Pension Benefits (Narrative) (Details) - USD ($)		9 Months Ended	12 Months Ended
	Aug. 25, 2016	Jan. 31, 2017	Apr. 30, 2016
Defined Benefit Plan Disclosure [Line Items]
Expected company contributions to pension plan		$ 27,300,000
Expected company contributions to pension plan, discretionary funding	$ 20,000,000
Pension contribution		$ 27,300,000	$ 5,000,000