Amortizable Intangible Assets - Amortizable Intangible Assets (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 1,444,729		$ 1,428,426
Accumulated Amortization	(705,174)		(683,746)
Net Carrying Value	739,555		744,680
Purchased customer accounts
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	1,415,155		1,398,986
Accumulated Amortization	(677,933)		(656,799)
Net Carrying Value	$ 737,222		742,187
Weighted Average Life (Years)	15 years	15 years
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 29,574		29,440
Accumulated Amortization	(27,241)		(26,947)
Net Carrying Value	$ 2,333		$ 2,493
Weighted Average Life (Years)	6 years 9 months 18 days	6 years 9 months 18 days