Share-Based Compensation (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jan. 27, 2012	Jan. 28, 2011	Jan. 27, 2012	Jan. 28, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation Cost	$ 3,399	$ 2,457	$ 5,946	$ 4,919
Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation Cost	437	474	846	1,187
Nonvested Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation Cost	2,526	1,622	4,065	3,371
Performance Based Stock Unit [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation Cost	$ 436	$ 361	$ 1,035	$ 361