Leases - Additional Information Related to Leases (Details) - USD ($)	3 Months Ended
	Jul. 31, 2021	Jul. 31, 2020
Cash Paid For Amounts Included In The Measurement Of Lease Liabilities [Abstract]
Operating cash flows for finance leases	$ 25,000	$ 14,000
Operating cash flows for operating leases	6,610,000	6,142,000
Financing cash flows for financing leases	279,000	92,000
Right-of-use assets obtained in exchange for new finance lease liabilities	654,000	109,000
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 3,026,000	$ 155,000
Weighted average remaining lease term (years)
Weighted average remaining lease term - finance leases	2 years 9 months 14 days	3 years 2 months 19 days
Weighted average remaining lease term - operating leases	6 years 4 months 20 days	7 years 3 months 29 days
Weighted average discount rate
Weighted average discount rate - finance leases (as a percent)	2.94%	3.08%
Weighted average discount rate - operating leases (as a percent)	3.19%	3.54%