Great Lakes Dredge & Dock (GLDD) 10-Q 3 Aug 21 2021 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2021	Jul. 28, 2021
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Trading Symbol	GLDD
Entity Registrant Name	Great Lakes Dredge & Dock Corporation
Entity Central Index Key	0001372020
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Shell Company	false
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Address, Address Line One	9811 Katy Freeway
Entity Address, Address Line Two	Suite 1200
Entity Address, City or Town	Houston
Entity Address, State or Province	TX
Entity Common Stock, Shares Outstanding		65,657,699
Entity Current Reporting Status	Yes
Entity File Number	001-33225
Entity Tax Identification Number	20-5336063
City Area Code	346
Local Phone Number	359-1010
Entity Address, Postal Zip Code	77024
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock (Par Value $0.0001)
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	DE
Document Quarterly Report	true
Document Transition Report	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
CURRENT ASSETS:
Cash and cash equivalents	$ 180,767	$ 216,510
Accounts receivable—net	35,741	38,990
Contract revenues in excess of billings	34,556	32,106
Inventories	32,758	34,689
Prepaid expenses and other current assets	39,330	40,398
Total current assets	323,152	362,693
PROPERTY AND EQUIPMENT—Net	422,552	383,042
OPERATING LEASE ASSETS	52,777	65,188
GOODWILL	76,576	76,576
INVENTORIES—Noncurrent	61,578	58,413
OTHER	12,998	12,112
TOTAL	949,633	958,024
LIABILITIES AND EQUITY
Accounts payable	79,863	71,308
Accrued expenses	37,230	52,899
Operating lease liabilities	14,255	19,472
Billings in excess of contract revenues	28,833	32,608
Total current liabilities	160,181	176,287
LONG-TERM DEBT	320,696	323,735
OPERATING LEASE LIABILITIES—Noncurrent	38,877	45,879
DEFERRED INCOME TAXES	59,458	56,466
OTHER	10,324	8,989
Total liabilities	589,536	611,356
COMMITMENTS AND CONTINGENCIES (Note 8)
EQUITY:
Common stock—$.0001 par value; 90,000 authorized, 65,654 and 65,023 shares issued and outstanding at June 30, 2021 and December 31, 2020, respectively.	6	6
Additional paid-in capital	304,977	304,757
Retained earnings	51,856	40,937
Accumulated other comprehensive income	3,258	968
Total equity	360,097	346,668
TOTAL	$ 949,633	$ 958,024

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2021	Dec. 31, 2020
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	65,654,000	65,023,000
Common stock, shares outstanding	65,654,000	65,023,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Income Statement [Abstract]
Contract revenues	$ 169,914	$ 167,920	$ 347,547	$ 385,615
Type of Revenue [Extensible List]	gldd:ContractMember	gldd:ContractMember	gldd:ContractMember	gldd:ContractMember
Costs of contract revenues	$ 146,992	$ 134,904	$ 291,549	$ 284,125
Type of Cost, Good or Service [Extensible List]	gldd:ContractMember	gldd:ContractMember	gldd:ContractMember	gldd:ContractMember
Gross profit	$ 22,922	$ 33,016	$ 55,998	$ 101,490
General and administrative expenses	14,224	14,804	30,546	30,375
Gain on sale of assets—net	(138)	(39)	(32)	(184)
Operating income	8,836	18,251	25,484	71,299
Interest expense—net	(6,657)	(6,725)	(13,243)	(13,355)
Other income (expense)	755	565	896	(556)
Income before income taxes	2,934	12,091	13,137	57,388
Income tax provision	(829)	(3,131)	(2,218)	(14,441)
Net income	$ 2,105	$ 8,960	$ 10,919	$ 42,947
Basic earnings per share	$ 0.03	$ 0.14	$ 0.17	$ 0.66
Basic weighted average shares	65,646	64,864	65,458	64,659
Diluted earnings per share	$ 0.03	$ 0.14	$ 0.16	$ 0.65
Diluted weighted average shares	66,137	65,758	66,187	65,802

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Statement Of Income And Comprehensive Income [Abstract]
Net income		$ 2,105	$ 8,960	$ 10,919	$ 42,947
Net change in cash flow derivative hedges—net of tax	[1]	404	3,440	2,290	(3,686)
Comprehensive income		$ 2,509	$ 12,400	$ 13,209	$ 39,261
[1]	Net of income tax (provision) benefit of $(136) and $1,162 for the three months ended June 30, 2021 and 2020 respectively.  Net of income tax (provision) of $(773) and $(1,255) for the six months ended June 30, 2021 and 2020 respectively.

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Statement Of Income And Comprehensive Income [Abstract]
Net unrealized loss on derivatives, tax	$ (136)	$ 1,162	$ (773)	$ (1,255)

