Stock-Based Awards (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended	12 Months Ended
	Oct. 25, 2014	Jul. 26, 2014
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to stock options	$ 2.7
Total compensation cost not yet recognized, period for recognition	2 years 2 months 12 days
Restricted Share Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to stock options	5.8
Total compensation cost not yet recognized, period for recognition	2 years 4 months 24 days
Granted	984
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	398,640	398,931
Performance Restricted Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to stock options	9.7
Total compensation cost not yet recognized, period for recognition	1 year 6 months
Compensation expense	$ 4.5
RSUs outstanding	34,209
Granted	68,418
Forfeited or cancelled		312,163
Share-based Compensation by Share-based Payment Award, Equity Awards Other than Options, Target Shares Expected to be Canceled		48,313
Share-based Compensation by Share-based Payment Award, Equity Awards Other than Options, Supplemental Shares Expected to be Canceled		263,850
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	897,403	1,190,184
Supplemental Shares | Performance Restricted Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted	34,209
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	207,061
Target Shares | Performance Restricted Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	690,342