Leases - Supplemental cash flow information (Details) - USD ($) $ in Thousands	6 Months Ended
	Oct. 31, 2021	Oct. 31, 2020
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows from operating leases	$ 22,727	$ 21,479
Operating cash flows from finance leases	4,424	5,925
Financing cash flows from finance leases	15,154	14,629
Right-of-use assets obtained in exchange for lease obligations
Operating leases	29,145	17,216
Finance leases	$ 13,034	$ 12,342