Entity Central Index Key Accounts receivable, noncurrent and contract receivable retainage. Document and Entity Information Document And Entity Information [Abstract] Document Type Document Type Amendment Flag Amendment Flag Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Trading Symbol Trading Symbol Entity Registrant Name Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding Entity Common Stock Shares Outstanding Statement Of Financial Position [Abstract] ASSETS Assets [Abstract] CURRENT ASSETS: Assets Current [Abstract] Cash and cash equivalents Cash And Cash Equivalents At Carrying Value Accounts receivable—net Accounts Receivable Net Current Contract revenues in excess of billings Costs In Excess Of Billings On Uncompleted Contracts Or Programs Expected To Be Collected Within One Year Inventories Inventory Net Prepaid expenses and other current assets Prepaid Expense And Other Assets Current Total current assets Assets Current PROPERTY AND EQUIPMENT—Net Property Plant And Equipment Net GOODWILL AND OTHER INTANGIBLE ASSETS—Net Intangible Assets Net Including Goodwill INVENTORIES—Noncurrent Inventory Noncurrent INVESTMENTS IN JOINT VENTURES Investments In Affiliates Subsidiaries Associates And Joint Ventures ASSETS HELD FOR SALE—Noncurrent Disposal Group Including Discontinued Operation Assets Noncurrent OTHER Other Assets Noncurrent TOTAL Assets LIABILITIES AND EQUITY Liabilities And Stockholders Equity [Abstract] Accounts payable Accounts Payable Current Accrued expenses Accrued Liabilities Current Billings in excess of contract revenues Billings In Excess Of Cost Current portion of long-term debt Long Term Debt Current Total current liabilities Liabilities Current LONG-TERM DEBT Long Term Debt Noncurrent REVOLVING CREDIT FACILITY Long Term Line Of Credit DEFERRED INCOME TAXES Deferred Tax Liabilities Noncurrent OTHER Other Liabilities Noncurrent Total liabilities Liabilities COMMITMENTS AND CONTINGENCIES (Note 9) Commitments And Contingencies EQUITY: Stockholders Equity [Abstract] Common stock—$.0001 par value; 90,000 authorized, 62,485 and 61,897 shares issued; 62,207 and 61,619 shares outstanding at March 31, 2018 and December 31, 2017, respectively. Common Stock Value Treasury stock, at cost Treasury Stock Value Additional paid-in capital Additional Paid In Capital Common Stock Accumulated deficit Retained Earnings Accumulated Deficit Accumulated other comprehensive income Accumulated Other Comprehensive Income Loss Net Of Tax Total equity Stockholders Equity TOTAL Liabilities And Stockholders Equity Common stock, par value Common Stock Par Or Stated Value Per Share Common stock, shares authorized Common Stock Shares Authorized Common stock, shares issued Common Stock Shares Issued Common stock, shares outstanding Common Stock Shares Outstanding Income Statement [Abstract] Contract revenues Revenues Costs of contract revenues Contract Revenue Cost Gross profit Gross Profit General and administrative expenses General And Administrative Expense (Gain) loss on sale of assets—net Gains Losses On Sales Of Assets Operating loss Operating Income Loss Interest expense—net Interest Income Expense Nonoperating Net Other income (expense) Other Nonoperating Income Expense Loss from continuing operations before income taxes Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest Income tax benefit Income Tax Expense Benefit Loss from continuing operations Income Loss From Continuing Operations Loss from discontinued operations, net of income taxes Income Loss From Discontinued Operations Net Of Tax Net loss Net Income Loss Basic loss per share attributable to continuing operations Income Loss From Continuing Operations Per Basic Share Basic loss per share attributable to discontinued operations, net of tax Income Loss From Discontinued Operations Net Of Tax Per Basic Share Basic loss per share Earnings Per Share Basic Basic weighted average shares Weighted Average Number Of Shares Outstanding Basic Diluted loss per share attributable to continuing operations Income Loss From Continuing Operations Per Diluted Share Diluted loss per share attributable to discontinued operations, net of tax Income Loss From Discontinued Operations Net Of Tax Per Diluted Share Diluted loss per share Earnings Per Share Diluted Diluted weighted average shares Weighted Average Number Of Diluted Shares Outstanding Statement Of Income And Comprehensive Income [Abstract] Net loss Currency translation adjustment—net of tax Other Comprehensive Income Foreign Currency Transaction And Translation Gain Loss Arising During Period Net Of Tax Net unrealized gain on derivatives—net of