Pension Benefits (Narrative) (Details) - USD ($)		9 Months Ended
	Aug. 25, 2016	Jan. 31, 2018	Jan. 31, 2017
Pension and Other Postretirement Benefit Expense [Abstract]
Expected company contributions to pension plan		$ 19,300,000
Expected company contributions to pension plan, discretionary funding	$ 13,600,000.0
Pension contribution			$ 27,300,000