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings (Accumulated Deficit) [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
BALANCE - value at Dec. 31, 2019	$ 279,399	$ 6	$ 302,189	$ (23,091)	$ 295
BALANCE - shares at Dec. 31, 2019		64,283
Share-based compensation, value	3,130		3,130
Share-based compensation, shares		61
Vesting of restricted stock units and impact of shares withheld for taxes, value	(2,106)		(2,106)
Vesting of restricted stock units and impact of shares withheld for taxes, shares		412
Exercise of stock options and purchases from employee stock purchase plan, value	1,318		1,318
Exercise of stock options and purchases from employee stock purchase plan, shares		191
Net income	42,947			42,947
Other comprehensive income (loss)—net of tax	(3,686)				(3,686)
BALANCE - value at Jun. 30, 2020	321,002	$ 6	304,531	19,856	(3,391)
BALANCE - shares at Jun. 30, 2020		64,947
BALANCE - value at Mar. 31, 2020	306,629	$ 6	302,558	10,896	(6,831)
BALANCE - shares at Mar. 31, 2020		64,795
Share-based compensation, value	1,455		1,455
Share-based compensation, shares		22
Vesting of restricted stock units and impact of shares withheld for taxes, value	(178)		(178)
Vesting of restricted stock units and impact of shares withheld for taxes, shares		24
Exercise of stock options and purchases from employee stock purchase plan, value	696		696
Exercise of stock options and purchases from employee stock purchase plan, shares		106
Net income	8,960			8,960
Other comprehensive income (loss)—net of tax	3,440				3,440
BALANCE - value at Jun. 30, 2020	321,002	$ 6	304,531	19,856	(3,391)
BALANCE - shares at Jun. 30, 2020		64,947
BALANCE - value at Dec. 31, 2020	346,668	$ 6	304,757	40,937	968
BALANCE - shares at Dec. 31, 2020		65,023
Share-based compensation, value	2,564		2,564
Share-based compensation, shares		73
Vesting of restricted stock units and impact of shares withheld for taxes, value	(3,784)		(3,784)
Vesting of restricted stock units and impact of shares withheld for taxes, shares		410
Exercise of stock options and purchases from employee stock purchase plan, value	1,440		1,440
Exercise of stock options and purchases from employee stock purchase plan, shares		148
Net income	10,919			10,919
Other comprehensive income (loss)—net of tax	2,290				2,290
BALANCE - value at Jun. 30, 2021	360,097	$ 6	304,977	51,856	3,258
BALANCE - shares at Jun. 30, 2021		65,654
BALANCE - value at Mar. 31, 2021	356,610	$ 6	303,999	49,751	2,854
BALANCE - shares at Mar. 31, 2021		65,620
Share-based compensation, value	798		798
Share-based compensation, shares		12
Exercise of stock options and purchases from employee stock purchase plan, value	180		180
Exercise of stock options and purchases from employee stock purchase plan, shares		22
Net income	2,105			2,105
Other comprehensive income (loss)—net of tax	404				404
BALANCE - value at Jun. 30, 2021	$ 360,097	$ 6	$ 304,977	$ 51,856	$ 3,258
BALANCE - shares at Jun. 30, 2021		65,654

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
OPERATING ACTIVITIES:
Net income	$ 10,919	$ 42,947
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation and amortization	20,681	18,707
Deferred income taxes	2,218	14,441
Gain on sale of assets	(32)	(184)
Amortization of deferred financing fees	1,715	805
Share-based compensation expense	2,564	3,130
Changes in assets and liabilities:
Accounts receivable	3,249	(14,109)
Contract revenues in excess of billings	(2,450)	2,123
Inventories	(1,233)	(4,733)
Prepaid expenses and other current assets	4,131	10,733
Accounts payable and accrued expenses	(2,668)	(8,229)
Billings in excess of contract revenues	(3,775)	(179)
Other noncurrent assets and liabilities	282	2,008
Cash provided by operating activities	35,601	67,460
INVESTING ACTIVITIES:
Purchases of property and equipment	(64,828)	(21,076)
Proceeds from dispositions of property and equipment	223	936
Cash used in investing activities	(64,605)	(20,140)
FINANCING ACTIVITIES:
Deferred financing fees	(4,395)
Taxes paid on settlement of vested share awards	(3,784)	(2,106)
Exercise of options and purchases from employee stock plans	1,440	1,318
Cash used in financing activities	(6,739)	(788)
Net (decrease) increase in cash, cash equivalents and restricted cash	(35,743)	46,532
Cash, cash equivalents and restricted cash at beginning of period	216,510	186,995
Cash, cash equivalents and restricted cash at end of period	180,767	233,527
Supplemental Cash Flow Information
Cash paid for interest	13,984	12,548
Cash paid for income taxes	332	175
Non-cash Investing and Financing Activities
Property and equipment purchased but not yet paid	$ 11,139	$ 4,608

Basis of Presentation

Basis of Presentation	6 Months Ended
	Jun. 30, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation	1. Basis of presentation The unaudited condensed consolidated financial statements and notes herein should be read in conjunction with the audited consolidated financial statements of Great Lakes Dredge & Dock Corporation and Subsidiaries (the “Company” or “Great Lakes”) and the notes thereto, included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020. The condensed consolidated financial statements included herein have been prepared by the Company without audit, pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) have been condensed or omitted pursuant to the SEC’s rules and regulations, although management believes that the disclosures are adequate and make the information presented not misleading. In the opinion of management, all adjustments, which are of a normal and recurring nature (except as otherwise noted), that are necessary to present fairly the Company’s financial position as of June 30, 2021 and December 31, 2020, and its results of operations for the three and six months ended June 30, 2021 and 2020 and cash flows for the six months ended June 30, 2021 and 2020 have been included. 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 is generally hired on a project-by-project basis. Costs of contract revenues vary significantly depending on the type and location of work performed and assets utilized. The Company has one operating segment which is also the Company’s reportable segment and reporting unit of which the Company tests goodwill for impairment. The Company performed its most recent annual test of impairment as of July 1, 2020 with no indication of impairment as of the test date. The Company will perform its next scheduled annual test of goodwill in the third quarter of 2021. On August 4, 2020, the Company announced that its board of directors approved a share repurchase program, authorizing, but not obligating, the repurchase of up to an aggregate amount of $75.0 million of its common stock from time to time through July 31, 2021. The condensed consolidated results of operations and comprehensive income for the interim periods presented herein are not necessarily indicative of the results to be expected for the full year.

