Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amounts	$ 103,466	$ 123,740
Accumulated Amortization	(50,984)	(60,169)
Net Carrying Amounts	52,482	63,571
Customer relationships
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amounts	94,181	97,497
Accumulated Amortization	(47,080)	(44,185)
Net Carrying Amounts	47,101	53,312
Non-compete agreements
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amounts	1,345	1,479
Accumulated Amortization	(848)	(831)
Net Carrying Amounts	497	648
Customer backlog
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amounts	1,021	10,353
Accumulated Amortization	(65)	(5,941)
Net Carrying Amounts	956	4,412
Trade name
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amounts	98	449
Accumulated Amortization	(6)	(281)
Net Carrying Amounts	92	168
Developed software
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amounts	6,821	13,962
Accumulated Amortization	(2,985)	(8,931)
Net Carrying Amounts	$ 3,836	$ 5,031