Rent Expense on Operating Leases (Detail) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Schedule of Operating Leases [Line Items]
Rent expense	$ 308,561,000	$ 276,030,000	$ 300,609,000
Sublease proceeds	(4,700,000)	(7,090,000)	(6,114,000)
Net rent expense	$ 303,861,000	$ 268,940,000	$ 294,495,000