Goodwill and Intangible Assets - Schedule of Amounts Related to Finite-Lived Intangible Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Gross Balance	$ 250,148	$ 168,716
Accumulated Amortization	95,294	66,167
Total Intangible Assets—Net	154,854	102,549
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Gross Balance	164,782	108,782
Accumulated Amortization	53,446	36,700
Total Intangible Assets—Net	$ 111,336	$ 72,082
Customer Relationships | Minimum
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	7 years	7 years
Customer Relationships | Maximum
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	15 years	15 years
Covenants Not to Compete
Finite-Lived Intangible Assets [Line Items]
Gross Balance	$ 29,942	$ 25,832
Accumulated Amortization	21,469	17,572
Total Intangible Assets—Net	$ 8,473	$ 8,260
Covenants Not to Compete | Minimum
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	4 years	4 years
Covenants Not to Compete | Maximum
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	5 years	5 years
Trade Names
Finite-Lived Intangible Assets [Line Items]
Gross Balance	$ 16,938	$ 12,738
Accumulated Amortization	12,849	10,230
Total Intangible Assets—Net	$ 4,089	$ 2,508
Trade Names | Minimum
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	1 year	1 year
Trade Names | Maximum
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	5 years	5 years
Proprietary Software and Other Software Licenses
Finite-Lived Intangible Assets [Line Items]
Gross Balance	$ 21,007
Accumulated Amortization	6,132
Total Intangible Assets—Net	$ 14,875
Proprietary Software and Other Software Licenses | Minimum
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	3 years
Proprietary Software and Other Software Licenses | Maximum
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	5 years
Patent
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	16 years	16 years
Gross Balance	$ 17,479	$ 17,479
Accumulated Amortization	1,398	306
Total Intangible Assets—Net	$ 16,081	$ 17,173
Proprietary Software
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life		3 years
Gross Balance		$ 3,885
Accumulated Amortization		1,359
Total Intangible Assets—Net		$ 2,526