Segment Information (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024 USD ($) segment	Sep. 30, 2023 USD ($) segment	Sep. 30, 2024 USD ($) segment	Sep. 30, 2023 USD ($) segment	Dec. 31, 2023 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment	2	2	2	2
Contract revenues	$ 226,675	$ 168,476	$ 579,514	$ 510,184
Operating income (loss)	7,781	2,561	1,889	(6,043)
Depreciation and amortization			(11,961)	(13,874)
Assets	430,329		430,329		$ 416,893
Property and equipment, net of depreciation	86,254		86,254		$ 87,834
Marine
Segment Reporting Information [Line Items]
Contract revenues	140,013	80,913	377,291	260,754
Marine | Foreign
Segment Reporting Information [Line Items]
Contract revenues	22,800	4,500	48,800	14,500
Concrete
Segment Reporting Information [Line Items]
Contract revenues	86,662	87,563	202,223	249,430
Concrete | Foreign
Segment Reporting Information [Line Items]
Contract revenues	0	0	0	0
Operating Segments | Marine
Segment Reporting Information [Line Items]
Contract revenues	140,013	80,913	377,291	260,754
Operating income (loss)	5,485	2,001	(4,847)	(587)
Depreciation and amortization	(4,552)	(4,771)	(14,405)	(12,418)
Assets	318,864	269,409	318,864	269,409
Property and equipment, net of depreciation	80,916	82,914	80,916	82,914
Operating Segments | Concrete
Segment Reporting Information [Line Items]
Contract revenues	86,662	87,563	202,223	249,430
Operating income (loss)	2,296	560	6,736	(5,456)
Depreciation and amortization	(1,016)	(1,322)	(3,153)	(4,464)
Assets	111,465	110,813	111,465	110,813
Property and equipment, net of depreciation	5,338	6,671	5,338	6,671
Intersegment Eliminations
Segment Reporting Information [Line Items]
Contract revenues	$ 100	$ 100	$ 1,800	$ 100