Accrued Insurance Claims (Details)	Apr. 29, 2017 USD ($) state	Jul. 30, 2016 USD ($)
Accrued Insurance Claims [Line Items]
Number of States with State-Sponsored Insurance Fund | state	2
Aggregate stop loss coverage for automobile liability, general liability, and workers' compensation claims before adjustment	$ 103,700,000
Insurance liability, annual retained risk loss	400,000
Accrued Insurance	101,000,000	$ 89,700,000
Accrued insurance claims, Noncurrent	60,726,000	52,835,000
Maximum
Accrued Insurance Claims [Line Items]
Retained risk of loss, general liability and workers' compensation, maximum automobile liability	1,000,000
Other Noncurrent Assets [Member]
Accrued Insurance Claims [Line Items]
Insurance recoveries/receivables related to accrued claims	$ 8,900,000	$ 5,700,000