Document And Entity Information
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate
us-gaap_DerivativeGainLossOnDerivativeNet
Derivative, Gain (Loss) on Derivative, Net, Total
Note To Financial Statement Details Textual
Significant Accounting Policies
Note 1 - Nature of Operations and Accounting Policies
Equity Option [Member]
Note 2 - Business Acquisitions
Note 3 - Equipment Acquisitions and Dispositions
us-gaap_SecuredLongTermDebt
Secured Long-term Debt, Noncurrent
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsDiscountForPostvestingRestrictions
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Discount for Postvesting Restrictions
Note 4 - Investments, at Equity, and Advances to 50% or Less Owned Companies
Note 5 - Construction Reserve Funds
Note 6 - Leases
Note 7 - Long-term Debt
Note 8 - Income Taxes
Note 9 - Derivative Instruments and Hedging Strategies
Note 10 - Fair Value Measurements
Note 13 - Noncontrolling Interests in Subsidiaries
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate
Note 15 - Share Based Compensation
Note 16 - Related Party Transactions
us-gaap_LiabilitiesCurrent
Total current liabilities
Note 17 - Commitments and Contingencies
Note 18 - Major Customers and Segment Information
Note 19 - Supplemental Information for Statements of Cash Flows
us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term
Note 21 - Quarterly Financial Information (Unaudited)
Other current liabilities
Schedule II - Valuation and Qualifying Accounts
Note 1 - Nature of Operations and Accounting Policies - Deferred Revenues (Details)
Note 1 - Nature of Operations and Accounting Policies - Cash, Cash Equivalents and Restricted Cash (Details)
Note 1 - Nature of Operations and Accounting Policies - Property and Equipment Useful Life (Details)
Note 1 - Nature of Operations and Accounting Policies - Summary of Property and Equipment (Details)
Note 1 - Nature of Operations and Accounting Policies - Deferred Gain Activity (Details)
Note 1 - Nature of Operations and Accounting Policies - Accumulated Other Comprehensive Income (Details)
Note 2 - Business Acquisitions - Allocation of the Purchase Price for the Company's Acquisitions (Details)
Note 3 - Equipment Acquisitions and Dispositions - Equipment Acquisitions and Dispositions (Details)
Note 4 - Investments, at Equity, and Advances to 50% or Less Owned Companies - Equity Investments (Details)
Note 4 - Investments, at Equity, and Advances to 50% or Less Owned Companies - Consolidation Net Assets (Details)
Note 5 - Construction Reserve Funds - Construction Reserve Funds (Details)
Granted, weight average grant price (in dollars per share)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value
Note 6 - Leases - Schedule of Future Minimum Rental Payments (Details)
us-gaap_DerivativeNumberOfInstrumentsHeld
Derivative, Number of Instruments Held, Total
Note 7 - Long-term Debt - Schedule of long-term Debt Obligation (Details)
Vested, weight average grant price (in dollars per share)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue
Note 7 - Long-term Debt - Schedule of Long-term Debt Maturities (Details)
Note 8 - Income Taxes - Schedule of Income before Income Tax (Details)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
Non-Vested, weight average grant price (in dollars per share)
Non-Vested, weight average grant price (in dollars per share)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod
Forfeited (in shares)
Note 8 - Income Taxes - Components of Income Tax Expense (Benefit) (Details)
Note 8 - Income Taxes - Income Tax Rate Reconciliation (Details)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
Outstanding as of the beginning of year (in shares)
Outstanding as of the end of year (in shares)
Note 8 - Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details)
Note 9 - Derivative Instruments and Hedging Strategies - Derivative Instruments (Details)
Note 9 - Derivative Instruments and Hedging Strategies - Effect of Derivative Instruments on Other Comprehensive Income (Loss) (Details)
Note 9 - Derivative Instruments and Hedging Strategies - Gains (Losses) on Derivative Instruments (Details)
Granted (in shares)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
Note 10 - Fair Value Measurements - Assets and Liabilities on Recurring Basis (Details)
Vested, shares (in shares)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod
Vested (in shares)
Note 10 - Fair Value Measurements - Estimated Fair Value (Details)
Note 10 - Fair Value Measurements - Other Assets and Liabilities at Fair Value (Details)
Note 13 - Noncontrolling Interests in Subsidiaries - Noncontrolling Interest (Details)
us-gaap_LongTermDebtCurrent
Portion due within one year
Current portion of long-term debt
Note 15 - Share Based Compensation - Equity Incentive Plan Transactions (Details)
Note 15 - Share Based Compensation - Restricted Stock Transactions (Details)
Other comprehensive (loss) income
Other comprehensive income
Note 15 - Share Based Compensation - Stock Option Transactions (Details)
Note 16 - Related Party Transactions - Related Party Transactions (Details)
us-gaap_OtherComprehensiveIncomeLossTax
Income tax (expense) benefit
Income tax benefit (expense)
Note 17 - Commitments and Contingencies - Expected Payment (Details)
Other comprehensive income (loss)
Other comprehensive (loss) income, net
Other comprehensive income, net
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block]
Note 18 - Major Customers and Segment Information - Summary of Reportable Segments (Details)
Note 18 - Major Customers and Segment Information - Income (Loss) in Equity Method Investments (Details)
Exercisable, weight average grant price (in dollars per share)
us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term
Note 19 - Supplemental Information for Statements of Cash Flows - Supplemental Information (Details)
Note 21 - Quarterly Financial Information (Details)
Schedule II - Valuation and Qualifying Accounts (Details)
Notes To Financial Statements
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value
Notes To Financial Statements [Abstract]
us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
Total equity
Balance
Balance
Exercisable, shares (in shares)
us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value
Granted, weight average grant price (in dollars per share)
us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValue
Non-Vested, weight average grant price (in dollars per share)
Non-Vested, weight average grant price (in dollars per share)
us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfShares
Non-Vested, shares (in shares)
Non-Vested, shares (in shares)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price, Ending Balance
Accounts payable and accrued expenses
Deferred revenues
Exercised (in dollars per share)
Accrued wages and benefits
Accrued income taxes
Director share awards
The amount of expense for director stock awards.
Lessee, Operating Leases [Text Block]
smhi_StockRepurchasedDuringPeriodValueExerciseOfWarrants
Exercise of Warrants
Equity impact of the value of stock that has been repurchased during the period, due to the exercise of warrants, and has not been retired and is held in treasury.
us-gaap_DefinedBenefitPensionPlanLiabilitiesCurrent
Liability, Defined Benefit Pension Plan, Current
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance
Outstanding as of the beginning of year (in shares)
Outstanding as of the end of year (in shares)
Proceeds from exercise of stock options and warrants
Amount of cash inflow from exercise of stock options and warrants granted.
smhi_RestrictedStockVesting
Restricted stock vesting
The value of restricted stock that has vested during the period
smhi_ClassOfWarrantOrRightExercisedDuringPeriod
Class of Warrant or Right, Exercised During Period
The number of warrants or rights exercised during period.
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod
Expired (in shares)
Warrants and Rights [Text Block]
The entire disclosure for warrants and rights.
PIPE Warrants [Member]
Related to the PIPE Warrants.
smhi_ClassOfWarrantOrRightExercisedDuringPeriodExercisePrice
Class of Warrant or Right, Exercised During Period, Exercise Price
Exercise price per share of warrants or rights exercised during period.
us-gaap_PolicyTextBlockAbstract
Accounting Policies
Carlyle Warrants [Member]
Related to the Carlyle Warrants.
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPricePurchaseDate
Share-based Compensation Arrangement by Share-based Payment Award, Discount from Market Price, Purchase Date
Merchant Navy Ratings Pension Fund [Member]
Related to the Merchant Navy Ratings Pension Fund.
