Quarterly Financial Data (Unaudited) (Details) (USD $) In Thousands, except Per 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
Quarterly Financial Data (Unaudited) [Abstract]
Total revenue	$ 700,010	$ 608,514	$ 673,234	$ 598,437	$ 612,942	$ 582,525	$ 640,277	$ 598,691	$ 2,580,195	$ 2,434,435	$ 2,404,515
Gross profit	483,839	418,899	437,843	412,130	419,388	402,751	420,887	418,938	1,752,711	1,661,964	1,658,697
Income before income taxes	48,552	27,935	36,312	33,489	21,761	19,586	40,642	33,702	146,288	115,691	115,709
Net income	$ 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 - basic	$ 1.49	$ 0.82	$ 1.11	$ 1.04	$ 0.77	$ 0.66	$ 1.24	$ 1.04	$ 4.47	$ 3.70	$ 3.71
Net income per share - diluted	$ 1.47	$ 0.81	$ 1.10	$ 1.03	$ 0.75	$ 0.64	$ 1.20	$ 1.01	$ 4.40	$ 3.61	$ 3.62
Number of weeks in the fourth quarter	14