenues deferred during the year	2,042	8,134	3,518
Revenues recognized during the year	(3,490)	(4,706)	(12,295)
Balance at end of year	$ 3,307	$ 4,755	$ 1,327

Nature of Operations and Accounting Policies - Schedule Of Cash, Cash Equivalents And Restricted Cash From Continuing Operations (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Nature Of Operation And Accounting Policies [Abstract]
Cash	$ 32,666	$ 81,382
Restricted cash	3,352	3,104
Total	$ 36,018	$ 84,486

Nature of Operations and Accounting Policies - Schedule of Property and Equipment Useful Life (Details)	12 Months Ended
	Dec. 31, 2020
CTVs
Property Plant And Equipment [Line Items]
Estimated useful life (Year)	10 years
All Other Offshore Support Vessels
Property Plant And Equipment [Line Items]
Estimated useful life (Year)	20 years

Nature of Operations and Accounting Policies - Summary of Property and Equipment from Continuing Operations (Details) - USD ($)
$ in Thousands

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

$ 1,012,873

^[1]

$ 899,024

^[1]

$ 1,047,797

(291,538)

(308,917)

(418,340)

Offshore Support Vessels, Anchor Handling Towing Supply

721,335

590,107

$ 629,457

^[1],[2]

50,189

94,078

^[2]

(31,779)

(73,095)

^[2]

18,410

20,983

Fast Support Vessels

^[1],[3]

375,747

388,460

^[3]

(104,739)

(101,295)

Offshore Support Vessels, Supply

^[3]

271,008

287,165

^[1]

238,624

44,958

(15,991)

(8,471)

Offshore Support Vessels, Specialty

222,633

36,487

^[1]

14,805

(10,466)

Offshore Support Vessels, Liftboats

4,339

^[1]

321,751

327,028

(117,364)

(93,166)

204,387

233,862

^[1]

3,163

5,032

(3,138)

(4,518)

General Machinery and Spares

514

^[1]

7,746

7,650

(7,733)

(7,648)

Property, Plant and Equipment, Other Types

^[1],[4]

15,653

17,013

^[4]

(10,794)

(10,258)

^[4]

$ 4,859

$ 6,755

[1]	Includes property and equipment acquired in business acquisitions at acquisition date fair value, and net of the impact of recognized impairment charges.
[2]	Anchor Handling Towing Supply (“AHTS”).
[3]	Fast support vessels (“FSVs”)
[4]	Includes land, buildings, leasehold improvements, vehicles and other property and equipment.

Nature of Operations and Accounting Policies - Schedule of Deferred Gain Activity (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Balance at end of year	$ 0
Sale-leaseback and Financed Equipment Sales
Balance at beginning of year	11,026,000	$ 23,553,000
Amortization of deferred gains		(8,037,000)
Reclass of gain to Retained Earnings	(11,026,000)
Recognition of deferred gains included in losses on asset dispositions and impairments, net		(4,490,000)
Balance at end of year		11,026,000
Vessel Sales to Fifty Percent or Less Owned Subsidiaries
Balance at beginning of year	793,000	1,453,000
Amortization of deferred gains		(25,000)
Other	$ (793,000)	(635,000)
Balance at end of year		$ 793,000

Nature of Operations and Accounting Policies - Schedule of Accumulated Other Comprehensive (Loss) Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	$ 478,924	$ 565,351	$ 511,097
Other comprehensive (loss) income	1,242	18,163	(4,349)
Income tax benefit (expense)		(173)	46
Balance	401,836	478,924	565,351
Accumulated Foreign Currency Adjustment Attributable to Parent
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	4,685	(15,472)	(13,195)
Other comprehensive (loss) income	2,112	20,157	(2,277)
Balance	6,797	4,685	(15,472)
Accumulated Loss, Net, Cash Flow Hedge, Parent
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(3,137)	(1,316)	702
Other comprehensive (loss) income	(870)	(1,994)	(1,972)
Income tax benefit (expense)		173	(46)
Balance	(4,007)	(3,137)	(1,316)
AOCI Attributable to Parent
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	1,548	(16,788)	(12,493)
Other comprehensive (loss) income	1,242	18,163	(4,249)
Income tax benefit (expense)		173	(46)
Balance	2,790	1,548	(16,788)
Accumulated Foreign Currency Adjustment Attributable to Noncontrolling Interest
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(1,445)	(1,445)	(1,357)
Other comprehensive (loss) income			(88)
Balance	(1,445)	(1,445)	(1,445)
Accumulated Gain (Loss), Net, Cash Flow Hedge, Noncontrolling Interest
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(11)	(11)	1
Other comprehensive (loss) income			(12)
Balance	(11)	(11)	(11)
AOCI Attributable to Noncontrolling Interest
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	18,336	(4,395)	(881)
Other comprehensive (loss) income	1,242	18,163	(4,349)
Income tax benefit (expense)		173	(46)
Balance	$ 1,242	$ 18,336	$ (4,395)

Transformation, Facility Restructuring and Severance Charges - Additional Information (Details) - Transformation Plan - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Restructuring Cost And Reserve [Line Items]
Restructuring and related activities, description	The transformation plan, which began in the third quarter of 2019 and extended through the third quarter of 2020 (the “Transformation Plan”), included a workforce reduction, organization restructuring, facility consolidations and other cost reduction measures and efficiency initiatives across the Company’s geographic regions. These initiatives impacted all of the Company’s reportable segments and are expected to result in annualized recurring savings of at least $8.0 million. The Company continues to evaluate additional opportunities for further cost reductions to adapt to changing conditions caused by COVID-19 and other market conditions.
Restructuring charges	$ 1,187,000	$ 3,718,000
Severance charges	1,100,000
Other restructuring charges	62,000	$ 339,000
Restructuring Costs	4,900,000
Minimum
Restructuring Cost And Reserve [Line Items]
Expected annualized recurring savings	$ 8,000,000.0

Transformation, Facility Restructuring and Severance Charges - Schedule of Components of Restructuring Charges (Details) - Transformation Plan - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Restructuring Cost And Reserve [Line Items]
Severance Charges	$ 1,125	$ 3,379
Other Charges	62	339
Total Charges	1,187	3,718
UNITED STATES
Restructuring Cost And Reserve [Line Items]
Severance Charges	275	2,995
Other Charges	31	307
Total Charges	306	3,302
Middle East and Asia
Restructuring Cost And Reserve [Line Items]
Severance Charges	665	184
Other Charges	31	31
Total Charges	696	215
Europe
Restructuring Cost And Reserve [Line Items]
Severance Charges	185	200
Total Charges	$ 185	$ 200

Business Acquisitions - Additional Information (Details) - SEACOR Offshore Delta LLC $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) Vessel	Jun. 30, 2020 USD ($) Vessel	May 31, 2020
Sale And Purchase Agreement
Equity Method Investment Ownership Percentage		100.00%
Purchase price payable for membership interest		$ 28.2
Purchase price payable to sellers at closing of transaction		8.4
Purchase price for membership interests annual installment payment in first year		1.0
Purchase price for membership interests annual installment payment in second year		2.5
Purchase price for membership interests annual installment payment in third year		2.5
Purchase price for membership interests annual installment payment in fourth year		$ 13.7
Purchase price fixed accrued interest rate in first year		1.50%
Purchase price fixed accrued interest rate in second year		7.00%
Purchase price fixed accrued interest rate in third year		7.50%
Purchase price fixed accrued interest rate in fourth year		8.00%
Sale And Purchase Agreement \| Platform Supply Vessels
Number of vessels owned \| Vessel	8	8
Number of vessels owned with high specification \| Vessel	2
Number of vessels owned with identical specification \| Vessel	6
Deferred Purchase Agreements \| Platform Supply Vessels
Business acquisition, aggregate amount outstanding	$ 95.3	$ 100.8
Business acquisition, amortization period of purchase price	10 years
Debt instrument, description of floating interest rate basis	three-month LIBOR plus 4.0
Debt instrument, basis spread on floating interest rate	4.00%
Number of vessels delivered to the company \| Vessel	7
SEACOR Offshore Asia \| Sale And Purchase Agreement
Equity Method Investment Ownership Percentage			50.00%

Business Acquisitions - Summary of Purchase Price Allocation of Acquired Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Schedule Of Investments [Line Items]
Equity Investment In SEACOR Offshore Delta (f/k/a SEACOSCO)	$ (75,308)		$ (120,831)
SEACOR Offshore Delta LLC
Schedule Of Investments [Line Items]
Current Assets		$ 7,700
Fixed Assets		142,282
Current Liabilities		(23,929)
Book Value of Debt Acquired		100,759
Discount on Debt Acquired		25,190
Fair Value of Debt Acquired		(75,569)
Total Cost Basis for Purchase		50,484
Purchase Price		(28,150)
Acquisition costs		(112)
Equity Investment In SEACOR Offshore Delta (f/k/a SEACOSCO)		(22,222)
Total Cost Basis for Purchase		$ (50,484)

Equipment Acquisitions and Dispositions - Additional Information (Details)

12 Months Ended

Jan. 12, 2021

USD ($)

Jan. 12, 2021

GBP (£)

Dec. 31, 2020

USD ($)

Vessel

Dec. 31, 2019

USD ($)

Vessel

Dec. 31, 2019

GBP (£)

Vessel

Dec. 31, 2018

USD ($)

Capital expenditures and payments on equipment

$ 20,800,000

$ 44,800,000

$ 35,600,000

Issuance of stock

$ 42,996,000

Gain (loss) on disposition of property, plant and equipment

^[1]

^[2]

$ 5,500,000

$ 5,700,000

Proceeds from sale of business

$ 20,674,000

55,321,000

10,655,000

Proceeds from deposits

1,100,000

100,000

Proceeds from sale of property, plant, and equipment, including deposits

753,662,000

660,913,000

55,300,000

12,300,000

Proceeds from sale of property, plant, and equipment, excluding deposits for future vessel sales

