Leases - Components of Lease Costs (Details) - USD ($)	12 Months Ended
	Apr. 30, 2023	Apr. 30, 2022	Apr. 30, 2021
Lease, Cost [Abstract]
Reduction in the carrying value of right-of-use assets	$ 1,720,000	$ 1,404,000	$ 635,000
Interest on lease liabilities	105,000	106,000	73,000
Operating lease cost	26,592,000	27,610,000	27,192,000
Operating cash flows for finance leases	105,000	106,000	73,000
Operating cash flows for operating leases	26,906,000	25,100,000	24,371,000
Financing cash flows for financing leases	1,714,000	1,379,000	608,000
Right-of-use assets obtained in exchange for new finance lease liabilities	1,138	1,862	2,222
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 11,109	$ 7,482	$ 8,914
Weighted average remaining lease term - finance leases	1 year 11 months 26 days	2 years 3 months 25 days	2 years 11 months 12 days
Weighted average remaining lease term - operating leases	4 years 10 months 2 days	5 years 9 months 7 days	6 years 7 months 13 days
Weighted average discount rate - finance leases (percent)	3.69%	2.91%	2.95%
Weighted average discount rate - operating leases (percent)	3.35%	3.20%	3.23%