Goodwill and Other Intangible Assets - Schedule of Intangible Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Amount	$ 1,662,326	$ 1,520,461
Intangible assets, Accumulated Amortization	722,021	653,626
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Amount	1,422,569	1,295,803
Intangible assets, Accumulated Amortization	622,440	566,884
Trademarks and Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Amount	176,950	161,851
Intangible assets, Accumulated Amortization	74,551	66,494
Other [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Amount	62,807	62,807
Intangible assets, Accumulated Amortization	$ 25,030	$ 20,248