Earnings Per Share

Earnings Per Share	6 Months Ended
	Jun. 30, 2021
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. The computations for basic and diluted earnings per share are as follows: Three Months Ended Six Months Ended (shares in thousands) June 30, June 30, 2021 2020 2021 2020 Net income $ 2,105 $ 8,960 $ 10,919 $ 42,947 Weighted-average common shares outstanding — basic 65,646 64,864 65,458 64,659 Effect of stock options and restricted stock units 491 894 729 1,143 Weighted-average common shares outstanding — diluted 66,137 65,758 66,187 65,802 Earnings per share — basic $ 0.03 $ 0.14 $ 0.17 $ 0.66 Earnings per share — diluted $ 0.03 $ 0.14 $ 0.16 $ 0.65

Accrued Expenses

Accrued Expenses	6 Months Ended
	Jun. 30, 2021
Payables And Accruals [Abstract]
Accrued Expenses	3 . Accrued expenses Accrued expenses at June 30, 2021 and December 31, 2020 were as follows: June 30, December 31, 2021 2020 Insurance $ 17,365 $ 14,754 Payroll and employee benefits 7,744 21,675 Income and other taxes 1,995 2,164 Interest 1,728 3,285 Contract reserves 750 2,491 Other 7,648 8,530 Total accrued expenses $ 37,230 $ 52,899

Long-term Debt

Long-term Debt	6 Months Ended
	Jun. 30, 2021
Debt Disclosure [Abstract]
Long-Term Debt	4 . Long-term debt Credit agreement As of June 30, 2021 and December 31, 2020, the Company had no borrowings outstanding under our $200,000 amended and restated revolving credit and security agreement (as amended, the “Amended Credit Agreement”). There were $35,909 and $36,407 of letters of credit outstanding and $163,764 and $163,231 of availability under the Amended Credit Agreement as of June 30, 2021 and December 31, 2020, respectively. The availability under the Amended Credit Agreement is suppressed by $327 as of June 30, 2021 and December 31, 2020, as a result of certain limitations set forth in the Amended Credit Agreement. Senior Notes and subsidiary guarantors In May 2021 the Company sold $325 million of unsecured 5.25% Senior Notes (the “2029 Notes”) pursuant to a private offering. The 2029 Notes were priced to investors at par and will mature on June 1, 2029. The Company used the net proceeds from the offering, together with cash on hand, to redeem all $325 million aggregate principal amount of its outstanding 8.000% Senior Notes due 2022 (the “8% Notes”). Approximately $1.0 million of deferred financing fees related to the 8% Notes were extinguished and are presented within net interest expense in the Statement of Operations. The Company’s obligations under these 2029 Notes are guaranteed by each of the Company’s existing and future 100% owned domestic subsidiaries that are co-borrowers or guarantors under its Amended Credit Agreement. Such guarantees are full, unconditional and joint and several. The parent company issuer has no independent assets or operations and all non-guarantor subsidiaries have been determined to be minor.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	5 . Fair value measurements Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. A fair value hierarchy has been established by GAAP that requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The accounting guidance describes three levels of inputs that may be used to measure fair value: Level 1—Quoted prices in active markets for identical assets or liabilities. Level 2—Observable inputs other than Level 1 prices such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The Company utilizes the market approach to measure fair value for its financial assets and liabilities. The market approach uses prices and other relevant information generated by market transactions involving identical or comparable assets or liabilities. At times, the Company holds certain derivative contracts that it uses to manage commodity price risk. The Company does not hold or issue derivatives for speculative or trading purposes. The fair values of these financial instruments are summarized as follows: Fair Value Measurements at Reporting Date Using Description At June 30, 2021 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Fuel hedge contracts $ 4,802 $ - $ 4,802 $ - Fair Value Measurements at Reporting Date Using Description At December 31, 2020 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Fuel hedge contracts $ 1,739 $ - $ 1,739 $ - Fuel hedge contracts The Company is exposed to certain market risks, primarily commodity price risk as it relates to diesel fuel purchase requirements, which occur in the normal course of business. The Company enters into heating oil commodity swap contracts to hedge the risk that fluctuations in diesel fuel prices could have an adverse impact on cash flows associated with its domestic dredging contracts. The Company’s typical goal is to hedge approximately 80% of the fuel requirements for work in domestic backlog. As of June 30, 2021, the Company was party to various swap arrangements to hedge the price of its diesel fuel purchase requirements for work in its backlog to be performed through June 2022. As of June 30, 2021, there were 8.7 million gallons remaining on these contracts which represent approximately 80% of the Company’s forecasted domestic fuel purchases through June 2022. Under these swap agreements, the Company will pay fixed prices ranging from $1.22 to $1.90 per gallon. At June 30, 2021 and December 31, 2020 the fair value asset of the fuel hedge contracts were estimated to be $4,802 and $1,739, respectively, and are recorded in prepaid expenses and other current assets. For fuel hedge contracts considered to be highly effective, the losses reclassified to earnings from changes in fair value of derivatives, net of cash settlements and taxes, for the six months ended June 30, 2021 were $3,404. The remaining gains and losses included in accumulated other comprehensive loss at June 30, 2021 will be reclassified into earnings over the next twelve months, corresponding to the period during which the hedged fuel is expected to be utilized. Changes in the fair value of fuel hedge contracts not considered highly effective are recorded as cost of contract revenues in the Statement of Operations. The fair values of fuel hedges are corroborated using inputs that are readily observable in public markets; therefore, the Company determines fair value of these fuel hedges using Level 2 inputs. The Company is exposed to counterparty credit risk associated with non-performance of its various derivative instruments. The Company’s risk would be limited to any unrealized gains on current positions. To help mitigate this risk, the Company transacts only with counterparties that are rated as investment grade or higher. In addition, all counterparties are monitored on a continuous basis. The fair value of the fuel hedge contracts outstanding as of June 30, 2021 and December 31, 2020 is as follows: Fair Value at June 30, December 31, Balance Sheet Location 2021 2020 Asset derivatives: Derivatives designated as hedging instruments Fuel hedge contracts Prepaid expenses and other current assets $ 4,802 $ 1,739 Accumulated other comprehensive income (loss) Changes in the components of the accumulated balances of other comprehensive income (loss) are as follows: Three Months Ended Six Months Ended June 30, June 30, 2021 2020 2021 2020 Derivatives: Reclassification of derivative (gains) losses to earnings—net of tax (1,878 ) 2,490 (3,404 ) 3,828 Change in fair value of derivatives—net of tax 2,282 950 5,694 (7,514 ) Net change in cash flow derivative hedges—net of tax $ 404 $ 3,440 $ 2,290 $ (3,686 ) Adjustments reclassified from accumulated balances of other comprehensive income (loss) to earnings are as follows: Three Months Ended Six Months Ended June 30, June 30, Statement of Operations Location 2021 2020 2021 2020 Derivatives: Fuel Costs of contract revenues $ (2,513 ) $ 3,340 (4,554 ) 5,132 Income tax (provision) benefit (635 ) 850 (1,150 ) 1,304 $ (1,878 ) $ 2,490 $ (3,404 ) $ 3,828 Other financial instruments The carrying value of financial instruments included in current assets and current liabilities approximates fair value due to the short-term maturities of these instruments. Based on timing of the cash flows and comparison to current market interest rates, the carrying value of our revolving credit agreement approximates fair value. In May 2021 the Company issued $325,000 of 5.25% Senior Notes, which were outstanding at June 30, 2021 (see Note 4, Long-term debt). The 2029 Notes are senior unsecured obligations of the Company and its subsidiaries that guarantee the 2029 Notes. The fair value of the senior notes was $334,783 at June 30, 2021, which is a Level 1 fair value measurement as the senior notes’ value was obtained using quoted prices in active markets. It is impracticable to determine the fair value of outstanding letters of credit or performance, bid and payment bonds due to uncertainties as to the amount and timing of future obligations, if any.

