Goodwill and Intangible Assets (Intangible Assets) (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Total intangible assets
Cost	$ 381,940	$ 381,940
Accumulated Amortization	(199,449)	(198,331)
Accumulated Impairment Charge	(113,067)	(113,067)
Carrying Value	69,424	70,542
Trade Names
Finite-Lived intangible assets
Cost	69,250	69,250
Accumulated Amortization	(27,004)	(25,886)
Accumulated Impairment Charge	(23,232)	(23,232)
Carrying Value	$ 19,014	$ 20,132
Weighted-Average Amortization Period	20 years	20 years
Customer relationships
Finite-Lived intangible assets
Cost	$ 39,800	$ 39,800
Accumulated Amortization	(23,155)	(23,155)
Accumulated Impairment Charge	(16,645)	(16,645)
Carrying Value	0	0
Construction contract backlog
Finite-Lived intangible assets
Cost	149,290	149,290
Accumulated Amortization	(149,290)	(149,290)
Carrying Value	0	0
Trade Names
Indefinite-lived intangible assets
Cost	117,600	117,600
Accumulated Impairment Charge	(67,190)	(67,190)
Carrying Value	50,410	50,410
Contractor license
Indefinite-lived intangible assets
Cost	6,000	6,000
Accumulated Impairment Charge	(6,000)	(6,000)
Finite-Lived intangible assets
Carrying Value	$ 0	$ 0