Segment Information - Summary (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Segment Reporting Information [Line Items]
Contract revenues	$ 164,017	$ 137,061	$ 433,941	$ 304,607
Operating income (loss)	9,531	(8,325)	9,357	(11,230)
Depreciation and amortization expense			(25,765)	(18,831)
Total Assets	468,207		468,207		$ 461,462
Property and equipment, net	161,243		161,243		$ 165,989
Operating Segments | Heavy Civil Marine Construction
Segment Reporting Information [Line Items]
Contract revenues	82,169	90,068	224,550	257,614
Operating income (loss)	3,272	(10,746)	(1,082)	(13,651)
Depreciation and amortization expense	(5,547)	(5,585)	(15,790)	(16,239)
Total Assets	306,788	348,074	306,788	348,074
Property and equipment, net	146,361	149,162	146,361	149,162
Operating Segments | Commercial Concrete Construction
Segment Reporting Information [Line Items]
Contract revenues	81,848	46,993	209,391	46,993
Operating income (loss)	6,259	2,421	10,439	2,421
Depreciation and amortization expense	(3,015)	(2,592)	(9,975)	(2,592)
Total Assets	161,419	156,325	161,419	156,325
Property and equipment, net	$ 14,882	$ 14,759	$ 14,882	$ 14,759