Document And Entity Information - USD ($)	12 Months Ended
Document And Entity Information - USD ($)	Dec. 31, 2015	Feb. 19, 2016	Jun. 30, 2015
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	FY
Trading Symbol	GLDD
Entity Registrant Name	Great Lakes Dredge & Dock CORP
Entity Central Index Key	0001372020
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		60,431,841
Entity Public Float			$ 330,554,110
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
CURRENT ASSETS:
Cash and cash equivalents	$ 14,184	$ 42,389
Accounts receivable—net	130,777	113,188
Contract revenues in excess of billings	81,195	82,557
Inventories	35,963	34,735
Prepaid expenses	7,924	4,708
Other current assets	59,690	64,667
Total current assets	329,733	342,244
PROPERTY AND EQUIPMENT—Net	430,210	399,445
GOODWILL	83,576	86,326
OTHER INTANGIBLE ASSETS — Net	2,428	8,963
INVENTORIES—Noncurrent	41,646	36,262
INVESTMENTS IN JOINT VENTURES	3,761	7,889
OTHER	10,271	12,105
TOTAL	901,625	893,234
CURRENT LIABILITIES:
Accounts payable	118,846	119,971
Accrued expenses	72,277	70,041
Billings in excess of contract revenues	7,061	4,639
Current portion of long term debt	7,506	5,859
Total current liabilities	205,690	200,510
7 3/8% SENIOR NOTES	274,909	274,880
REVOLVING CREDIT FACILITY	20,000
NOTES PAYABLE	54,382	49,497
DEFERRED INCOME TAXES	74,006	92,007
OTHER	20,465	20,377
Total liabilities	$ 649,452	$ 637,271
COMMITMENTS AND CONTINGENCIES (Note 13)
EQUITY:
Common stock—$.0001 par value; 90,000 authorized, 60,709 and 60,170 shares issued; 60,431 and 60,170 outstanding at December 31, 2015 and December 31, 2014, respectively.	$ 6	$ 6
Treasury stock, at cost	(1,433)
Additional paid-in capital	283,247	278,166
Accumulated deficit	(27,664)	(21,475)
Accumulated other comprehensive loss	(1,983)	(734)
Total equity	252,173	255,963
TOTAL	$ 901,625	$ 893,234

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2015	Dec. 31, 2014
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	90,000,000	90,000,000
Common stock, shares issued	60,709,000	60,170,000
Common stock, shares outstanding	60,431,000	60,170,000

Consolidated Statements Of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
CONTRACT REVENUES	$ 856,878	$ 806,831	$ 731,418
COSTS OF CONTRACT REVENUES	760,955	714,335	631,123
GROSS PROFIT	95,923	92,496	100,295
OPERATING EXPENSES:
GENERAL AND ADMINISTRATIVE EXPENSES	71,069	67,911	68,039
PROCEEDS FROM LOSS OF USE CLAIM			(13,372)
IMPAIRMENT OF GOODWILL	2,750
(GAIN) LOSS ON SALE OF ASSETS—Net	(855)	732	(5,773)
Total operating income	22,959	23,853	51,401
OTHER EXPENSE:
Interest expense—net	(24,365)	(19,967)	(21,941)
Equity in earnings (loss) of joint ventures	(6,051)	2,895	1,208
Gain on bargain purchase acquisition		2,197
Other income (expense)	(1,229)	210	(351)
Total other expense	(31,645)	(14,665)	(21,084)
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	(8,686)	9,188	30,317
INCOME TAX (PROVISION) BENEFIT	2,497	11,530	(10,460)
INCOME (LOSS) FROM CONTINUING OPERATIONS	(6,189)	20,718	19,857
Loss from discontinued operations, net of income taxes		(10,423)	(54,850)
NET INCOME (LOSS)	(6,189)	10,295	(34,993)
Net loss attributable to noncontrolling interest			632
NET INCOME (LOSS) ATTRIBUTABLE TO COMMON STOCKHOLDERS OF GREAT LAKES DREDGE & DOCK CORPORATION	$ (6,189)	$ 10,295	$ (34,361)
Basic earnings (loss) per share attributable to income from continuing operations	$ (0.10)	$ 0.35	$ 0.33
Basic loss per share attributable to loss on discontinued operations, net of income taxes		(0.17)	(0.91)
Basic earnings (loss) per share attributable to common stockholders of Great Lakes Dredge & Dock Corporation	$ (0.10)	$ 0.18	$ (0.58)
Basic weighted average shares	60,410	59,938	59,495
Diluted earnings (loss) per share attributable to income from continuing operations	$ (0.10)	$ 0.34	$ 0.33
Diluted loss per share attributable to loss on discontinued operations, net of income taxes		(0.17)	(0.90)
Diluted earnings (loss) per share attributable to common stockholders of Great Lakes Dredge & Dock Corporation	$ (0.10)	$ 0.17	$ (0.57)
Diluted weighted average shares	60,410	60,522	60,101

