Goodwill and Other Intangible Assets - Gross Carrying Amounts and Accumulated Amortization Relating to Other Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 789,480	$ 653,627
Accumulated Amortization	(170,970)	(132,414)
Net	618,510	521,213	$ 547,515
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	603,966	494,516
Accumulated Amortization	(150,350)	(115,636)
Net	453,616	378,880
Trademarks
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	180,416	153,346
Accumulated Amortization	(16,154)	(11,922)
Net	164,262	141,424
Non-competition agreements
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	5,098	5,765
Accumulated Amortization	(4,466)	(4,856)
Net	$ 632	$ 909