Goodwill and Intangibles - Intangible Assets and Accumulated Amortization Balances (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 205,312	$ 202,687
Accumulated Amortization	(116,987)	(103,085)
Net Carrying Amount	88,325	99,602
Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	156,189	157,286
Accumulated Amortization	(109,906)	(98,937)
Net Carrying Amount	46,283	58,349
Other
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	49,123	45,401
Accumulated Amortization	(7,081)	(4,148)
Net Carrying Amount	$ 42,042	$ 41,253