Deferred Compensation and Retirement Plans - Fair Value Measurements of Defined Benefit Plan Assets (Detail) - Deferred compensation and pension plans - USD ($) $ in Thousands	Apr. 30, 2024	Apr. 30, 2023
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit plan assets	$ 18,523	$ 19,085
Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit plan assets	18,033	18,350
Money market funds
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit plan assets	490	735
Level 1
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit plan assets	490	735
Level 1 | Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit plan assets	0	0
Level 1 | Money market funds
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit plan assets	490	735
Level 2
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit plan assets	18,033	18,350
Level 2 | Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit plan assets	18,033	18,350
Level 2 | Money market funds
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit plan assets	0	0
Level 3
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit plan assets	0	0
Level 3 | Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit plan assets	0	0
Level 3 | Money market funds
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit plan assets	$ 0	$ 0