Lease Commitment - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012 Y	Dec. 31, 2011	Dec. 31, 2010
Operating Leased Assets [Line Items]
Operating lease agreement, expiration (in years)	22
Rent expense	$ 85.5	$ 75.3	$ 57.9

Rental expense incurred for leased assets including furniture and equipment which has not been recognized in costs and expenses applicable to sales and revenues; for example, cost of goods sold or other operating costs and expenses.

No definition available.

Name:	us-gaap_LeaseAndRentalExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration