Pension Benefits (Narrative) (Details) $ in Thousands			3 Months Ended	6 Months Ended	12 Months Ended
	Dec. 30, 2020 USD ($)	Apr. 30, 2020 plan	Oct. 31, 2021 USD ($)	Oct. 31, 2021 USD ($)	Apr. 30, 2021 USD ($)	Apr. 30, 2020 plan
Defined Benefit Plan Disclosure [Line Items]
Number of defined benefit pension plans | plan		1				2
Pension contribution				$ 0	$ 0
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Expected termination costs	$ 1,600		$ 400	$ 600	$ 400