Amortizable Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 1,139,173	$ 1,030,351
Accumulated Amortization	(513,875)	(463,813)
Net Carrying Value	625,298	566,538
Purchased customer accounts [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	1,111,022	1,005,031
Accumulated Amortization	(489,204)	(439,623)
Net Carrying Value	621,818	565,408
Weighted Average Life (years)	14 years 10 months 24 days	14 years 10 months 24 days
Non-compete agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	28,151	25,320
Accumulated Amortization	(24,671)	(24,190)
Net Carrying Value	$ 3,480	$ 1,130
Weighted Average Life (years)	7 years	7 years 2 months 12 days