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period
Restricted Assets Disclosure [Text Block]
Current Liabilities:
us-gaap_Assets
Assets, Total
Plan Name [Axis]
Plan Name [Domain]
Property and Equipment:
us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Total
us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition
Mergers, Acquisitions and Dispositions Disclosures [Text Block]
Disclosure of Compensation Related Costs, Share-based Payments [Text Block]
Equity Award [Domain]
us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders
Distributions to noncontrolling interests
us-gaap_MinorityInterestDecreaseFromRedemptions
Purchase of subsidiary shares from noncontrolling interests, net of tax
us-gaap_RestrictedCashAndCashEquivalents
Restricted cash
Award Type [Axis]
Net Loss attributable to Noncontrolling Interests in Subsidiaries
Net Income (Loss) Attributable to Noncontrolling Interest, Total
Director Stock Awards [Member]
Related to director stock awards.
Receivables:
Comprehensive Loss attributable to Noncontrolling Interests in Subsidiaries
Commitments and Contingencies Disclosure [Text Block]
us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment
Accumulated depreciation
us-gaap_PropertyPlantAndEquipmentNet
Net property and equipment
Consolidation of 50% or less owned companies
us-gaap_NoncontrollingInterestIncreaseFromBusinessCombination
Historical cost
Construction in progress
us-gaap_PensionAndOtherPostretirementBenefitExpense
Pension and Other Postretirement Benefits Cost (Reversal of Cost), Total
Net loss
Net Loss
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest, Total
Net Loss
Derivative instruments (included in other receivables)
us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest
Comprehensive Loss
Embedded Derivative Financial Instruments [Member]
Derivative Instrument [Axis]
Derivative Contract [Domain]
smhi_ProceedsFromSaleOfPropertyPlantAndEquipmentExcludingDepositsForFutureVesselSales
Proceeds from Sale of Property, Plant, and Equipment, Excluding Deposits for Future Vessel Sales
The cash inflow from the sale of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale, excluding deposits for the future sales of vessels.
Marketable security gains (losses), net
Marketable security (gains) losses, net
us-gaap_MultiemployerPlanContributionsByEmployer
Multiemployer Plan, Contributions by Employer
Investments, at Equity, and Advances to 50% or Less Owned Companies
Equity in (Losses) Earnings of 50% or Less Owned Companies, Net of Tax
Income (Loss) from Equity Method Investments, Total
Equity in (earnings) losses of 50% or less owned companies, net of tax
Investments at equity
us-gaap_EquityMethodInvestments
Equity Method Investments
Long-term Debt Obligation [Member]
Related to a long-term debt obligation.
Income Before Income Tax Expense (Benefit) and Equity in Earnings of 50% or Less Owned Companies
Loss Before Income Tax Benefit and Equity in Earnings (Losses) of 50% or Less Owned Companies
Income Tax Benefit
us-gaap_IncomeTaxExpenseBenefit
Multiemployer Plan Name [Domain]
Gains (losses) on derivative instruments
Derivative gains, net
Derivative (gains), net
Multiemployer Plan Name [Axis]
Operating expenses
us-gaap_OperatingExpenses
us-gaap_DefinedContributionPlanCostRecognized
Defined Contribution Plan, Cost
Restricted cash
us-gaap_RestrictedCash
Administrative and general
us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay
Cash
us-gaap_Cash
Cash equivalents
us-gaap_CashEquivalentsAtCarryingValue
Cash and cash equivalents
Amendment Flag
Use of Estimates, Policy [Policy Text Block]
us-gaap_GainLossOnSaleOfBusiness
Gain (Loss) on Disposition of Business
New Accounting Pronouncements, Policy [Policy Text Block]
us-gaap_GainLossOnSaleOfPropertyPlantEquipment
Gain (Loss) on Disposition of Property Plant Equipment, Total
Current Fiscal Year End Date
Basis of Accounting [Text Block]
Offshore Support Vessels, Anchor Handling Towing Supply [Member]
Represents information pertaining to anchor handling towing supply included within offshore support vessels.
Document Fiscal Period Focus
Document Fiscal Year Focus
Consolidation, Policy [Policy Text Block]
Offshore Support Vessels, Specialty [Member]
Represents information pertaining to specialty vessels included within offshore support vessels.
Offshore Support Vessels, Standby Safety [Member]
Represents information pertaining to standby safety vessels included within offshore support vessels.
Document Period End Date
Offshore Support Vessels, Supply [Member]
Represents information pertaining to supply vessels included within offshore support vessels.
General Machinery and Spares [Member]
Represents information pertaining to general machinery and spares.
Entity Emerging Growth Company
Document Type
Loss on Debt Extinguishment
Gain (Loss) on Extinguishment of Debt, Total
Offshore Support Vessels, Liftboats [Member]
Represents information pertaining to liftboats included within offshore support vessels.
us-gaap_AssetImpairmentCharges
Asset Impairment Charges, Total
Entity Small Business
Entity Shell Company
Entity Ex Transition Period
smhi_AmortizationOfDeferredGainsIncludedInGainsOnAssetDispositionsAndImpairmentsNet
Recognition of deferred gains included in losses on asset dispositions and impairments, net
Represents the amount of amortization of deferred gains included in gains on asset dispositions and impairments, net.
Document Information [Line Items]
Document Information [Table]
Entity Public Float
Entity Filer Category
Entity Current Reporting Status
Entity Voluntary Filers
Entity Well-known Seasoned Issuer
us-gaap_ImpairmentOfLongLivedAssetsHeldForUse
Impairment of Long-Lived Assets Held-for-use
us-gaap_ConcentrationRiskPercentage1
Concentration Risk, Percentage
Statement of Comprehensive Income [Abstract]
Entity Central Index Key
Entity Registrant Name
Entity [Domain]
Legal Entity [Axis]
Customer Concentration Risk [Member]
us-gaap_AmortizationOfDeferredCharges
Amortization of deferred gains
us-gaap_AmortizationOfIntangibleAssets
Amortization of Intangible Assets, Total
Geographic Concentration Risk [Member]
Concentration Risk Type [Axis]
Concentration Risk Type [Domain]
Entity Common Stock, Shares Outstanding (in shares)
Sales Revenue, Net [Member]
Trading Symbol
Concentration Risk Benchmark [Axis]
Concentration Risk Benchmark [Domain]
us-gaap_TableTextBlock
Notes Tables
us-gaap_GainLossOnSaleOfOtherAssets
Gain from other sales
Bad debt (recoveries) expense
Operating
Related Party Transaction [Axis]
Related Party Transaction [Domain]
us-gaap_InterestExpense
Interest expense
Accrued capital, repair and maintenance expenditures
Carrying value as of the balance sheet date of obligations incurred through that date and payable for capital, repair and maintenance expenditures. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).
Deferred financing cost amortization
us-gaap_DisclosureTextBlockAbstract
Notes to Financial Statements
Convertible Senior Notes Converted to Warrants [Member]
Represents the conversion of convertible senior notes to warrants.
Derivative Instruments and Hedging Activities Disclosure [Text Block]
us-gaap_InterestExpenseRelatedParty
Interest Expense, Related Party
Other
The amount of other adjustment to deferred gain on sale of property.
Subsequent Event [Member]
Falcon Global Holdings [Member]
Represents Falcon Global Holdings, a subsidiary of the company.
FGUSA Credit Facility [Member]
Represents the credit agreement entered by FGUSA who is a wholly-owned subsidiary of FGH.
Pound Sterling Debt [Member]
Represents the debt borrowed in pound sterling.
Subsequent Event Type [Axis]
Euro Debt [Member]
Represents the debt borrowed in Euro.
Subsequent Event Type [Domain]
Pension and Other Postretirement Benefits Disclosure [Text Block]
Subsequent Events [Text Block]
Warrants Issued in Private Placement [Member]
Represents the warrants issued in a private placement.
Segment Reporting, Policy [Policy Text Block]
smhi_JointVentureContributionFromNoncontrollingInterest
Joint Venture, Contribution from Noncontrolling Interest
The amount of contribution from noncontrolling interest shareholders.
smhi_JointVentureTotalCapital
Joint Venture, Total Capital
The total capital contributed by parent and noncontrolling interest shareholders to the joint venture.
Foreign Currency Transactions and Translations Policy [Policy Text Block]
Self Insurance Reserve [Policy Text Block]
Other Assets
Title of Individual [Axis]
Business Combinations Policy [Policy Text Block]
Relationship to Entity [Domain]
Earnings Per Share, Policy [Policy Text Block]
Comprehensive Income, Policy [Policy Text Block]
smhi_JointVentureContributionFromPreviousJointVenture
Joint Venture, Contribution from Previous Joint Venture
The amount of contribution from previous joint venture.
Income Tax, Policy [Policy Text Block]
us-gaap_LesseeOperatingLeaseTermOfContract
Lessee, Operating Lease, Term of Contract
us-gaap_AssetsCurrent
Total current assets
Stockholders' Equity Note Disclosure [Text Block]
us-gaap_DeferredTaxAssetsValuationAllowance
Valuation Allowance
us-gaap_DeferredTaxAssetsNet
Total deferred tax assets
Deferred Charges, Policy [Policy Text Block]
Share Distribution [Member]
us-gaap_DeferredTaxAssetsLiabilitiesNet
Net deferred tax liabilities
Goodwill and Intangible Assets, Intangible Assets, Policy [Policy Text Block]
us-gaap_DeferredTaxAssetsOther
Other
Impairment or Disposal of Long-Lived Assets, Including Intangible Assets, Policy [Policy Text Block]
us-gaap_DeferredTaxAssetsGross
Total deferred tax assets
Inventories
Operating Revenues
Revenue from Contract with Customer, Including Assessed Tax
us-gaap_InventoryValuationReserves
Inventory Valuation Reserves, Ending Balance
SEACOR Marlin LLC [Member]
Related to the entity SEACOR Marlin LLC.
smhi_EquityMethodInvestmentOwnershipPercentSold
Equity Method Investment, Ownership, Percent Sold
The percentage ownership of equity method investments that was sold during the period.
Foreign currency losses, net
Foreign currency losses, net
Other DNB Credit Facilities [Member]
Related to the other DNB credit facilities.
Loan Facility With DNB Bank ASA [Member]
Related to the loan facility with DNB Bank ASA.
Term Loan to Acquire Two Vessels [Member]
Related to a term loan to acquire two vessels.
smhi_IncreaseDecreaseInTransitionTaxLiability
Increase (Decrease) in Transition Tax Liability
The amount of increase (decrease) in transition tax liability.
Estimated useful life (Year)
Construction in Progress [Member]
Schedule of Segment Reporting Information, by Segment [Table Text Block]
Trade receivables, allowance for doubtful accounts
Trade, net of allowance for doubtful accounts of $860 and $4,039 in 2018 and 2017, respectively
us-gaap_NumberOfReportableSegments
Number of Reportable Segments
Property, Plant and Equipment, Other Types [Member]
Property, Plant and Equipment, Policy [Policy Text Block]
Other, net
Property, Plant and Equipment, Type [Axis]
us-gaap_NonoperatingIncomeExpense
Property, Plant and Equipment, Type [Domain]
Segment Reporting Disclosure [Text Block]
us-gaap_DeferredTaxAssetsOperatingLossCarryforwards
Federal Net Operating Loss Carryforwards
Current Assets:
us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents
Total
Exercise of Warrants (in shares)
Number of shares of stock issued during the period pursuant to exercise of warrants.
us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations
Cash, Cash Equivalents and Restricted Cash, Beginning of Year
Cash, Cash Equivalents and Restricted Cash, End of Year
Inventory, Policy [Policy Text Block]
Private Placement [Member]
Interest income
us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect
Net (Decrease) in Cash, Cash Equivalents and Restricted Cash
smhi_NumberOfVesselsJointVentured
Number of Vessels Joint Ventured
Represents the number of vessels joint ventured.
us-gaap_NetCashProvidedByUsedInFinancingActivities
Net cash provided by (used in) financing activities
smhi_NumberOfVesselsOwned
Number of Vessels Owned
Represents the number of vessels owned.
smhi_NumberOfVessels
Number of Vessels
Represents the number of vessels.
Sale of Stock [Axis]
MEXMAR Offshore [Member]
Information pertaining to MEXMAR Offshore.
Sale of Stock [Domain]
Effects of Exchange Rate Changes on Cash, Cash Equivalents and Restricted Cash
Change in Accounting Principle for Unamortized Deferred Gains [Member]
Information pertaining to the change in accounting principle for unamortized deferred gains.
Operating Loss
Operating Loss
Operating Loss
Change in Accounting Principle for Equipment, Office and Land Leases [Member]
Information pertaining to the change in accounting principle for equipment, office and land leases.
invest_DerivativeNotionalAmount
Derivative, Notional Amount
us-gaap_NetCashProvidedByUsedInOperatingActivities
Net cash (used in) provided by operating activities
Other Income (Expense):
us-gaap_DeferredTaxLiabilitiesOther
Other
us-gaap_NetCashProvidedByUsedInInvestingActivities
Net cash used in investing activities
us-gaap_DeferredTaxLiabilities
Total deferred tax liabilities
All Other Offshore Support Vessels [Member]
Information pertaining to all other offshore support vessels.
Crew Transfer Vessels [Member]
Information pertaining to crew transfer vessels.
Schedule of Cash, Cash Equivalents and Restricted Cash [Table Text Block]
Tabular disclosure of the components of cash, cash equivalents and restricted cash.
Direct Vessel Profit
FSV Offshore Support Vessels [Member]
Information pertaining to FSV offshore support vessels.
Direct Costs and Expenses
Property, Plant and Equipment, Estimated Useful Life [Table Text Block]
Tabular disclosure of estimated useful life of physical assets used in the normal conduct of business and not intended for resale.
Derivatives, Policy [Policy Text Block]
us-gaap_SaleLeasebackTransactionCurrentPeriodGainRecognized
Amortization of deferred gains against charter expense
smhi_PaymentsToAcquirePropertyPlantAndEquipmentAndFairValueDerivativeHedges
Payments to Acquire Property, Plant and Equipment and Fair Value Derivative Hedges
The cash outflow associated with the acquisition of long-lived, physical assets and fair value of derivative hedges.
Return of investments and advances from 50% or less owned companies
The cash inflow from investments 50% or less owned due to distributions classified as return of capital.
smhi_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLessNoncontrollingInterest
Purchase price (1)
Amount recognized as of the acquisition date for the assets in excess of (less than) the aggregate liabilities assumed, less the noncontrolling interest in the acquiree.
us-gaap_ProceedsFromPaymentsForOtherFinancingActivities
Distribution of SEACOR Marine restricted stock to Company personnel by SEACOR Holdings
us-gaap_DeferredTaxLiabilitiesInvestmentInNoncontrolledAffiliates
Investments in 50% or Less Owned Companies
Marketable Securities, Policy [Policy Text Block]
Removed from service
Number of Equipment Removed from Service
Represents the number of equipment removed from service.
Shedule of Vessel Acquired and Disposed of [Table Text Block]
Tabular disclosure of vessels acquired and disposed of during the period.
Concentration Risk, Credit Risk, Policy [Policy Text Block]
Tow-supply Vessel [Member]
Information pertaining to the tow-supply vessel.
Offshore Terminal Vessel [Member]
Information pertaining to the offshore terminal vessel.
us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment
Property and equipment
ROV Support Vessels [Member]
Information pertaining to ROV support vessels.
smhi_GuaranteeOfOutstandingCharterReceivables
Guarantee of Outstanding Charter Receivables
Represents the amount of guarantee of outstanding charter receivables.
Nautical Power [Member]
Information pertaining to Nautical Power.
