Property and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Property, Plant and Equipment
Property, plant and equipment, gross	$ 262,677	$ 268,224
Less: accumulated depreciation	(199,736)	(195,948)
Property, plant and equipment net book value of depreciable assets	62,941	72,276
Property and equipment, net of depreciation	89,585	100,977
Automobiles and trucks
Property, Plant and Equipment
Property, plant and equipment, gross	2,008	2,232
Building and improvements
Property, Plant and Equipment
Property, plant and equipment, gross	36,931	36,952
Construction equipment
Property, Plant and Equipment
Property, plant and equipment, gross	125,521	130,660
Vessels and other equipment
Property, Plant and Equipment
Property, plant and equipment, gross	91,308	91,495
Office equipment
Property, Plant and Equipment
Property, plant and equipment, gross	6,909	6,885
Construction in progress
Property, Plant and Equipment
Property, plant and equipment, gross	1,696	816
Land
Property, Plant and Equipment
Property, plant and equipment, gross	$ 24,948	$ 27,885