Amortizable Intangible Assets - Amortizable Intangible Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 1,428,426	$ 1,384,689
Accumulated Amortization	(683,746)	(600,047)
Net Carrying Value	744,680	784,642
Purchased customer accounts
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	1,398,986	1,355,550
Accumulated Amortization	(656,799)	(574,285)
Net Carrying Value	$ 742,187	$ 781,265
Weighted Average Life (Years)	15 years	14 years 10 months 24 days
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 29,440	$ 29,139
Accumulated Amortization	(26,947)	(25,762)
Net Carrying Value	$ 2,493	$ 3,377
Weighted Average Life (Years)	6 years 9 months 18 days	6 years 9 months 18 days