Revenue (Details) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2026 USD ($) segment	Mar. 31, 2025 USD ($)	Dec. 31, 2025 segment
Disaggregation of Revenue [Line Items]
Contract revenues	$ 216,301	$ 188,653
Number of reportable segments | segment	2		2
Marine
Disaggregation of Revenue [Line Items]
Contract revenues	$ 110,129	127,163
Marine | Construction
Disaggregation of Revenue [Line Items]
Contract revenues	92,683	104,482
Marine | Dredging
Disaggregation of Revenue [Line Items]
Contract revenues	14,081	16,911
Marine | Specialty Services
Disaggregation of Revenue [Line Items]
Contract revenues	3,365	5,770
Concrete
Disaggregation of Revenue [Line Items]
Contract revenues	106,172	61,490
Concrete | Structural
Disaggregation of Revenue [Line Items]
Contract revenues	9,753	13,721
Concrete | Light Commercial
Disaggregation of Revenue [Line Items]
Contract revenues	$ 96,419	$ 47,769