Consolidated Statements of Comprehensive Income (Loss) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2015

Dec. 31, 2014

Dec. 31, 2013

Statement Of Income And Comprehensive Income [Abstract]

Net income (loss)

$ (6,189)

$ 10,295

$ (34,993)

Currency translation adjustment—net of tax

^[1]

(1,249)

(62)

(397)

Net unrealized (gain) loss on derivatives—net of tax

^[2]

(199)

304

Other comprehensive loss—net of tax

(1,249)

(261)

(93)

Comprehensive income (loss)

(7,438)

10,034

(35,086)

Comprehensive loss attributable to noncontrolling interests

632

Comprehensive income (loss) attributable to Great Lakes Dredge & Dock Corporation

$ (7,438)

$ 10,034

$ (34,454)

[1]	Net of income tax benefit of $827, $41 and $261 for the years ended December 31, 2015, 2014 and 2013, respectively.
[2]	Net of income tax (provision) benefit of $(132) and $204 for the years ended December 31, 2014 and 2013, respectively.

Consolidated Statements of Comprehensive Income (Loss) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement Of Income And Comprehensive Income [Abstract]
Currency translation adjustment, tax	$ 827	$ 41	$ 261
Net unrealized (gain) loss on derivatives-net of tax		$ (132)	$ 204

Consolidated Statements Of Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings (Accumulated Deficit) [Member]	Accumulated Other Comprehensive Loss [Member]	Noncontrolling Interests [Member]
BALANCE - value at Dec. 31, 2012	$ 273,425	$ 6		$ 271,418	$ 2,591	$ (380)	$ (210)
BALANCE - shares at Dec. 31, 2012		59,359
Share-based compensation, Value	3,251			3,251
Share-based compensation, Shares		96
Vesting of restricted stock units, including impact of shares withheld for taxes, value	(308)			(308)
Vesting of restricted stock units, including impact of shares withheld for taxes, shares		75
Exercise of stock options and purchases from employee stock plans, Value	668			668
Exercise of stock options and purchases from employee stock plans, Shares		140
Excess income tax benefit from share-based compensation	154			154
Purchase of noncontrolling interests	(3)						(3)
Net loss	(34,993)				(34,361)		(632)
Other comprehensive loss—net of tax	(93)					(93)
BALANCE - value at Dec. 31, 2013	242,101	$ 6		275,183	(31,770)	(473)	(845)
BALANCE - shares at Dec. 31, 2013		59,670
Share-based compensation, Value	2,694			2,694
Share-based compensation, Shares		118
Vesting of restricted stock units, including impact of shares withheld for taxes, value	(497)			(497)
Vesting of restricted stock units, including impact of shares withheld for taxes, shares		111
Exercise of stock options and purchases from employee stock plans, Value	1,568			1,568
Exercise of stock options and purchases from employee stock plans, Shares		271
Excess income tax benefit from share-based compensation	206			206
Purchase of noncontrolling interests	(143)			(988)			$ 845
Net loss	10,295				10,295
Other comprehensive loss—net of tax	(261)					(261)
BALANCE - value at Dec. 31, 2014	255,963	$ 6		278,166	(21,475)	(734)
BALANCE - shares at Dec. 31, 2014		60,170
Share-based compensation, Value	4,040			4,040
Share-based compensation, Shares		154
Vesting of restricted stock units, including impact of shares withheld for taxes, value	(267)			(267)
Vesting of restricted stock units, including impact of shares withheld for taxes, shares		115
Exercise of stock options and purchases from employee stock plans, Value	$ 1,365			1,365
Exercise of stock options and purchases from employee stock plans, Shares	86	270
Excess income tax benefit from share-based compensation	$ (57)			(57)
Purchase of treasury stock, value	(1,433)		$ (1,433)
Purchase of treasury stock, shares			(278)
Net loss	(6,189)				(6,189)
Other comprehensive loss—net of tax	(1,249)					(1,249)
BALANCE - value at Dec. 31, 2015	$ 252,173	$ 6	$ (1,433)	$ 283,247	$ (27,664)	$ (1,983)
BALANCE - shares at Dec. 31, 2015		60,709	(278)

Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
OPERATING ACTIVITIES:
Net income (loss)	$ (6,189)	$ 10,295	$ (34,993)
Loss from discontinued operations, net of income taxes		(10,423)	(54,850)
Income from continuing operations	(6,189)	20,718	19,857
Adjustments to reconcile net income to net cash flows used in operating activities:
Depreciation and amortization	64,585	50,129	46,622
Equity in (earnings) loss of joint ventures	771	(2,895)	(1,208)
Cash distributions from joint ventures	8,384	19,955
Deferred income taxes	(2,689)	(14,504)	(304)
(Gain) loss on dispositions of property and equipment	(855)	732	(5,773)
Impairment of goodwill	2,750
Gain on adjustment of contingent consideration	(8,444)	(1,086)
Amortization of deferred financing fees	2,766	1,453	1,153
Gain on bargain purchase acquisition		(2,197)
Unrealized foreign currency (gain) loss	(1,054)	593	(179)
Unrealized net loss from mark-to-market valuations of derivatives	1,359	3,029
Share-based compensation expense	4,040	2,694	3,251
Excess income tax benefit from share-based compensation	57	(206)	(154)
Changes in assets and liabilities:
Accounts receivable	(20,190)	11,012	36,260
Contract revenues in excess of billings	48	(5,677)	(17,142)
Inventories	(6,612)	120	(5,144)
Prepaid expenses and other current assets	(9,730)	1,780	(10,124)
Accounts payable and accrued expenses	306	(14,113)	22,622
Billings in excess of contract revenues	2,325	(2,624)	(2,900)
Other noncurrent assets and liabilities	(2,506)	(1,759)	(490)
Net cash flows provided by operating activities of continuing operations	29,122	67,154	86,347
Net cash flows used in operating activities of discontinued operations		(18,352)	(11,524)
Cash provided by operating activities	29,122	48,802	74,823
INVESTING ACTIVITIES:
Purchases of property and equipment	(74,455)	(91,910)	(66,654)
Proceeds from dispositions of property and equipment	1,322	68	6,953
Proceeds from (payments on) vendor performance obligations (Note 13)		(3,100)	13,600
Payments for acquisitions of businesses, net of cash acquired		(27,048)
Net cash flows used in investing activities of continuing operations	(73,133)	(121,990)	(46,101)
Net cash flows provided by (used in) investing activities of discontinued operations		5,275	(153)
Cash used in investing activities	(73,133)	(116,715)	(46,254)
FINANCING ACTIVITIES:
Proceeds from term loan facility	2,640	47,360
Repayments of term loan facility	(5,000)	(417)
Proceeds from issuance of 7 3/8% senior notes		24,880
Deferred financing fees	(111)	(2,532)
Repayment of long term note payable	(443)		(13,047)
Distributions paid to minority interests			(3)
Taxes paid on settlement of vested share awards	(267)	(497)	(308)
Purchase of noncontrolling interest		(205)	(3)
Proceeds from equipment debt	410
Repayments of equipment debt	(1,201)	(235)
Exercise of stock options and purchases from employee stock plans	1,365	1,568	668
Excess income tax benefit from share-based compensation	(57)	206	154
Purchase of treasury stock	(1,433)
Borrowings under revolving loans	179,500	236,500	227,000
Repayments of revolving loans	(159,500)	(271,500)	(192,000)
Cash provided by financing activities	15,903	35,128	22,464
Effect of foreign currency exchange rates on cash and cash equivalents	(97)	(164)	(135)
Net increase (decrease) in cash and cash equivalents	(28,205)	(32,949)	50,898
Cash and cash equivalents at beginning of period	42,389	75,338	24,440
Cash and cash equivalents at end of period	14,184	42,389	75,338
Supplemental Cash Flow Information
Cash paid for interest	25,391	18,901	20,083
Cash paid (refunded) for income taxes	586	(10,544)	1,793
Non-cash Investing and Financing Activities
Property and equipment purchased but not yet paid	7,380	10,316	$ 3,552
Property and equipment purchased on capital leases and equipment notes	2,190	3,665
Property & equipment purchased on notes payable	$ 15,569
Magnus [Member]
Non-cash Investing and Financing Activities
Purchase price of Magnus assets comprised of promissory notes and other liabilities		$ 16,210

Nature Of Business And Summary Of Significant Accounting Policies

12 Months Ended

Dec. 31, 2015

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Nature Of Business And Summary Of Significant Accounting Policies

1. NATURE OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Organization—Great Lakes Dredge & Dock Corporation and its subsidiaries (the “Company” or “Great Lakes”) are in the business of marine construction, primarily dredging, and soil, water and sediment environmental and remediation services. The Company’s primary dredging customers are domestic and foreign government agencies, as well as private entities, and its environmental and remediation customers are general contractors, corporations, environmental engineering and construction firms that commission projects and local government and municipal agencies.