Share-Based Compensation

Share-Based Compensation	6 Months Ended
	Jun. 30, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-Based Compensation	6 . Share-based compensation On May 5, 2021, the Company’s stockholders approved the Great Lakes Dredge & Dock Corporation 2021 Long-Term Incentive Plan (the “Incentive Plan”), which previously had been approved by the Company’s board of directors subject to stockholder approval. The Incentive Plan replaces the 2017 Long-Term Incentive Plan (the “Prior Plan”) and is largely based on the Prior Plan, but with updates to the available shares and other administrative changes. The Incentive Plan permits the granting of stock options, stock appreciation rights, restricted stock and restricted stock units to the Company’s employees and directors for up to 1.5 million shares of common stock, plus the number of shares that remained available for future grant under the Prior Plan as of the effectiveness of the Incentive Plan. The Prior Plan permitted the granting of stock options, stock appreciation rights, restricted stock and restricted stock units to the Company’s employees and directors for up to 3.3 million shares of common stock, plus an additional 1.7 million shares underlying equity awards issued under the 2007 Long-Term Incentive Plan. During the six months ended June 30, 2021, the Company granted 307 thousand restricted stock units to certain employees. In addition, all non-employee directors on the Company’s board of directors are paid a portion of their board-related compensation in stock grants or restricted stock units. Compensation cost charged to expense related to share-based compensation arrangements was $798 and $1,455 for the three months ended June 30, 2021 and 2020, respectively. Compensation cost charged to expense related to share-based compensation arrangements was $2,564 and $3,130 for the six months ended June 30, 2021 and 2020, respectively.

