Segment Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) segment	Dec. 31, 2022 USD ($) segment	Dec. 31, 2021 USD ($) segment
Segment Reporting Information [Line Items]
Number of reportable segments | segment	2	2	2
Contract revenues	$ 711,778	$ 748,322	$ 601,360
Operating income (loss)	(6,630)	(8,030)	(9,317)
Depreciation and amortization	(18,844)	(20,915)	(22,608)
Assets	416,893	367,155
Property and equipment, net of depreciation	87,834	100,977
Marine Segment
Segment Reporting Information [Line Items]
Contract revenues	395,917	339,213	263,915
Marine Segment | Foreign
Segment Reporting Information [Line Items]
Contract revenues	36,100	6,700	2,900
Concrete Segment
Segment Reporting Information [Line Items]
Contract revenues	315,861	409,109	337,445
Concrete Segment | Foreign
Segment Reporting Information [Line Items]
Contract revenues	0	0	0
Operating Segments | Marine Segment
Segment Reporting Information [Line Items]
Contract revenues	395,917	339,213	263,915
Operating income (loss)	3,670	9,787	5,760
Depreciation and amortization	(18,219)	(16,592)	(17,287)
Assets	318,684	239,369
Property and equipment, net of depreciation	82,215	91,390
Operating Segments | Concrete Segment
Segment Reporting Information [Line Items]
Contract revenues	315,861	409,109	337,445
Operating income (loss)	(10,300)	(17,817)	(15,077)
Depreciation and amortization	(5,659)	(7,465)	(8,143)
Assets	98,209	127,786
Property and equipment, net of depreciation	5,619	9,587
Intersegment Eliminations
Segment Reporting Information [Line Items]
Contract revenues		$ 200
Intersegment Eliminations | Maximum
Segment Reporting Information [Line Items]
Contract revenues	$ 100		$ 100