Principles of Consolidation and Basis of Presentation—The consolidated financial statements include the accounts of Great Lakes Dredge & Dock Corporation and its majority-owned subsidiaries. All intercompany accounts and transactions are eliminated in consolidation. The equity method of accounting is used for investments in unconsolidated investees in which the Company has significant influence, but not control. Other investments, if any, are carried at cost.

Use of Estimates—The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America (“GAAP”) requires management to make estimates and assumptions that affect certain reported amounts and disclosures. Accordingly, actual results could differ from those estimates.

Revenue and Cost Recognition on Contracts—Substantially all of the Company’s contracts for dredging services are fixed-price contracts, which provide for remeasurement based on actual quantities dredged. The majority of the Company’s environmental & remediation contracts are also fixed-price contracts, with others performed on a time-and-materials basis. Contract revenues are recognized under the percentage-of-completion method based on the Company’s engineering estimates of the physical percentage completed for dredging projects and based on costs incurred to date compared to total estimated costs for fixed-price environmental & remediation projects. For dredging projects, costs of contract revenues are adjusted to reflect the gross profit percentage expected to be achieved upon ultimate completion. For environmental & remediation contracts, contract revenues are adjusted to reflect the estimated gross profit percentage. Revisions in estimated gross profit percentages are recorded in the period during which the change in circumstances is experienced or becomes known. As the duration of most of the Company’s contracts is one year or less, the cumulative net impact of these revisions in estimates, individually and in the aggregate across our projects, does not significantly affect our results across annual reporting periods. Provisions for estimated losses on contracts in progress are made in the period in which such losses are determined. Change orders are not recognized in revenue until the recovery is probable and collectability is reasonably assured. Claims for additional compensation due to the Company are not recognized in contract revenues until such claims are settled. Billings on contracts are generally submitted after verification with the customers of physical progress and may not match the timing of revenue recognition. The difference between amounts billed and recognized as revenue is reflected in the balance sheet as either contract revenues in excess of billings or billings in excess of contract revenues. Modifications may be negotiated when a change from the original contract specification is encountered, and a change in project scope, performance methodology and/or material disposal is necessary. Thus, the resulting modification is considered a change in the scope of the original project to which it relates. Significant expenditures incurred incidental to major contracts are deferred and recognized as contract costs based on contract performance over the duration of the related project. These expenditures are reported as prepaid expenses.

The components of costs of contract revenues include labor, equipment (including depreciation, maintenance, insurance and long-term rentals), subcontracts, fuel, supplies, short-term rentals and project overhead. Hourly labor generally is hired on a project-by-project basis. Much of our domestic dredging hourly labor force is represented by labor unions with collective bargaining agreements that expire at various dates during 2016 through 2018, which historically have been extended without disruption. The environmental & remediation segment’s hourly labor force is made up of union and non-union employees. Project costs, excluding labor, have averaged approximately 20% to 22% of total costs of contract revenues over the prior three years.

During the year, both dredging equipment utilization and the timing of fixed cost expenditures fluctuate significantly. Accordingly, the Company allocates these fixed equipment costs to interim periods in proportion to dredging revenues recognized over the year, to better match revenues and expenses. Specifically, at each interim reporting date the Company compares actual dredging revenues earned to date on the Company’s dredging contracts to expected annual revenues and recognizes dredging equipment costs on the same proportionate basis. In the fourth quarter, any over or under allocated equipment costs are recognized such that the expense for the year equals actual equipment costs incurred during the year. As a result of this methodology, the recorded expense in any interim period may be higher or lower than the actual equipment costs incurred in that interim period.

For some environmental & remediation contracts, the Company has entered into unincorporated construction joint ventures under which certain portions of a larger project are performed. These investments are accounted for under the proportionate consolidation method for income statement reporting and under the equity method for balance sheet reporting. The Company’s interests in any profits and assets and proportionate share in any losses and liabilities are recognized based on the Company’s stated percentage partnership interest in the project. For projects related to proportionately consolidated joint ventures, we include only the Company’s percentage ownership of each joint venture's backlog.

Classification of Current Assets and Liabilities—The Company includes in current assets and liabilities amounts realizable and payable in the normal course of contract completion, unless completion of such contracts extends significantly beyond one year.

