Leases - Additional Information Related to Leases (Details) - USD ($)	6 Months Ended
	Oct. 31, 2020	Oct. 31, 2019
Cash Paid For Amounts Included In The Measurement Of Lease Liabilities [Abstract]
Operating cash flows for finance leases	$ 30,000	$ 105,000
Operating cash flows for operating leases	12,164,000	11,783,000
Financing cash flows for financing leases	210,000	1,203,000
Right-of-use assets obtained in exchange for new finance lease liabilities	941	643
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 6,788	$ 24,178
Weighted average remaining lease term (years)
Weighted average remaining lease term - finance leases	3 years 2 months 4 days	3 years 4 months 9 days
Weighted average remaining lease term - operating leases	7 years 29 days	6 years 6 months 3 days
Weighted average discount rate
Weighted average discount rate - finance leases (as a percent)	3.02%	3.20%
Weighted average discount rate - operating leases (as a percent)	3.31%	4.26%