tax Other Comprehensive Income Loss Derivatives Qualifying As Hedges Net Of Tax Other comprehensive income (loss)—net of tax Other Comprehensive Income Loss Net Of Tax Comprehensive loss Comprehensive Income Net Of Tax Currency translation adjustment, tax Other Comprehensive Income Foreign Currency Translation Gain Loss Arising During Period Tax Net unrealized gain on derivatives, tax Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Tax Vesting of restricted stock units shares including impact of shares withheld for taxes. Vesting of restricted stock units value including impact of shares withheld for taxes. Statement Of Stockholders Equity [Abstract] Statement [Table] Statement [Table] Equity Components Statement Equity Components [Axis] Equity Component Equity Component [Domain] Common Stock [Member] Common Stock [Member] Treasury Stock [Member] Treasury Stock [Member] Additional Paid-In Capital [Member] Additional Paid In Capital [Member] Accumulated Deficit [Member] Retained Earnings [Member] Accumulated Other Comprehensive Loss [Member] Accumulated Other Comprehensive Income [Member] Statement [Line Items] Statement [Line Items] BALANCE - value BALANCE - shares Shares Outstanding Cumulative effect of recent accounting pronouncements New Accounting Pronouncement Or Change In Accounting Principle Effect Of Adoption Quantification Share-based compensation, value Stock Issued During Period Value Share Based Compensation Share-based compensation, shares Stock Issued During Period Shares Share Based Compensation Vesting of restricted stock units, including impact of shares withheld for taxes, value Vesting Of Restricted Stock Units Value Including Impact Of Shares Withheld For Taxes Vesting of restricted stock units, including impact of shares withheld for taxes, shares Vesting Of Restricted Stock Units Shares Including Impact Of Shares Withheld For Taxes Exercise of options and purchases from employee stock plans, value Stock Issued During Period Value Stock Options Exercised Exercise of options and purchases from employee stock plans, shares Stock Issued During Period Shares Stock Options Exercised Net loss Other comprehensive income (loss)—net of tax BALANCE - value BALANCE - shares Cash distributions from joint ventures. Other non-cash restructuring items. Amortization of deferred financing cost and other non cash interest expense. Increase decrease in costs in excess of billings on uncompleted contracts or programs expected to be collected within one year. Statement Of Cash Flows [Abstract] OPERATING ACTIVITIES: Net Cash Provided By Used In Operating Activities [Abstract] Loss from continuing operations Adjustments to reconcile net loss to net cash flows provided by (used in) operating activities: Adjustments To Reconcile Net Income Loss To Cash Provided By Used In Operating Activities [Abstract] Depreciation and amortization Depreciation Depletion And Amortization Equity in earnings of joint ventures Income Loss From Equity Method Investments Cash distributions from joint ventures Cash Distributions From Joint Ventures Deferred income taxes Deferred Income Tax Expense Benefit Gain on sale of assets Other non-cash restructuring items Other Non Cash Restructuring Items Amortization of deferred financing fees Amortization Of Deferred Financing Cost And Other Non Cash Interest Expense Unrealized net (gain) loss from mark-to-market valuations of derivatives Unrealized Gain Loss On Derivatives Unrealized foreign currency gain Foreign Currency Transaction Gain Loss Unrealized Share-based compensation expense Share Based Compensation Changes in assets and liabilities: Increase Decrease In Operating Capital [Abstract] Accounts receivable Increase Decrease In Accounts Receivable Contract revenues in excess of billings Increase Decrease In Costs In Excess Of Billings On Uncompleted Contracts Or Programs Expected To Be Collected Within One Year Inventories Increase Decrease In Inventories Prepaid expenses and other current assets Increase Decrease In Prepaid Deferred Expense And Other Assets Accounts payable and accrued expenses Increase Decrease In Accounts Payable And Accrued Liabilities Billings in excess of contract revenues Increase Decrease In Billing In Excess Of Cost Of Earnings Other noncurrent assets and liabilities Increase Decrease In Other Noncurrent Assets And Liabilities Net Cash provided by (used in) operating activities Net Cash Provided By Used In Operating Activities INVESTING ACTIVITIES: Net Cash Provided By Used In Investing Activities [Abstract] Purchases of property and equipment Payments To Acquire Property Plant And Equipment Proceeds