Amortizable Intangible Assets - Amortizable Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 1,394,718	$ 1,384,689
Accumulated Amortization	(619,805)	(600,047)
Net Carrying Value	774,913	784,642
Purchased customer accounts
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	1,365,525	1,355,550
Accumulated Amortization	(593,742)	(574,285)
Net Carrying Value	771,783	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	29,193	29,139
Accumulated Amortization	(26,063)	(25,762)
Net Carrying Value	$ 3,130	$ 3,377
Weighted Average Life (Years)	6 years 9 months 18 days	6 years 9 months 18 days