54,200,000

$ 12,200,000

ERRV Fleet Business

Gain (loss) on disposition of property, plant and equipment

(9,100,000)

Proceeds from sale of business

27,390,000

23,400,000

Additional consideration

$ 0

$ 5,200,000

£ 4,000,000

Number of additional joint ventures held interests | Vessel

Acquired | Vessel

Crew Transfer Vessels | Subsequent Event

Sale of equity percentage

100.00%

Aggregate purchase price | £

£ 32,800,000

Issuance of stock

$ 42,600,000

Debt outstanding under revolving credit facility | £

£ 20,400,000

Windcat Workboats | Subsequent Event

Gain (loss) on disposition of property, plant and equipment

$ 22,800,000

Vessel Under Construction

Gain (loss) on disposition of property, plant and equipment

$ 1,200,000

Proceeds from property, plant, and equipment, including deposits and gain on sale

21,600,000

Proceeds from sale of business

20,700,000

Proceeds from deposits

$ 900,000

Vessel under Construction and Other Equipment

Anchor Handling Towing Supply

Specialty Vessel

Fast Support Vessels

^[2]

Vessels | ERRV Fleet Business

Liftboats

Platform Supply Vessels

[1]	Excludes three CTVs as assets held for sale and seven PSVs acquired as part of the SEACOSCO Acquisition (See “Note 3. Business Acquisitions”).
[2]	Excludes two CTVs as assets held for sale.

Equipment Acquisitions and Dispositions - Schedule of Vessel Acquired and Disposed (Details)

12 Months Ended

Dec. 31, 2020

Vessel

Dec. 31, 2019

Dec. 31, 2018

^[1]

^[2]

^[3]

^[4]

Fast Support Vessels

^[2]

Offshore Support Vessels, Supply

^[3]

^[4]

^[1]

^[2]

Offshore Support Vessels, Liftboats

^[3]

Anchor Handling Towing Supply

^[3]

^[4]

^[3]

^[4]

Specialty Vessel

^[3]

[1]	Excludes three CTVs as assets held for sale and seven PSVs acquired as part of the SEACOSCO Acquisition (See “Note 3. Business Acquisitions”).
[2]	Excludes two CTVs as assets held for sale.
[3]	Excludes three vessels that were previously removed from service (two AHTS vessels and one specialty vessel).
[4]	Excludes one CTV from assets held for sale.

Equipment Acquisitions and Dispositions - Schedule of Vessel Acquired and Disposed (Parenthetical) (Details)	12 Months Ended
	Dec. 31, 2020 Vessel	Dec. 31, 2019 Vessel	Dec. 31, 2018 Vessel
Property Plant And Equipment [Line Items]
Number of equipment removed from service excludes from major equipment dispositions	3
Crew Transfer Vessels
Property Plant And Equipment [Line Items]
Number of equipment held for sale excluded from deliveries of offshore support vessels	3	2	2
Number of equipment held for sale excluded from major equipment dispositions			1
Platform Supply Vessels
Property Plant And Equipment [Line Items]
Number of equipment acquired excludes from deliveries of offshore support vessels	7
Anchor Handling Towing Supply
Property Plant And Equipment [Line Items]
Number of equipment removed from service excludes from major equipment dispositions	2
Specialty Vessel
Property Plant And Equipment [Line Items]
Number of equipment removed from service excludes from major equipment dispositions	1

Investments, at Equity, and Advances to 50% or Less Owned Companies - Schedule of Equity Investments (Details) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2020

Sep. 30, 2020

Jun. 30, 2020

Mar. 31, 2020

Dec. 31, 2019

Sep. 30, 2019

Jun. 30, 2019

Mar. 31, 2019

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Dec. 20, 2018

49.00%

$ 75,308

$ 120,831

$ 75,308

$ 120,831

Current assets

178,696

194,661

178,696

194,661

Current liabilities

131,804

120,297

131,804

120,297

36,044

$ 36,201

$ 33,925

$ 35,667

42,478

$ 46,996

$ 45,014

$ 39,965

141,837

174,453

$ 179,161

Operating (Loss) Income

83,346

100,070

82,979

Net Loss

$ (38,847)

$ (18,077)

$ (6,066)

$ (19,992)

$ (21,918)

$ (18,240)

$ (30,264)

$ (28,273)

$ (82,982)

$ (98,695)

(82,052)

20.00%

50.00%

49.00%

$ 50,037

$ 54,249

$ 50,037

$ 54,249

SeaCosco

^[1]

50.00%

^[1]

37,480

OSV Partners

^[2]

30.40%

^[2]

$ 9,094

10,668

$ 9,094

10,668

SEACOR Marlin LLC

49.00%

$ 7,979

7,929

$ 7,979

7,929

MEXMAR Offshore

^[3]

49.00%

^[3]

$ 1,960

Offshore Vessel Holdings

49.00%

Other Offshore Marine Services Joint Ventures

$ 2,388

7,905

$ 2,388

7,905

Other Offshore Marine Services Joint Ventures | Minimum

$ 3,850

2,600

$ 3,850

2,600

Other Offshore Marine Services Joint Ventures | Maximum

20.00%

All Other Excluding MexMar, Falcon Global, Sea-Cat Crewzer and Sea-Cat Crewzer II

50.00%

Operating and administrative

$ 142,228

116,517

75,529

Depreciation

27,044

27,412

25,359

Costs and expenses

169,272

143,929

100,888

Loss on Asset Dispositions and Impairments, Net

(166)

(262)

Operating (Loss) Income

(8,491)

(7,405)

4,013

Net Loss

(18,229)

(36,816)

(14,861)

All Other Excluding MexMar, Falcon Global, Sea-Cat Crewzer and Sea-Cat Crewzer II | Equity Method Investment, Nonconsolidated Investee or Group of Investees

Current assets

$ 109,687

106,051

109,687

106,051

Noncurrent assets

259,424

607,541

259,424

607,541

Current liabilities

109,074

104,423

109,074

104,423

Noncurrent liabilities

$ 115,626

$ 331,357

115,626

331,357

$ 160,781

$ 136,690

$ 105,163

[1]	^{The Company acquired the}^remaining^50%^{of the SEACOSCO Joint Venture that it did not own on June 30, 2020.}
[2]	^{The Company owns}^66.7^{% of the General Partner and}^29.7^{% of the limited Partner}^.
[3]	^{This Joint Venture holds the investment in UP Offshore}^.

Investments, at Equity, and Advances to 50% or Less Owned Companies - Schedule of Equity Investments (Parenthetical) (Details)

Dec. 31, 2020

Dec. 20, 2018

49.00%

General Partner

66.70%

Limited Partner

29.70%

SeaCosco

^[1]

50.00%

[1]	^{The Company acquired the}^remaining^50%^{of the SEACOSCO Joint Venture that it did not own on June 30, 2020.}

Investments, at Equity, and Advances to 50% or Less Owned Companies - Additional Information (Details)

12 Months Ended

Dec. 18, 2019

USD ($)

Dec. 28, 2018

USD ($)

Dec. 20, 2018

USD ($)

Sep. 28, 2018

USD ($)

Vessel

Sep. 13, 2018

USD ($)

Dec. 31, 2020

USD ($)

Vessel

Dec. 31, 2019

USD ($)

Vessel

Equipment

Dec. 31, 2018

USD ($)

Consolidated retained earnings

$ 20,700,000

$ 14,700,000

$ 10,000,000.0

Equity method investment, other than temporary impairment

49.00%

$ 0

$ 1,200,000

50.00%

20.00%

MEXICO

Mexmar Offshore International

Noncontrolling interest, ownership percentage by noncontrolling owners

49.00%

51.00%

Offshore Vessel Holdings

Noncontrolling interest, ownership percentage by noncontrolling owners

$ 10,000,000.0

51.00%

Noncontrolling Interest, ownership percentage by parent

49.00%

Payments to acquire interest in joint venture

$ 4,900,000

Financing agreement

$ 2,400,000

Offshore Support Vessels, Supply

Offshore Support Vessels, Supply | Offshore Vessel Holdings

Number of equipment operated | Equipment

Jack up Drillings [Member] | Offshore Vessel Holdings

Number of equipment operated | Equipment

F S V Offshore Support Vessels | Offshore Vessel Holdings

Number of equipment operated | Equipment

Capital distributions from equity investees

$ 0

9,800,000

$ 300,000

300,000

49.00%

MexMar | Offshore Support Vessels

Number of equipment operated | Vessel

OSV Partners

Number of equipment operated | Vessel

600,000

Investment in affiliates, amount of preferred equity offering participated

$ 5,000,000.0

5,000,000.0

Payments to acquire interest in subsidiaries and affiliates, total

$ 1,100,000

1,100,000

Commitment to invest additional funds if call by general partner

1,100,000

Payments to acquire loans receivable

$ 2,100,000

^[1]

30.40%

SEACOR Marlin LLC

Equity method investment, ownership, percent sold

51.00%

Proceeds from divestiture of interest in joint venture

$ 8,000,000.0

Gain (loss) on disposition of business

$ 400,000

Other Offshore Marine Services Joint Ventures

49.00%

Number of equipment operated | Vessel

Capital distributions from equity investees

$ 2,100,000

2,100,000

Return of capital equity method investment

300,000

500,000

Equity method investment, other than temporary impairment

$ 1,200,000

Other Offshore Marine Services Joint Ventures | Maximum

$ 100,000

Other Offshore Marine Services Joint Ventures | Minimum

50.00%

Amortization of finance lease asset

20.00%

[1]	^{The Company owns}^66.7^{% of the General Partner and}^29.7^{% of the limited Partner}^.