Revenue

Revenue	6 Months Ended
	Jun. 30, 2021
Revenue From Contract With Customer [Abstract]
Revenue	7 . Revenue At June 30, 2021, the Company had $454,402 of remaining performance obligations, which the Company refers to as total backlog. Approximately 93% of the Company’s backlog will be completed in 2021 with the remaining balance expected to be completed in 2022. Revenue by category The following series of tables presents our revenue disaggregated by several categories. Domestically, our work generally is performed in coastal waterways and deep-water ports. The U.S. dredging market consists of four primary types of work: capital, coastal protection, maintenance and rivers & lakes. The Company’s contract revenues by type of work, for the periods indicated, were as follows: Three Months Ended Six Months Ended June 30, June 30, Revenues 2021 2020 2021 2020 Dredging: Capital—U.S. $ 79,399 $ 63,440 $ 157,005 $ 146,989 Capital—foreign 1,613 3,981 6,322 10,843 Coastal protection 46,631 56,038 93,262 135,888 Maintenance 37,278 41,968 82,579 84,353 Rivers & lakes 4,993 2,493 8,379 7,542 Total revenues $ 169,914 $ 167,920 $ 347,547 $ 385,615 The Company’s contract revenues by type of customer, for the periods indicated, were as follows: Three Months Ended Six Months Ended June 30, June 30, Revenues 2021 2020 2021 2020 Dredging: Federal government $ 127,331 $ 133,496 $ 258,063 $ 299,263 State and local government 37,069 29,693 71,844 72,025 Private 3,901 750 11,318 3,484 Foreign 1,613 3,981 6,322 10,843 Total revenues $ 169,914 $ 167,920 $ 347,547 $ 385,615 Accounts receivable at June 30, 2021 and December 31, 2020 are as follows: June 30, December 31, 2021 2020 Completed contracts $ 12,526 $ 12,347 Contracts in progress 15,393 21,239 Retainage 8,386 5,968 36,305 39,554 Allowance for doubtful accounts (564 ) (564 ) Total accounts receivable—net $ 35,741 $ 38,990 The components of contracts in progress at June 30, 2021 and December 31, 2020 are as follows: June 30, December 31, 2021 2020 Costs and earnings in excess of billings: Costs and earnings for contracts in progress $ 317,984 $ 199,964 Amounts billed (291,493 ) (168,569 ) Costs and earnings in excess of billings for contracts in progress 26,491 31,395 Costs and earnings in excess of billings for completed contracts 10,177 2,823 Total contract revenues in excess of billings $ 36,668 $ 34,218 Current portion of contract revenues in excess of billings $ 34,556 $ 32,106 Long-term contract revenues in excess of billings 2,112 2,112 Total contract revenues in excess of billings $ 36,668 $ 34,218 Billings in excess of costs and earnings: Amounts billed $ (382,785 ) $ (550,468 ) Costs and earnings for contracts in progress 353,952 517,860 Total billings in excess of contract revenues $ (28,833 ) $ (32,608 ) At June 30, 2021 and December 31, 2020, costs to fulfill a contract with a customer recognized as an asset were $6,887 and $10,501, respectively, and are recorded in other current assets and other noncurrent assets. These costs relate to pre-contract and pre-construction activities. During the three and six months ended June 30, 2021 and 2020, the Company amortized $5,909 and $3,612, and 11,756 and 8,804 respectively, of pre-construction costs.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2021
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	8 . Commitments and contingencies Commercial commitments Performance and bid bonds are customarily required for dredging and marine construction projects. The Company has bonding agreements with Argonaut Insurance Company, Berkley Insurance Company, Chubb Surety and Liberty Mutual Insurance Company, under which the Company can obtain performance, bid and payment bonds. The Company also has outstanding bonds with Travelers Casualty, Surety Company of America and Zurich American Insurance Company. Bid bonds are generally obtained for a percentage of bid value and amounts outstanding typically range from $1,000 to $10,000. At June 30, 2021, the Company had outstanding performance bonds with a notional amount of approximately $1,143,833. The revenue value remaining in backlog totaled approximately $454,402. Certain foreign projects performed by the Company have warranty periods, typically spanning no more than one to three years beyond project completion, whereby the Company retains responsibility to maintain the project site to certain specifications during the warranty period. Generally, any potential liability of the Company is mitigated by insurance, shared responsibilities with consortium partners, and/or recourse to owner-provided specifications. Legal proceedings and other contingencies As is customary with negotiated contracts and modifications or claims to competitively bid contracts with the federal government, the government has the right to audit the books and records of the Company to ensure compliance with such contracts, modifications, or claims, and the applicable federal laws. The government has the ability to seek a price adjustment based on the results of such audit. Any such audits have not had, and are not expected to have, a material impact on the financial position, operations, or cash flows of the Company. Various legal actions, claims, assessments and other contingencies arising in the ordinary course of business are pending against the Company and certain of its subsidiaries. The Company will defend itself vigorously on all matters. These matters are subject to many uncertainties, and it is possible that some of these matters could ultimately be decided, resolved, or settled adversely to the Company. Although the Company is subject to various claims and legal actions that arise in the ordinary course of business, except as described below, the Company is not currently a party to any material legal proceedings or environmental claims. The Company records an accrual when it is probable a liability has been incurred and the amount of loss can be reasonably estimated. The Company does not believe any of these proceedings, individually or in the aggregate, would be expected to have a material effect on results of operations, cash flows or financial condition. On April 23, 2014, the Company completed the sale of NASDI, LLC (“NASDI”) and Yankee Environmental Services, LLC (“Yankee”), which together comprised the Company’s historical demolition business, to a privately owned demolition company. On January 14, 2015, the Company and its subsidiary, NASDI Holdings, LLC, brought an action in the Delaware Court of Chancery to enforce the terms of the Company's agreement to sell NASDI and Yankee. Under the terms of the agreement, the Company received cash of $5,309 and retained the right to receive additional proceeds based upon future collections of outstanding accounts receivable and work in process existing at the date of close. The Company seeks specific performance of the buyer’s obligation to collect and to remit the additional proceeds, and other related relief. Defendants have filed counterclaims alleging that the Company misrepresented the quality of its contracts and receivables prior to the sale. The Company denies defendants’ allegations. In addition, the Company has been granted a judgment in the amount of $21,934 based upon the buyer’s default of its obligations to indemnify the Company for losses resulting from failure to perform in accordance with terms of surety performance bond. The defendants filed a notice of appeal from that judgement. The Company continues to aggressively pursue collection from the buyer on outstanding amounts owed under the sale and the indemnification. An estimate of a range of potential gains or losses relating to these matters cannot reasonably be made. On April 22, 2021, the U.S. Attorney’s Office for the Eastern District of Louisiana filed a bill of information against the Company charging the Company with a negligent discharge violation of the Clean Water Act arising from a September 2016 oil spill. The spill occurred during the Company’s Cheniere Ronquille project and resulted in the discharge of around one hundred sixty government may initiate suspension or debarment proceedings against us, which might prohibit us from bidding for, entering into or completing certain government projects. The Company also remains subject to potential liability for restitution in connection with this criminal matter and potential liability in a pending civil suit arising from the same matter. Although the Company does not know whether proceedings will be initiated or result in prohibitions, or the impact of any such resulting prohibitions, the Company does not expect any such proceedings or prohibitions to cause a material disruption to its business, financial condition or results of operations. On September 27, 2019, the EPA Region 4 filed an administrative complaint against the Company relating to a project the Company performed at PortMiami from 2013-2015 alleging violations of Section 103 of the Marine Protection, Research, and Sanctuaries Act (“MPRSA”) and failure to report violations of the MPRSA. In July 2021, the parties executed a consent agreement wherein the Company agreed to pay $500 as a civil penalty. Lease obligations The Company leases certain operating equipment and office facilities under long-term operating leases expiring at various dates through 2030. The equipment leases contain renewal or purchase options that specify prices at the then fair value upon the expiration of the lease terms. The leases also contain default provisions that are triggered by an acceleration of debt maturity under the terms of the Company’s Amended Credit Agreement, or, in certain instances, cross default to other equipment leases and certain lease arrangements require that the Company maintain certain financial ratios comparable to those required by its Amended Credit Agreement. Additionally, the leases typically contain provisions whereby the Company indemnifies the lessors for the tax treatment attributable to such leases based on the tax rules in place at lease inception. The tax indemnifications do not have a contractual dollar limit. To date, no lessors have asserted any claims against the Company under these tax indemnification provisions.

