Segment Information (Tables)

12 Months Ended

Dec. 31, 2017

Segment Reporting [Abstract]

Segment Reporting By Segment

	2017			2016			2015
Dredging:
Contract revenues	$	592,159		$	637,468		$	681,255
Operating income (loss)		(13,353	)		34,108			64,073
Depreciation and amortization		55,962			54,826			50,556
Total assets		878,458			912,880			872,297
Property and equipment—net		396,925			399,479			397,468
Goodwill		76,576			76,576			76,576
Investment in joint ventures		—			381			1
Capital expenditures		63,912			84,263			82,000
Environmental & infrastructure:
Contract revenues		112,607			133,637			181,710
Operating loss		(10,172	)		(19,428	)		(41,114	)
Depreciation and amortization		4,558			8,197			14,029
Total assets		78,806			81,166			127,907
Property and equipment—net		10,369			13,529			32,742
Goodwill		7,000			7,000			7,000
Investment in joint ventures		2,714			4,353			3,760
Capital expenditures		2,156			949			7,279
Intersegment:
Contract revenues		(2,263	)		(3,520	)		(6,087	)
Total assets		(124,907	)		(100,458	)		(102,080	)
Total:
Contract revenues		702,503			767,585			856,878
Operating income (loss)		(23,525	)		14,680			22,959
Depreciation and amortization		60,520			63,023			64,585
Total assets		832,357			893,588			898,124
Property and equipment—net		407,294			413,008			430,210
Goodwill		83,576			83,576			83,576
Investment in joint ventures		2,714			4,734			3,761
Capital expenditures		66,068			85,212			89,279

Revenue Related to Dredging Projects By Type Of Work

	2017		2016		2015
Capital dredging — U.S.	$	185,113	$	219,914	$	207,058
Capital dredging — foreign		42,306		59,413		139,945
Coastal protection dredging		191,070		215,041		184,060
Maintenance dredging		134,923		92,274		120,055
Rivers & lakes		38,747		50,826		30,137
Total dredging	$	592,159	$	637,468	$	681,255

Revenues And Gross Profit From Foreign Project Operations

	2017			2016			2015
Contract revenues	$	42,306		$	59,413		$	139,945
Costs of contract revenues		(73,958	)		(66,729	)		(105,951	)
Gross profit	$	(31,652	)	$	(7,316	)	$	33,994