Construction Reserve Funds - Additional Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) ExtensionPeriod	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Restricted Cash And Investments [Abstract]
Construction reserve funds commitment period	3 years
Number of extension period \| ExtensionPeriod	2
Construction reserve funds extension period	1 year
Short-term construction reserve funds	$ 4.2
Construction reserve fund withdrawals	$ 9.1	$ 15.2	$ 17.3

Leases - Additional Information (Details) $ in Thousands		12 Months Ended
Leases - Additional Information (Details) $ in Thousands	Jan. 01, 2019 USD ($)	Dec. 31, 2020 USD ($) Vessel	Dec. 31, 2019 USD ($)
Lessee Lease Description [Line Items]
Right-of-Use Asset - Operating Leases		$ 7,134	$ 16,537
Operating Lease, Liability		11,375
Retained earnings		(51,839)	27,076
Operating Lease, Impairment Loss		$ 5,900	$ 5,300
Number of Operating Leases Impaired		2	1
Anchor Handling Towing Supply
Lessee Lease Description [Line Items]
Number of operating leases on equipment \| Vessel		2
Liftboats
Lessee Lease Description [Line Items]
Number of operating leases on equipment \| Vessel		1
Fast Support Vessels
Lessee Lease Description [Line Items]
Number of operating leases on equipment \| Vessel		1
Vessels \| Minimum
Lessee Lease Description [Line Items]
Operating lease, lease terms (in duration)		8 months
Vessels \| Maximum
Lessee Lease Description [Line Items]
Operating lease, lease terms (in duration)		12 months
Other Equipment \| Minimum
Lessee Lease Description [Line Items]
Operating lease, lease terms (in duration)		11 months
Other Equipment \| Maximum
Lessee Lease Description [Line Items]
Operating lease, lease terms (in duration)		312 months
Accounting Standards Update 2016-02
Lessee Lease Description [Line Items]
Right-of-Use Asset - Operating Leases	$ 33,700
Operating Lease, Liability	31,900
Accounting Standards Update 2016-02 \| Change in Accounting Principle for Unamortized Deferred Gains
Lessee Lease Description [Line Items]
Cumulative effect on retained earnings, Before tax	11,000
Cumulative effect on retained earnings, Tax	2,300
Accounting Standards Update 2016-02 \| Cumulative Effect, Period of Adoption, Adjustment \| Change in Accounting Principle for Equipment, Office and Land Leases
Lessee Lease Description [Line Items]
Retained earnings	1,700
Accounting Standards Update 2016-02 \| Cumulative Effect, Period of Adoption, Adjustment \| Change in Accounting Principle for Unamortized Deferred Gains
Lessee Lease Description [Line Items]
Retained earnings	$ 8,700

Leases - Summary of Future Minimum Payments For Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Operating Leases
2021	$ 7,855
2022	639
2023	628
2024	559
2025	539
Years subsequent to 2025	4,215
Operating lease payments due	14,435
Interest component	(3,060)
Total operating leases	11,375
Current portion of long-term operating lease liabilities	(7,030)	$ (14,896)
Long-term operating lease liabilities	4,345	$ 9,255
Finance Leases
2021	42
2022	39
2023	39
2024	36
Total finance leases	156
Interest component	(15)
Finance Leases	141
Current portion of long-term finance lease liabilities	(36)
Long-term finance lease liabilities	$ 105

Leases - Summary of Components of Leases Expense (Details) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2020

Dec. 31, 2019

Leases [Abstract]

Operating lease expense

^[1]

$ 6,205

$ 13,442

Finance lease cost:

^[1]

Interest on lease liabilities

^[2]

Short-term lease costs

^[1]

1,320

2,398

Total lease expense

$ 7,537

$ 15,840

[1]	Included in selling, general and administrative expenses and amortization costs in the consolidated statements of loss.
[2]	Included in interest expense in the consolidated statements of loss.

Leases - Summary of Supplemental Cash Flow Information Related to Leases (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($)
Leases [Abstract]
Operating cash flows from operating leases	$ 14,785
Right-of-use assets obtained for operating lease liabilities	1,706
Right-of-use assets obtained for finance lease liabilities	$ 140

Leases - Summary of Other Information Related to Leases (Details)	Dec. 31, 2020
Leases [Abstract]
Weighted average remaining lease term, in years - operating leases	7 years 7 months 6 days
Weighted average remaining lease term, in years - finance leases	4 years 2 months 12 days
Weighted average discount rate - operating leases	4.70%
Weighted average discount - finance leases	5.30%

Long Term Debt - Schedule of Long-term Debt Obligations (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 521,877	$ 405,093
Current portion due within one year	(32,377)	(17,802)
Unamortized debt discount	(44,864)	(26,343)
Deferred financing costs	(4,126)	(5,234)
Long-term debt, less current portion	440,510	355,714
Recourse Long-Term Debt
Debt Instrument [Line Items]
Long-term Debt, Gross	399,028	282,244
Non-Recourse Long-Term Debt
Debt Instrument [Line Items]
Long-term Debt, Gross	122,849	122,849
Convertible Senior Notes \| Recourse Long-Term Debt
Debt Instrument [Line Items]
Long-term Debt, Gross	125,000	125,000
SEACOR Marine Foreign Holdings Credit Facility \| Recourse Long-Term Debt
Debt Instrument [Line Items]
Long-term Debt, Gross	100,750	113,750
Falcon Global USA Term Loan Facility \| Non-Recourse Long-Term Debt
Debt Instrument [Line Items]
Long-term Debt, Gross	102,349	102,349
Sea-Cat Crewzer III Term Loan Facility \| Recourse Long-Term Debt
Debt Instrument [Line Items]
Long-term Debt, Gross	21,653	24,128
SEACOR Offshore Delta (f/k/a SEACOSCO) Acquisition Debt \| Recourse Long-Term Debt
Debt Instrument [Line Items]
Long-term Debt, Gross	19,705
SEACOR Delta (f/k/a SEACOSCO) Shipyard Financing \| Recourse Long-Term Debt
Debt Instrument [Line Items]
Long-term Debt, Gross	95,317
Falcon Global USA Revolver \| Non-Recourse Long-Term Debt
Debt Instrument [Line Items]
Long-term Debt, Gross	15,000	15,000
SEACOR Alpine Shipyard Financing \| Recourse Long-Term Debt
Debt Instrument [Line Items]
Long-term Debt, Gross	31,103	10,534
SEACOR 88/888 Term Loan \| Recourse Long-Term Debt
Debt Instrument [Line Items]
Long-term Debt, Gross	5,500	5,500
SEACOR 88/888 Term Loan \| Non-Recourse Long-Term Debt
Debt Instrument [Line Items]
Long-term Debt, Gross	5,500	5,500
BNDES Equipment Construction Finance Notes \| Recourse Long-Term Debt
Debt Instrument [Line Items]
Long-term Debt, Gross		3,332
Windcat Workboats Facilities \| Current Liabilities
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 27,626	$ 24,537

Long Term Debt - Schedule of Long-term Debt Obligations (Parenthetical) (Details)

12 Months Ended

Dec. 31, 2020

Vessel

Dec. 31, 2019

^[2]

Dec. 31, 2018

^[2]

Debt Instrument [Line Items]

Number of vessels acquired

^[1]

SEACOR Delta (f/k/a SEACOSCO) Shipyard Financing | SeaCosco

Debt Instrument [Line Items]

Number of vessels acquired

[1]	Excludes three CTVs as assets held for sale and seven PSVs acquired as part of the SEACOSCO Acquisition (See “Note 3. Business Acquisitions”).
[2]	Excludes two CTVs as assets held for sale.

Long Term Debt - Schedule of Long-term Debt Maturities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Debt Disclosure [Abstract]
2021	$ 32,377
2022	38,484
2023	244,983
2024	134,523
2025	11,365
Years subsequent to 2025	60,145
Long-term Debt, Gross	$ 521,877	$ 405,093