Earnings Per Share (Tables)

Earnings Per Share (Tables)	6 Months Ended
	Jun. 30, 2021
Earnings Per Share [Abstract]
Computations for Basic and Diluted Earnings Per Share	The computations for basic and diluted earnings per share are as follows: Three Months Ended Six Months Ended (shares in thousands) June 30, June 30, 2021 2020 2021 2020 Net income $ 2,105 $ 8,960 $ 10,919 $ 42,947 Weighted-average common shares outstanding — basic 65,646 64,864 65,458 64,659 Effect of stock options and restricted stock units 491 894 729 1,143 Weighted-average common shares outstanding — diluted 66,137 65,758 66,187 65,802 Earnings per share — basic $ 0.03 $ 0.14 $ 0.17 $ 0.66 Earnings per share — diluted $ 0.03 $ 0.14 $ 0.16 $ 0.65

Accrued Expenses (Tables)

Accrued Expenses (Tables)	6 Months Ended
	Jun. 30, 2021
Payables And Accruals [Abstract]
Accrued Expenses	Accrued expenses at June 30, 2021 and December 31, 2020 were as follows: June 30, December 31, 2021 2020 Insurance $ 17,365 $ 14,754 Payroll and employee benefits 7,744 21,675 Income and other taxes 1,995 2,164 Interest 1,728 3,285 Contract reserves 750 2,491 Other 7,648 8,530 Total accrued expenses $ 37,230 $ 52,899

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2021
Fair Value Disclosures [Abstract]
Schedule of Fair Values of Financial Instruments and Nonfinancial Assets and Liabilities Measured at the Reporting Date	The fair values of these financial instruments are summarized as follows: Fair Value Measurements at Reporting Date Using Description At June 30, 2021 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Fuel hedge contracts $ 4,802 $ - $ 4,802 $ - Fair Value Measurements at Reporting Date Using Description At December 31, 2020 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Fuel hedge contracts $ 1,739 $ - $ 1,739 $ -
Schedule of Fair Value of Fuel Hedge Contracts Balance Sheet Location	The fair value of the fuel hedge contracts outstanding as of June 30, 2021 and December 31, 2020 is as follows: Fair Value at June 30, December 31, Balance Sheet Location 2021 2020 Asset derivatives: Derivatives designated as hedging instruments Fuel hedge contracts Prepaid expenses and other current assets $ 4,802 $ 1,739
Changes in Components of Accumulated Other Comprehensive Income (Loss)	Changes in the components of the accumulated balances of other comprehensive income (loss) are as follows: Three Months Ended Six Months Ended June 30, June 30, 2021 2020 2021 2020 Derivatives: Reclassification of derivative (gains) losses to earnings—net of tax (1,878 ) 2,490 (3,404 ) 3,828 Change in fair value of derivatives—net of tax 2,282 950 5,694 (7,514 ) Net change in cash flow derivative hedges—net of tax $ 404 $ 3,440 $ 2,290 $ (3,686 )
Adjustments Reclassified from Accumulated Balances Other Comprehensive Income (Loss) to Earnings	Adjustments reclassified from accumulated balances of other comprehensive income (loss) to earnings are as follows: Three Months Ended Six Months Ended June 30, June 30, Statement of Operations Location 2021 2020 2021 2020 Derivatives: Fuel Costs of contract revenues $ (2,513 ) $ 3,340 (4,554 ) 5,132 Income tax (provision) benefit (635 ) 850 (1,150 ) 1,304 $ (1,878 ) $ 2,490 $ (3,404 ) $ 3,828

Revenue (Tables)

Revenue (Tables)	6 Months Ended
	Jun. 30, 2021
Revenue From Contract With Customer [Abstract]
Summary of Contract Revenues by Type of Work and Customer	The Company’s contract revenues by type of work, for the periods indicated, were as follows: Three Months Ended Six Months Ended June 30, June 30, Revenues 2021 2020 2021 2020 Dredging: Capital—U.S. $ 79,399 $ 63,440 $ 157,005 $ 146,989 Capital—foreign 1,613 3,981 6,322 10,843 Coastal protection 46,631 56,038 93,262 135,888 Maintenance 37,278 41,968 82,579 84,353 Rivers & lakes 4,993 2,493 8,379 7,542 Total revenues $ 169,914 $ 167,920 $ 347,547 $ 385,615 The Company’s contract revenues by type of customer, for the periods indicated, were as follows: Three Months Ended Six Months Ended June 30, June 30, Revenues 2021 2020 2021 2020 Dredging: Federal government $ 127,331 $ 133,496 $ 258,063 $ 299,263 State and local government 37,069 29,693 71,844 72,025 Private 3,901 750 11,318 3,484 Foreign 1,613 3,981 6,322 10,843 Total revenues $ 169,914 $ 167,920 $ 347,547 $ 385,615
Schedule of Accounts Receivable	Accounts receivable at June 30, 2021 and December 31, 2020 are as follows: June 30, December 31, 2021 2020 Completed contracts $ 12,526 $ 12,347 Contracts in progress 15,393 21,239 Retainage 8,386 5,968 36,305 39,554 Allowance for doubtful accounts (564 ) (564 ) Total accounts receivable—net $ 35,741 $ 38,990
Components of Contracts in Progress	The components of contracts in progress at June 30, 2021 and December 31, 2020 are as follows: June 30, December 31, 2021 2020 Costs and earnings in excess of billings: Costs and earnings for contracts in progress $ 317,984 $ 199,964 Amounts billed (291,493 ) (168,569 ) Costs and earnings in excess of billings for contracts in progress 26,491 31,395 Costs and earnings in excess of billings for completed contracts 10,177 2,823 Total contract revenues in excess of billings $ 36,668 $ 34,218 Current portion of contract revenues in excess of billings $ 34,556 $ 32,106 Long-term contract revenues in excess of billings 2,112 2,112 Total contract revenues in excess of billings $ 36,668 $ 34,218 Billings in excess of costs and earnings: Amounts billed $ (382,785 ) $ (550,468 ) Costs and earnings for contracts in progress 353,952 517,860 Total billings in excess of contract revenues $ (28,833 ) $ (32,608 )

Basis of Presentation (Narrativ

Basis of Presentation (Narrative) (Details)	6 Months Ended
	Jun. 30, 2021segment	Aug. 04, 2020USD ($)
Organization Consolidation and Presentation [Line Items]
Number of operating Segments	1
Number of reportable segments	1
Number of reportable segment with goodwill	1
Common Stock [Member] | Maximum [Member]
Organization Consolidation and Presentation [Line Items]
Stock repurchase program, authorized amount | $		$ 75,000,000