Cash Equivalents—The Company considers all highly liquid investments with a maturity at purchase of three months or less to be cash equivalents.

Accounts Receivable—Accounts receivable represent amounts due or billable under the terms of contracts with customers, including amounts related to retainage. The Company anticipates collection of retainage generally within one year, and accordingly presents retainage as a current asset. The Company provides an allowance for estimated uncollectible accounts receivable when events or conditions indicate that amounts outstanding are not recoverable.

Inventories—Inventories consist of pipe and spare parts used in the Company’s dredging operations. Pipe and spare parts are purchased in large quantities; therefore, a certain amount of pipe and spare part inventories is not anticipated to be used within the current year and is classified as long-term. Spare part inventories are stated at weighted average historical cost, and are charged to expense when used in operations. Pipe inventory is recorded at cost and amortized to expense over the period of its use.

Property and Equipment—Capital additions, improvements, and major renewals are classified as property and equipment and are carried at depreciated cost. Maintenance and repairs that do not significantly extend the useful lives of the assets or enhance the capabilities of such assets are charged to expenses as incurred. Depreciation is recorded over the estimated useful lives of property and equipment using the straight-line method and the mid-year depreciation convention. The estimated useful lives by class of assets are:

Class		Useful Life (years)
Buildings and improvements		10
Furniture and fixtures		5-10
Vehicles, dozers, and other light operating equipment and systems		3-5
Heavy operating equipment (dredges and barges)		10-30

Leasehold improvements are amortized over the shorter of their remaining useful lives or the remaining terms of the leases.

Goodwill and Other Intangible Assets—Goodwill represents the excess of acquisition cost over fair value of the net assets acquired. Other identifiable intangible assets mainly represent developed technology and databases, customer relationships, and customer contracts acquired in business combinations and are being amortized over a one to five-year period. Goodwill is tested annually for impairment in the third quarter of each year, or more frequently should circumstances dictate. GAAP requires that goodwill of a reporting unit be tested for impairment between annual tests if an event occurs or circumstances change that would more likely than not reduce the fair value of a reporting unit below its carrying amount.

The Company assesses the fair values of its reporting units using both a market-based approach and an income-based approach. Under the income approach, the fair value of the reporting unit is based on the present value of estimated future cash flows. The income approach is dependent on a number of factors, including estimates of future market growth trends, forecasted revenues and expenses, appropriate discount rates and other variables. The estimates are based on assumptions that the Company believes to be reasonable, but such assumptions are subject to unpredictability and uncertainty. Changes in these estimates and assumptions could materially affect the determination of fair value, and may result in the impairment of goodwill in the event that actual results differ from those estimates.

The market approach measures the value of a reporting unit through comparison to comparable companies. Under the market approach, the Company uses the guideline public company method by applying estimated market-based enterprise value multiples to the reporting unit’s estimated revenue and Adjusted EBITDA. The Company analyzes companies that performed similar services or are considered peers. Due to the fact that there are no public companies that are direct competitors, the Company weighs the results of this approach less than the income approach.

The Company has three operating segments: dredging, Terra and Magnus, which were aggregated into two reportable segments: dredging and environmental & remediation. As Terra and Magnus have similarity in economic margins, services, production processes, customer types, distribution methods and regulatory environment, they were aggregated into one reporting segment. The historical demolition business has been retrospectively presented as discontinued operations and is no longer reflected in continuing operations. The Company has determined that the operating segments are the Company’s three reporting units.

Long-Lived Assets—Long-lived assets are comprised of property and equipment and intangible assets subject to amortization. Long-lived assets to be held and used are reviewed for possible impairment whenever events indicate that the carrying amount of such assets may not be recoverable by comparing the undiscounted cash flows associated with the assets to their carrying amounts. If such a review indicates an impairment, the carrying amount would be reduced to fair value. No triggering events were identified in 2015 or 2014. If long-lived assets are to be disposed, depreciation is discontinued, if applicable, and the assets are reclassified as held for sale at the lower of their carrying amounts or fair values less estimated costs to sell.

The Company capitalizes construction in progress and records a corresponding long-term liability for build-to-suit lease agreements where we are considered the owner during the construction period for accounting purposes. There was no build-to-suit equipment capitalized at December 31, 2015.

Self-insurance Reserves—The Company self-insures costs associated with its seagoing employees covered by the provisions of Jones Act, workers’ compensation claims, hull and equipment liability, and general business liabilities up to certain limits. Insurance reserves are established for estimates of the loss that the Company may ultimately incur on reported claims, as well as estimates of claims that have been incurred but not yet reported. In determining its estimates, the Company considers historical loss experience and judgments about the present and expected levels of cost per claim. Trends in actual experience are a significant factor in the determination of such reserves.

