Debt Senior Credit Agreement (Details)		3 Months Ended
	Sep. 09, 2015 USD ($)	Jan. 28, 2017 USD ($)	Jul. 30, 2016 USD ($)
Line of Credit Facility [Line Items]
Debt Instrument, Increase (Decrease), Net		$ 35,000,000
Debt Instrument, Covenant Compliance, Consolidated Leverage Ratio, Maximum		3.50
Letters of credit outstanding amount		$ 57,600,000
Debt Instrument, Covenant Compliance, Consolidated Interest Coverage Ratio, Maximum		3.00
Additional borrowing availability			$ 392,400,000
Standby Letters of Credit
Line of Credit Facility [Line Items]
Line of credit current borrowing capacity	$ 200,000,000
Letters of credit outstanding amount		$ 57,600,000	$ 57,600,000
Incremental Facility, Minimum [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Face Amount	150,000,000
Credit Agreement - Term Loan (matures April 2020)
Line of Credit Facility [Line Items]
Debt Instrument, Face Amount	$ 385,000,000
Debt Instrument, Covenant Compliance, Consolidated Leverage Ratio, Maximum	2.25
Credit Agreement - Revolving facility (matures April 2020)
Line of Credit Facility [Line Items]
Line of credit current borrowing capacity	$ 450,000,000