Earnings Per Share - (Computati

Earnings Per Share - (Computations for Basic and Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings Per Share [Abstract]
Net income	$ 2,105	$ 8,960	$ 10,919	$ 42,947
Weighted-average common shares outstanding — basic	65,646	64,864	65,458	64,659
Effect of stock options and restricted stock units	491	894	729	1,143
Weighted-average common shares outstanding — diluted	66,137	65,758	66,187	65,802
Basic earnings per share	$ 0.03	$ 0.14	$ 0.17	$ 0.66
Diluted earnings per share	$ 0.03	$ 0.14	$ 0.16	$ 0.65

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Payables And Accruals [Abstract]
Insurance	$ 17,365	$ 14,754
Payroll and employee benefits	7,744	21,675
Income and other taxes	1,995	2,164
Interest	1,728	3,285
Contract reserves	750	2,491
Other	7,648	8,530
Total accrued expenses	$ 37,230	$ 52,899

Long-Term Debt (Narrative) (Det

Long-Term Debt (Narrative) (Details) - USD ($)	1 Months Ended
	May 31, 2021	Jun. 30, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Revolving credit facility		$ 0	$ 0
Letters of credit outstanding		35,909,000	36,407,000
Letter of credit remaining borrowing capacity		163,764,000	163,231,000
Availability under credit agreement suppressed		327,000	327,000
2029 Notes [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 325,000,000
Debt instrument, interest rate, stated percentage	5.25%
Maturity date	Jun. 1, 2029
Existing and future owned domestic subsidiaries percent	100.00%
8.000% Senior Notes Due in 2022 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 325,000,000
Debt instrument, interest rate, stated percentage	8.00%
Deferred financing fees	$ 1,000,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		$ 200,000,000	$ 200,000,000

Fair Value Measurements (Schedu

Fair Value Measurements (Schedule of Fair Values of Financial Instruments and Nonfinancial Assets and Liabilities Measured at the Reporting Date) (Details) - Fuel Hedge Contracts [Member] - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value, Net Asset (Liability)	$ 4,802	$ 1,739
Significant Other Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value, Net Asset (Liability)	$ 4,802	$ 1,739

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details) gal in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021USD ($)$ / gal	Jun. 30, 2020USD ($)	Jun. 30, 2021USD ($)$ / galgal	Jun. 30, 2020USD ($)	May 31, 2021USD ($)	Dec. 31, 2020USD ($)
Derivatives Fair Value [Line Items]
Derivative underlying hedge percent			80.00%
Derivative, Nonmonetary Notional Amount, Volume | gal			8.7
Fair value hedge assets	$ 4,802,000		$ 4,802,000			$ 1,739,000
Reclassification of derivative (gains) losses to earnings—net of tax	1,878,000	$ (2,490,000)	3,404,000	$ (3,828,000)
5.25% Senior Notes [Member]
Derivatives Fair Value [Line Items]
Debt instrument, face amount					$ 325,000,000
Stated interest rate					5.25%
5.25% Senior Notes [Member] | Fair Value, Inputs, Level 1 [Member]
Derivatives Fair Value [Line Items]
Fair value of debt	$ 334,783,000		$ 334,783,000
Minimum [Member]
Derivatives Fair Value [Line Items]
Fixed price range | $ / gal	1.22		1.22
Maximum [Member]
Derivatives Fair Value [Line Items]
Fixed price range | $ / gal	1.90		1.90
Fuel Hedge Contracts [Member]
Derivatives Fair Value [Line Items]
Derivative underlying hedge percent			80.00%

Fair Value Measurements (Sche_2

Fair Value Measurements (Schedule of Fair Value of Fuel Hedge Contracts Balance Sheet Location) (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Derivatives Fair Value [Line Items]
Asset derivatives	$ 4,802	$ 1,739
Prepaid Expenses and Other Current Assets [Member] | Derivatives Designated as Hedging Instruments [Member] | Fuel Hedge Contracts [Member]
Derivatives Fair Value [Line Items]
Asset derivatives	$ 4,802	$ 1,739

Fair Value Measurements (Change

Fair Value Measurements (Changes in Components of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Fair Value Disclosures [Abstract]
Reclassification of derivative (gains) losses to earnings—net of tax		$ (1,878)	$ 2,490	$ (3,404)	$ 3,828
Change in fair value of derivatives—net of tax		2,282	950	5,694	(7,514)
Net change in cash flow derivative hedges—net of tax	[1]	$ 404	$ 3,440	$ 2,290	$ (3,686)
[1]	Net of income tax (provision) benefit of $(136) and $1,162 for the three months ended June 30, 2021 and 2020 respectively.  Net of income tax (provision) of $(773) and $(1,255) for the six months ended June 30, 2021 and 2020 respectively.

Fair Value Measurements (Adjust

Fair Value Measurements (Adjustments Reclassified from Accumulated Balances Other Comprehensive Income (Loss) to Earnings) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Derivative Instruments Gain Loss [Line Items]
Costs of contract revenues	$ 146,992	$ 134,904	$ 291,549	$ 284,125
Income tax (provision) benefit	(829)	(3,131)	(2,218)	(14,441)
Net income (loss)	(2,105)	(8,960)	(10,919)	(42,947)
Fuel Hedge Contracts [Member] | Accumulated Gain Loss Net Cash Flow Hedge Parent [Member] | Reclassification Out of Accumulated Other Comprehensive Income [Member]
Derivative Instruments Gain Loss [Line Items]
Costs of contract revenues	(2,513)	3,340	(4,554)	5,132
Income tax (provision) benefit	(635)	850	(1,150)	1,304
Net income (loss)	$ (1,878)	$ 2,490	$ (3,404)	$ 3,828

Share-Based Compensation (Narra

Share-Based Compensation (Narrative) (Details) - USD ($) shares in Thousands, $ in Thousands	May 11, 2017	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	May 05, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units				307
Share-based compensation expense		$ 798	$ 1,455	$ 2,564	$ 3,130
Employees and Directors [Member] | 2021 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, number of shares available for grant						1,500
Employees and Directors [Member] | 2017 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, number of shares available for grant	3,300
Employees and Directors [Member] | 2007 Long-Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Underlying equity awards issued	1,700

