Debt Senior Credit Agreement (Details)		3 Months Ended
	Sep. 09, 2015 USD ($)	Jan. 23, 2016 USD ($)	Jul. 25, 2015 USD ($)
Line of Credit Facility [Line Items]
Debt covenant compliance, consolidated leverage maximum (ratio)		3.50
Letters of credit outstanding amount		$ 57,700,000	$ 54,400,000
Debt Instrument, Covenant Compliance, Consolidated Interest Coverage Ratio, Maximum		3.00
Additional borrowing availability		$ 289,100,000	300,300,000
Standby Letters of Credit
Line of Credit Facility [Line Items]
Line of credit current borrowing capacity	$ 200,000,000
Letters of credit outstanding amount		$ 57,700,000	$ 54,400,000
Credit Agreement - Term Loan (matures April 2020)
Line of Credit Facility [Line Items]
Debt Instrument, Face Amount	$ 150,000,000
Debt covenant compliance, consolidated leverage maximum (ratio)	2.25
Credit Agreement - Revolving facility (matures April 2020)
Line of Credit Facility [Line Items]
Line of credit current borrowing capacity	$ 450,000,000