Annual report pursuant to Section 13 and 15(d)

Deferred Compensation And Retirement Plans - Fair Value Measurements of Defined Benefit Plan Assets (Detail)

v3.20.2
Deferred Compensation And Retirement Plans - Fair Value Measurements of Defined Benefit Plan Assets (Detail) - Deferred Compensation and Pension Plans - USD ($)
$ in Thousands
Apr. 30, 2020
Apr. 30, 2019
Defined Benefit Plan Disclosure [Line Items]    
Total defined benefit plan assets $ 24,235 $ 25,131
Mutual Funds    
Defined Benefit Plan Disclosure [Line Items]    
Total defined benefit plan assets 24,041 24,931
Money Market Funds    
Defined Benefit Plan Disclosure [Line Items]    
Total defined benefit plan assets 194 200
Fair Value, Inputs, Level 1    
Defined Benefit Plan Disclosure [Line Items]    
Total defined benefit plan assets 194 200
Fair Value, Inputs, Level 1 | Money Market Funds    
Defined Benefit Plan Disclosure [Line Items]    
Total defined benefit plan assets 194 200
Fair Value, Inputs, Level 2    
Defined Benefit Plan Disclosure [Line Items]    
Total defined benefit plan assets 24,041 24,931
Fair Value, Inputs, Level 2 | Mutual Funds    
Defined Benefit Plan Disclosure [Line Items]    
Total defined benefit plan assets $ 24,041 $ 24,931