Long Term Debt - Additional Information (Details) $ / shares in Units, € in Millions							1 Months Ended	12 Months Ended
	Feb. 24, 2021 USD ($)	Dec. 18, 2020 USD ($)	Mar. 03, 2020 EUR (€)	Sep. 26, 2018 USD ($)	Jul. 05, 2018 USD ($)	May 02, 2018 USD ($) $ / shares shares	Apr. 30, 2018 USD ($) $ / shares shares	Dec. 31, 2020 USD ($)	Dec. 31, 2020 EUR (€)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Jun. 29, 2020 Vessel	Oct. 31, 2019 Vessel	Oct. 31, 2018 USD ($)	Feb. 08, 2018 USD ($)	May 24, 2016 EUR (€)	Apr. 21, 2016 EUR (€)	Dec. 01, 2015 USD ($) $ / shares
Debt Instrument [Line Items]
Repayments of long-term debt, total								$ 22,601,000		$ 23,974,000	$ 41,932,000
Debt instrument, increase (decrease), net,				$ 30,100,000
Loss on extinguishment of debt											$ 638,000
Number of additional vessels owned \| Vessel														2
Long-term Debt Obligation
Debt Instrument [Line Items]
Letters of credit outstanding, amount								500,000
Carlyle Group
Debt Instrument [Line Items]
Convertible debt, total																				$ 175,000,000.0
Convertible Senior Notes Converted to Warrants \| Carlyle Group
Debt Instrument [Line Items]
Debt instrument, convertible, conversion ratio						37.73	37.73
Debt instrument, face amount						$ 1,000	$ 1,000
Class of warrant or right, exercise price of warrants or rights \| $ / shares						$ 0.01	$ 0.01
Debt conversion, original debt, amount						$ 50,000,000	$ 50,000,000.0
Debt conversion, converted instrument, shares issued \| shares						1,886,792	1,900,000
Debt instrument, convertible, conversion price \| $ / shares						$ 26.50	$ 26.50
Carlyle Warrants
Debt Instrument [Line Items]
Class of warrant or right, exercise price of warrants or rights \| $ / shares																				$ 0.01
Warrants and rights outstanding, term						25 years
SEACOR Alpine Shipyard Financing
Debt Instrument [Line Items]
Debt instrument, interest rate										5.00%
Percentage of amount of loan financed										70.00%
Debt instrument, term of delivery										4 years
Windcat Workboats Facilities
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity \| €																		€ 25.0
Debt instrument, maturity date			Dec. 31, 2021
Debt instrument, extended maturity date			Dec. 31, 2022
Application fee paid in conjunction with amendment and amortized over credit facility term \| €			€ 0.1
Proceeds from lines of credit \| €									€ 1.0
Debt instrument, increase (decrease), net,								$ 1,100,000
Loan Facility With DNB Bank ASA
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity				$ 130,000.0
Debt instrument, interest rate, effective percentage				4.00%
Debt instrument, maturity period				2023
Debt instrument, periodic payment, principal				$ 3,300,000
Loan Facility With DNB Bank ASA \| Interest Rate Swap
Debt Instrument [Line Items]
Derivative, notional amount																$ 65,000,000.0
Other DNB Credit Facilities
Debt Instrument [Line Items]
Repayments of lines of credit				101,300,000
Long-term debt, total				99,900,000
Interest payable				1,400,000
Loss on extinguishment of debt				$ 600,000
BNDES Equipment Construction Finance Notes
Debt Instrument [Line Items]
Number of vessels purchased from the company \| Vessel															2
Convertible Senior Notes 3.75%
Debt Instrument [Line Items]
Debt instrument, interest rate						4.25%	4.25%													3.75%
Convertible debt, total						$ 125,000,000.0	$ 125,000,000.0													$ 175,000,000.0
Debt instrument, convertible, conversion ratio											23.26
Debt instrument, face amount											$ 1,000
Three Point Seven Five Percentage Convertible Notes
Debt Instrument [Line Items]
Debt instrument, interest rate, effective percentage											7.95%
Embedded derivative, fair value of embedded derivative liability																				$ 27,300,000
Sea-Cat Crewzer III
Debt Instrument [Line Items]
Repayments of long-term debt, total											$ 3,100,000
Debt instrument, interest rate, effective percentage												2.76%
Debt instrument, face amount \| €																			€ 27.6
Proceeds from issuance of debt												$ 7,100,000	$ 22,800,000
Debt issuance costs, gross													$ 2,700,000
Term Loan to Acquire Two Vessels
Debt Instrument [Line Items]
Debt instrument, interest rate, effective percentage					3.75%
Debt instrument, face amount					$ 11,000,000.0
Claims recoverable amount under borrowings					$ 5,500,000
Claims recoverable under borrowings percentage of obligations outstanding					50.00%
Debt instrument, maturity year								2023	2023
Term Loan to Acquire Two Vessels \| Interest Rate Swap
Debt Instrument [Line Items]
Derivative, notional amount																$ 5,500,000
FGUSA Omnibus Amendment \| Term and Revolving Loan Facility
Debt Instrument [Line Items]
Debt agreement maximum borrowing capacity																	$ 131,100,000
Seventh FGUSA Credit Facility Amendment \| Subsequent Event
Debt Instrument [Line Items]
Repayment terms	the extension from March 2021 to June 2021 of the commencement of monthly repayment of the term loan, with payments being the lesser of (a) $0.8 million and (b) the amount outstanding under the term loan
Repayments of long-term debt, total	$ 800,000
Extension term of Guaranty	3 months
Deferred Purchase Agreements \| SEACOR Offshore Delta (f/k/a SEACOSCO)
Debt Instrument [Line Items]
Purchase price payable for equity method investment in first year								$ 1,000,000.0
Purchase price payable for equity method investment in second year								2,500,000
Purchase price payable for equity method investment in third year								2,500,000
Purchase price payable for equity method investment in fourth year								$ 13,700,000
Purchase price fixed accrued interest rate in first year								1.50%
Purchase price fixed accrued interest rate in second year								7.00%
Purchase price fixed accrued interest rate in third year								7.50%
Purchase price fixed accrued interest rate in fourth year								8.00%
Deferred Purchase Agreements \| SEACOR Offshore Delta (f/k/a SEACOSCO) \| Platform Supply Vessels
Debt Instrument [Line Items]
Equity method investment, amortization of purchase price								10 years	10 years
Debt instrument, description of floating interest rate basis								three-month LIBOR plus 4.0%	three-month LIBOR plus 4.0%
Debt instrument, basis spread on floating interest rate								4.00%	4.00%
Tax Refund Agreement
Debt Instrument [Line Items]
Estimated tax refund receivable		$ 31,200,000

Income Taxes - Additional Information (Details) - USD ($) $ in Millions		12 Months Ended
	Jun. 26, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes [Line Items]
Effective income tax rate reconciliation, at federal statutory Income tax rate, percent		21.00%	21.00%	21.00%	35.00%
Income tax benefit and equity in earnings (losses)		50.00%
Income tax refunds		$ 1.6
Foreign tax credits		0.3
Expected tax refund		$ 0.4
Increase (decrease) in transition tax liability			$ 2.3
Current income tax expense (benefit), nonqualified withdrawal of funds from capital construction fund				$ 1.4
Effective income tax rate reconciliation, percent, total		23.40%	9.40%	14.60%
Interest expense suspended		$ 4.4	$ 6.6	$ 3.6
Suspended interest deductible		3.3
Interest expense carryforward		$ 11.3
Interest expense suspended, limitation percentage		30.00%
Operating loss carryforwards, percentage of taxable income, utilization limitation		80.00%
Operating loss carryforwards, total		$ 42.2		$ 67.6
Operating loss carryforwards, expiration period				20 years
Operating loss carryforwards, valuation allowance, total		2.5
Tax Refund Agreement
Income Taxes [Line Items]
Expected to cash tax refunds receivable	$ 31.2
Percentage of net operating losses facilitate tax savings	35.00%
Transaction fee	$ 3.0
Cash tax refunds receivable without restrict to use		23.1
Cash tax refunds receivable with restrict to use		$ 8.1

Income Taxes - Schedule of Income before Income Tax (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes [Line Items]
Income before income tax expense (benefit) and equity in earnings of 50% or less owned companies	$ (98,107)	$ (84,474)	$ (92,433)
United States
Income Taxes [Line Items]
Income before income tax expense (benefit) and equity in earnings of 50% or less owned companies	(83,560)	(71,833)	(72,540)
Foreign
Income Taxes [Line Items]
Income before income tax expense (benefit) and equity in earnings of 50% or less owned companies	(17,748)	(23,663)	(28,675)
Eliminations
Income Taxes [Line Items]
Income before income tax expense (benefit) and equity in earnings of 50% or less owned companies	$ 3,201	$ 11,022	$ 8,782

Income Taxes - Components of Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Federal, current	$ (30,838)	$ (6)	$ 5,987
State, current	123	(78)	3
Foreign, current	5,533	5,005	3,307
Current income tax expense	(25,182)	4,921	9,297
Federal, deferred	2,435	(12,594)	(21,466)
State, deferred	(139)	(224)	(1,404)
Foreign, deferred	(38)	(72)	110
Deferred income tax benefit	2,258	(12,890)	(22,760)
Income Tax (Benefit) Expense	$ (22,924)	$ (7,969)	$ (13,463)

Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Statutory rate	(21.00%)	(21.00%)	(21.00%)	(35.00%)
U.S. federal income tax law changes	(11.80%)
SEACOR Holdings share awards to Company personnel	0.30%		0.20%
Exclusion of foreign subsidiaries with accumulated losses and withholding tax	7.70%	7.40%	9.30%
Noncontrolling interests	1.30%	1.70%	(1.60%)
State taxes		(0.30%)	(1.50%)
Return to provision	(0.40%)	2.80%	(0.50%)
Other	0.50%		0.50%
Effective Tax Rate	(23.40%)	(9.40%)	(14.60%)

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax liabilities:
Property and equipment	$ 58,676	$ 63,827
Investments in 50% or Less Owned Companies	2,925	3,039
Other	4,819	10,612
Total deferred tax liabilities	66,420	77,478
Deferred tax assets:
Federal Net Operating Loss Carryforwards	23,061	28,664
Other	10,073	16,561
Total deferred tax assets	33,134	45,225
Valuation Allowance	(2,536)	(1,311)
Total deferred tax assets	30,598	43,914
Net deferred tax liabilities	$ 35,822	$ 33,564

Derivative Instruments and Hedging Strategies - Schedule of Fair Value of Derivative Assets and Liabilities From Continuing Operations (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Not Designated as Hedging Instrument
Derivative [Line Items]
Derivative Liability	$ 895	$ 5,205
Not Designated as Hedging Instrument \| Forward Exchange Contract
Derivative [Line Items]
Derivative Liability	893
Not Designated as Hedging Instrument \| Non-current Liabilities
Derivative [Line Items]
Embedded derivative, fair value of embedded derivative liability	2	5,205
Designated as Hedging Instrument \| Cash Flow Hedging
Derivative [Line Items]
Derivative Liability	3,698	2,925
Designated as Hedging Instrument \| Current Liabilities \| Interest Rate Swap \| Cash Flow Hedging
Derivative [Line Items]
Derivative Liability	$ 3,698	$ 2,925

