Net Income Per Share and Weighted Average Shares (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Aug. 03, 2012	Apr. 27, 2012	Jan. 27, 2012	Oct. 28, 2011	Jul. 29, 2011	Apr. 29, 2011	Jan. 28, 2011	Oct. 29, 2010	Aug. 03, 2012	Jul. 29, 2011	Jul. 30, 2010
Net Income Per Share and Weighted Average Shares [Abstract]
Net income per share numerator	$ 34,696	$ 18,974	$ 25,609	$ 23,802	$ 17,543	$ 15,154	$ 28,777	$ 23,734	$ 103,081	$ 85,208	$ 85,258
Net income per share denominator: [Abstract]
Basic weighted average shares outstanding (in shares)									23,067,566	22,998,200	23,007,856
Add potential dilution: [Abstract]
Stock options and nonvested stock and stock awards (in shares)									340,560	636,475	571,896
Diluted weighted average shares outstanding (in shares)									23,408,126	23,634,675	23,579,752