Debt (Details) (USD $)	Nov. 25, 2011	Feb. 28, 2011	Nov. 26, 2010	Nov. 25, 2011 Amended and Restated Receivables Purchase Agreement [Member]	Sep. 21, 2011 Amended and Restated Receivables Purchase Agreement [Member]	Nov. 25, 2011 Secured Credit Agreement [Member]	Nov. 25, 2011 Publicly Traded Debt [Member]	Feb. 28, 2011 Publicly Traded Debt [Member]	Nov. 26, 2010 Publicly Traded Debt [Member]	Feb. 29, 2012 7.375% senior notes, due 2016 [Member]	Nov. 25, 2011 7.375% senior notes, due 2016 [Member]	Feb. 28, 2011 7.375% senior notes, due 2016 [Member]	Nov. 26, 2010 7.375% senior notes, due 2016 [Member]	Feb. 29, 2012 7.375% notes, due 2016 [Member]	Nov. 25, 2011 7.375% notes, due 2016 [Member]	Feb. 28, 2011 7.375% notes, due 2016 [Member]	Nov. 26, 2010 7.375% notes, due 2016 [Member]	Nov. 25, 2011 6.10% senior notes, due 2028 [Member]	Feb. 28, 2011 6.10% senior notes, due 2028 [Member]	Nov. 26, 2010 6.10% senior notes, due 2028 [Member]
Long-term debt
Long-term debt	$ 234,642,000	$ 232,688,000	$ 232,078,000				$ 234,600,000	$ 232,700,000	$ 232,100,000		$ 213,864,000	$ 213,077,000	$ 212,832,000		$ 20,597,000	$ 19,430,000	$ 19,065,000	$ 181,000	$ 181,000	$ 181,000
Secured credit agreement amended and restated						350,000,000
Maximum available financing of receivables purchase agreement				70,000,000	80,000,000
Maximum available under receivables purchase agreement after amendment					70,000,000
Quoted market prices of Corporation's publicly and non-publicly traded debt							243,600,000	237,500,000	237,400,000
Quoted market prices of Corporation's publicly traded debt, carrying value	234,642,000	232,688,000	232,078,000				234,600,000	232,700,000	232,100,000		213,864,000	213,077,000	212,832,000		20,597,000	19,430,000	19,065,000	181,000	181,000	181,000
Additional renewal period of liquidity commitments					364 days
Interest rate of debt										7.375%	7.375%			7.375%				6.10%
Debt (Textuals) [Abstract]
Balances outstanding under the Corporation's credit facility	0	0	0
Balances outstanding under receivables purchase agreement	0	0	0
Letters of credit outstanding	31,800,000
Debt due within one year	0	0	0
Long-term debt net of unamortized discounts	$ 20,200,000	$ 22,200,000	$ 22,800,000