Deferred Compensation and Retirement Plans - Components Of Net Periodic Benefit Costs (Detail) - Medical and Life Insurance - Hay Group - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2023	Apr. 30, 2022	Apr. 30, 2021
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0	$ 0	$ 0
Interest cost	195	110	140
Net prior service credit amortization	(308)	(308)	(308)
Amortization of actuarial gain	(74)	0	0
Net periodic benefit cost	$ (187)	$ (198)	$ (168)