Accrued Insurance Claims (Details) - USD ($)	Jul. 30, 2016	Jul. 25, 2015	Jul. 26, 2014
Accrued Insurance Claims [Line Items]
Aggregate stop loss coverage for automobile liability, general liability, and workers' compensation claims before adjustment		$ 59,500,000
Insurance liability, annual retained risk loss		250,000
Retained risk of loss per participant for employee health plan for claim amounts that aggregate across all participants in excess of $250,000		550,000
Health plan participant threshold		250,000
Accrued insurance		87,300,000	$ 66,000,000
Accrued insurance claims, Noncurrent		51,476,000	$ 33,782,000
Insurance recoveries/receivables related to accrued claims		9,500,000
Other Current Assets
Accrued Insurance Claims [Line Items]
Insurance recoveries/receivables related to accrued claims		600,000
Non-Current Other Assets
Accrued Insurance Claims [Line Items]
Insurance recoveries/receivables related to accrued claims		8,900,000
Scenario, Forecast
Accrued Insurance Claims [Line Items]
Aggregate stop loss coverage for automobile liability, general liability, and workers' compensation claims before adjustment	$ 84,600,000
Maximum
Accrued Insurance Claims [Line Items]
Retained risk of loss, general liability and workers' compensation, maximum automobile liability		$ 1,000,000