Income Taxes—The provision for income taxes includes federal, foreign, and state income taxes currently payable and those deferred because of temporary differences between the financial statement and tax basis of assets and liabilities. Recorded deferred income tax assets and liabilities are based on the estimated future tax effects of differences between the financial and tax basis of assets and liabilities, given the effect of currently enacted tax laws. The Company’s current policy is to repatriate all earnings from foreign subsidiaries’ operations as generated and at this time no amounts are considered to be permanently reinvested in those operations.

Hedging Instruments—At times, the Company designates certain derivative contracts as a cash flow hedge as defined by GAAP. Accordingly, the Company formally documents, at the inception of each hedge, all relationships between hedging instruments and hedged items, as well as our risk-management objective and strategy for undertaking hedge transactions. This process includes linking all derivatives to highly-probable forecasted transactions.

The Company formally assesses, at inception and on an ongoing basis, the effectiveness of hedges in offsetting changes in the cash flows of hedged items. Hedge accounting treatment may be discontinued when (1) it is determined that the derivative is no longer highly effective in offsetting changes in the cash flows of a hedged item (including hedged items for forecasted future transactions), (2) the derivative expires or is sold, terminated or exercised, (3) it is no longer probable that the forecasted transaction will occur or (4) management determines that designating the derivative as a hedging instrument is no longer appropriate. If management elects to stop hedge accounting, it would be on a prospective basis and any hedges in place would be recognized in accumulated other comprehensive income (loss) until all the related forecasted transactions are completed or are probable of not occurring.

Foreign Currency Translation—The financial statements of the Company’s foreign subsidiaries where the operations are primarily denominated in the foreign currency are translated into U.S. dollars for reporting. Balance sheet accounts are translated at the current foreign exchange rate at the end of each period and income statement accounts are translated at the average foreign exchange rate for each period. Gains and losses on foreign currency translations are reflected as a currency translation adjustment, net of tax, in accumulated other comprehensive income (loss). Foreign currency transaction gains and losses are included in other income (expense).

Noncontrolling Interest—On January 1, 2009 the Company acquired a 65% interest in Yankee Environmental Services, LLC (“Yankee”). On April 23, 2014, the Company entered into and completed the sale of NASDI, LLC and Yankee, its two former subsidiaries that comprised the historical demolition business. As a result of the sale, the Company purchased the noncontrolling interest related to the membership interest the Company did not own in Yankee. Noncontrolling interest at December 31, 2013 is related to the membership interest the Company did not own in Yankee.

Recent Accounting Pronouncements— In November 2015, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update No. 2015-17 (“ASU 2015-17”), Income Taxes: Balance Sheet Classifications of Deferred Taxes (Topic 740) which simplifies the presentation of deferred income taxes by requiring that deferred tax liabilities and assets be classified as noncurrent in the balance sheet. The update is effective for public companies for fiscal years beginning after December 15, 2016, including interim periods within that reporting period. The guidance may be adopted prospectively or retrospectively and early adoption is permitted. As of December 31, 2015, the Company has elected to early adopt this ASU 2015-17 on a prospective basis and therefore, prior years were not retrospectively adjusted. See Note 10 for additional information.

In April 2015, the FASB issued Accounting Standard Update No. 2015-03 (“ASU 2015-03”), Interest - Imputation of Interest: Simplifying the Presentation of Debt Issuance Costs which requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. This update is effective for fiscal years beginning after December 15, 2015, and is required to be applied retrospectively. The Company does not expect a material impact to our consolidated financial statements as a result of such requirement.

In May 2014, the FASB issued Accounting Standard Update No. 2014-09 (“ASU 2014-09”), Revenue from Contracts with Customers (Topic 606), which supersedes the existing revenue recognition requirements. ASU 2014-09 is based on the principle that revenue is recognized to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 has been deferred to be effective for fiscal years beginning after December 15, 2017, including interim periods within that reporting period, which will be our first quarter of fiscal 2018. Early adoption is permitted in fiscal 2017. The Company is currently evaluating which transition method to use and assessing the impact of the adoption of ASU 2014-09 on our consolidated financial statements.

Nature Of Business And Summary Of Significant Accounting Policies (Policy)

12 Months Ended

Dec. 31, 2015

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Principles Of Consolidation And Basis Of Presentation

Use Of Estimates

Revenue and Cost Recognition on Contracts

Classification of Current Assets and Liabilities

Cash Equivalents

Cash Equivalents—The Company considers all highly liquid investments with a maturity at purchase of three months or less to be cash equivalents.

