Document and Entity Information Document And Entity Information [Abstract] Statement [Table] Statement [Line Items] Document Type Amendment Flag Document Period End Date Document Fiscal Year Focus Document Fiscal Period Focus Trading Symbol Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Entity Filer Category Entity Common Stock, Shares Outstanding Entity Public Float Entity Voluntary Filers Entity Well-known Seasoned Issuer Entity Current Reporting Status Consolidated Balance Sheets [Abstract] Assets Abstract ASSETS Assets, Current [Abstract] CURRENT ASSETS: Cash and cash equivalents Cash and cash equivalents at end of period Cash and cash equivalents at beginning of period Accounts receivable2 Accounts receivable-net Current portion of accounts receivable-net Costs In Excess Of Billings On Uncompleted Contracts Or Programs Expected To Be Collected Within One Year Current portion of contract revenues in excess of billings Contract revenues in excess of billings Inventory Net Inventories Due from Affiliate, Current Receivables from affiliates Prepaid expenses Other current assets AssetsHeldForSaleCurrent Assets held for sale Assets, Current Total current assets PROPERTY AND EQUIPMENT - Net PROPERTY AND EQUIPMENT-Net Property and equipment - net Property and equipment - net GOODWILL Goodwill, Ending Balance Goodwill, Beginning Balance Goodwill OtherIntangibleAssetsNet OTHER INTANGIBLE ASSETS-Net INVENTORIES - Noncurrent INVENTORIES-Noncurrent INVESTMENTS IN JOINT VENTURES INVESTMENTS IN JOINT VENTURES Investment in joint ventures Assets Held-for-sale, Other, Noncurrent ASSETS HELD FOR SALE-Noncurrent Other noncurrent assets OTHER Assets Total assets TOTAL Liabilities and Equity [Abstract] LIABILITIES AND EQUITY Liabilities, Current [Abstract] CURRENT LIABILITIES: Accounts payable Accrued Liabilities Current Accrued expenses Total accrued expenses Billings in excess of contract revenues Total billings in excess of contract revenues Long-term Debt, Current Maturities Current portion of long term debt LiabilitiesOfAssetsHeldForSale Liabilities held for sale Liabilities, Current Total current liabilities Due to Affiliate, Current Payables to affiliates Senior Notes 7 3/8% SENIOR NOTES 7.375% senior notes LongTermLineOfCredit REVOLVING CREDIT FACILITY Revolving credit facility Notes Payable, Noncurrent NOTES PAYABLE DEFERRED INCOME TAXES Net noncurrent deferred tax liabilites LIABILITIES HELD FOR SALE-Noncurrent LIABILITIES HELD FOR SALE-Noncurrent OTHER Other Investments in subsidiaries. Investments in subsidiaries INVESTMENTS IN SUBSIDIARIES Liabilities Total liabilities COMMITMENTS ANDCONTINGENCIES COMMITMENTS AND CONTINGENCIES (Note 13) EQUITY: Common stock-$.0001 par value; 90,000,000 authorized, 58,671,956 and 58,542,038 shares issued and outstanding at June 30, 2010 and December 31, 2009, respectively. Common stock-$.0001 par value; 90,000 authorized, 60,170 and 59,670 shares issued and outstanding at December 31, 2014 and December 31, 2013, respectively. Additional paid-in capital Accumulated deficit Accumulated deficit Accumulated other comprehensive income (loss) Accumulated other comprehensive loss Stockholders' Equity Attributable to Parent Total Great Lakes Dredge & Dock Corporation equity NONCONTROLLING INTERESTS NONCONTROLLING INTERESTS Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest BALANCE - value BALANCE - value Total equity Liabilities and Equity TOTAL Common Stock, Par Value Common stock, par value Common Stock, Shares authorized Common stock, shares authorized Common Stock, Shares issued Common stock, shares issued Common Stock, Shares outstanding Common stock, shares outstanding Consolidated Statements Of Operations [Abstract] Contract revenues Revenues Contract revenues Costs of contract revenues Costs of contract revenues Costs of contract revenues Gross Profit Gross profit Operating Expenses [Abstract] OPERATING EXPENSES: General and administrative expenses General and administrative expenses General and administrative expenses Gain (Loss) Related to Litigation Settlement Proceeds from loss of use claim Gain (Loss) on Sale of Other Assets Gain on sale of assets-net (GAIN) LOSS ON SALE OF ASSETS-Net Operating Income (Loss) Operating income (loss) Total operating income Nonoperating Income (Expense) [Abstract] OTHER EXPENSE: Interest expense - net Interest expense-net Proceeds from Equity Method Investment, Dividends or Distributions Equity in earnings of joint ventures Gain on bargain purchase acquisition Gain on bargain purchase acquisition Other Nonoperating Income (Expense) Other income (expense) Foreign Currency Transaction Loss, before Tax Loss on foreign currency transactions-net Nonoperating Income (Expense) Total other expense Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES Income tax provision Income tax (provision) benefit Income tax (provision) benefit IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest Income from continuing operations Income from continuing operations