Amortizable Intangible Assets - Amortizable Intangible Assets (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 1,472,136		$ 1,428,426
Accumulated Amortization	(726,784)		(683,746)
Net Carrying Value	745,352		744,680
Purchased customer accounts
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	1,442,512		1,398,986
Accumulated Amortization	(699,252)		(656,799)
Net Carrying Value	$ 743,260		742,187
Weighted Average Life (Years)	15 years	15 years
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 29,624		29,440
Accumulated Amortization	(27,532)		(26,947)
Net Carrying Value	$ 2,092		$ 2,493
Weighted Average Life (Years)	6 years 9 months 18 days	6 years 9 months 18 days