Offshore Vessel Holdings [Member]
Information pertaining to Offshore Vessel Holdings.
smhi_EquityMethodInvestmentSummarizedFinancialInformationDepreciation
Depreciation
The amount of depreciation reported by an equity method investment of the entity.
smhi_EquityMethodInvestmentSummarizedFinancialInformationOperatingAndAdministrative
Operating and administrative
The amount of the operating and administrative costs reported by an equity method investment of the entity.
smhi_EquityMethodInvestmentSummarizedFinancialInformationOperatingCostsAndExpenses
The amount of operating costs and expenses reported by an equity method investment of the entity.
us-gaap_CostsAndExpenses
All Other Excluding MexMar, Falcon Global, Sea-Cat Crewzer and Sea-Cat Crewzer II [Member]
Information pertaining to all other equity investments excluding MexMar, Falcon Global, Sea-Cat Crewzer and Sea-Cat Crewzer II.
Falcon Global, Sea-Cat Crewzer and Sea-Cat Crewzer II [Member]
Information pertaining to Falcon Global, Sea-Cat Crewzer and Sea-Cat Crewzer II.
Geographic Distribution, Domestic [Member]
smhi_ConstructionReserveFundActivityNet
Represents the net amount of construction reserve fund.
Geographic Distribution, Foreign [Member]
smhi_ConstructionReserveFundWithdrawals
Withdrawals
Represents the amount of withdrawals for construction reserve fund.
Loss on Asset Dispositions and Impairments, Net
The amount of income (loss) on asset dispositions and impairments reported by an equity method investment of the entity.
Costs and Expenses:
us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiability
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability
Issuance of warrants
us-gaap_ProceedsFromIssuanceOfWarrants
Geographic Distribution [Axis]
Geographic Distribution [Domain]
Deposits
Represents the amount of deposits for construction reserve fund.
us-gaap_ProceedsFromIssuanceOfPrivatePlacement
Proceeds from Issuance of Private Placement
smhi_NumberOfVesselsLeased
Number of Vessels Leased
Represents number of vessels leased.
Issuance of stock
State, Current
State, deferred
Three Point Seven Five Percentage Convertible Notes [Member]
Represents the 3.75% convertible notes.
Vessel Sales to Fifty Percent or Less Owned Subsidiaries [Member]
Represents information pertaining to 50% or less owned subsidiaries.
smhi_OperatingLeasesFutureMinimumPaymentsDueInFiveYearsAndThereafter
2023 and beyond
Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fifth fiscal year following the latest fiscal year and thereafter. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.
Sale-leaseback and Financed Equipment Sales [Member]
Represents information pertaining to sale-leaseback and financed equipment sales.
Foreign, Current
smhi_NumberOfOperatingLeasesImpaired
Number of Operating Leases Impaired
Represents number of operating leases impaired.
Foreign, deferred
us-gaap_ProceedsFromSaleOfInterestInPartnershipUnit
Proceeds from Sale of Interest in Partnership Unit
smhi_DebtInstrumentFinalBaloonPayment
Debt Instrument, Final Baloon Payment
The amount of the final payment due on a debt instrument at maturity.
BNDES [Member]
Represents information about BNDES.
Federal, Current
Windcat Workboats Ltd. [Member]
Represents information about Windcat Workboats Ltd.
Federal, deferred
Sea-Cat Crewzer III [Member]
Represents information about Sea-Cat Crewzer III.
C-Lift [Member]
Represents C-Lift.
us-gaap_ProceedsFromIssuanceOfRedeemablePreferredStock
Proceeds from Issuance of Redeemable Preferred Stock
smhi_InterestExpenseSuspended
Interest Expense Suspended
Represent the amount of interest expense suspended.
Cypress CKOR LLC [Member]
Represents information pertaining to Cypress CKOR LLC, or to the acquisition of Cypress CKOR LLC.
Current
Current Income Tax Expense
smhi_InterestExpenseSuspendedLimitationPercentage
Interest Expense Suspended, Limitation Percentage
Represents the limitation percentage on interest expense suspended.
smhi_OperatingLossCarryforwardsPercentageOfTaxableIncomeUtilizationLimitation
Operating Loss Carryforwards, Percentage of Taxable Income, Utilization Limitation
Represents the percentage of taxable income as a limitation to future utilization of net operating loss.
Distributions to noncontrolling interests
smhi_CurrentIncomeTaxExpenseBenefitNonqualifiedWithdrwalOfFundsFromCapitalConstructionFund
Current Income Tax Expense (Benefit), Nonqualified Withdrwal of Funds from Capital Construction Fund
Amount of current income tax expense (benefit) pertaining to taxable income (loss) related to nonqualified withdrwal of funds from Capital Construction Fund.
smhi_OperatingLossCarryforwardsExpirationPeriod
Operating Loss Carryforwards, Expiration Period
Represents expiration period of operating loss carryforwards.
SEACOR 88/888 [Member]
Represents information about SEACOR 88/888.
smhi_PaymentsForProceedsFromDerivativeInstrumentsOperatingActivities
Cash settlements on derivative transactions, net
The net amount of cash paid for or received to settle derivatives during the period not designated as hedges.
Schedule II Valuation and Qualifying Accounts [Table Text Block]
Tabular disclosure of Schedule II Valuation and Qualifying Accounts.
Issuance of noncontrolling interests
smhi_AdjustmentsToAdditionalPaidInCapitalTrueUpOfNonControllingInterest
Amount of increase (decrease) to additional paid in capital (APIC) resulting from a true-up of non-controlling interests.
Eliminations [Member]
Represents information about Eliminations.
Domestic U.S. Holders Affiliated With The McCall Family of Louisiana [Member]
Represents domestic U.S. holders affiliated with the McCall family of Louisiana.
SEACOR Marine Foreign Holdings [Member]
Represents information about SEACOR Marine Foreign Holdings.
Non-current Liabilities [Member]
Represents information about non-current liabilities.
Current Liabilities [member]
Represents information about current liabilities.
Current Assets [Member]
Represents information about current assets.
smhi_AcquiredVesselsPriorOperationPeriod
Acquired Vessels Prior Operation Period
This element represents the period in which acquired vessels have been operated by the Company.
smhi_NumberOfAcquisitionTransactions
Number of Acquisition Transactions
Represents the number of interest acquisition transactions.
Seabulk Overseas [Member]
Represents wholly owned subsidiary Seabulk Overseas.
us-gaap_PaymentsOfDebtIssuanceCosts
Payments of Debt Issuance Costs
Revenue Sharing Pooling Agreement [Member]
Represents the revenue sharing pooling agreement.
Other Comprehensive Loss:
Joint Venture Interest Rate Swap [Member]
Represents information about joint venture interest rate swap.
State and Local Jurisdiction [Member]
Perenco [Member]
Represents Perenco, a major customer of the company
smhi_OwnershipPercentage
Ownership Percentage
Represents the ownership percentage of a consolidated entity.
Income Tax Authority [Axis]
Exchange Warrants [Member]
Represents information about Exchange Warrants.
Income Tax Authority [Domain]
smhi_NumberOfMajorCustomers
Number of Major Customers
Represents the number of major customers accounting for 10% or more of the specified concentration risk benchmark, which includes, but not limited to, sales revenue, accounts receivable, etc.
Domestic Tax Authority [Member]
Foreign Tax Authority [Member]
us-gaap_RepaymentsOfLongTermDebt
Repayments of Long-term Debt, Total
Payments on long-term debt
smhi_AdjustmentToStockholdersEquityDueToUnamortizedDebtDiscount
Adjustment to Stockholders Equity Due to Unamortized Debt Discount
Represents the amount of adjustment to stockholders equity due to unamortized debt discount.
smhi_CommonStockHeldInTreasuryInExchangeForPaymentOfWarrantsConverted
Common Stock Held in Treasury in Exchange for Payment of Warrants Converted
Represents information about common stock held in treasury in exchange for payment of warrants converted.
Other Equity Method Investment [Member]
Represents the equity method investment that classified as other.
Ten Largest Customers [Member]
Represents the ten largest customers of the company.
Distributed by SEACOR Holdings in connection with the Spin-off (in shares)
smhi_DistributionOfRestrictedStockInConnectionWithSpinoff
Distribution of Restricted Stock in Connection with Spin-off
The number of restricted stock distributed to the company in connection with a spin-off.
