Deferred Compensation and Retirement Plans - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 31, 2022	Jan. 31, 2021	Jan. 31, 2022	Jan. 31, 2021	Apr. 30, 2021
Defined Benefit Plan Disclosure [Line Items]
Increase in market value of the underlying COLI investments			$ 3,897	$ 8,575
Recognized investment income (expense)	$ (7,700)	$ 15,200	$ 2,400	27,200
Minimum
Defined Benefit Plan Disclosure [Line Items]
Option to receive employee benefits by quarterly installments periods			1 year
Maximum
Defined Benefit Plan Disclosure [Line Items]
Option to receive employee benefits by quarterly installments periods			15 years
CSV of COLI Contracts
Defined Benefit Plan Disclosure [Line Items]
Increase in market value of the underlying COLI investments	1,700	4,700	$ 3,900	8,600
Deferred Compensation Plan | CSV of COLI Contracts
Defined Benefit Plan Disclosure [Line Items]
Gross CSV	261,000		261,000		$ 241,300
Outstanding policy loans	79,800		$ 79,800		$ 80,000
Executive Capital Accumulation Plan
Defined Benefit Plan Disclosure [Line Items]
Deferred compensation arrangement vesting period			5 years
Gain (loss) on deferred compensation plan	$ (7,000)	$ 14,500	$ 3,100	$ 26,300