Earnings Per Share (Details) (USD $) In Thousands, except Share data	3 Months Ended		6 Months Ended
	Jul. 30, 2011	Jul. 31, 2010	Jul. 30, 2011	Jul. 31, 2010
Earnings Per Share
Net income	$ 43,391	$ 30,455	$ 89,309	$ 65,856
Net income allocated to participating securities	(573)	(216)	(1,110)	(440)
Net income available to common shareholders	$ 42,818	$ 30,239	$ 88,199	$ 65,416
Weighted average common shares outstanding-basic	171,282,434	177,499,286	173,081,952	177,417,471
Dilutive effect of stock options outstanding	1,212,573	1,275,130	1,216,112	1,389,066
Weighted average common and common equivalent shares outstanding-diluted	172,495,007	178,774,416	174,298,064	178,806,537
Net income per common share-basic	$ 0.25	$ 0.17	$ 0.51	$ 0.37
Net income per common share-Diluted	$ 0.25	$ 0.17	$ 0.51	$ 0.37
Anti-dilutive securities excluded from computation of diluted EPS	3,980,832	3,445,097	3,964,669	3,306,313