Summary of Supplemental Disclosures of Cash Flow Information and Non-Cash Financing and Investing Activities (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Supplemental Cash Flow Elements [Abstract]
Interest	$ 13,223	$ 12,928
Income taxes	81,156	60,918
Other payable issued for purchased customer accounts	503	25,775
Notes payable issued or assumed for purchased customer accounts		59
Estimated acquisition earn-out payables and related charges	2,064	15,055
Notes received on the sale of fixed assets and customer accounts	$ 1,107	$ 1,116