Revenue (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025 USD ($) segment	Sep. 30, 2024 USD ($) segment	Sep. 30, 2025 USD ($) segment	Sep. 30, 2024 USD ($) segment
Disaggregation of Revenue [Line Items]
Contract revenues	$ 225,097	$ 226,675	$ 619,037	$ 579,514
Number of reportable segments | segment	2	2	2	2
Marine
Disaggregation of Revenue [Line Items]
Contract revenues	$ 142,943	$ 140,013	$ 405,409	$ 377,291
Marine | Construction
Disaggregation of Revenue [Line Items]
Contract revenues	116,815	123,141	336,128	327,955
Marine | Dredging
Disaggregation of Revenue [Line Items]
Contract revenues	23,761	12,902	58,372	39,649
Marine | Specialty Services
Disaggregation of Revenue [Line Items]
Contract revenues	2,367	3,970	10,909	9,687
Concrete
Disaggregation of Revenue [Line Items]
Contract revenues	82,154	86,662	213,628	202,223
Concrete | Structural
Disaggregation of Revenue [Line Items]
Contract revenues	11,482	15,572	37,785	44,040
Concrete | Light Commercial
Disaggregation of Revenue [Line Items]
Contract revenues	$ 70,672	$ 71,090	$ 175,843	$ 158,183