Accounts Receivable

Inventories

Property, Plant and Equipment

Class		Useful Life (years)
Buildings and improvements		10
Furniture and fixtures		5-10
Vehicles, dozers, and other light operating equipment and systems		3-5
Heavy operating equipment (dredges and barges)		10-30

Leasehold improvements are amortized over the shorter of their remaining useful lives or the remaining terms of the leases.

Goodwill and Other Intangible Assets

Long-Lived Assets

Self-insurance Reserves

Income Taxes

Hedging Instruments

Foreign Currency Translation

Noncontrolling Interest

Recent Accounting Pronouncements

Earnings per share

12 Months Ended

Dec. 31, 2015

Earnings Per Share [Abstract]

Earnings Per Share

2. EARNINGS PER SHARE

Basic earnings per share is computed by dividing net income attributable to common stockholders by the weighted-average number of common shares outstanding during the reporting period. Diluted earnings per share is computed similar to basic earnings per share except that it reflects the potential dilution that could occur if dilutive securities or other obligations to issue common stock were exercised or converted into common stock. For the year ended December 31, 2015, the dilutive effect of 431 thousand stock options (“NQSO”) and restricted stock units (“RSU”) were excluded from the diluted weighted-average common shares outstanding as the Company incurred a loss during this period. For the year ended December 31, 2015 and 2014, 1,179 shares and 540 shares of NQSOs and RSUs were excluded from the calculation of diluted earnings per share based on the application of the treasury stock method, as such NQSOs and RSUs were determined to be anti-dilutive.

The computations for basic and diluted earnings per share for the years ended December 31, 2015, 2014 and 2013 are as follows:

(shares in thousands)
		2015			2014			2013
Income (loss) from continuing operations	$	(6,189	)	$	20,718		$	19,857
Loss on discontinued operations, net of income taxes, attributable to Great Lakes Dredge & Dock Corporation		—			(10,423	)		(54,218	)
Net income (loss) attributable to common stockholders of Great Lakes Dredge & Dock Corporation	$	(6,189	)	$	10,295		$	(34,361	)

Weighted-average common shares outstanding — basic		60,410			59,938			59,495
Effect of stock options and restricted stock units		—			584			606

Weighted-average common shares outstanding — diluted		60,410			60,522			60,101

Earnings (loss) per share from continuing operations — basic	$	(0.10	)	$	0.35		$	0.33
Earnings (loss) per share from continuing operations — diluted	$	(0.10	)	$	0.34		$	0.33

Restricted And Escrowed Cash	12 Months Ended
Restricted And Escrowed Cash	Dec. 31, 2015
Cash And Cash Equivalents [Abstract]
Restricted And Escrowed Cash	3. RESTRICTED AND ESCROWED CASH At December 31, 2015 and 2014, other noncurrent assets include $1,500 of cash held in escrow as security for the Company’s lease rental obligation under a long-term equipment operating lease. At December 31, 2015 and 2014, other current assets include $2,242 and $2,314, respectively, of cash held in escrow related to an outstanding lawsuit at our historical demolition business.

- Definition

The entire disclosure for cash and cash equivalent footnotes, which may include the types of deposits and money market instruments, applicable carrying amounts, restricted amounts and compensating balance arrangements. Cash and equivalents include: (1) currency on hand (2) demand deposits with banks or financial institutions (3) other kinds of accounts that have the general characteristics of demand deposits (4) short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Generally, only investments maturing within three months from the date of acquisition qualify.

+ References + Details

Accounts Receivable And Contracts In Progress

12 Months Ended

Dec. 31, 2015

Receivables [Abstract]

Accounts Receivables And Contracts In Progress

4. ACCOUNTS RECEIVABLE AND CONTRACTS IN PROGRESS

Accounts receivable at December 31, 2015 and 2014 are as follows:

		2015			2014
Completed contracts	$	37,111		$	15,342
Contracts in progress		70,787			72,459
Retainage		27,203			27,371
		135,101			115,172
Allowance for doubtful accounts		(754	)		(578	)

Total accounts receivable—net	$	134,347		$	114,594

Current portion of accounts receivable—net	$	130,777		$	113,188
Long-term accounts receivable and retainage		3,570			1,406
Total accounts receivable—net	$	134,347		$	114,594

The components of contracts in progress at December 31, 2015 and 2014 are as follows:

