Segment Information - Summary (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Contract revenues	$ 162,214	$ 140,162	$ 137,420	$ 138,757	$ 144,295	$ 164,017	$ 140,301	$ 129,623	$ 578,553	$ 578,236	$ 466,498
Operating income (loss)	10,840	$ (5,354)	$ (2,466)	$ (1,482)	(5,283)	$ 9,531	$ 281	$ (455)	1,538	4,074	(7,999)
Depreciation and amortization									(29,491)	(34,162)	$ (28,083)
Assets	433,285				447,676				433,285	447,676
Property and equipment, net	146,278				158,082				146,278	158,082
Operating Segments | Heavy Civil Marine Construction Segment
Segment Reporting Information [Line Items]
Contract revenues									285,736	284,632
Operating income (loss)									(18,406)	(12,403)
Depreciation and amortization									(20,370)	(21,398)
Assets	260,935				279,362				260,935	279,362
Property and equipment, net	128,421				143,425				128,421	143,425
Operating Segments | Commercial Concrete Segment
Segment Reporting Information [Line Items]
Contract revenues									292,817	293,604
Operating income (loss)									19,944	16,477
Depreciation and amortization									(9,121)	(12,764)
Assets	172,350				168,314				172,350	168,314
Property and equipment, net	$ 17,857				$ 14,657				$ 17,857	$ 14,657