Goodwill and Other Intangible Assets - Schedule of Intangible Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Amount	$ 1,659,430	$ 1,659,500
Intangible assets, Accumulated Amortization	767,309	744,854
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Amount	1,420,166	1,420,224
Intangible assets, Accumulated Amortization	659,469	641,089
Trademarks and Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Amount	176,457	176,471
Intangible assets, Accumulated Amortization	79,833	77,208
Other [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Amount	62,807	62,805
Intangible assets, Accumulated Amortization	$ 28,007	$ 26,557