Revenue (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023 USD ($) segment	Jun. 30, 2022 USD ($) segment	Jun. 30, 2023 USD ($) segment	Jun. 30, 2022 USD ($) segment
Disaggregation of Revenue [Line Items]
Contract revenues	$ 182,534	$ 194,575	$ 341,708	$ 369,506
Number of reportable segments | segment	2	2	2	2
Marine Segment
Disaggregation of Revenue [Line Items]
Contract revenues	$ 100,543	$ 82,319	$ 179,841	$ 166,799
Marine Segment | Construction
Disaggregation of Revenue [Line Items]
Contract revenues	77,721	53,210	131,733	112,362
Marine Segment | Dredging
Disaggregation of Revenue [Line Items]
Contract revenues	14,819	24,320	35,549	46,486
Marine Segment | Specialty Services
Disaggregation of Revenue [Line Items]
Contract revenues	8,003	4,789	12,559	7,951
Concrete Segment
Disaggregation of Revenue [Line Items]
Contract revenues	81,991	112,256	161,867	202,707
Concrete Segment | Structural
Disaggregation of Revenue [Line Items]
Contract revenues	13,837	17,864	29,581	31,540
Concrete Segment | Light Commercial
Disaggregation of Revenue [Line Items]
Contract revenues	$ 68,154	$ 94,392	$ 132,286	$ 171,167