Platform Supply Vessels [Member]
Represents the information pertaining to the platform supply vessels.
Restricted Stock, Spin-off [Member]
Represents the information pertaining to the restricted stock related to the spin-off.
Cash and Cash Equivalents, Unrestricted Cash and Cash Equivalents, Policy [Policy Text Block]
2017 Equity Incentive Plan [Member]
Represents the information pertaining to 2017 Equity Incentive Plan.
Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block]
Employee Stock Purchase Plan [Member]
Represents the information pertaining to the Employee Stock Purchase Plan..
Receivables, Policy [Policy Text Block]
smhi_PaymentsForDistributionOfRestrictedStockSpinOff
Payments for Distribution of Restricted Stock, Spin-off
The amount of payments for the distribution of restricted stock in connection with a spin-off.
Fabrikant and Gellert [Member]
Related to Fabrikant and Gellert.
Gellert [Member]
Related to Gellert.
Accounting Policies [Abstract]
Fabrikant [Member]
Related to Fabrikant.
Second Lien Debt [Member]
Related to second lien debt.
United Kingdom Merchant Navy Officers Pension Fund [Member]
Related to the United Kingdom Merchant Navy Officers Pension Fund.
Foreign Pension Plan [Member]
Related to foreign pension plans.
smhi_PensionAndOtherPostretirementBenefitPlansTotalFundingDeficit
Pension and Other Post-retirement Benefit Plans, Total Funding Deficit
Amount of total funding deficit for pension and other post-retirement benefit plans.
us-gaap_PartnersCapitalAccountContributions
Partners' Capital Account, Contributions
Other Defined Contribution Plan [Member]
Related to other defined contribution plan.
Schedule of Income (Loss) in Equity Method Investment [Table Text Block]
A tabular disclosure of income (loss) recognized from equity method investments.
us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption
Cumulative Effect of New Accounting Principle in Period of Adoption
Impact of adoption of accounting principle
Windcat Offshore Logistics [Member]
Related to Windcat Offshore Logistics.
Interest Rate Swap 2 [Member]
Related to an interest rate swap.
Assets of Investment in Non-controlling Interest [Table Text Block]
Tabular disclosure of assets of investment in non-controlling interest.
Total Assets(1)
smhi_AssetsExcludingCorporateAssets
The amount of assets, excluding corporate assets.
Sea-cat Crewzer I and II [Member]
Related to Sea-cat Crewzer I and II.
us-gaap_ProceedsFromIssuanceOfLongTermDebt
Proceeds from Issuance of Long-term Debt, Total
Basic and Diluted Weighted Average Common Shares Outstanding: (in shares)
us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount
us-gaap_RepaymentsOfLinesOfCredit
Repayments of Lines of Credit
Basic and Diluted Loss Per Common Share of SEACOR Marine Holdings Inc. (in dollars per share)
us-gaap_OperatingLossCarryforwards
Operating Loss Carryforwards, Total
us-gaap_ProceedsFromLinesOfCredit
Proceeds from Lines of Credit, Total
Due to SEACOR Holdings
us-gaap_OperatingLossCarryforwardsValuationAllowance
Operating Loss Carryforwards, Valuation Allowance, Total
Statement of Financial Position [Abstract]
us-gaap_EarningsPerShareDiluted
Diluted Income (Loss) Per Common Share of SEACOR Marine Holdings Inc. (in dollars per share)
Other
us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments
us-gaap_EffectiveIncomeTaxRateContinuingOperations
Effective Income Tax Rate Reconciliation, Percent, Total
Business Acquisition [Axis]
U.S. federal income tax law changes
us-gaap_EarningsPerShareBasic
Basic Income (Loss) Per Common Share of SEACOR Marine Holdings Inc. (in dollars per share)
Business Acquisition, Acquiree [Domain]
Statement of Cash Flows [Abstract]
Exclusion of foreign subsidiaries with accumulated losses and withholding tax
Statement of Stockholders' Equity [Abstract]
Noncontrolling interests
us-gaap_ProceedsFromIssuanceOfDebt
Proceeds from Issuance of Debt
Quarterly Financial Information [Table Text Block]
SEACOR Holdings share awards to Company personnel
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]
Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block]
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]
Non-deductible expenses
Type of Restructuring [Domain]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Table Text Block]
Employee Severance [Member]
State taxes
us-gaap_BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue
Minority Interest
Restructuring Type [Axis]
us-gaap_PaymentsForProceedsFromOtherInvestingActivities
Net decrease in construction reserve funds
Cash Flows from Financing Activities:
us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent
Statutory rate
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]
us-gaap_IncomeTaxReconciliationChangeInEnactedTaxRate
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount
Principal payments on notes due from equity investees
Repayment of Notes Receivable from Related Parties
Conversion Revolving Credit Facility from Windcat Workboats [Member]
Information pertaining to the conversion of revolving credit facility from Windcat Workboats.
Capital distributions from equity investees
Proceeds from Equity Method Investment, Distribution, Return of Capital
us-gaap_PaymentsForProceedsFromHedgeInvestingActivities
Cash settlements on derivative transactions, net
smhi_DebtAgreementMaximumBorrowingCapacity
Debt Agreement, Maximum Borrowing Capacity
Maximum borrowing capacity under a debt agreement on the amount that could be borrowed with a combination of, but not limited to, a line of credit and term loan.
Falcon Global USA LLC [Member]
Information pertaining to Falcon Global USA LLC.
smhi_PaymentsForDebtorInPossessionObligations
Payments for Debtor-in-possession Obligations
Amount of cash outflow for debtor-in-possession obligations.
Term Loan [Member]
Information pertaining to the term loan.
Series A Preferred Stock [Member]
Sale of subsidiary to joint venture
Proceeds from Divestiture of Interest in Joint Venture
us-gaap_PaymentsToAcquireInterestInJointVenture
Payments to Acquire Interest in Joint Venture
Carlyle Group [Member]
Information pertaining to Carlyle Group.
us-gaap_PaymentsToAcquireInterestInSubsidiariesAndAffiliates
Payments to Acquire Interest in Subsidiaries and Affiliates, Total
us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther
Other Liabilities
Other
us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired
Business acquisitions, net of cash acquired
us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesLongTermDebt
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt
Long-Term Debt
us-gaap_PaymentsToAcquireAdditionalInterestInSubsidiaries
Purchase of subsidiary shares from noncontrolling interests
us-gaap_PaymentsToAcquireEquityMethodInvestments
Investments in and advances to 50% or less owned companies
SeaCosco Offshore LLC [Member]
Information pertaining to SeaCosco Offshore LLC.