Derivative Instruments and Hedging Strategies - Additional Information (Details) $ in Thousands, € in Millions, £ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)	Dec. 31, 2020 GBP (£)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2020 EUR (€)	Dec. 20, 2018
Derivative [Line Items]
Derivative losses on cash flow hedges	$ (2,139)		$ (1,901)	$ (1,939)
Equity method investment, ownership percentage						49.00%
Estimated fair value of derivative instruments from continuing operations	4,600
Credit risk adjustment	300
Interest Rate Swap
Derivative [Line Items]
Derivative losses on cash flow hedges	$ (2,139)		$ (1,901)	(1,939)
Forward Exchange Contract \| Windcat Workboats Holdings Ltd
Derivative [Line Items]
Proceeds to be received from sale of business \| £		£ 31.5
Maximum
Derivative [Line Items]
Equity method investment, ownership percentage	50.00%		50.00%		50.00%
Minimum
Derivative [Line Items]
Equity method investment, ownership percentage	20.00%				20.00%
Minimum \| SEACOR Marine Foreign Holdings
Derivative [Line Items]
Equity method investment, ownership percentage	50.00%				50.00%
Cash Flow Hedging
Derivative [Line Items]
Derivative losses on cash flow hedges	$ (700)		$ (1,300)	$ 1,600
Cash Flow Hedging \| Interest Rate Swap \| Designated as Hedging Instrument \| Windcat Workboats Holdings Ltd
Derivative [Line Items]
Derivative, number of instruments held, total	2				2
Derivative, fixed interest rate	0.03%				0.03%
Derivative, notional amount	$ 20,400				€ 15.0
Cash Flow Hedging \| Interest Rate Swap \| Designated as Hedging Instrument \| SEACOR 88/888
Derivative [Line Items]
Derivative, fixed interest rate	3.175%				3.175%
Derivative, notional amount	$ 5,500
Cash Flow Hedging \| Interest Rate Swap \| Designated as Hedging Instrument \| MexMar
Derivative [Line Items]
Equity method investment, ownership percentage	49.00%				49.00%
Derivative, number of instruments held, total	5				5
Derivative, notional amount	$ 69,400
Cash Flow Hedging \| 3.32% Interest Rate Swap Agreement \| Designated as Hedging Instrument \| SEACOR Marine Foreign Holdings
Derivative [Line Items]
Derivative, fixed interest rate	3.32%				3.32%
Derivative, notional amount	$ 7,800
Cash Flow Hedging \| 3.195% Interest Rate Swap Agreement \| Designated as Hedging Instrument \| SEACOR Marine Foreign Holdings
Derivative [Line Items]
Derivative, fixed interest rate	3.195%				3.195%
Derivative, notional amount	$ 43,000
Cash Flow Hedging \| Maximum \| Interest Rate Swap \| Designated as Hedging Instrument \| MexMar
Derivative [Line Items]
Derivative, fixed interest rate	2.10%				2.10%
Cash Flow Hedging \| Minimum \| Interest Rate Swap \| Designated as Hedging Instrument \| MexMar
Derivative [Line Items]
Derivative, fixed interest rate	1.71%				1.71%
Derivative Liabilities \| Fair Value Hedging
Derivative [Line Items]
Recognized gain (loss) on hedged item in fair value hedge	$ (900)

Derivative Instruments and Hedging Strategies - Effect of Derivative Instruments on Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Derivative losses on cash flow hedges	$ (2,139)	$ (1,901)	$ (1,939)
Interest Rate Swap
Derivative losses on cash flow hedges	(2,139)	(1,901)	(1,939)
Joint Venture Interest Rate Swap
Derivative losses on cash flow hedges	(156)	(645)	(76)
Interest Expense
Reclassification of derivative losses on cash flow hedges	$ 1,425	$ 552	$ 31

Derivative Instruments and Hedging Strategies - Gains (Losses) on Derivative Instruments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Gains (losses) on derivative instruments	$ 4,310	$ 71	$ 2,854
Embedded Derivative Financial Instruments
Gains (losses) on derivative instruments	5,203	$ 71	1,556
Interest Rate Swap
Gains (losses) on derivative instruments			$ 1,298
Foreign Exchange Option
Gains (losses) on derivative instruments	$ (893)

Fair Value Measurements - Schedule of Fair Value of Assets and Liabilities Measured on Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($)
$ in Thousands

Dec. 31, 2020

Dec. 31, 2019

Fair Value, Inputs, Level 1

Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]

Construction reserve funds

$ 12,893

Fair Value, Inputs, Level 2

Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]

Derivative Liability

$ 4,591

2,925

Fair Value, Inputs, Level 3

Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]

Conversion Option Liability on Convertible Senior Notes

^[1]

$ 2

$ 5,205

[1]	For the year ended December 31, 2020, the Company recognized a $5.2 million gain in the fair market valuation of the Conversion Option on the Convertible Senior Notes, as valued by an independent third-party

Fair Value Measurements - Schedule of Fair Value of Assets and Liabilities Measured on Recurring Basis (Details) (Parenthetical) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)
Fair Value Disclosures [Abstract]
Derivative, gain (loss) on derivative, net, total	$ 5.2

Fair Value Measurements - Schedule of Estimated Fair Values of Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Reported Value Measurement
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash, cash equivalents and restricted cash	$ 36,018	$ 84,486
Investments, at cost, in 50% or less owned companies (included in other assets)	132	132
Long-term debt, including current portion	472,887	373,516
Estimate of Fair Value Measurement \| Fair Value, Inputs, Level 1
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash, cash equivalents and restricted cash	36,018	84,486
Estimate of Fair Value Measurement \| Fair Value, Inputs, Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term debt, including current portion	$ 470,561	$ 356,086

Fair Value Measurements - Schedule of Other Assets and Liabilities Measured at Fair Value (Details) - Fair Value, Inputs, Level 2 - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Fast Support Vessels
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Property and equipment		$ 1,858
Liftboats
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Property and equipment	$ 43,005
Anchor Handling Towing Supply
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Property and equipment		$ 520

Fair Value Measurements - Additional Information (Details)	12 Months Ended
	Dec. 31, 2020 USD ($) Investment	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Impairment charges	$ 18,800,000	$ 12,000,000.0	$ 14,600,000
Number of marked investments, at equity, in 50% or less owned companies \| Investment	2
Investments, at equity, in 50% or less owned companies	$ 75,308,000	$ 120,831,000
Seabulk Tims I and Offshore Vessel Holdings
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments, at equity, in 50% or less owned companies	$ 0

Warrants - Additional Information (Details) - $ / shares	Sep. 18, 2020	Sep. 01, 2020	Jun. 14, 2019	Jun. 08, 2019	May 28, 2019	Dec. 31, 2020	Dec. 31, 2019
Class Of Warrant Or Right [Line Items]
Class of warrant or right, exercised during period	83,367	255,307	64,440	64,440	380,000
Class of warrant or right, outstanding						1,488,292	1,826,966
Number of shares withheld in an exercise to purchase warrants as payment for the exercise	354		49
Warrants Transactions
Class Of Warrant Or Right [Line Items]
Class of warrant or right, exercise price per share						$ 0.01
Class of warrant or right, number of securities called by warrants or rights						2,560,456
Class of warrant or right, outstanding						1,488,292

Stockholders' Equity - Additional Information (Details)
€ in Millions, £ in Millions

1 Months Ended

12 Months Ended

Sep. 18, 2020

Sep. 01, 2020

Mar. 20, 2020

Jun. 14, 2019

Jun. 08, 2019

May 28, 2019

Mar. 15, 2019

USD ($)

Mar. 15, 2019

EUR (€)

Jan. 25, 2019

USD ($)

Jan. 25, 2019

GBP (£)

Jan. 09, 2019

USD ($)

Vessel

Apr. 30, 2018

Dec. 31, 2020

USD ($)

Dec. 31, 2019

USD ($)

Dec. 31, 2018

USD ($)

Jun. 09, 2020

Jan. 01, 2019

USD ($)

Dec. 31, 2017

USD ($)

Class of warrant or right, exercised during period

83,367

255,307

64,440

380,000

Class of warrant or right, outstanding

1,488,292

1,826,966

Number of shares withheld in an exercise to purchase warrants as payment for the exercise

354

Cumulative Effect of New Accounting Principle in Period of Adoption | $

^[1]

^[2]

Common stock value | $

$ 235,000

$ 219,000

401,836,000

478,924,000

$ 565,351,000

$ 511,097,000

Retained Earnings [Member]

Cumulative Effect of New Accounting Principle in Period of Adoption | $

$ (51,839,000)

$ 27,076,000

$ 137,250,000

$ 204,442,000

Retained Earnings [Member] | Accounting Standards Update 2016-02 | Cumulative Effect, Period of Adoption, Adjustment

Cumulative Effect of New Accounting Principle in Period of Adoption | $

$ 10,400,000

Private Placement

Stock Issued During Period, Shares, New Issues

603,872

750,000

Acquired | Vessel

Common stock value | $

$ 7,800

Windcat Workboats Facilities | Seabulk Overseas

Business acquisition, percentage of voting interests acquired

6.25%

100.00%

Business acquisition, exchange for consideration

50,000

Business combination, consideration transferred, total

$ 1,400,000

€ 1.2

$ 2,000,000.0

£ 1.6

Falcon Global Holdings

Business acquisition, percentage of voting interests acquired

28.00%

Business acquisition, exchange for consideration

900,000

Ownership percentage by parent

100.00%

2017 Equity Incentive Plan

Common shares registered for issuance

2,174,000

Common shares remaining available for issuance

24,821

2020 Equity Incentive Plan

Common shares registered for issuance

2,114,821

Common shares authorized for issuance

2,080,000

Common shares remaining available for issuance

1,928,832

Exchange Warrants

Class of warrant or right, outstanding

1,488,292

Number of shares withheld in an exercise to purchase warrants as payment for the exercise

354

[1]	Excludes three CTVs as assets held for sale and seven PSVs acquired as part of the SEACOSCO Acquisition (See “Note 3. Business Acquisitions”).
[2]	Excludes two CTVs as assets held for sale.

