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Segment Information (Details) $ in Thousands	3 Months Ended								12 Months Ended
Segment Information (Details) $ in Thousands	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) segment	Dec. 31, 2018 USD ($) segment	Dec. 31, 2017 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments \| segment									2	2
Contract revenues	$ 199,793	$ 199,507	$ 165,985	$ 143,105	$ 99,211	$ 125,073	$ 159,767	$ 136,843	$ 708,390	$ 520,894	$ 578,553
Operating income (loss)	2,701	$ 6,092	$ (423)	$ (6,177)	(104,795)	$ (7,405)	$ 4,591	$ 7,069	2,193	(100,540)	1,538
Depreciation and amortization									(26,096)	(31,799)	$ (29,491)
Assets	394,844				312,870				394,844	312,870
Property and equipment, net of depreciation	132,348				148,003				132,348	148,003
Marine
Segment Reporting Information [Line Items]
Contract revenues									369,138	243,883
Marine \| Mexico and the Caribbean
Segment Reporting Information [Line Items]
Contract revenues									11,400	12,200
Concrete
Segment Reporting Information [Line Items]
Contract revenues									339,252	277,011
Concrete \| Foreign
Segment Reporting Information [Line Items]
Contract revenues									0	0
Operating Segments \| Marine
Segment Reporting Information [Line Items]
Contract revenues									369,138	243,883
Operating income (loss)									1,057	(61,012)
Depreciation and amortization									(19,889)	(22,657)
Assets	264,681				190,503				264,681	190,503
Property and equipment, net of depreciation	114,873				128,168				114,873	128,168
Operating Segments \| Concrete
Segment Reporting Information [Line Items]
Contract revenues									339,252	277,011
Operating income (loss)									1,136	(39,528)
Depreciation and amortization									(8,519)	(9,142)
Assets	130,163				122,367				130,163	122,367
Property and equipment, net of depreciation	$ 17,475				$ 19,835				17,475	19,835
Intersegment Eliminations
Segment Reporting Information [Line Items]
Contract revenues									$ 1,200	$ 2,500