from dispositions of property and equipment Proceeds From Sale Of Property Plant And Equipment Cash used in investing activities Net Cash Provided By Used In Investing Activities Non cash repayments of debt with proceeds from sale leaseback transactions. FINANCING ACTIVITIES: Net Cash Provided By Used In Financing Activities [Abstract] Deferred financing fees Payment Of Financing And Stock Issuance Costs Repayments of debt Repayments Of Debt Taxes paid on settlement of vested share awards Payments Related To Tax Withholding For Share Based Compensation Exercise of options and purchases from employee stock plans Proceeds From Stock Options Exercised Borrowings under revolving loans Proceeds From Long Term Lines Of Credit Repayments of revolving loans Repayments Of Long Term Lines Of Credit Cash provided by (used in) financing activities Net Cash Provided By Used In Financing Activities Effect of foreign currency exchange rates on cash and cash equivalents Effect Of Exchange Rate On Cash And Cash Equivalents Net decrease in cash, cash equivalents and restricted cash Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect Cash, cash equivalents and restricted cash at beginning of period Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Cash, cash equivalents and restricted cash at end of period Supplemental Cash Flow Information Supplemental Cash Flow Information [Abstract] Cash paid for interest Interest Paid Net Cash paid for income taxes Income Taxes Paid Net Non-cash Investing and Financing Activities Cash Flow Noncash Investing And Financing Activities Disclosure [Abstract] Property and equipment purchased but not yet paid Capital Expenditures Incurred But Not Yet Paid Repayments of debt with proceeds from sale-leaseback transactions Non Cash Repayments Of Debt With Proceeds From Sale Leaseback Transactions Organization Consolidation And Presentation Of Financial Statements [Abstract] Basis Of Presentation Basis Of Presentation And Significant Accounting Policies [Text Block] Earnings Per Share [Abstract] Earnings Per Share Earnings Per Share [Text Block] Payables And Accruals [Abstract] Accrued Expenses Accounts Payable And Accrued Liabilities Disclosure [Text Block] Debt Disclosure [Abstract] Long-Term Debt Long Term Debt [Text Block] Fair Value Disclosures [Abstract] Fair Value Measurements Fair Value Disclosures [Text Block] Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] Share-Based Compensation Disclosure Of Compensation Related Costs Share Based Payments [Text Block] Revenue From Contract With Customer [Abstract] Revenue Revenue From Contract With Customer [Text Block] Restructuring And Related Activities [Abstract] Restructuring Charges Restructuring And Related Activities Disclosure [Text Block] Commitments And Contingencies Disclosure [Abstract] Commitments And Contingencies Commitments And Contingencies Disclosure [Text Block] Equity Method Investments And Joint Ventures [Abstract] Investments Cost And Equity Method Investments Disclosure [Text Block] Business Combinations [Abstract] Business Combinations And Dispositions Business Acquisition Integration Restructuring And Other Related Costs [Text Block] Segment Reporting [Abstract] Segment Information Segment Reporting Disclosure [Text Block] Recent Accounting Pronouncements New Accounting Pronouncements Policy Policy [Text Block] Schedule of Reconciliation of Cash, Cash Equivalents and Restricted Cash Schedule Of Restricted Cash And Cash Equivalents [Text Block] Schedule of Quarterly Impact of Change in Accounting Policy on Condensed Consolidated Statements of Operations and Condensed Consolidated Balance Sheets Schedule Of New Accounting Pronouncements And Changes In Accounting Principles [Text Block] Computations For Basic And Diluted Earnings (Loss) Per Share Schedule Of Earnings Per Share Basic And Diluted Table [Text Block] Accrued Expenses Schedule Of Accrued Liabilities Table [Text Block] Schedule of Fair Values Of Financial Instruments and Nonfinancial Assets and Liabilities Measured (Table) (Text Block) Schedule Of Fair Values Of Financial Instruments And Nonfinancial Assets And Liabilities Measured At The Reporting Date Schedule Of Fair Values Of Financial Instruments And Nonfinancial Assets And Liabilities Measured Table [Text Block] Schedule Of Fair Value Of Fuel Hedge Contracts Balance Sheet Location Fair Value By Balance Sheet Grouping [Text Block] Changes In Components Of Accumulated Other Comprehensive Income (Loss) Schedule Of Accumulated Other Comprehensive Income Loss Table [Text Block] Adjustments Reclassified From Accumulated Balances Other Comprehensive Income (Loss) To Earnings Reclassification Out Of Accumulated Other Comprehensive Income Table [Text Block] Revenue recognition. Revenue recognition. Revenue Recognition [Table] Revenue Recognition [Table] Adjustments for New Accounting Pronouncements Adjustments For New Accounting Pronouncements [Axis] Type of Adoption Type Of Adoption [Member] ASU 2014-09 [Member] Accounting Standards Update201409 [Member] Revenue Recognition [Line Items] Revenue Recognition [Line Items] Summary of Impact of Change in Accounting Principle on Consolidated Balance Sheets Schedule Of Condensed Balance Sheet Table [Text Block] Summary of Impact of Change in Accounting Principle on Consolidated Statements of Operations Schedule Of Condensed Income Statement Table [Text Block] Summary of Segment and Type of Work and Customer, Contract Revenues Disaggregation Of Revenue Table [Text Block] Schedule of Accounts Receivable Schedule Of Accounts Notes Loans And Financing Receivable [Text Block] Components of Contracts in Progress Costs In Excess Of Billings And Billings In Excess Of Costs Table [Text Block] Schedule of Restructuring Charges Schedule Of Restructuring And Related Costs [Text Block] Schedule Of Discontinued Operations Schedule Of Disposal Groups Including Discontinued Operations Income Statement Balance Sheet And Additional Disclosures [Text Block] Segment Reporting By Segment Schedule Of Segment Reporting Information By Segment [Text Block] Organization consolidation and presentation. Organization consolidation and presentation. Organization Consolidation And Presentation [Table] Organization Consolidation And Presentation [Table] Accounting Standards Update 2016-18 [Member] Accounting Standards Update201618 [Member] Organization Consolidation and Presentation [Line Items] Organization Consolidation And Presentation [Line Items] Restricted cash included in other long-term assets Restricted Cash And Cash Equivalents Noncurrent Cash, cash equivalents and restricted cash at end of period Initial Application Period Cumulative Effect Transition Initial Application Period Cumulative Effect Transition [Axis] Initial Application Period Cumulative Effect Transition Initial Application Period Cumulative Effect Transition [Domain] Difference between Revenue Guidance in Effect before and after Topic 606 [Member] Difference Between Revenue Guidance In Effect Before And After Topic606 [Member] Income tax benefit Comprehensive loss Deferred income taxes Accounting Standards Update 2014-09 [Member] Range Range [Axis] Range Range [Member] Maximum [Member] Maximum [Member] Minimum [Member] Minimum [Member] Cumulative net adjustment to the beginning retained earnings balance New Accounting Pronouncement Or Change In Accounting Principle Cumulative Effect Of Change On Equity Or Net Assets1 Number of reportable segments with goodwill. Number of operating Segments Number Of Operating Segments Number of reportable segments Number Of Reportable Segments Number of reportable segments with goodwill Number Of Reportable Segments With Goodwill Securities excluded from computation of earnings per share amount due to loss. Shares excluded from computation of diluted earnings per share Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount Securities excluded from computation of earnings per share amount due to loss Securities Excluded From Computation Of Earnings Per Share Amount Due To Loss Loss from continuing operations Weighted-average common shares outstanding — basic Effect of stock options and restricted stock units Weighted Average Number Diluted Shares Outstanding Adjustment Weighted-average common shares outstanding — diluted Loss per share from continuing operations — basic Loss per share from continuing operations — diluted Accrued liabilities adjustments under percentage of completion method. Insurance Accrued Insurance Current Interest Interest Payable Current Payroll and employee benefits Employee Related Liabilities Current Accrued rent Accrued Rent Current Percentage of completion adjustment Accrued Liabilities Adjustments Under Percentage Of Completion Method Income and other taxes Taxes Payable Current Other Other Accrued Liabilities Current Total accrued expenses Line of credit facility optional increase capacity. Debt Instrument [Table] Debt Instrument [Table] Credit Facility Credit Facility [Axis] Credit Facility Credit Facility [Domain] Revolving Credit Facility [Member] Revolving Credit Facility [Member] Standby Letters of Credit [Member] Standby Letters Of Credit [Member] Swingline loans. Swingline Loans [Member] Swingline Loans [Member] Scenario Statement Scenario [Axis] Scenario, Unspecified Scenario Unspecified [Domain] Scenario Forecast [Member] Scenario Forecast [Member] Variable Rate Variable Rate [Axis] Variable Rate Variable Rate [Domain] Base Rate [Member] Base Rate [Member] LIBOR Rate [Member] London Interbank Offered Rate L I B O R [Member] Debt Instrument Debt Instrument [Axis] Debt Instrument, Name Debt Instrument Name [Domain] Eight percent senior notes due in two thousand twenty two. 8.000% Senior Notes Due in 2022 [Member] Eight Percent Senior Notes Due In Two Thousand Twenty Two [Member] Seven point three seven five senior notes due in two thousand nineteen. 