Deferred Costs - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	Aug. 24, 2012	Feb. 29, 2012	Aug. 26, 2011
Deferred Costs and Future Payment Commitment for Retail Supply Agreements [Line Items]
Allowance for deferred costs related to supply agreements	$ 8.4	$ 10.0	$ 10.3