Intangible Assets - Summary of Intangible Assets, Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	$ 165,121	$ 138,135
Accumulated amortization	(52,942)	(37,357)
Intangible assets, net	112,179	100,778
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	159,566	133,660
Other [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	$ 5,555	$ 4,475