Revenue (Narrative) (Details)

Revenue (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Revenue From Contract With Customer [Line Items]
Revenue, remaining performance obligation	$ 454,402		$ 454,402
Percentage of performance obligation to be recognized as revenue			93.00%
Performance obligation, expected to be recognized as revenue year			2021
Remaining performance obligation, expected timing of satisfaction, year	2022		2022
Amortization on pre-construction costs	$ 5,909	$ 3,612	$ 11,756	$ 8,804
Other Current and Noncurrent Assets [Member]
Revenue From Contract With Customer [Line Items]
Costs to fulfill a contract with customer recognized as an asset	$ 6,887		$ 6,887		$ 10,501

Revenue (Summary of Type of Wor

Revenue (Summary of Type of Work, Contract Revenues) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregation Of Revenue [Line Items]
Revenues	$ 169,914	$ 167,920	$ 347,547	$ 385,615
Type of Work [Member] | Operating Segment [Member] | Dredging [Member]
Disaggregation Of Revenue [Line Items]
Revenues	169,914	167,920	347,547	385,615
Type of Work [Member] | Operating Segment [Member] | Dredging [Member] | Capital-U.S. [Member]
Disaggregation Of Revenue [Line Items]
Revenues	79,399	63,440	157,005	146,989
Type of Work [Member] | Operating Segment [Member] | Dredging [Member] | Capital-Foreign [Member]
Disaggregation Of Revenue [Line Items]
Revenues	1,613	3,981	6,322	10,843
Type of Work [Member] | Operating Segment [Member] | Dredging [Member] | Coastal Protection [Member]
Disaggregation Of Revenue [Line Items]
Revenues	46,631	56,038	93,262	135,888
Type of Work [Member] | Operating Segment [Member] | Dredging [Member] | Maintenance [Member]
Disaggregation Of Revenue [Line Items]
Revenues	37,278	41,968	82,579	84,353
Type of Work [Member] | Operating Segment [Member] | Dredging [Member] | Rivers & Lakes [Member]
Disaggregation Of Revenue [Line Items]
Revenues	$ 4,993	$ 2,493	$ 8,379	$ 7,542

Revenue (Summary of Type of Cus

Revenue (Summary of Type of Customer, Contract Revenues) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregation Of Revenue [Line Items]
Revenues	$ 169,914	$ 167,920	$ 347,547	$ 385,615
Type of Customer [Member] | Operating Segment [Member] | Dredging [Member]
Disaggregation Of Revenue [Line Items]
Revenues	169,914	167,920	347,547	385,615
Type of Customer [Member] | Operating Segment [Member] | Dredging [Member] | Federal Government [Member]
Disaggregation Of Revenue [Line Items]
Revenues	127,331	133,496	258,063	299,263
Type of Customer [Member] | Operating Segment [Member] | Dredging [Member] | State and Local Government [Member]
Disaggregation Of Revenue [Line Items]
Revenues	37,069	29,693	71,844	72,025
Type of Customer [Member] | Operating Segment [Member] | Dredging [Member] | Private [Member]
Disaggregation Of Revenue [Line Items]
Revenues	3,901	750	11,318	3,484
Type of Customer [Member] | Operating Segment [Member] | Dredging [Member] | Foreign [Member]
Disaggregation Of Revenue [Line Items]
Revenues	$ 1,613	$ 3,981	$ 6,322	$ 10,843

Revenue (Schedule of Accounts R

Revenue (Schedule of Accounts Receivable) (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Receivables [Abstract]
Completed contracts	$ 12,526	$ 12,347
Contracts in progress	15,393	21,239
Retainage	8,386	5,968
Accounts receivable, gross	36,305	39,554
Allowance for doubtful accounts	(564)	(564)
Total accounts receivable—net	$ 35,741	$ 38,990

Revenue (Components of Contract

Revenue (Components of Contracts in Progress) (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Accounts Notes And Loans Receivable [Line Items]
Costs and earnings in excess of billings for contracts in progress	$ 26,491	$ 31,395
Costs and earnings in excess of billings for completed contracts	10,177	2,823
Total contract revenues in excess of billings	36,668	34,218
Current portion of contract revenues in excess of billings	34,556	32,106
Long-term contract revenues in excess of billings	2,112	2,112
Total billings in excess of contract revenues	(28,833)	(32,608)
Costs And Earnings In Excess Of Billings [Member]
Accounts Notes And Loans Receivable [Line Items]
Costs and earnings for contracts in progress	317,984	199,964
Amounts billed	(291,493)	(168,569)
Billings In Excess Of Costs And Earnings [Member]
Accounts Notes And Loans Receivable [Line Items]
Costs and earnings for contracts in progress	353,952	517,860
Amounts billed	$ (382,785)	$ (550,468)

Commitments and Contingencies (

Commitments and Contingencies (Narrative) (Details)	Jun. 15, 2021USD ($)	Apr. 22, 2021bbl	Jan. 14, 2015USD ($)	Apr. 23, 2014USD ($)	Jul. 31, 2021USD ($)	Jun. 30, 2021USD ($)
Commitments And Contingencies [Line Items]
Outstanding performance bonds						$ 1,143,833,000
Revenue value remaining from outstanding performance bonds						454,402,000
Proceeds from Legal Settlements			$ 5,309,000
Fine for violation	$ 1,000,000
Subsequent Event [Member]
Commitments And Contingencies [Line Items]
Civil penalty					$ 500,000
Indemnification Commitment [Member]
Commitments And Contingencies [Line Items]
Aggregate demolition surety performance bond				$ 21,934,000
Crude Oil [Member]
Commitments And Contingencies [Line Items]
Quantity of oil spill | bbl		160
Minimum [Member]
Commitments And Contingencies [Line Items]
Bids bond range						$ 1,000,000
Warranty periods						1 year
Maximum [Member]
Commitments And Contingencies [Line Items]
Bids bond range						$ 10,000,000
Warranty periods						3 years