Insurance Reserves (Detail) (USD $) In Millions, unless otherwise specified	Dec. 25, 2011	Dec. 26, 2010
Insurance Reserves [Line Items]
Estimated corporate insurance reserves	$ 19.3	$ 19.0
Total amount committed under letters of credit	$ 14.4

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

No definition available.

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant