Pension Benefits (Narrative) (Details) - USD ($)		3 Months Ended	6 Months Ended
	Aug. 25, 2016	Oct. 31, 2017	Oct. 31, 2017	Oct. 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			$ 8,300,000	$ 27,300,000