Income (Loss) From Discontinued Operations, Net Of Tax Loss from discontinued operations, net of income taxes Income (loss) from discontinued operations, net of income taxes Net Income (Loss) Attributable to Parent Net Income (Loss) Attributable to Parent Net income attributable to common stockholders of Great Lakes Dredge & Dock Corporation Net loss attributable to noncontrolling interests Net loss attributable to noncontrolling interest Net income NET INCOME (LOSS) IncomeLossFromContinuingOperationsPerBasicShare Basic earnings per share attributable to income from continuing operations Earnings per share from continuing operations - basic IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare Basic loss per share attributable to loss on discontinued operations, net of income taxes Basic earnings per share attributable to Great Lakes Dredge & Dock Corporation Basic earnings (loss) per share attributable to common stockholders of Great Lakes Dredge & Dock Corporation Earnings per share - basic Basic weighted average shares Weighted-average common shares outstanding - basic Basic weighted average shares IncomeLossFromContinuingOperationsPerDilutedShare Diluted earnings per share attributable to income from continuing operations Earnings per share from continuing operations - diluted IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare Diluted loss per share attributable to loss on discontinued operations, net of income taxes Diluted earnings per share attributable to Great Lakes Dredge & Dock Corporation Diluted earnings (loss) per share attributable to common stockholders of Great Lakes Dredge & Dock Corporation Earnings per share - diluted Diluted weighted average shares Weighted-average common shares outstanding - diluted Diluted weighted average shares Consolidated Statements of Comprehensive Income (Loss) [Abstract] Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax Currency translation adjustment-net of tax Change in fair value of derivatives-net of tax Net unrealized (gain) loss on derivatives-net of tax Net unrealized gain on derivatives-net of tax Other Comprehensive Income (Loss), Net of Tax Other comprehensive loss-net of tax Other comprehensive loss-net of tax Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Comprehensive loss attributable to noncontrolling interests Total comprehensive income (loss) Comprehensive income (loss) attributable to Great Lakes Dredge & Dock Corporation Other Comprehensive Income (Loss), Foreign Currency Translation Gain (Loss) Arising During Period, Tax Currency translation adjustment, tax Reclassification of derivative gains (losses) to earnings, tax Net unrealized gain on derivatives-net of tax Consolidated Statements Of Equity [Abstract] Statement, Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Parent [Member] Parent [Member] Common Stock [Member] Common Stock [Member] Additional Paid In Capital [Member] Additional Paid-In Capital [Member] Retained Earnings [Member] Retained Earnings (Accumulated Deficit) [Member] Accumulated Other Comprehensive Income [Member] Accumulated Other Comprehensive Loss [Member] Noncontrolling Interest [Member] Noncontrolling Interests [Member] Shares, Issued BALANCE - shares BALANCE - shares Share-based compensation, Value Share-based compensation, Shares Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures Vesting of restricted stock units, including impact of shares withheld for taxes, value Vesting of RSU's Vesting of restricted stock units, including impact of shares withheld for taxes, shares Exercise of stock options, Value Exercise of stock options, Shares Options exercised Adjustment to Additional Paid in Capital, Income Tax Effect from Share-based Compensation, Net Excess income tax benefit from share based compensation Dividends, Common Stock, Cash Dividends declared and paid Dividends, Share-based Compensation Dividend equivalents paid on restricted stock units Distributions paid to noncontrolling interests. Distributions paid to noncontrolling interests Purchase of noncontrolling interests Dividends declared per share Consolidated Statements Of Cash Flows [Abstract] Noncash or Part Noncash Acquisitions by Unique Description [Axis] Noncash Or Part Noncash Acquisition Name [Domain] Noncash or Part Noncash Acquisition, Name [Domain] Terra [Member] Terra [Member] Terra [Member] Magnus [Member] Magnus [Member] Magnus [Member] OPERATING ACTIVITIES: IncomeLossFromContinuingOperations Income from continuing operations Adjustments to reconcile net income to net cash flows used in operating activities: Depreciation and amortization Equity in loss of joint ventures Equity in (earnings) loss of joint ventures, net of cash distributions Due from Joint Ventures Cash distributions from joint ventures Deferred Income Tax Expense Benefit Deferred income taxes Gain on dispositions of property and equipment (Gain) loss on dispositions of property and equipment Gain (loss) on adjustment of contingent earnout. Gain (Loss) On Adjustment