Deferred Compensation and Retirement Plans - Components of Net Periodic Benefits Costs (Detail) - Deferred Compensation Plan - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2024	Apr. 30, 2023	Apr. 30, 2022
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 43,879	$ 40,843	$ 37,952
Interest cost	13,447	9,511	4,028
Amortization of actuarial loss	818	945	2,170
Net prior service credit amortization	(97)	(97)	(97)
Expected return on plan assets	(1,088)	(1,156)	(1,554)
Net periodic benefit cost	$ 56,959	$ 50,046	$ 42,499