Deferred Compensation and Retirement Plans - Components of Net Periodic Benefits Costs (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2024	Oct. 31, 2023	Oct. 31, 2024	Oct. 31, 2023
Defined Benefit Plan Disclosure [Line Items]
Expected long-term rate of return on plan assets			6.00%	6.00%
Deferred Compensation Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 11,825	$ 11,346	$ 22,480	$ 21,179
Interest cost	4,513	3,436	8,964	6,793
Amortization of actuarial loss	32	183	64	367
Expected return on plan assets	(266)	(272)	(532)	(544)
Net periodic service credit amortization	(102)	(102)	(203)	(203)
Net periodic benefit costs	$ 16,002	$ 14,591	$ 30,773	$ 27,592