Leases - Components of Lease Costs (Details)	12 Months Ended
	Apr. 30, 2020 USD ($)
Lease, Cost [Abstract]
Reduction in the carrying value of right-of-use assets	$ 2,582,000
Interest on lease liabilities	205,000
Operating lease cost	25,405,000
Operating cash flows for finance leases	205,000
Operating cash flows for operating leases	22,595,000
Financing cash flows for financing leases	2,512,000
Right-of-use assets obtained in exchange for new finance lease liabilities	1,650
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 72,703
Weighted average remaining lease term - finance leases	3 years 4 months 9 days
Weighted average remaining lease term - operating leases	7 years 4 months 28 days
Weighted average discount rate - finance leases (percent)	3.19%
Weighted average discount rate - operating leases (percent)	4.27%