Class of Stock [Axis]
Class of Stock [Domain]
Cash assumed on consolidation of 50% or less owned companies
Cash Acquired from Acquisition
us-gaap_PaymentsToAcquireBusinessesGross
Payments to Acquire Businesses, Gross
Comprehensive Income (Loss) [Table Text Block]
us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOther
Other current liabilities
Other current liabilities
us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable
Accounts payable
us-gaap_PaymentsToAcquireLoansReceivable
Payments to Acquire Loans Receivable
us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentAssets
Investments, at Equity, and Advances to 50% or Less Owned Companies
Investments, at Equity, and Advances to 50% or Less Owned Companies
Schedule of Derivative Instruments, Effect on Other Comprehensive Income (Loss) [Table Text Block]
us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment
Property and Equipment
Derivatives Not Designated as Hedging Instruments [Table Text Block]
Hedging Relationship [Domain]
Fair Value Hedging [Member]
Cash Flow Hedging [Member]
us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsMarketableSecurities
Marketable securities
Not Designated as Hedging Instrument [Member]
us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables
Trade and other receivables
Income Tax Disclosure [Text Block]
Hedging Relationship [Axis]
us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther
Other current assets
Hedging Designation [Axis]
us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents
Cash
Hedging Designation [Domain]
Designated as Hedging Instrument [Member]
Schedule of Maturities of Long-term Debt [Table Text Block]
us-gaap_GuaranteeObligationsMaximumExposure
Guarantor Obligations, Maximum Exposure, Undiscounted
Payments received on third-party leases and notes receivable, net
us-gaap_BusinessCombinationConsiderationTransferred1
Business Combination, Consideration Transferred, Total
Share-based Compensation, Stock Options, Activity [Table Text Block]
Share-based Compensation, Activity [Table Text Block]
us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired
Business Acquisition, Percentage of Voting Interests Acquired
Guarantor Obligations, Nature [Axis]
Guarantor Obligations, Nature [Domain]
Nonvested Restricted Stock Shares Activity [Table Text Block]
Proceeds from issuance of long-term debt, net of issue costs
us-gaap_PaymentsForAdvanceToAffiliate
Payments for Advance to Affiliate
Revolving Credit Facility [Member]
Retirement Plan Type [Axis]
Retirement Plan Type [Domain]
Credit Facility [Axis]
Proceeds from disposition of property and equipment
Credit Facility [Domain]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]
Exchange of receivable for investment in 50% or less owned company
us-gaap_CumulativeEffectOnRetainedEarningsNetOfTax1
Cumulative Effect on Retained Earnings, Net of Tax, Total
us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
Payments to Acquire Property, Plant, and Equipment, Total
Purchases of property and equipment
us-gaap_IncrementalCommonSharesAttributableToConversionOfDebtSecurities
Incremental Common Shares Attributable to Conversion of Debt Securities, Total
us-gaap_PaymentsToAcquireMachineryAndEquipment
Payments to Acquire Machinery and Equipment
Income taxes (paid) refunded, net
us-gaap_OperatingLeaseImpairmentLoss
Operating Lease, Impairment Loss
Long-term debt, including current portion
us-gaap_NetIncomeLoss
Net Loss attributable to SEACOR Marine Holdings Inc.
Net Income (Loss) attributable to SEACOR Marine Holdings Inc.
Restricted Stock [Member]
us-gaap_InterestCostsIncurredCapitalized
Capitalized Interest Costs, Including Allowance for Funds Used During Construction, Total
Stock Compensation Plan [Member]
Employee Stock Option [Member]
Antidilutive Securities [Axis]
Antidilutive Securities, Name [Domain]
Long-term Debt, Type [Axis]
Long-term Debt, Type [Domain]
Ownership percentage
Equity Method Investment, Ownership Percentage
Cash Flows from Investing Activities:
us-gaap_RevenueFromRelatedParties
Revenue from Related Parties
us-gaap_RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty
Related Party Transaction, Expenses from Transactions with Related Party
us-gaap_RelatedPartyTransactionRate
Related Party Transaction, Rate
BRAZIL
Decrease in accounts payable, accrued expenses and other liabilities
us-gaap_DeferredFinanceCostsGross
Debt Issuance Costs, Gross
Related party transactions
Related Party Transaction, Amounts of Transaction
Related Party Transactions Disclosure [Text Block]
Schedule of Related Party Transactions [Table Text Block]
us-gaap_DebtInstrumentIncreaseDecreaseForPeriodNet
Debt Instrument, Increase (Decrease), Net, Total
UNITED KINGDOM
us-gaap_DebtInstrumentConvertibleConversionPrice1
Debt Instrument, Convertible, Conversion Price
us-gaap_AllocatedShareBasedCompensationExpense
Allocated Share-based Compensation Expense, Total
us-gaap_DebtInstrumentConvertibleConversionRatio1
Debt Instrument, Convertible, Conversion Ratio
us-gaap_ComprehensiveIncomeNetOfTax
Comprehensive Loss attributable to SEACOR Marine Holdings Inc.
us-gaap_DebtInstrumentPeriodicPaymentPrincipal
Debt Instrument, Periodic Payment, Principal
Restricted stock vesting (in shares)
us-gaap_IncreaseDecreaseInContractWithCustomerLiability
Increase (Decrease) in Contract with Customer, Liability
Balance (in shares)
Balance (in shares)
Balance (in shares)
Preferred stock, shares outstanding (in shares)
us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Debt Instrument, Basis Spread on Variable Rate
us-gaap_DebtInstrumentInterestRateStatedPercentage
Debt Instrument, Interest Rate, Stated Percentage
us-gaap_DebtInstrumentInterestRateEffectivePercentage
Debt Instrument, Interest Rate, Effective Percentage
us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets
Decrease (increase) in prepaid expenses and other assets
us-gaap_DebtInstrumentFaceAmount
Debt Instrument, Face Amount
Interim Period, Costs Not Allocable [Domain]
Nature of Expense [Axis]
Debt Instrument [Axis]
Debt Instrument, Name [Domain]
us-gaap_AdjustmentsToAdditionalPaidInCapitalOther
Adjustments to Additional Paid in Capital, Other
us-gaap_IncreaseDecreaseInReceivables
(Increase) decrease in receivables
Schedule of Long-term Debt Instruments [Table Text Block]
Issuance of Warrants
us-gaap_AdjustmentsToAdditionalPaidInCapitalWarrantIssued
Amortization of employee share awards
us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue
Quarterly Financial Information [Text Block]
us-gaap_TreasuryStockValueAcquiredCostMethod
Restricted stock vesting
us-gaap_TreasuryStockValue
Shares held in treasury of 4,007 and 0 in 2018 and 2017, respectively, at cost
us-gaap_StockIssuedDuringPeriodSharesPurchaseOfAssets
Stock Issued During Period, Shares, Purchase of Assets
Long-term Debt [Text Block]
us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Line of Credit Facility, Remaining Borrowing Capacity
Exercise of options (in shares)
Exercised (in shares)
Officer [Member]
Distribution of SEACOR Marine restricted stock to Company personnel by SEACOR Holdings (in shares)
Stock Issued During Period, Shares, Restricted Stock Award, Gross
us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Line of Credit Facility, Maximum Borrowing Capacity
Exercise of options
us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised
Distribution of SEACOR Marine restricted stock to Company personnel by SEACOR Holdings
us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardGross
us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage
Related Party [Axis]
Related Party [Domain]
Granted - 2017 Plan (in shares)
Granted, shares (in shares)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod
Forfeited (in shares)
us-gaap_WarrantsAndRightsOutstandingTerm
Warrants and Rights Outstanding, Term
Arrangements and Non-arrangement Transactions [Domain]
Acquisition of consolidated joint venture
us-gaap_StockGrantedDuringPeriodValueSharebasedCompensation
Issuance of Common Stock (in shares)
Stock Issued During Period, Shares, New Issues
Director share awards
us-gaap_StockIssuedDuringPeriodValueIssuedForServices
Director share awards (in shares)
us-gaap_StockIssuedDuringPeriodSharesIssuedForServices
us-gaap_LiabilitiesAndStockholdersEquity
smhi_CommitmentToInvestAdditionalFundsIfCallByGeneralPartner
Commitment to Invest Additional Funds if Call By General Partner
Amount of commitment to invest additional funds in preferred equity if called by general partner.