Noncontrolling Interests in Subsidiaries - Schedule of Noncontrolling Interests in the Company's Consolidated Subsidiaries (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Mar. 19, 2020	Dec. 31, 2019
Minority Interest [Line Items]
Noncontrolling interest	$ 319		$ 21,432
Falcon Global
Minority Interest [Line Items]
Noncontrolling interest, ownership percentage by noncontrolling owners		28.00%
Noncontrolling interest			21,119
Other Noncontrolling Interests
Minority Interest [Line Items]
Noncontrolling interest, ownership percentage by noncontrolling owners	1.80%
Noncontrolling interest	$ 319		$ 313

Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which is directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent (that is, noncontrolling interest, previously referred to as minority interest).

+ References + Details

Noncontrolling Interests in Subsidiaries - Schedule of Noncontrolling Interests in the Company's Consolidated Subsidiaries (Parenthetical) (Details)	Mar. 19, 2020
Falcon Global
Minority Interest [Line Items]
Noncontrolling interest, ownership percentage by noncontrolling owners	28.00%

Noncontrolling Interests in Subsidiaries - Additional Information (Details) - USD ($) $ in Thousands			3 Months Ended								12 Months Ended
	Mar. 20, 2020	Mar. 19, 2020	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Minority Interest [Line Items]
Net income (loss), including portion attributable to noncontrolling interest, total			$ (38,847)	$ (18,077)	$ (6,066)	$ (19,992)	$ (21,918)	$ (18,240)	$ (30,264)	$ (28,273)	$ (82,982)	$ (98,695)	$ (82,052)
Net income (loss) attributable to noncontrolling interest, total											$ (4,067)	$ (5,858)	$ (4,444)
Falcon Global Holdings
Minority Interest [Line Items]
Business acquisition, percentage of voting interests acquired	28.00%
Business acquisition, exchange for consideration	900,000
Noncontrolling Interest, ownership percentage by parent	28.00%	72.00%
Net income (loss), including portion attributable to noncontrolling interest, total		$ 16,600
Net income (loss) attributable to noncontrolling interest, total		$ 4,600
Falcon Global Holdings
Minority Interest [Line Items]
Business acquisition, percentage of voting interests acquired	100.00%
Falcon Global Holdings \| Common Stock
Minority Interest [Line Items]
Business acquisition, exchange for consideration	900,000

The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

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Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Savings and Multi-employer Pension Plans - Additional Information (Details) € in Millions, £ in Millions, $ in Millions		3 Months Ended		12 Months Ended
	Jan. 01, 2019	Jun. 30, 2018 USD ($)	Jun. 30, 2018 EUR (€)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2014 USD ($)	Nov. 07, 2018 GBP (£)	Dec. 31, 2015 USD ($)	Dec. 31, 2013 USD ($)
Pension And Other Postretirement Benefits Disclosure [Line Items]
Defined contribution plan, employer matching contribution, percent of employees' gross pay	1.00%			2.00%
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Amount				$ 0.3	$ 0.2
Other Defined Contribution Plan
Pension And Other Postretirement Benefits Disclosure [Line Items]
Defined contribution plan, cost				$ 0.4	$ 0.3	$ 0.2
United Kingdom Merchant Navy Officers Pension Fund \| Foreign Pension Plan
Pension And Other Postretirement Benefits Disclosure [Line Items]
Pension and other postretirement benefits cost (reversal of cost), total							$ 19.4
Pension and other postretirement benefits invoice										$ 2.6
Pension and other post-retirement benefit plans, total funding deficit \| £								£ 9.0
Merchant Navy Ratings Pension Fund
Pension And Other Postretirement Benefits Disclosure [Line Items]
Multiemployer plan, contributions by employer		$ 1.2	€ 0.9
Merchant Navy Ratings Pension Fund \| Foreign Pension Plan
Pension And Other Postretirement Benefits Disclosure [Line Items]
Pension and other post-retirement benefit plans, total funding deficit									$ 6.9

Share Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jun. 09, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Payments for distribution of restricted stock, spin-off				$ 2,700
Allocated share-based compensation expense, total	$ 4,800
Employee service share-based compensation, nonvested awards, compensation cost not yet recognized, total	$ 4,700	$ 6,500	$ 6,800
Share-based compensation arrangement by share-based payment award, fair value assumptions, expected dividend rate	0.00%	0.00%
Share-based compensation arrangement by share-based payment award, fair value assumptions, expected volatility rate	76.10%	51.10%
Share-based compensation arrangement by share-based payment award, fair value assumptions, discount for postvesting restrictions	0.52%	2.10%
Share-based compensation arrangement by share-based payment award, fair value assumptions, expected term	9 years 11 months 1 day	9 years 9 months
Share-based compensation arrangement by share-based payment award, options, exercises in period, intrinsic value	$ 1,600
Exercise of options (in shares)	0	113,750
Share-based compensation arrangement by share-based payment award, options, outstanding, intrinsic value	$ 0
Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Distribution of restricted stock in connection with spin-off				120,693
Employee service share-based compensation, nonvested awards, compensation cost not yet recognized, period for recognition	1 year 3 months
Share-based compensation arrangement by share-based payment award, equity instruments other than options, grants in period, weighted average grant date fair value	$ 6.81
Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Employee service share-based compensation, nonvested awards, compensation cost not yet recognized, period for recognition	10 months 20 days
2017 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, number of shares authorized	2,174,000
Share-based compensation arrangement by share-based payment award, number of shares available for grant	24,821
Percentage of number of common stock shares outstanding	10.00%
Allocated share-based compensation expense, total		$ 5,300	$ 4,400
2017 Equity Incentive Plan \| Restricted Stock \| Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period		1 year
2017 Equity Incentive Plan \| Restricted Stock \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period		4 years
2017 Equity Incentive Plan \| Employee Stock Option \| Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period		1 year
2017 Equity Incentive Plan \| Employee Stock Option \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period		4 years
2020 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, number of shares authorized					2,080,000
Share-based compensation arrangement by share-based payment award, number of shares available for grant					1,928,832
Common shares registered for issuance					2,114,821
Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, number of shares authorized		300,000
Share-based compensation arrangement by share-based payment award, discount from market price, purchase date				85.00%
Period of common stock reserved for issuance		10 years
2017 Plan and 2020 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, options, outstanding, exercise price, ending balance	$ 3.60	$ 8.73
2017 Plan and 2020 Plan \| Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, equity instruments other than options, grants in period, weighted average grant date fair value	$ 6.40	$ 13.28

Share Based Compensation - Schedule of Equity Incentive Plan Transactions (Details) - shares

12 Months Ended

Dec. 31, 2020

Dec. 31, 2019

Outstanding as of the beginning of year (in shares)

913,569

805,566

Outstanding as of the end of year (in shares)

261,972

230,503

Exercised (in shares)

113,750

Forfeited (in shares)

55,000

8,750

1,120,541

913,569

Director Stock Awards

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

59,900

30,197

Restricted Stock

Outstanding as of the beginning of year (in shares)

303,609

192,346

Outstanding as of the end of year (in shares)

289,452

^[1]

245,400

Vested (in shares)

143,697

131,937

Forfeited (in shares)

12,650

2,200

436,714

303,609

[1]	Excludes 240,800 grants of performance-based stock units that are not considered outstanding until such time that they become probable to vest.

Share Based Compensation - Schedule of Equity Incentive Plan Transactions (Details) (Parenthetical)	Dec. 31, 2020 shares
Performance Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares outstanding	240,800

Share Based Compensation - Schedule of Restricted Stock Transactions (Details) - Restricted Stock - $ / shares

12 Months Ended

Dec. 31, 2020

Dec. 31, 2019

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Outstanding as of the beginning of year (in shares)

303,609

192,346

Non-Vested, weight average grant price (in dollars per share)

$ 20.46

Granted, weight average grant price (in dollars per share)

289,452

^[1]

245,400

$ 6.81

Vested, shares (in shares)

143,697

131,937

Vested, weight average grant price (in dollars per share)

$ 13.43

Forfeited (in shares)

12,650

2,200

Forfeited, weight average grant price (in dollars per share)

$ 12.30

Outstanding as of the end of year (in shares)

436,714

303,609

Non-Vested, weight average grant price (in dollars per share)

$ 11.60

$ 20.46

[1]	Excludes 240,800 grants of performance-based stock units that are not considered outstanding until such time that they become probable to vest.

Share Based Compensation - Schedule of Stock Option Transactions (Details) - $ / shares

12 Months Ended

Dec. 31, 2020

Dec. 31, 2019

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Non-Vested, shares (in shares)

913,569

Non-Vested, weight average grant price (in dollars per share)

$ 14.81

Granted, shares (in shares)

261,972

230,503

Granted, weight average grant price (in dollars per share)

$ 3.68

Exercise of options (in shares)

113,750

Forfeited, shares (in shares)

55,000

Forfeited, weight average grant price (in dollars per share)

$ 13.43

Non-Vested, shares (in shares)

1,120,541

913,569

Non-Vested, weight average grant price (in dollars per share)

$ 12.49

$ 14.81

Exercisable, shares (in shares)

^[1]

716,965

Exercisable, weight average grant price (in dollars per share)

$ 13.03

[1]	The weighted average remaining contractual term is 8.18 years.

