Leases - Additional Information Related to Leases (Details) - USD ($)	9 Months Ended
	Jan. 31, 2021	Jan. 31, 2020
Cash Paid For Amounts Included In The Measurement Of Lease Liabilities [Abstract]
Operating cash flows for finance leases	$ 50,000	$ 157,000
Operating cash flows for operating leases	18,161,000	16,731,000
Financing cash flows for financing leases	384,000	1,883,000
Right-of-use assets obtained in exchange for new finance lease liabilities	1,531	1,399
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 6,886	$ 29,622
Weighted average remaining lease term (years)
Weighted average remaining lease term - finance leases	3 years 21 days	3 years 5 months 8 days
Weighted average remaining lease term - operating leases	6 years 10 months 20 days	6 years 4 months 17 days
Weighted average discount rate
Weighted average discount rate - finance leases (as a percent)	3.00%	3.20%
Weighted average discount rate - operating leases (as a percent)	3.29%	4.26%