Deferred Compensation and Retirement Plans - Components of Net Periodic Benefits Costs (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2023	Oct. 31, 2022	Oct. 31, 2023	Oct. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Expected long-term rate of return on plan assets			6.00%	5.50%
Deferred Compensation Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 11,346	$ 10,484	$ 21,179	$ 19,627
Interest cost	3,436	2,437	6,793	4,824
Amortization of actuarial loss	183	218	367	436
Expected return on plan assets	(272)	(289)	(544)	(578)
Net periodic service credit amortization	(102)	(102)	(203)	(203)
Net periodic benefit costs	$ 14,591	$ 12,748	$ 27,592	$ 24,106