Intangible Assets - Summary of Intangible Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 252,525	$ 243,085
Accumulated Amortization	(120,360)	(114,697)
Customer Relationships
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	191,305	183,445
Accumulated Amortization	(81,619)	(77,016)
Trade Names
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	52,061	51,361
Accumulated Amortization	(36,556)	(36,082)
Subcontractor Relationships
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	5,440	4,700
Accumulated Amortization	(584)	(131)
Non-compete Agreements
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	3,719	3,579
Accumulated Amortization	$ (1,601)	$ (1,468)