Segment Information - Summary (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Segment Reporting Information [Line Items]
Contract revenues	$ 138,757	$ 129,623
Operating loss	(1,482)	(455)
Depreciation and amortization expense	(7,528)	(8,550)
Total Assets	431,438		$ 447,676
Property and equipment, net	153,916		$ 158,082
Operating Segments | Marine Construction
Segment Reporting Information [Line Items]
Contract revenues	67,180	62,415
Operating loss	(7,707)	(3,143)
Depreciation and amortization expense	(5,255)	(5,067)
Total Assets	261,176	305,270
Property and equipment, net	139,221	150,978
Operating Segments | Concrete Construction
Segment Reporting Information [Line Items]
Contract revenues	71,577	67,208
Operating loss	6,225	2,688
Depreciation and amortization expense	(2,273)	(3,483)
Total Assets	170,262	147,009
Property and equipment, net	$ 14,695	$ 15,033