Revenue (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($) segment	Mar. 31, 2022 USD ($) segment
Disaggregation of Revenue [Line Items]
Contract revenues	$ 159,174	$ 174,931
Number of reportable segments | segment	2	2
Marine Segment
Disaggregation of Revenue [Line Items]
Contract revenues	$ 79,298	$ 84,480
Marine Segment | Construction
Disaggregation of Revenue [Line Items]
Contract revenues	54,012	59,152
Marine Segment | Dredging
Disaggregation of Revenue [Line Items]
Contract revenues	20,730	22,166
Marine Segment | Specialty Services
Disaggregation of Revenue [Line Items]
Contract revenues	4,556	3,162
Concrete Segment
Disaggregation of Revenue [Line Items]
Contract revenues	79,876	90,451
Concrete Segment | Structural
Disaggregation of Revenue [Line Items]
Contract revenues	15,744	13,676
Concrete Segment | Light Commercial
Disaggregation of Revenue [Line Items]
Contract revenues	$ 64,132	$ 76,775