Segment Information - Summary (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Segment Reporting Information [Line Items]
Contract revenues	$ 143,105	$ 136,843
Operating (loss) income	(6,177)	7,069
Depreciation and amortization expense	(7,040)	(6,780)
Total assets	340,791		$ 312,870
Property and equipment, net of depreciation	136,841		$ 148,003
Marine
Segment Reporting Information [Line Items]
Contract revenues	61,487	62,791
Concrete
Segment Reporting Information [Line Items]
Contract revenues	81,618	74,052
Intersegment Eliminations
Segment Reporting Information [Line Items]
Contract revenues		100
Operating Segments | Marine
Segment Reporting Information [Line Items]
Contract revenues	61,487	62,791
Operating (loss) income	(6,456)	6,265
Depreciation and amortization expense	(4,946)	(4,731)
Total assets	213,162	255,484
Property and equipment, net of depreciation	118,596	127,078
Operating Segments | Concrete
Segment Reporting Information [Line Items]
Contract revenues	81,618	74,052
Operating (loss) income	279	804
Depreciation and amortization expense	(2,094)	(2,049)
Total assets	127,220	166,949
Property and equipment, net of depreciation	$ 18,245	$ 17,790