Annual report pursuant to Section 13 and 15(d)

Deferred Compensation and Retirement Plans - Additional Information (Detail)

v3.19.2
Deferred Compensation and Retirement Plans - Additional Information (Detail)
 12 Months Ended
Apr. 30, 2019
USD ($)
Person
Apr. 30, 2018
USD ($)
Person
Apr. 30, 2017
USD ($)
Defined Benefit Plan Disclosure [Line Items]      
Recognized investment income(expense) $ 8,134,000 $ 10,278,000 $ 10,842,000
Increase in market value of the underlying COLI investments 6,160,000 7,776,000 4,918,000
Net CSV 126,000,000 120,087,000  
CSV of COLI Contracts      
Defined Benefit Plan Disclosure [Line Items]      
Outstanding policy loans 93,200,000 66,700,000  
Total death benefits payable, net of loans 223,600,000 226,000,000  
Increase in market value of the underlying COLI investments 6,200,000 7,800,000 4,900,000
Net CSV $ 126,000,000 120,100,000  
Equity Securities | Minimum      
Defined Benefit Plan Disclosure [Line Items]      
Target allocation range 40.00%    
Equity Securities | Maximum      
Defined Benefit Plan Disclosure [Line Items]      
Target allocation range 50.00%    
Debt Securities | Minimum      
Defined Benefit Plan Disclosure [Line Items]      
Target allocation range 45.00%    
Debt Securities | Maximum      
Defined Benefit Plan Disclosure [Line Items]      
Target allocation range 55.00%    
Other Assets | Minimum      
Defined Benefit Plan Disclosure [Line Items]      
Target allocation range 0.00%    
Other Assets | Maximum      
Defined Benefit Plan Disclosure [Line Items]      
Target allocation range 10.00%    
Long Term Performance Unit Plan      
Defined Benefit Plan Disclosure [Line Items]      
Value per unit award $ 50,000    
Annual Benefit Payments per vested unit after anniversary period $ 25,000    
Number of payments after the seventh anniversary of the grant date 5 years    
Vesting percentage on each anniversary date 25.00%    
Enhanced Wealth Accumulation Plan      
Defined Benefit Plan Disclosure [Line Items]      
Participant contribution period towards deferred compensation plans (in years) 8 years    
Participant after tax contribution period towards deferred compensation plans (in years) 15 years    
Additional deferred units to acquire (in years) 5 years    
Senior Executive Incentive Plan      
Defined Benefit Plan Disclosure [Line Items]      
Participant contribution period towards deferred compensation plans (in years) 4 years    
Participant after tax contribution period towards deferred compensation plans (in years) 15 years    
Pension Plans, Defined Benefit      
Defined Benefit Plan Disclosure [Line Items]      
Participant employment term, maximum years 20 years    
Medical and Life Insurance plan | Hay Group      
Defined Benefit Plan Disclosure [Line Items]      
Benefit plan, number of participants | Person 126    
Reduction in benefit obligation   (4,008,000)  
Total benefit obligation $ 7,310,000 7,157,000 12,147,000
International Retirement Plans      
Defined Benefit Plan Disclosure [Line Items]      
Total benefit obligation $ 14,700,000 $ 13,700,000  
Long-term benefit obligation accrued, number of participants | Person 2,777 2,423  
Company's contributions $ 13,300,000 $ 11,800,000  
Executive Capital Accumulation Plan      
Defined Benefit Plan Disclosure [Line Items]      
Total benefit obligation 130,161,000 128,430,000 111,584,000
Company's contributions 8,500,000 6,200,000 6,200,000
Gain (loss) on deferred compensation plan 8,700,000 11,100,000 10,600,000
Company's contributions, unamortized portion $ 16,800,000 19,200,000  
Executive Capital Accumulation Plan | Minimum      
Defined Benefit Plan Disclosure [Line Items]      
Deferred compensation arrangement vesting period 4 years    
Executive Capital Accumulation Plan | Maximum      
Defined Benefit Plan Disclosure [Line Items]      
Deferred compensation arrangement vesting period 5 years    
Defined Contribution Plan      
Defined Benefit Plan Disclosure [Line Items]      
Company's matching contributions $ 2,700,000 2,300,000  
Percentage contribution by the participants to defined contribution plan 50.00%    
Deferred Compensation Plan      
Defined Benefit Plan Disclosure [Line Items]      
Total benefit obligation $ 148,369,000 126,494,000 $ 121,042,000
Deferred Compensation Plan | CSV of COLI Contracts      
Defined Benefit Plan Disclosure [Line Items]      
Gross CSV 219,200,000 186,800,000  
Outstanding policy loans 93,200,000 $ 66,700,000  
Company Owned Life Insurance Held In Trust | CSV of COLI Contracts      
Defined Benefit Plan Disclosure [Line Items]      
Net CSV 115,700,000    
Total death benefits, net of loans held in trust $ 178,700,000