Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	Apr. 30, 2022	Apr. 30, 2021	Apr. 30, 2020
Income Tax Disclosure [Abstract]
Income taxes at the statutory rates	21.00%	21.00%	21.00%
Federal tax credits	(1.80%)	(1.50%)	(1.90%)
State income taxes, net of federal tax benefit	3.80%	3.50%	4.00%
Impact of phased-in state law changes, net of federal benefit	(0.80%)	0.00%	(0.20%)
ASU 2016-09 benefit (stock-based compensation)	(1.00%)	(0.60%)	(0.50%)
Other	1.70%	0.80%	0.50%
Effective income tax rate	22.90%	23.20%	22.90%