		2015			2014
Costs and earnings in excess of billings:
Costs and earnings for contracts in progress	$	230,159		$	833,368
Amounts billed		(176,283	)		(759,877	)
Costs and earnings in excess of billings for contracts in progress		53,876			73,491

Costs and earnings in excess of billings for completed contracts		27,319			9,066

Total contract revenues in excess of billings	$	81,195		$	82,557

Billings in excess of costs and earnings:
Amounts billed	$	(207,550	)	$	(181,698	)
Costs and earnings for contracts in progress		200,489			177,059

Total billings in excess of contract revenues	$	(7,061	)	$	(4,639	)

Property And Equipment

12 Months Ended

Dec. 31, 2015

Property Plant And Equipment [Abstract]

Property And Equipment

5. PROPERTY AND EQUIPMENT

Property and equipment at December 31, 2015 and 2014 are as follows:

		2015			2014
Land	$	9,864		$	9,220
Buildings and improvements		5,896			5,729
Furniture and fixtures		10,587			8,863
Operating equipment		783,732			698,977

Total property and equipment		810,079			722,789

Accumulated depreciation		(379,869	)		(323,344	)

Property and equipment — net	$	430,210		$	399,445

Depreciation expense was $58,050, $48,569 and $45,531, for the years ended December 31, 2015, 2014 and 2013, respectively.

Goodwill And Other Intangible Assets

12 Months Ended

Dec. 31, 2015

Goodwill And Intangible Assets Disclosure [Abstract]

Goodwill And Other Intangible Assets

6. GOODWILL AND OTHER INTANGIBLE ASSETS

The Company’s annual goodwill impairment test is conducted in the third quarter of each year and interim evaluations are performed when the Company determines that a triggering event has occurred that would more likely than not reduce the fair value of goodwill below its carrying value. Due to a decline in the overall financial performance and declining cash flows in the Terra reporting unit, the Company concluded there was a triggering event that required an interim impairment test for the reporting unit in the second quarter of 2015.

The Company performed step one of the goodwill impairment test as of June 30, 2015, which compared the fair value of the Terra reporting unit against its carrying amount, including goodwill. In deriving the fair value of the Terra reporting unit, the Company used both a market-based approach and an income-based approach. Under the income approach, the fair value of the reporting unit is based on the present value of estimated future cash flows. Under the market approach, the Company uses the guideline public company method by applying estimated market-based enterprise value multiples to the reporting unit’s estimated revenue and Adjusted EBITDA from continuing operations. Based on the first step analysis, management concluded that the fair value of the Terra reporting unit was less than its carrying value; therefore, the Company performed step two of the goodwill impairment analysis.

Step two of the goodwill impairment analysis measures the impairment charge by allocating the reporting unit’s fair value to all of the assets and liabilities of the reporting unit in a hypothetical analysis that calculates implied fair value of goodwill in the same manner as if the reporting unit was being acquired in a business combination. Any excess of the carrying value of the reporting unit’s goodwill over the implied fair value of the reporting unit’s goodwill is recorded as a loss on impairment of goodwill.

Management determined that the Terra reporting unit’s implied fair value of goodwill was below the carrying value as of June 30, 2015. As a result, the Company recorded an impairment charge of $2,750 in the second quarter of 2015.

The Company performed its annual goodwill impairment test for the remaining reporting units in the third quarter and no additional impairment was recorded for the year ended December 31, 2015. As of the test date, the fair value of the remaining reporting units was substantially in excess of their carrying values. The Company will perform its next scheduled annual test of goodwill in the third quarter of 2016 should no triggering events occur which would require a test prior to the next annual test.

The change in the carrying amount of goodwill during the years ended December 31, 2015 and 2014 is as follows:

	Dredging Segment		Environmental & Remediation Segment			Total
Balance – January 1, 2014	$	76,576	$	2,750		$	79,326
Acquisition of Magnus Pacific		—		7,000			7,000
Balance – December 31, 2014		76,576		9,750			86,326

Impairment of goodwill		—		(2,750	)		(2,750	)
Balance – December 31, 2015	$	76,576	$	7,000		$	83,576

At December 31, 2015 and 2014, the net book value of identifiable intangible assets was as follows:

As of December 31, 2015	Cost		Accumulated Amortization		Net
Non-compete agreements	$	3,085	$	1,625	$	1,460
Trade names		1,037		873		164
Other		1,306		502		804
	$	5,428	$	3,000	$	2,428

As of December 31, 2014
Non-compete agreements	$	3,085	$	940	$	2,145
Customer relationships		51		34		17
Acquired backlog		6,278		1,395		4,883
Trade names		1,037		185		852
Other		1,306		240