7.375% Senior Notes Due In 2019 [Member] Seven Point Three Seven Five Senior Notes Due In Two Thousand Nineteen [Member] Long-term Debt, Type Longterm Debt Type [Axis] Long-term Debt, Type Longterm Debt Type [Domain] Senior Notes [Member] Senior Notes [Member] Vessels and ancillary equipment. Vessels and Ancillary Equipment [Member] Vessels And Ancillary Equipment [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Line of credit facility, maximum borrowing capacity Line Of Credit Facility Maximum Borrowing Capacity Line of credit facility optional increase capacity Line Of Credit Facility Optional Increase Capacity Capital expenditures by credit parties. Expenses related to buy-out operating leases Operating Lease Expense Capital expenditures by credit parties Capital Expenditures By Credit Parties Fixed charge coverage ratio trigger for maximum availability under credit agreement for five consecutive days. Fixed charge coverage ratio trigger for maximum availability under credit agreement for one day. Fixed charge coverage ratio. Fixed charge coverage ratio Fixed Charge Coverage Ratio Maximum availability of earnings under credit agreement for five consecutive days Fixed Charge Coverage Ratio Trigger For Maximum Availability Under Credit Agreement For Five Consecutive Days Maximum availability of earnings under credit agreement for one day Fixed Charge Coverage Ratio Trigger For Maximum Availability Under Credit Agreement For One Day Revolving credit facility, maturity date Line Of Credit Facility Expiration Date1 Debt instrument, basis spread on variable rate Debt Instrument Basis Spread On Variable Rate1 Unused fee percentage Line Of Credit Facility Unused Capacity Commitment Fee Percentage Revolving credit facility Lines Of Credit Current Letters of credit outstanding Letters Of Credit Outstanding Amount Letter of credit remaining borrowing capacity Line Of Credit Facility Remaining Borrowing Capacity Availability under credit agreement suppressed Line Of Credit Facility Current Borrowing Capacity Face value of senior notes issued, percentage. Redemption of notes. Debt instrument, face amount Debt Instrument Face Amount Debt instrument, interest rate, stated percentage Debt Instrument Interest Rate Stated Percentage Maturity date Debt Instrument Maturity Date Face value of senior notes issued, percentage Face Value Of Senior Notes Issued Percentage Net proceeds from issuance Proceeds From Issuance Of Debt Redemption of notes Redemption Of Notes Owned domestic subsidiaries percent. Owned Domestic Subsidiaries Percent Owned Domestic Subsidiaries Percent Long-term debt, current maturities Long-term debt, excluding current Maturities Net proceeds from sale-leaseback of a vessel yielding Sale Leaseback Transaction Net Proceeds Financing Activities Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table] Hedging Relationship Derivative Instruments Gain Loss By Hedging Relationship [Axis] Hedging Relationship Hedging Relationship [Domain] Fuel hedge contracts. Fuel Hedge Contracts [Member] Fuel Hedge Contracts [Member] Fair Value, Hierarchy Fair Value By Fair Value Hierarchy Level [Axis] Fair Value Hierarchy Fair Value Measurements Fair Value Hierarchy [Domain] Fair Value, Inputs, Level 1 [Member] Fair Value Inputs Level1 [Member] Significant Other Observable Inputs (Level 2) [Member] Fair Value Inputs Level2 [Member] Significant Unobservable Inputs (Level 3) [Member] Fair Value Inputs Level3 [Member] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] Fair Value, Net Asset (Liability) Fair Value Net Asset Liability Derivative underlying hedge percent. Fair Values Derivatives Balance Sheet Location By Derivative Contract Type By Hedging Designation [Table] Fair Values Derivatives Balance Sheet Location By Derivative Contract Type By Hedging Designation [Table] Income Statement Location Income Statement Location [Axis] Income Statement Location Income Statement Location [Domain] Other Income (Expense) [Member] Other Nonoperating Income Expense [Member] Derivatives Fair Value [Line Items] Derivatives Fair Value [Line Items] Derivative underlying hedge percent Derivative Underlying Hedge Percent Derivative, Nonmonetary Notional Amount, Volume Derivative Nonmonetary Notional Amount Volume Fixed price range Derivative Swap Type Fixed Price Fair value hedge assets Fair Value Hedge Assets At Fair Value Reclassification of derivative losses to earnings-net of tax Other Comprehensive Income Loss Reclassification Adjustment From A O C I On Derivatives Net Of Tax Balance Sheet Location Balance Sheet Location [Axis] Balance Sheet Location Balance Sheet Location [Domain] Prepaid Expenses and Other Current Assets [Member] Prepaid Expenses And Other Current Assets [Member] Hedging Designation Hedging Designation [Axis] Hedging Designation Hedging Designation [Domain] Derivatives Designated as Hedging Instruments [Member] Designated As Hedging Instrument [Member] Asset derivatives Cumulative translation adjustments—net of tax Reclassification of derivative (gains) losses to earnings—net of tax Change in fair value of derivatives—net of tax Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax Net unrealized gain on derivatives—net of tax Derivative Instruments Gain Loss By Hedging Relationship By Income Statement Location By Derivative Instrument Risk [Table] Derivative Instruments Gain Loss By Hedging Relationship By Income Statement Location By Derivative Instrument Risk [Table] Accumulated Net Gain Loss From Designated Or Qualifying Cash Flow Hedges Accumulated Net Gain Loss From Designated Or Qualifying Cash Flow Hedges [Member] Reclassification out of Accumulated Other Comprehensive Income Reclassification Out Of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income Reclassification Out Of Accumulated Other Comprehensive Income [Domain] Reclassification Out Of Accumulated Other Comprehensive Income Reclassification Out Of Accumulated Other Comprehensive Income [Member] Derivative Instruments Gain Loss [Line Items] Derivative Instruments Gain Loss [Line Items] Costs of contract revenues Net income (loss) Reversal of cumulative translation adjustment Other Comprehensive Income Loss Foreign Currency Transaction And Translation Reclassification Adjustment From A O C I Realized Upon Sale Or Liquidation Net Of Tax Stated interest rate Fair value of debt Debt Instrument Fair Value Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] Title of Individual Title Of Individual [Axis] Relationship to Entity Title Of Individual With Relationship To Entity [Domain] Employees and directors. Employees And Directors [Member] Employees And Directors [Member] Plan Name Plan Name [Axis] Plan Name Plan Name [Domain] Two thousand seventeen long-term incentive plan. 2017 Long-Term Incentive Plan [Member] Two Thousand Seventeen Long Term Incentive Plan [Member] Two thousand seven long-term incentive plan. 2007 Long-Term Incentive Plan [Member] Two Thousand Seven Long Term Incentive Plan [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share Based Compensation Arrangement By Share Based Payment Award [Line Items] Share-based compensation arrangement by share-based payment award, number of shares available for grant Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Available For Grant Underlying equity awards issued Share Based Compensation Arrangement By Share Based Payment Award Shares Issued In Period Restricted stock units Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period New Accounting Pronouncements And Changes In Accounting Principles [Abstract] New Accounting Pronouncements Or Change In Accounting Principle [Table] New Accounting Pronouncements Or Change In Accounting Principle [Table] New Accounting Pronouncements Or Change In Accounting Principle [Line Items] New Accounting Pronouncements Or Change In Accounting Principle [Line Items] Other current assets Other Assets Current Other Percentage of performance obligation to be recognized as revenue. Performance obligation expected to be recognized as revenue, year. Segments Statement Business Segments [Axis] Segments Segment [Domain] Dredging. Dredging [Member] Dredging [Member] Geographical Statement Geographical [Axis] Geographical Segment Geographical [Domain] Foreign. Foreign [Member] Foreign [Member] Other current and noncurrent assets. Other Current and Noncurrent Assets [Member] Other Current And Noncurrent Assets [Member] Revenue, remaining performance obligation Revenue Remaining Performance Obligation Percentage of performance obligation to be recognized as revenue Percentage Of Performance Obligation To Be Recognized As Revenue Performance