Goodwill and Intangible Assets - Summary of Goodwill and Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Goodwill
Gross Carrying Amount	$ 66,065	$ 66,060
Accumulated Amortization	0	0
Net Carrying Amount	66,065	66,060
Amortizable Intangible Assets
Accumulated Amortization	14,467	10,880
Net Carrying Amount	22,899
Total intangible assets, Gross Carrying Amount	65,832	65,820
Total intangible assets, Net Carrying Amount	51,365	54,940
Trade names
Amortizable Intangible Assets
Indefinite-lived Intangible Assets	28,466	28,455
Backlog
Amortizable Intangible Assets
Gross Carrying Amount	5,289	5,289
Accumulated Amortization	5,289	4,039
Net Carrying Amount	0	1,250
Customer relationships
Amortizable Intangible Assets
Gross Carrying Amount	31,381	31,381
Accumulated Amortization	8,914	6,623
Net Carrying Amount	22,467	24,758
Trade names
Amortizable Intangible Assets
Gross Carrying Amount	696	695
Accumulated Amortization	264	218
Net Carrying Amount	432	477
T&D
Goodwill
Gross Carrying Amount	40,224	40,224
Accumulated Amortization	0	0
Net Carrying Amount	40,224	40,224
C&I
Goodwill
Gross Carrying Amount	25,841	25,836
Accumulated Amortization	0	0
Net Carrying Amount	$ 25,841	$ 25,836