us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAdjustedBalance1
Balance
Reported Value Measurement [Member]
Issuance of Common Stock
us-gaap_StockIssuedDuringPeriodValueNewIssues
Stock Issued During Period, Value, New Issues
UNITED STATES
Conversion option liability on Convertible Senior Notes
Embedded Derivative, Fair Value of Embedded Derivative Liability
Retained earnings
Accumulated other comprehensive loss, net of tax
smhi_InvestmentInAffiliatesAmountOfPreferredEquityOffereingParticipated
Investment in Affiliates, Amount of Preferred Equity Offereing Participated
Amount of preferred equity offering participated
Changes in operating assets and liabilities:
us-gaap_OperatingLeaseLiability
Operating Lease, Liability, Total
us-gaap_GeneralPartnersCapitalAccount
General Partners' Capital Account, Total
us-gaap_OperatingLeaseRightOfUseAsset
Operating Lease, Right-of-Use Asset
Deferred income tax benefit
Deferred Income Tax Benefit
Restricted stock amortization
us-gaap_DebtConversionConvertedInstrumentSharesIssued1
Debt Conversion, Converted Instrument, Shares Issued
us-gaap_LimitedPartnersCapitalAccount
Limited Partners' Capital Account, Total
us-gaap_DebtConversionOriginalDebtAmount1
Debt Conversion, Original Debt, Amount
Debt Conversion Description [Axis]
Debt Conversion, Name [Domain]
Debt discount and issue cost amortization, net
Equipment received to settle notes receivable
us-gaap_Depreciation
Depreciation, Total
Property and equipment, Fair Value Disclosure
Property and equipment, Fair Value Disclosure
Depreciation and amortization
Losses on Asset Dispositions and Impairments, Net
Losses on asset dispositions and impairments, net
Africa [Member]
Cash, cash equivalents and restricted cash
Shares held in treasury (in shares)
us-gaap_AssetsNet
Net Assets, Ending Balance
Common stock, $.01 par value, 60,000,000 shares authorized; 20,443,215 and 17,675,356 shares issued in 2018 and 2017, respectively
Measurement Frequency [Axis]
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Fair Value, Measurement Frequency [Domain]
Fair Value, Measurements, Recurring [Member]
Common stock, shares authorized (in shares)
Common stock, shares issued (in shares)
Common stock, par value (in dollars per share)
Range [Domain]
Maximum [Member]
Minimum [Member]
us-gaap_PaymentsForPurchaseOfSecuritiesOperatingActivities
Purchases of marketable securities
Ownership [Domain]
Product and Service [Axis]
Product and Service [Domain]
Range [Axis]
Investment, Name [Domain]
Schedule of Cash Flow, Supplemental Disclosures [Table Text Block]
us-gaap_OperatingLeasesRentExpenseNet
Operating Leases, Rent Expense, Net, Total
Impaired Long-Lived Assets Held and Used by Type [Axis]
Ownership [Axis]
Impaired Long-Lived Assets Held and Used, Asset Name [Domain]
Preferred stock, $.01 par value, 10,000,000 shares authorized; none issued nor outstanding
Preferred stock, shares issued (in shares)
Interest paid, excluding capitalized interest
Cash Flow, Supplemental Disclosures [Text Block]
Investment, Name [Axis]
Geographical [Axis]
Property, Plant and Equipment Disclosure [Text Block]
Geographical [Domain]
Property, Plant and Equipment [Table Text Block]
Preferred stock, shares authorized (in shares)
Europe [Member]
us-gaap_ProceedsFromOtherOperatingActivities
Other, net
Portion at Fair Value Measurement [Member] [Default]
Preferred stock, par value (in dollars per share)
Estimate of Fair Value Measurement [Member]
Measurement Basis [Axis]
Proceeds from sale of marketable securities
Fair Value, Inputs, Level 3 [Member]
Fair Value Hierarchy and NAV [Domain]
Customer [Axis]
Customer [Domain]
Fair Value, Inputs, Level 1 [Member]
Fair Value, Inputs, Level 2 [Member]
Fair Value Hierarchy and NAV [Axis]
Dividends received from 50% or less owned companies
Noncontrolling interests in subsidiaries
Noncontrolling interest
Noncontrolling interests in subsidiaries
Cash Flows from Operating Activities:
Revenue Recognition, Policy [Policy Text Block]
Statement [Line Items]
Additional paid-in capital
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
AOCI Attributable to Parent [Member]
Partner Type of Partners' Capital Account, Name [Domain]
SEACOR Marine Holdings Inc. stockholders' equity:
Equity Method Investments, Fair Value Disclosure
General Partner [Member]
Limited Partner [Member]
Adjustments for Change in Accounting Principle [Axis]
Adjustments for Change in Accounting Principle [Domain]
Partner Type [Axis]
Schedule of Other Assets, Noncurrent [Table Text Block]
Fair Value Disclosures [Text Block]
Fair Value, by Balance Sheet Grouping [Table Text Block]
Accounting Standards Update 2016-16 [Member]
us-gaap_EquityMethodInvestmentSummarizedFinancialInformationNetIncomeLoss
Net Income
us-gaap_EquityMethodInvestmentUnrealizedIntercompanyProfitLossNotEliminatedAmount
Equity Method Investment, Unrealized Intercompany Profit (Loss) Not Eliminated, Amount
us-gaap_EquityMethodInvestmentSummarizedFinancialInformationRevenue
Operating Revenues
us-gaap_Liabilities
Total liabilities
us-gaap_EquityMethodInvestmentSummarizedFinancialInformationIncomeLossFromContinuingOperationsBeforeExtraordinaryItems
Operating Income
Prepaid expenses and other
Counterparty Name [Axis]
us-gaap_ChangeInUnrealizedGainLossOnHedgedItemInFairValueHedge1
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge
us-gaap_EquityMethodInvestmentSummarizedFinancialInformationCurrentLiabilities
Current liabilities
Counterparty Name [Domain]
us-gaap_EquityMethodInvestmentSummarizedFinancialInformationNoncurrentLiabilities
Noncurrent liabilities
Consolidation Items [Domain]
us-gaap_EquityMethodInvestmentSummarizedFinancialInformationCurrentAssets
Current assets
us-gaap_EquityMethodInvestmentSummarizedFinancialInformationNoncurrentAssets
Noncurrent assets
us-gaap_ContractWithCustomerLiability
Contract with Customer, Liability, Total
Balance at beginning of year
Balance at end of year
Derivative Liability
Consolidation Items [Axis]
Accounting Standards Update 2016-02 [Member]
us-gaap_InterestPayableCurrentAndNoncurrent
Interest Payable
us-gaap_EquityMethodInvestmentOtherThanTemporaryImpairment
Equity Method Investment, Other than Temporary Impairment
Consolidated Entities [Axis]
Consolidated Entities [Domain]
Type of Adoption [Domain]
us-gaap_LettersOfCreditOutstandingAmount
Letters of Credit Outstanding, Amount
Adjustments for New Accounting Pronouncements [Axis]
Equity Method Investments and Joint Ventures Disclosure [Text Block]
Equity Method Investments [Table Text Block]
Accumulated Gain (Loss), Net, Cash Flow Hedge, Noncontrolling Interest [Member]
Accumulated Foreign Currency Adjustment Attributable to Noncontrolling Interest [Member]
Noncontrolling Interest [Member]
AOCI Attributable to Noncontrolling Interest [Member]
Retained Earnings [Member]
Equity Method Investments [Member]
Primary financial statement caption encompassing equity method investments.
Convertible Senior Notes 3.75% [Member]
Information pertaining to the 3.75% Convertible Senior Notes.
Treasury Stock [Member]
Offshore Support Vessels [Member]
Information pertaining to the offshore support vessels.
Additional Paid-in Capital [Member]
us-gaap_DeferredGainOnSaleOfProperty
Balance at beginning of year
Balance at end of year
Common Stock [Member]
Equity Components [Axis]
Equity Component [Domain]
us-gaap_LongTermDebt
Long-term Debt, Total
us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
Class of Warrant or Right, Exercise Price of Warrants or Rights
Class of Warrant or Right [Axis]
Class of Warrant or Right [Domain]
us-gaap_ClassOfWarrantOrRightOutstanding
Class of Warrant or Right, Outstanding
us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
Class of Warrant or Right, Number of Securities Called by Warrants or Rights
Acquired
Number of Equipment Acquired
Represents the number of of equipment acquired.
smhi_NumberOfEquipmentSold
Number of Equipment Sold
Represents the number of equipment sold.
Schedule of Deferred Gain [Table Text Block]
Tabular disclosure of schedule of deferred gains during the period.
Liftboats [Member]
Information pertaining to liftboats.
Anchor Handling Towing Supply [Member]
Information pertaining to anchor handling towing supply.
