2.2.0.25 true Sheet 00 - Document - Document and Entity Information Document and Entity Information http://gulfmark.com/role/DocumentAndEntityInformation false R1.xml false Sheet 0110 - Statement - Consolidated Balance Sheets Consolidated Balance Sheets http://gulfmark.com/role/BalanceSheets false R2.xml false Sheet 0111 - Statement - Consolidated Balance Sheets (Parenthetical) Consolidated Balance Sheets (Parenthetical) http://gulfmark.com/role/BalanceSheetsParenthetical false R3.xml false Sheet 0120 - Statement - Consolidated Statements of Operations Consolidated Statements of Operations http://gulfmark.com/role/StatementsOfOperations false R4.xml false Sheet 0130 - Statement - Consolidated Statements of Stockholders' Equity Consolidated Statements of Stockholders' Equity http://gulfmark.com/role/StatementOfStockholdersEquity false R5.xml false Sheet 0140 - Statement - Consolidated Statements of Comprehensive Income (Loss) Consolidated Statements of Comprehensive Income (Loss) http://gulfmark.com/role/CondensedConsolidatedStatementOfComprehensiveIncome false R6.xml false Sheet 0150 - Statement - Consolidated Statements of Cash Flows Consolidated Statements of Cash Flows http://gulfmark.com/role/StatementsOfCashFlows false R7.xml false Sheet 0201 - Disclosure - Nature of Operations and Summary of Significant Accounting Policies Nature of Operations and Summary of Significant Accounting Policies http://gulfmark.com/role/NatureOfOperationsAndSummaryOfSignificantAccountingPolicies false R8.xml false Sheet 0202 - Disclosure - Impairment Charges Impairment Charges http://gulfmark.com/role/ImpairmentCharges false R9.xml false Sheet 0203 - Disclosure - Rigdon Acquisition Rigdon Acquisition http://gulfmark.com/role/RigdonAcquisition false R10.xml false Sheet 0204 - Disclosure - Vessel Acquisitions and Dispositions Vessel Acquisitions and Dispositions http://gulfmark.com/role/VesselAcquisitionsAndDispositions false R11.xml false Sheet 0205 - Disclosure - Goodwill and Intangibles Goodwill and Intangibles http://gulfmark.com/role/GoodwillAndIntangibles false R12.xml false Sheet 0206 - Disclosure - Long-Term Debt Long-Term Debt http://gulfmark.com/role/LongTermDebt false R13.xml false Sheet 0207 - Disclosure - Income Taxes Income Taxes http://gulfmark.com/role/IncomeTaxes false R14.xml false Sheet 0208 - Disclosure - Commitments and Contingencies Commitments and Contingencies http://gulfmark.com/role/CommitmentsAndContingencies false R15.xml false Sheet 0209 - Disclosure - Equity Incentive Plans Equity Incentive Plans http://gulfmark.com/role/EquityIncentivePlans false R16.xml false Sheet 0210 - Disclosure - Employee Benefit Plans Employee Benefit Plans http://gulfmark.com/role/EmployeeBenefitPlans false R17.xml false Sheet 0211 - Disclosure - Stockholders' Equity Stockholders' Equity http://gulfmark.com/role/StockholdersEquity false R18.xml false Sheet 0212 - Disclosure - Derivative Financial Instruments Derivative Financial Instruments http://gulfmark.com/role/DerivativeFinancialInstruments false R19.xml false Sheet 0213 - Disclosure - Fair Value Measurements Fair Value Measurements http://gulfmark.com/role/FairValueMeasurements false R20.xml false Sheet 0214 - Disclosure - Operating Segment Information