Revenue (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($) segment	Mar. 31, 2023 USD ($) segment
Disaggregation of Revenue [Line Items]
Contract revenues	$ 160,672	$ 159,174
Number of reportable segments | segment	2	2
Marine Segment
Disaggregation of Revenue [Line Items]
Contract revenues	$ 106,325	$ 79,298
Marine Segment | Construction
Disaggregation of Revenue [Line Items]
Contract revenues	88,789	54,012
Marine Segment | Dredging
Disaggregation of Revenue [Line Items]
Contract revenues	14,670	20,730
Marine Segment | Specialty Services
Disaggregation of Revenue [Line Items]
Contract revenues	2,866	4,556
Concrete Segment
Disaggregation of Revenue [Line Items]
Contract revenues	54,347	79,876
Concrete Segment | Structural
Disaggregation of Revenue [Line Items]
Contract revenues	11,573	15,744
Concrete Segment | Light Commercial
Disaggregation of Revenue [Line Items]
Contract revenues	$ 42,774	$ 64,132