Stock-Based Awards (Details) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended	6 Months Ended
	Jan. 25, 2014	Jan. 25, 2014	Jul. 27, 2013
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to stock options	$ 4.9	$ 4.9
Total compensation cost not yet recognized, period for recognition	2 years 4 months 7 days
Restricted Share Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to RSUs	7.9	7.9
Total compensation cost not yet recognized, period for recognition	3 years 0 months 7 days
Granted		94,456
RSUs outstanding	416,285	416,285	463,318
Performance Restricted Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to RSUs	15.3	15.3
Total compensation cost not yet recognized, period for recognition	1 year 8 months 16 days
Compensation expense	$ 8.9	$ 8.9
Granted		429,485
RSUs outstanding	1,212,017	1,212,017	1,315,138
Performance Restricted Share Units | Target Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted		373,465
RSUs outstanding	764,548	764,548
Performance Restricted Share Units | Supplemental Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted		56,020
RSUs outstanding	447,469	447,469
Performance Restricted Share Units | Scenario, Forecast
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Forfeited or cancelled		265,000