Operating Segment Information http://gulfmark.com/role/OperatingSegmentInformation false R21.xml false Sheet 0215 - Disclosure - Unaudited Quarterly Financial Data Unaudited Quarterly Financial Data http://gulfmark.com/role/UnauditedQuarterlyFinancialData false R22.xml false Book All Reports All Reports false 1 55 8 0 3 128 false false BalanceAsOf_31Dec2009_Additional_Paid_In_Capital_Member 1 BalanceAsOf_30Jun2010 1 BalanceAsOf_31Dec2009_Common_Class_A_Member 4 BalanceAsOf_31Dec2009_Treasury_Stock_Member 2 TwelveMonthsEnded_31Dec2008_Accumulated_Other_Comprehensive_Income_Member 2 BalanceAsOf_31Dec2007_Retained_Earnings_Member 1 BalanceAsOf_31Dec2008 2 BalanceAsOf_31Dec2009_Common_Class_B_Member 3 TwelveMonthsEnded_31Dec2009_Treasury_Stock_Member 2 TwelveMonthsEnded_31Dec2009_Retained_Earnings_Member 1 BalanceAsOf_31Dec2010_Treasury_Stock_Member 2 BalanceAsOf_31Dec2010_Retained_Earnings_Member 1 Jan-01-2010_Dec-31-2010 77 BalanceAsOf_31Dec2007_Additional_Paid_In_Capital_Member 1 TwelveMonthsEnded_31Dec2009_Accumulated_Other_Comprehensive_Income_Member 2 BalanceAsOf_31Dec2007 2 BalanceAsOf_31Dec2009 40 BalanceAsOf_31Dec2008_Retained_Earnings_Member 1 BalanceAsOf_31Dec2007_Deferred_Compensation_Share_Based_Payments_Member 1 TwelveMonthsEnded_31Dec2008_Retained_Earnings_Member 1 BalanceAsOf_31Dec2010_Common_Class_A_Member 4 TwelveMonthsEnded_31Dec2010_Common_Stock_Member 2 TwelveMonthsEnded_31Dec2010_Treasury_Stock_Member 2 BalanceAsOf_31Dec2008_Additional_Paid_In_Capital_Member 1 BalanceAsOf_31Dec2008_Treasury_Stock_Member 2 BalanceAsOf_31Dec2009_Deferred_Compensation_Share_Based_Payments_Member 1 TwelveMonthsEnded_31Dec2009_Common_Stock_Member 2 TwelveMonthsEnded_31Dec2010_Accumulated_Other_Comprehensive_Income_Member 2 TwelveMonthsEnded_31Dec2009 50 BalanceAsOf_31Dec2008_Common_Stock_Member 1 BalanceAsOf_31Dec2008_Deferred_Compensation_Share_Based_Payments_Member 1 TwelveMonthsEnded_31Dec2009_Additional_Paid_In_Capital_Member 3 BalanceAsOf_31Dec2010_Additional_Paid_In_Capital_Member 1 TwelveMonthsEnded_31Dec2008_Treasury_Stock_Member 2 BalanceAsOf_31Dec2010_Common_Stock_Member 1 BalanceAsOf_31Dec2010 40 BalanceAsOf_31Dec2009_Common_Stock_Member 1 TwelveMonthsEnded_31Dec2008_Deferred_Compensation_Share_Based_Payments_Member 1 BalanceAsOf_31Dec2010_Common_Class_B_Member 3 BalanceAsOf_23Feb2011 1 BalanceAsOf_31Dec2009_Retained_Earnings_Member 1 BalanceAsOf_31Dec2007_Treasury_Stock_Member 2 BalanceAsOf_31Dec2008_Accumulated_Other_Comprehensive_Income_Member 1 TwelveMonthsEnded_31Dec2008_Additional_Paid_In_Capital_Member 2 BalanceAsOf_31Dec2007_Common_Stock_Member 1 BalanceAsOf_31Dec2009_Accumulated_Other_Comprehensive_Income_Member 1 TwelveMonthsEnded_31Dec2008_Common_Stock_Member 2 TwelveMonthsEnded_31Dec2010_Additional_Paid_In_Capital_Member 3 TwelveMonthsEnded_31Dec2009_Deferred_Compensation_Share_Based_Payments_Member 1 BalanceAsOf_31Dec2007_Accumulated_Other_Comprehensive_Income_Member 1 TwelveMonthsEnded_31Dec2010_Retained_Earnings_Member 1 BalanceAsOf_31Dec2010_Accumulated_Other_Comprehensive_Income_Member 1 TwelveMonthsEnded_31Dec2010_Deferred_Compensation_Share_Based_Payments_Member 1 BalanceAsOf_31Dec2010_Deferred_Compensation_Share_Based_Payments_Member 1 TwelveMonthsEnded_31Dec2008 50 true true