Share Based Compensation - Schedule of Stock Option Transactions (Details) (Parenthetical)	12 Months Ended
	Dec. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-based compensation arrangement by share-based payment award, options, exercisable, weighted average remaining contractual term	8 years 2 months 4 days

Related Party Transactions - Additional Information (Details)
$ / shares in Units, € in Millions, £ in Millions

1 Months Ended

3 Months Ended

12 Months Ended

Sep. 18, 2020

Sep. 01, 2020

Jun. 26, 2020

USD ($)

Jun. 14, 2019

Jun. 08, 2019

May 28, 2019

Mar. 15, 2019

USD ($)

Mar. 15, 2019

EUR (€)

Jan. 25, 2019

USD ($)

Jan. 25, 2019

GBP (£)

Jan. 09, 2019

Dec. 20, 2018

USD ($)

Sep. 28, 2018

USD ($)

May 02, 2018

USD ($)

$ / shares

Dec. 01, 2015

USD ($)

Jul. 31, 2020

USD ($)

Apr. 30, 2018

USD ($)

$ / shares

Dec. 31, 2020

USD ($)

Sep. 30, 2020

USD ($)

Jun. 30, 2020

USD ($)

Mar. 31, 2020

USD ($)

Dec. 31, 2019

USD ($)

Sep. 30, 2019

USD ($)

Jun. 30, 2019

USD ($)

Mar. 31, 2019

USD ($)

Dec. 31, 2020

USD ($)

Dec. 31, 2019

USD ($)

Dec. 31, 2018

USD ($)

Dec. 31, 2017

USD ($)

Jan. 12, 2021

Dec. 28, 2018

Related Party Transaction, Rate

0.50%

Interest Expense, Related Party

$ 100,000

$ 200,000

$ 300,000

Class of warrant or right, outstanding | shares

49.00%

1,488,292

1,826,966

1,488,292

1,826,966

Issuance of Common Stock

$ 6,596,000

42,996,000

Class of warrant or right, exercised during period | shares

83,367

255,307

64,440

380,000

$ 95,000,000.0

Mexmar Offshore International

$ 10,000,000.0

Revenues

$ 36,044,000

$ 36,201,000

$ 33,925,000

$ 35,667,000

$ 42,478,000

$ 46,996,000

$ 45,014,000

$ 39,965,000

$ 141,837,000

174,453,000

$ 179,161,000

Noncontrolling interest, ownership percentage by noncontrolling owners

49.00%

51.00%

Offshore Vessel Holdings

Noncontrolling interest, ownership percentage by noncontrolling owners

51.00%

Issuance of Common Stock (in shares) | shares

10,000,000.0

Financing agreement

$ 2,400,000

Private Placement

603,872

750,000

Issuance of Common Stock

$ 15,000,000.0

Warrants Issued In Private Placement

Class of warrant or right, exercise price of warrants or rights | $ / shares

$ 0.01

Class of warrant or right, outstanding | shares

2,168,586

Class of warrant or right, number of securities called by warrants or rights | shares

674,164

Convertible Senior Notes 3.75%

Convertible debt, total

$ 125,000,000.0

$ 175,000,000.0

$ 125,000,000.0

Debt instrument, convertible, conversion ratio

23.26

Debt instrument, face amount

$ 1,000

Debt instrument, interest rate

4.25%

3.75%

4.25%

Lender Non Recourse

Debt instrument, convertible, terms of conversion feature

$ 70,000,000.0

Carlyle Group

Convertible debt, total

$ 175,000,000.0

Interest rate term

Interest on the Convertible Notes is payable semi-annually on June 15 and December 15 of each year, commencing June 15, 2016

Carlyle has not exercised this right subsequent to Mr. Hussein’s resignation but retains the right to appoint a member to the Board of Directors. Mr. Hussein has been designated by Carlyle to observe meetings of the Board of Directors pursuant to Carlyle’s observer rights under the Convertible Notes. This observation right will terminate at the time Carlyle owns less than $50.0 million in aggregate principal amount of the Convertible Notes or a combination of the Convertible Notes and our Common Stock representing less than 5.0% of the Company’s Common Stock outstanding on a fully diluted basis, assuming the conversion of all of the Convertible Notes and Warrants to purchase Common Stock held by Carlyle.

Class of warrant or right, outstanding | shares

1,488,292

Class of warrant or right, exercised during period | shares

83,367

64,440

Carlyle Group | Convertible Senior Notes Converted to Warrants

Debt conversion, original debt, amount

$ 50,000,000

$ 50,000,000.0

Class of warrant or right, exercise price of warrants or rights | $ / shares

$ 0.01

Debt instrument, convertible, conversion ratio

37.73

Debt instrument, face amount

$ 1,000

Debt instrument, convertible, conversion price | $ / shares

$ 26.50

Debt conversion, converted instrument, shares issued | shares

1,886,792

1,900,000

Talos Energy, Inc

Revenues

$ 1,500,000

$ 3,200,000

2,900,000

Windcat Workboats Facilities | CMB N.V. | Subsequent Event

Percentage sale of equity

100.00%

Windcat Workboats Facilities | Seabulk Overseas

Equity Method Investment Ownership Percentage

6.25%

100.00%

Ownership Percentage

100.00%

Business combination, consideration transferred, total

$ 1,400,000

€ 1.2

$ 2,000,000.0

£ 1.6

Business acquisition, exchange for consideration | shares

50,000

Limited Partner

29.70%

General Partner

Proceeds from Sale of Interest in Partnership Unit

66.70%

OSV Partners

7,500,000

^[1]

30.40%

OSV Partners | Limited Partner | Gellert

$ 5,000,000.0

OSV Partners | General Partner

$ 400,000

OSV Partners | Second Lien Debt

38.60%

Proceeds from issuance of debt

5,000,000.0

OSV Partners | Series A Preferred Stock

43.00%

Proceeds from Issuance of Redeemable Preferred Stock

2,500,000

Proceeds From issuance of additional redeemable preferred stock

2,500,000

Class of warrant or right, exercised during period | shares

43.00%

CME

255,307

380,000

5,000,000.0

49.00%

15,000,000.0

MEXMAR Offshore

^[2]

49.00%

10,000,000.0

Commitment to fund purchase

$ 5,000,000.0

MEXMAR Offshore | BRAZIL

Aggregate purchase price

$ 0

Long-term debt, total

$ 70,000,000

2,700,000

Loaned commitment amount

$ 1,960,000

MEXMAR Offshore | UP Offshore’s. | BRAZIL

Long-term debt, total

$ 5,500,000

Percentage of convertible notes converted into common stock

50.00%

Maximum | Carlyle Group

Convertible debt, total

$ 50,000,000.0

5.0

Percentage of convertible notes converted into common stock

20.00%

Minimum | Carlyle Group

10.0

Transition Services Agreement

$ 0

$ 600,000

4,500,000

Transition Services Agreement | Maximum

6,300,000

Tax Refund Agreement

Expected to cash tax refunds receivable

$ 31,200,000

Percentage of net operating losses facilitate tax savings

35.00%

Transaction fee

$ 3,000,000.0

Cash tax refunds receivable without restrict to use

23,100,000

Cash tax refunds receivable with restrict to use

8,100,000

Tax refunds restricted cash

$ 7,000,000.0

7,000,000.0

SEACOR Holdings

Guarantor Obligations, Maximum Exposure, Undiscounted

8,100,000

$ 22,800,000

8,100,000

$ 22,800,000

$ 40,600,000

SEACOR Holdings | Tax Refund Agreement

Cash tax refunds receivable without restrict to use

23,100,000

Cash tax refunds receivable with restrict to use

8,100,000

Officer | OSV Partners | Limited Partner | Fabrikant

Officer | OSV Partners | Limited Partner | Llorca

300,000

Officer | OSV Partners | Limited Partner | Fabrikant, Gellert and Llorca

$ 200,000

Officer | OSV Partners | Second Lien Debt | General Partner

39.60%

General Partners' Capital Account, Total

3.90%

$ 200,000

Officer | OSV Partners | Series A Preferred Stock | General Partner

General Partners' Capital Account, Total

3.90%

$ 200,000

Officer | Maximum | OSV Partners

Officer | Maximum | OSV Partners | Limited Partner

$ 1,500,000

Officer | Maximum | OSV Partners | General Partner

3.90%

General Partners' Capital Account, Total

5.00%

$ 300,000

[1]	^{The Company owns}^66.7^{% of the General Partner and}^29.7^{% of the limited Partner}^.
[2]	^{This Joint Venture holds the investment in UP Offshore}^.

Commitments and Contingencies - Additional Information (Details) R$ in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)	Dec. 31, 2020 BRL (R$)
Commitments And Contingencies [Line Items]
Unrecorded unconditional purchase obligation, total	$ 11.7
Unrecorded unconditional purchase obligation, due within one years	10.7
Unrecorded unconditional purchase obligation, due within two years	1.0
Unrecorded unconditional purchase obligation due within four years	$ 9.6
Deficiency Notice
Commitments And Contingencies [Line Items]
Cost allocation percentage	70.00%
Deficiency Notice \| Seabulk Overseas
Commitments And Contingencies [Line Items]
Cost allocation percentage	30.00%
Minimum \| Deficiency Notice
Commitments And Contingencies [Line Items]
Potential range of levies	$ 3.5	R$ 18,120
Maximum \| Deficiency Notice
Commitments And Contingencies [Line Items]
Potential range of levies	$ 2.5	R$ 12,870
Platform Supply Vessels
Commitments And Contingencies [Line Items]
Unrecorded unconditional purchase obligation, maximum quantity	1	1
FSV Offshore Support Vessels
Commitments And Contingencies [Line Items]
Unrecorded unconditional purchase obligation, maximum quantity	1	1

