Revenue (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023 USD ($) segment	Sep. 30, 2022 USD ($) segment	Sep. 30, 2023 USD ($) segment	Sep. 30, 2022 USD ($) segment
Disaggregation of Revenue [Line Items]
Contract revenues	$ 168,476	$ 182,621	$ 510,184	$ 552,127
Number of reportable segments | segment	2	2	2	2
Marine Segment
Disaggregation of Revenue [Line Items]
Contract revenues	$ 80,913	$ 76,098	$ 260,754	$ 242,897
Marine Segment | Construction
Disaggregation of Revenue [Line Items]
Contract revenues	58,162	56,765	189,895	169,127
Marine Segment | Dredging
Disaggregation of Revenue [Line Items]
Contract revenues	9,444	17,408	44,993	63,894
Marine Segment | Specialty Services
Disaggregation of Revenue [Line Items]
Contract revenues	13,307	1,925	25,866	9,876
Concrete Segment
Disaggregation of Revenue [Line Items]
Contract revenues	87,563	106,523	249,430	309,230
Concrete Segment | Structural
Disaggregation of Revenue [Line Items]
Contract revenues	12,268	15,070	41,849	46,610
Concrete Segment | Light Commercial
Disaggregation of Revenue [Line Items]
Contract revenues	$ 75,295	$ 91,453	$ 207,581	$ 262,620