Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment
Property, plant and equipment, gross	$ 268,224	$ 263,804
Less: accumulated depreciation	(195,948)	(191,542)
Property, plant and equipment net book value of depreciable assets	72,276	72,262
Property and equipment, net of depreciation	100,977	106,654
Automobiles and trucks
Property, Plant and Equipment
Property, plant and equipment, gross	2,232	2,337
Building and improvements
Property, Plant and Equipment
Property, plant and equipment, gross	36,952	34,796
Construction equipment
Property, Plant and Equipment
Property, plant and equipment, gross	130,660	137,786
Vessels and other equipment
Property, Plant and Equipment
Property, plant and equipment, gross	91,495	82,455
Office equipment
Property, Plant and Equipment
Property, plant and equipment, gross	6,885	6,430
Construction in progress
Property, Plant and Equipment
Property, plant and equipment, gross	816	6,507
Land
Property, Plant and Equipment
Property, plant and equipment, gross	$ 27,885	$ 27,885