Major Customers and Segment Information - Additional Information (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020 USD ($) Customer	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2020 USD ($) Customer	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Segment Reporting Information [Line Items]
Revenue from contract with customer, including assessed tax	$ 36,044	$ 36,201	$ 33,925	$ 35,667	$ 42,478	$ 46,996	$ 45,014	$ 39,965	$ 141,837	$ 174,453	$ 179,161
Income (loss) from equity method investments									$ (8,163)	(14,459)	(4,009)
Customer Concentration Risk \| Sales Revenue, Net \| Seacor Marine Arabia LLC
Segment Reporting Information [Line Items]
Revenue from contract with customer, including assessed tax										$ 30,800	$ 21,400
Concentration risk, percentage										17.00%	12.00%
Customer Concentration Risk \| Sales Revenue, Net \| Ten Largest Customers
Segment Reporting Information [Line Items]
Concentration risk, percentage									76.00%	61.00%	57.00%
Geographic Concentration Risk \| Sales Revenue, Net
Segment Reporting Information [Line Items]
Number of customer \| Customer	2								2
Geographic Concentration Risk \| Sales Revenue, Net \| Non-US
Segment Reporting Information [Line Items]
Income (loss) from equity method investments									$ (6,600)	$ (13,000)	$ (1,900)
Geographic Concentration Risk \| Sales Revenue, Net \| Zamil Offshore
Segment Reporting Information [Line Items]
Revenue from contract with customer, including assessed tax										$ 20,300	$ 12,200
Concentration risk, percentage										11.00%	7.00%
Geographic Concentration Risk \| Sales Revenue, Net \| Exxon Mobil
Segment Reporting Information [Line Items]
Revenue from contract with customer, including assessed tax									$ 24,800	$ 16,500	$ 3,100
Concentration risk, percentage									17.00%	9.00%	2.00%
Geographic Concentration Risk \| Sales Revenue, Net \| Saudi Aramco
Segment Reporting Information [Line Items]
Revenue from contract with customer, including assessed tax									$ 30,700	$ 10,500	$ 9,200
Concentration risk, percentage									21.00%	6.00%	5.00%
Geographic Concentration Risk \| Stockholders' Equity \| Non-US
Segment Reporting Information [Line Items]
Concentration risk, percentage									89.00%	75.00%	71.00%

Major Customers and Segment Information - Schedule of Segment Reporting Information, by Segment (Details) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2020

Sep. 30, 2020

Jun. 30, 2020

Mar. 31, 2020

Dec. 31, 2019

Sep. 30, 2019

Jun. 30, 2019

Mar. 31, 2019

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

$ 36,044

$ 36,201

$ 33,925

$ 35,667

$ 42,478

$ 46,996

$ 45,014

$ 39,965

$ 141,837

$ 174,453

$ 179,161

91,145

109,523

119,587

Administrative and general

50,692

64,930

59,574

40,051

39,791

41,616

Losses on Asset Dispositions and Impairments, Net

57,167

57,166

61,419

Other Costs and Expenses

104,743

112,797

115,999

(17,588)

(6,461)

(11,989)

Operating Loss

(16,915)

$ (13,179)

$ (17,824)

$ (23,721)

(10,555)

$ (5,566)

$ (18,591)

$ (19,616)

(71,639)

(54,328)

(68,414)

1,012,873

^[1]

899,024

^[1]

1,012,873

^[1]

899,024

^[1]

1,047,797

(291,538)

(308,917)

(291,538)

(308,917)

(418,340)

721,335

590,107

721,335

590,107

629,457

861,806

^[2]

817,926

^[3]

861,806

^[2]

817,926

^[3]

861,618

^[4]

Leased In Equipment

7,525

15,840

12,964

Time Charter

133,454

157,052

150,064

Bareboat Charter

2,855

5,131

4,635

Other Marine Services

5,528

12,270

24,462

Personnel

48,348

55,975

58,532

Repairs and Maintenance

14,661

21,401

24,385

Drydocking

Insurance and Loss Reserves

4,269

5,848

7,792

5,763

5,622

5,970

Fuel, Lubes and Supplies

Other Direct Costs and Expenses

8,128

10,622

12,904

9,976

10,055

10,004

UNITED STATES

15,205

44,323

53,564

16,206

35,367

32,700

(1,001)

8,956

20,864

21,427

21,947

23,227

257,592

297,392

257,592

297,392

432,336

(134,391)

(157,514)

(134,391)

(157,514)

(224,737)

123,201

139,878

123,201

139,878

207,599

UNITED STATES | Leased In Equipment

164,656

^[2]

224,229

^[3]

164,656

^[2]

224,229

^[3]

351,748

^[4]

UNITED STATES | Time Charter

4,272

10,894

8,240

UNITED STATES | Bareboat Charter

9,873

38,955

38,802

UNITED STATES | Other Marine Services

2,910

1,562

UNITED STATES | Personnel

2,422

3,806

14,762

UNITED STATES | Repairs and Maintenance

10,065

17,491

18,708

UNITED STATES | Drydocking

1,655

7,583

5,152

UNITED STATES | Insurance and Loss Reserves

1,167

4,594

1,957

UNITED STATES | Fuel, Lubes and Supplies

1,774

2,370

2,922

UNITED STATES | Other Direct Costs and Expenses

1,172

2,936

3,568

373

393

Africa

35,411

45,621

51,508

22,691

27,900

34,188

12,720

17,721

17,320

10,833

10,404

10,453

204,079

207,107

204,079

207,107

184,361

(60,535)

(57,136)

(60,535)

(57,136)

(55,206)

143,544

149,971

143,544

149,971

129,155

Africa | Leased In Equipment

153,399

^[2]

161,915

^[3]

153,399

^[2]

161,915

^[3]

140,335

^[4]

3,029

3,090

4,281

Africa | Time Charter

Africa | Other Marine Services

35,876

44,160

43,847

(465)

1,461

7,661

Africa | Personnel

Africa | Repairs and Maintenance

10,552

13,833

16,538

5,175

4,701

6,330

Africa | Drydocking

Africa | Insurance and Loss Reserves

2,014

490

2,085

Africa | Fuel, Lubes and Supplies

1,026

1,051

1,096

Africa | Other Direct Costs and Expenses

2,940

3,471

3,826

984

4,354

4,313

Middle East and Asia

54,209

55,981

49,185

35,497

31,928

38,718

18,712

24,053

10,467

16,595

16,400

18,762

361,514

292,446

361,514

292,446

306,897

(75,349)

(73,039)

(75,349)

(73,039)

(81,378)

286,165

219,407

286,165

219,407

225,519

Middle East and Asia | Leased In Equipment

289,314

^[2]

250,890

^[3]

289,314

^[2]

250,890

^[3]

260,002

^[4]

Middle East and Asia | Time Charter

170

173

224

Middle East and Asia | Other Marine Services

52,052

54,312

50,072

Middle East and Asia | Personnel

2,157

1,669

(887)

Middle East and Asia | Repairs and Maintenance

18,188

16,698

16,806

Middle East and Asia | Drydocking

5,232

7,182

11,172

Middle East and Asia | Insurance and Loss Reserves

759

600

1,362

Middle East and Asia | Fuel, Lubes and Supplies

1,721

1,449

1,371

Middle East and Asia | Other Direct Costs and Expenses

2,706

2,904

4,027

6,891

3,095

3,980

Latin America

24,890

16,419

23,532

11,979

8,517

8,388

12,911

7,902

15,144

5,481

6,205

7,908

130,769

57,534

130,769

57,534

124,177

(13,312)

(16,239)

(13,312)

(16,239)

(57,002)

117,457

41,295

117,457

41,295

67,175

Latin America | Leased In Equipment

179,942

^[2]

116,736

^[3]

179,942

^[2]

116,736

^[3]

137,983

^[4]

Latin America | Time Charter

Latin America | Bareboat Charter

23,806

11,460

17,343

Latin America | Other Marine Services

3,569

4,635

Latin America | Personnel

1,084

1,390

1,554

Latin America | Repairs and Maintenance

6,698

4,459

4,399

Latin America | Drydocking

2,131

1,348

1,011

Latin America | Insurance and Loss Reserves

329

161

128

Latin America | Fuel, Lubes and Supplies

462

311

495

Latin America | Other Direct Costs and Expenses

990

1,056

1,225

Europe Continuing Operations

1,369

1,182

1,130

12,122

12,109

1,372

4,772

5,811

5,593

7,350

6,298

(4,221)

2,831

2,210

1,069

58,919

44,545

58,919

44,545

(7,951)

(4,989)

(7,951)

(4,989)

(17)

50,968

39,556

50,968

39,556

Europe Continuing Operations | Leased In Equipment

$ 74,495

^[2]

$ 64,156

^[3]

74,495

^[2]

64,156

^[3]

(28,450)

^[4]

Europe Continuing Operations | Time Charter

1,673

214

Europe Continuing Operations | Bareboat Charter

11,847

8,165

Europe Continuing Operations | Other Marine Services

(55)

Europe Continuing Operations | Personnel

330

3,944

1,372

Europe Continuing Operations | Repairs and Maintenance

2,845

3,494

2,081

Europe Continuing Operations | Drydocking

468

587

720

Europe Continuing Operations | Insurance and Loss Reserves

2,260

Europe Continuing Operations | Fuel, Lubes and Supplies

780

441

Europe Continuing Operations | Other Direct Costs and Expenses

320

255

258

$ 359

$ 1,031

$ 188

[1]	Includes property and equipment acquired in business acquisitions at acquisition date fair value, and net of the impact of recognized impairment charges.
[2]	Total assets exclude $105.6 million of corporate assets, and $50.2 million of assets held for sale.
[3]	Total assets exclude $145.5 million of corporate assets, and $45.7 million of assets held-for-sale.
[4]	Total assets exclude $153.1 million of corporate assets, and $88.2 million of assets held-for-sale.

Major Customers and Segment Information - Schedule of Segment Reporting Information, by Segment (Parenthetical) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Assets, Total	$ 1,017,663	$ 1,009,193
Assets held for sale	50,200	45,700	$ 88,200
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Assets, Total	$ 105,600	$ 145,500	$ 153,100

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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