obligation, expected to be recognized as revenue year Performance Obligation Expected To Be Recognized As Revenue Year Remaining performance obligation, expected to be completed Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Year Revenue, description of timing Revenue Performance Obligation Description Of Timing Disaggregation Of Revenue [Abstract] Disaggregation Of Revenue [Table] Disaggregation Of Revenue [Table] Consolidation Items Consolidation Items [Axis] Consolidation Items Consolidation Items [Domain] Operating Segment [Member] Operating Segments [Member] Intersegment Revenue [Member] Intersegment Elimination [Member] Environmental and infrastructure segment. Environmental And Infrastructure [Member] Environmental And Infrastructure Segment [Member] Products and Services Product Or Service [Axis] Products and Services Products And Services [Domain] Capital dredging - U.S. [Member] Capital-U.S. [Member] Capital Dredging U S [Member] Capital dredging - Foreign [Member] Capital-Foreign [Member] Capital Dredging Foreign [Member] Beach Nourishment Dredging [Member] Coastal Protection [Member] Beach Nourishment Dredging [Member] Maintenance Dredging [Member] Maintenance [Member] Maintenance Dredging [Member] Rivers & Lakes [Member] Rivers & Lakes [Member] Rivers Lakes [Member] Disaggregation Of Revenue [Line Items] Disaggregation Of Revenue [Line Items] Revenues Revenue From Contract With Customer Excluding Assessed Tax Federal government. Federal Government [Member] Federal Government [Member] State and local government. State and Local Government [Member] State And Local Government [Member] Private. Private [Member] Private [Member] Other. Other [Member] Other [Member] Accounts receivable billed for long term completed contracts or programs. Accounts receivable billed for long term contracts or programs in progress. Receivables [Abstract] Completed contracts Accounts Receivable Billed For Long Term Completed Contracts Or Programs Contracts in progress Accounts Receivable Billed For Long Term Contracts Or Programs In Progress Retainage Contract Receivable Retainage Accounts receivable, gross Accounts Receivable Gross Allowance for doubtful accounts Allowance For Doubtful Accounts Receivable Total accounts receivable—net Accounts Receivable Net Long-term accounts receivable and retainage Accounts Receivable Noncurrent And Contract Receivable Retainage Costs and earnings for contracts in progress. Billings for contracts in progress. Costs and earnings in excess of billings for contracts in progress. Costs and earnings in excess of billings for completed contracts. Schedule Of Accounts Notes Loans And Financing Receivable [Table] Schedule Of Accounts Notes Loans And Financing Receivable [Table] Receivable Type Accounts Notes Loans And Financing Receivable By Receivable Type [Axis] Receivable Receivable Type [Domain] Costs and earnings in excess of billings. Costs And Earnings In Excess Of Billings [Member] Costs And Earnings In Excess Of Billings [Member] Billings in excess of costs and earnings. Billings In Excess Of Costs And Earnings [Member] Billings In Excess Of Costs And Earnings [Member] Accounts Notes And Loans Receivable [Line Items] Accounts Notes And Loans Receivable [Line Items] Costs and earnings for contracts in progress Costs And Earnings For Contracts In Progress Amounts billed Billings For Contracts In Progress Costs and earnings in excess of billings for contracts in progress Costs And Earnings In Excess Of Billings For Contracts In Progress Costs and earnings in excess of billings for completed contracts Costs And Earnings In Excess Of Billings For Completed Contracts Total contract revenues in excess of billings Total billings in excess of contract revenues Costs in excess of billings Costs In Excess Of Billings On Uncompleted Contracts Or Programs Revenue recognition, included in the billings in excess of contract revenues Contract With Customer Liability Revenue Recognized Costs to fulfill a contract with customer recognized as an asset Capitalized Contract Cost Gross Amortization on pre-construction costs Capitalized Contract Cost Accumulated Amortization Schedule Of Restructuring And Related Costs [Table] Schedule Of Restructuring And Related Costs [Table] Restructuring Type Restructuring Cost And Reserve [Axis] Type of Restructuring Type Of Restructuring [Domain] Severance [Member] Employee Severance [Member] Asset retirements. Asset Retirements [Member] Asset Retirements [Member] Pre-contract costs. Pre-contract Costs [Member] Precontract Costs [Member] Closeout costs. Closeout Costs [Member] Closeout Costs [Member] Depreciation. Depreciation [Member] Depreciation [Member] Loss on sale of assets. Loss on Sale of Assets [Member] Loss On Sale Of Assets [Member] Other items. Other Items [Member] Other Items [Member] Restructuring Cost And Reserve [Line Items] Restructuring Cost And Reserve [Line Items] Estimated restructuring charge Restructuring And Related Cost Expected Cost1 Restructuring and related cost, expected cost non-cash. Restructuring charge related to non-cash Restructuring And Related Cost Expected Cost Noncash Dredging segment. Dredging [Member] Dredging Segment [Member] Costs of contract revenues - depreciation. Costs of Contract Revenues - Depreciation [Member] Costs Of Contract Revenues Depreciation [Member] Costs of contract revenues - other. Costs of Contract Revenues - Other [Member] Costs Of Contract Revenues Other [Member] General and Administrative Expenses [Member] General And Administrative Expense [Member] Gain on sale of assets net. Gain on Sale of Assets—Net [Member] Gain On Sale Of Assets Net [Member] Restructuring charges Restructuring Charges Accrued rent expense Accrued Rent Current And Noncurrent Severance expense Severance Costs1 Bids bond range. Outstanding performance bonds. Revenue value remaining from outstanding performance bonds. Commitments and contingencies. Commitments and contingencies. Commitments And Contingencies [Table] Commitments And Contingencies [Table] Environmental And Infrastructure Segment [Member] Letter of Credit [Member] Letter Of Credit [Member] Loss Contingency Nature Loss Contingencies By Nature Of Contingency [Axis] Loss Contingency, Nature Loss Contingency Nature [Domain] Surety Bond [Member] Surety Bond [Member] Commitments And Contingencies [Line Items] Commitments And Contingencies [Line Items] Bids bond range Bids Bond Range Outstanding performance bonds Outstanding Performance Bonds Revenue value remaining from outstanding performance bonds Revenue Value Remaining From Outstanding Performance Bonds Aggregate demolition surety performance bond Loss Contingency Damages Sought Value Warranty periods. Warranty periods Warranty Periods Proceeds from Legal Settlements Proceeds From Legal Settlements Schedule Of Equity Method Investments [Table] Schedule Of Equity Method Investments [Table] Investment, Name Schedule Of Equity Method Investment Equity Method Investee Name [Axis] Investment, Name Equity Method Investee Name [Domain] TerraSea Environmental Solutions. TerraSea Environmental Solutions [Member] Terrasea Environmental Solutions [Member] Schedule Of Equity Method Investments [Line Items] Schedule Of Equity Method Investments [Line Items] Ownership percentage Equity Method Investment Ownership Percentage Schedule Of Business Acquisitions By Acquisition [Table] Schedule Of Business Acquisitions By Acquisition [Table] Operating Activities Statement Operating Activities Segment [Axis] Operating Activities Segment Operating Activities [Domain] NASDI, LLC and Yankee Environmental Services, LLC Segment Discontinued Operations [Member] Business Acquisition Business Acquisition [Axis] Business Acquisition, Acquiree Business Acquisition Acquiree [Domain] Magnus Pacific acquisition. Magnus Pacific Acquisition [Member] Magnus Pacific Acquisition [Member] Legal Entity Legal Entity [Axis] Entity Entity [Domain] Great Lakes Environmental & Infrastructure LLC. Great Lakes Environmental & Infrastructure, LLC [Member] Great Lakes Environmental And Infrastructure L L C [Member] Business Acquisition [Line Items] Business Acquisition [Line Items] Proceeds from divestiture of businesses Proceeds From Divestiture Of Businesses Loss contingency damages sought estimated value. Estimated surety bond claim, including associated expenses Loss Contingency Damages Sought Estimated Value Revenue Disposal Group Including Discontinued Operation Revenue Loss before income taxes from discontinued operations Discontinued Operation Income Loss From Discontinued Operation Before Income Tax Income tax benefit Discontinued Operation Tax Effect Of Discontinued Operation Loss from discontinued operations, net of income taxes Base purchase price Business Acquisition Cost Of Acquired Entity Transaction Costs Payments for previous acquisition Payments For Previous Acquisition Maximum potential aggregate earnout payment. Maximum potential aggregate earnout payment Maximum Potential Aggregate Earnout Payment Schedule Of Segment Reporting Information By Segment [Table] Schedule Of Segment Reporting Information By Segment [Table] Intersegment Revenues [Member] Dredging Segment [Member] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Operating income (loss)