Pension Benefits (Narrative) (Details) - USD ($)		3 Months Ended
	Aug. 25, 2016	Jul. 31, 2017	Jul. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Expected company contributions to pension plan		$ 19,300,000
Expected company contributions to pension plan, discretionary funding	$ 13,600,000.0
Pension contribution		$ 1,400,000	$ 27,300,000