Fast Support Vessels [Member]
Information pertaining to fast support vessels.
smhi_ProceedsFromSaleOfPropertyPlantAndEquipmentIncludingDeposits
Proceeds from Sale of Property, Plant, and Equipment, Including Deposits
The cash inflow from the sale of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale, including deposits.
Deferred Revenue, by Arrangement, Disclosure [Table Text Block]
smhi_ProceedsFromDeposits
Proceeds from Deposits
Amount of cash inflow for receipts of deposits.
Falcon Global [Member]
Information pertaining to Falcon Global.
Revenues deferred during the year
Sea-Cat Crewzer II [Member]
Information pertaining to Sea-Cat Crewzer II.
us-gaap_DeferredRevenueRevenueRecognized1
Revenues recognized during the year
smhi_NumberOfEquipmentOperated
Number of Equipment Operated
Represents the number of equipment operated.
us-gaap_ConvertibleDebt
Convertible Debt, Total
MexMar [Member]
Information pertaining to MexMar.
us-gaap_DeferredFinanceCostsNoncurrentNet
Issue costs
SEACOR Holdings [Member]
Information pertaining to SEACOR Holdings.
Sea-Cat Crewzer [Member]
Information pertaining to Sea-Cat Crewzer.
Windcat Workboats [Member]
Information pertaining to Windcat Workboats.
Supply Vessels [Member]
Information pertaining to supply vessels.
Segment Reconciling Items [Member]
Other Noncontrolling Interests [Member]
Information pertaining to other noncontrolling interests.
Construction reserve funds
Fair value portion of construction reserve funds.
Schedule of Noncontrolling Interest [Table Text Block]
Tabular disclosure of noncontrolling interest.
smhi_AllocableShareOfUncalledCapital
Allocable Share of Uncalled Capital
Represents the entity's allocable share of uncalled capital.
Balance Sheet Location [Axis]
Other Offshore Marine Services Joint Ventures [Member]
Information pertaining to other offshore marine services joint ventures.
Balance Sheet Location [Domain]
OSV Partners [Member]
Information pertaining to OSV Partners.
us-gaap_DebtInstrumentUnamortizedDiscount
Debt Instrument, Unamortized Discount, Total
Debt discount
Dynamic Offshore [Member]
Information pertaining to Dynamic Offshore.
Tranche A [Member]
Information pertaining to tranche A under a debt agreement.
General and Administrative Expense [Member]
Long-term Debt, Gross
Tranche B [Member]
Information pertaining to tranche B under a debt agreement.
Interest Expense [Member]
Transition Services Agreement [Member]
Information pertaining to the Transition Services Agreement.
Brazil, Mexico, Central and South America [Member]
Information pertaining to Brazil, Mexico, Central and South America.
Restructuring Charges [Member]
us-gaap_ValuationAllowancesAndReservesAdjustments
Allowance for doubtful accounts (deducted from trade and notes receivable)
Time Charter [Member]
Information pertaining to time charter.
Management Services [Member]
Information pertaining to management services.
us-gaap_ValuationAllowancesAndReservesBalance
Allowance for doubtful accounts (deducted from trade and notes receivable)
Allowance for doubtful accounts (deducted from trade and notes receivable)
Middle East and Asia [Member]
Information pertaining to Middle East and Asia.
Personnel [Member]
Information pertaining to personnel services.
us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense
Allowance for doubtful accounts (deducted from trade and notes receivable)
Repairs and Maintenance [Member]
Information pertaining to repairs and maintenance services.
Income Statement Location [Axis]
Bareboat Charter [Member]
Information pertaining to bareboat charter.
Income Statement Location [Domain]
us-gaap_ValuationAllowancesAndReservesDeductions
Allowance for doubtful accounts (deducted from trade and notes receivable)
Fuel, Lubes and Supplies [Member]
Information pertaining to fuel, lubes and supplies.
Type of Arrangement and Non-arrangement Transactions [Axis]
Other Direct Costs and Expenses [Member]
Information pertaining to other direct costs and expenses.
Drydocking [Member]
Information pertaining to drydocking services.
Insurance and Loss Reserves [Member]
Information pertaining to insurance and loss reserves.
Health Insurance [Member]
Information pertaining to health insurance.
Leased-in Equipment [Member]
Information pertaining leased-in equipment.
Noncontrolling interest percent
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners
smhi_IncomeLossFromContinuingOperationsBeforeEquityMethodInvestmentsAndNoncontrollingInterestAfterTax
Loss Before Equity in (Losses) Earnings of 50% or Less Owned Companies
Amount of income (loss) from continuing operations before income (loss) from equity method investments and income (loss) attributable to noncontrolling interest, but after tax of income (loss) from continuing operations.
Segments [Axis]
Segments [Domain]
Corporate Segment [Member]
Non-US [Member]
Scenario, Forecast [Member]
Net book value
smhi_PropertyPlantAndEquipmentExcludingConstructionInProgress
Amount after accumulated depreciation, depletion and amortization of physical assets, excluding construction in progress, used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.
SEC Schedule, 12-09, Schedule of Valuation and Qualifying Accounts Disclosure [Text Block]
Construction Reserve Funds
Amount of construction reserve funds as of the balance sheet date.
Statement [Table]
us-gaap_MinorityInterestOwnershipPercentageByParent
Noncontrolling Interest, Ownership Percentage by Parent
Scenario [Axis]
Scenario, Unspecified [Domain]
Investments, at cost, in 50% or less owned companies (included in other assets)
Deferred Gains [Policy Text Block]
Disclosure of accounting policy for the deferral and amortization of gains on asset sales to 50% or less owned companies and gains on sale and leaseback transactions of significant deferred charges.
smhi_ManagementFeeRelatedParty
SEACOR Holdings management fees
Amount of managements fees attributable to a related party.
Noncontrolling Interest Disclosure [Text Block]
smhi_GuranteeFeesRelatedParty
SEACOR Holdings guarantee fees
Amount of guarantee fees attributable to a related party.
us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears
2022
us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears
2020
us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears
2021
us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent
2019
Income Statement [Abstract]
us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree
2021
us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour
2022
us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive
2023
us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive
Years subsequent to 2023
us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths
2019
us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo
2020
us-gaap_UnrecordedUnconditionalPurchaseObligationMaximumQuantity
Unrecorded Unconditional Purchase Obligation, Maximum Quantity
Deferred Gains and Other Liabilities
Reclassification of derivative losses on cash flow hedges
Reclassification of derivative losses on cash flow hedges
Gain (Loss) Reclassified from OCI into Income (Effective Portion)
us-gaap_UnrecordedUnconditionalPurchaseObligationBalanceSheetAmount
Unrecorded Unconditional Purchase Obligation, Total
us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax
Derivative (losses) gains on cash flow hedges
Exchange Option Liability on Subsidiary Convertible Senior Notes
Deferred Income Taxes
us-gaap_DerivativeFairValueOfDerivativeNet
Derivative, Fair Value, Net, Total
us-gaap_UnrecordedUnconditionalPurchaseObligationBalanceOnFourthAnniversary
Unrecorded Unconditional Purchase Obligation, Due within Four Years
Conversion Option Liability on Convertible Senior Notes
us-gaap_UnrecordedUnconditionalPurchaseObligationBalanceOnFirstAnniversary
2019
us-gaap_UnrecordedUnconditionalPurchaseObligationBalanceOnSecondAnniversary
2020
Foreign currency translation (losses) gains, net
Reclassification of foreign currency translation losses to foreign currency losses, net
us-gaap_DefinedBenefitPensionPlanLiabilitiesNoncurrent
Liability, Defined Benefit Pension Plan, Noncurrent
us-gaap_StockholdersEquity
Unrecorded Unconditional Purchase Obligations Disclosure [Table Text Block]
us-gaap_LongTermDebtNoncurrent
Long-Term Debt
Interest Rate Swap [Member]
us-gaap_DerivativeFixedInterestRate
Derivative, Fixed Interest Rate
Foreign Exchange Option [Member]
us-gaap_OtherReceivablesNetCurrent
Other