Amortizable Intangible Assets - Amortizable Intangible Assets (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 1,476,948		$ 1,477,348
Accumulated Amortization	(791,429)		(769,894)
Net Carrying Value	685,519		707,454
Purchased customer accounts
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	1,447,280		1,447,680
Accumulated Amortization	(763,026)		(741,770)
Net Carrying Value	$ 684,254		705,910
Weighted Average Life (Years)	15 years	15 years
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 29,668		29,668
Accumulated Amortization	(28,403)		(28,124)
Net Carrying Value	$ 1,265		$ 1,544
Weighted Average Life (Years)	6 years 9 months 18 days	6 years 9 months 18 days