Debt - Senior Credit Agreement (Details)		6 Months Ended
	Sep. 15, 2015 USD ($)	Jan. 27, 2018 USD ($)	Jul. 29, 2017 USD ($)	Jul. 30, 2016 USD ($)
Line of Credit Facility [Line Items]
Debt instrument, covenant compliance, consolidated leverage ratio, maximum		3.50
Letters of credit outstanding amount		$ 48,600,000	$ 48,700,000	$ 57,600,000
Debt instrument, covenant compliance, consolidated interest coverage ratio, maximum		3.00
Additional borrowing availability		$ 401,400,000	401,300,000	$ 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		$ 48,600,000	$ 48,700,000
Incremental Facility, Minimum
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