Revenue (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2024 USD ($) segment	Dec. 31, 2023 USD ($) segment	Dec. 31, 2022 USD ($) segment
Disaggregation of Revenue [Line Items]
Contract revenues	$ 796,394	$ 711,778	$ 748,322
Number of reportable segments | segment	2	2	2
Marine
Disaggregation of Revenue [Line Items]
Contract revenues	$ 521,250	$ 395,917	$ 339,213
Marine | Construction
Disaggregation of Revenue [Line Items]
Contract revenues	448,321	297,462	239,656
Marine | Dredging
Disaggregation of Revenue [Line Items]
Contract revenues	57,048	60,667	85,414
Marine | Specialty Services
Disaggregation of Revenue [Line Items]
Contract revenues	15,881	37,788	14,143
Concrete
Disaggregation of Revenue [Line Items]
Contract revenues	275,144	315,861	409,109
Concrete | Structural
Disaggregation of Revenue [Line Items]
Contract revenues	61,545	53,827	57,425
Concrete | Light Commercial
Disaggregation of Revenue [Line Items]
Contract revenues	$ 213,599	$ 262,034	$ 351,684