Of Contingent Earnout Gain on adjustment of contingent earnout Amortization of deferred financing fees Foreign Currency Transaction Gain (Loss), Unrealized Unrealized foreign currency (gain) loss Unrealized foreign currency (gain) loss Unrealized net (gain) loss from mark-to-market valuations of derivatives Unrealized net (gain) loss from mark-to-market valuations of derivatives Share-based compensation expense Excess Tax Benefit from Share-based Compensation, Operating Activities Excess income tax benefit from share based compensation Changes in assets and liabilities: Accounts receivable 1 Accounts receivable Increase Decrease In Costs In Excess Of Billings On Uncompleted Contracts Or Programs Expected To Be Collected Within One Year Increase Decrease In Costs In Excess Of Billings On Uncompleted Contracts Or Programs Expected To Be Collected Within One Year Contract revenues in excess of billings Inventories Inventories Prepaid expenses and other current assets Prepaid expenses and other current assets Accounts payable and accrued expenses Increase Decrease In Billings In Excess Of Cost Increase Decrease In Billings In Excess Of Cost Billings in excess of contract revenues Increase (Decrease) in Other Noncurrent Assets and Liabilities, Net Other noncurrent assets and liabilities NetCashProvidedByUsedInOperatingActivitiesContinuingOperations Net cash flows provided by (used in) operating activities of continuing operations Net cash flows provided by operating activities of continuing operations CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations Net cash flows used in by operating activities of discontinued operations Net Cash Provided by (Used in) Operating Activities Cash provided by (used in) operating activities INVESTING ACTIVITIES: Purchases of property and equipment Purchases of property and equipment Dispositions of property and equipment Proceeds from dispositions of property and equipment Payments to Acquire Businesses, Net of Cash Acquired Acquisition of Terra assets Proceeds from vendor performance obligations Proceeds from vendor performance obligations Proceeds from (payments on) vendor performance obligations (Note 13) Payments for acquisitions of businesses, net of cash acquired Payments for acquisitions of businesses, net of cash acquired NetCashProvidedByUsedInInvestingActivitiesContinuingOperations Net cash flows used in investing activities of continuing operations Net cash flows used in investing activities of continuing operations CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations Net cash flows provided by (used in) investing activities of discontinued operations Net Cash Provided by (Used in) Investing Activities Cash used in investing activities FINANCING ACTIVITIES: Proceeds from Loan Originations Proceeds from term loan facility Proceeds from Issuance of Senior Long-term Debt Proceeds from issuance of 7 3/8% senior notes Repayments of Short-term Debt Repayments of term loan facility Payment of Financing and Stock Issuance Costs Deferred financing fees Repayments of Long-term Debt Repayment of long term note payable Payments to Noncontrolling Interests Distributions paid to minority interests Payments of Ordinary Dividends, Common Stock Dividends paid Payments for proceeds from accounts with affiliates. Payments For Proceeds From Accounts With Affiliates Net change in accounts with affiliates Payments Of Dividends Share Based Compensation Payments Of Dividends Share Based Compensation Dividend equivalents paid on restricted stock units Payments Related to Tax Withholding for Share-based Compensation Taxes paid on settlement of vested share awards Proceeds from Noncontrolling Interests Purchase of noncontrolling interest Repayment of capital lease debt Repayments of equipment debt Exercise of stock options Exercise of stock options and purchases from employee stock plans Excess Tax Benefit from Share-based Compensation, Financing Activities Excess income tax benefit from share-based compensation Borrowings under revolving loans Repayments of revolving loans Repayments of revolving loans NetCashProvidedByUsedInFinancingActivitiesContinuingOperations Net cash flows provided by (used in) financing activities of continuing operations Cash provided by (used in) financing activities of continuing operations Cash used in financing activities of discontinued operations Net cash flows provided by (used in) financing activities of discontinued operations Cash used in financing activities of discontinued operations Cash provided by financing activities Cash provided by (used in) financing activities Effect of Exchange Rate on Cash and Cash Equivalents Effect of foreign currency exchange rates on cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Net increase (decrease) in cash and cash equivalents Supplemental Cash Flow Information Cash paid for interest Cash paid (refunded) for income taxes Non-cash Investing and Financing Activities Property and equipment purchased but not yet paid