Annual report pursuant to Section 13 and 15(d)

Long-Term Debt - Additional Information (Detail)

v3.20.2
Long-Term Debt - Additional Information (Detail) - USD ($)
12 Months Ended
Dec. 16, 2019
Apr. 30, 2020
Apr. 30, 2019
Apr. 30, 2018
CSV of COLI Contracts        
Debt Instrument [Line Items]        
Outstanding policy loans   $ 92,300,000 $ 93,200,000  
Revolving Credit Facility        
Debt Instrument [Line Items]        
Line of credit facility, remaining borrowing capacity   646,000,000.0 420,200,000  
Line of credit facility borrowings     226,900,000  
Standby Letters of Credit        
Debt Instrument [Line Items]        
Long-term debt arrangement   4,000,000.0 2,900,000  
Standby Letters of Credit | Other Financial Institutions        
Debt Instrument [Line Items]        
Long-term debt arrangement   $ 11,300,000 $ 8,500,000  
Minimum | CSV of COLI Contracts        
Debt Instrument [Line Items]        
Average interest rate   4.76%    
Maximum | CSV of COLI Contracts        
Debt Instrument [Line Items]        
Average interest rate   8.00%    
4.625% Senior Unsecured Notes due 2027        
Debt Instrument [Line Items]        
Debt instrument, interest rate 4.625%      
Principal amount $ 400,000,000      
Debt instrument, unamortized discount $ 4,500,000      
Debt instrument, maturity date   Dec. 15, 2027    
Debt instrument, interest rate terms   interest payable semi-annually in arrears on June 15 and December 15 of each year, commencing on June 15, 2020    
Interest payment commencing date   Jun. 15, 2020    
Redemption price, percentage 100.00%      
Percentage of principal amount redeemable with equity offering proceeds 35.00%      
Redemption price, percentage of principal amount redeemed 104.625%      
Dividends payable per fiscal year $ 25,000,000      
Debt Instrument, change in control and rating decline, percentage of principal amount 101.00%      
Debt instrument, proceeds from offering used to repay outstanding debt $ 276,900,000      
Interest rate, effective percentage 4.86%      
Debt instrument, fair value   $ 372,500,000    
4.625% Senior Unsecured Notes due 2027 | Maximum        
Debt Instrument [Line Items]        
Leverage ratio to be attained for payment of dividends 3.50      
Credit Agreement        
Debt Instrument [Line Items]        
Credit agreement initiation date Dec. 16, 2019      
Average interest rate   3.34% 3.50% 2.60%
Unamortized debt issuance costs   $ 4,200,000 $ 4,000,000.0  
Credit Agreement | Revolving Credit Facility        
Debt Instrument [Line Items]        
Debt instrument term 5 years      
Line of credit facility, maximum borrowing capacity $ 650,000,000.0      
Line of credit facility, maturity date   Dec. 16, 2024    
Long-term debt   $ 0 $ 226,900,000  
Credit Agreement | Minimum        
Debt Instrument [Line Items]        
Pro forma liquidity $ 50,000,000.0      
Credit Agreement | Minimum | London Interbank Offered Rate (LIBOR)        
Debt Instrument [Line Items]        
Applicable margin on variable interest rate   1.125%    
Credit Agreement | Minimum | Base Rate Loans        
Debt Instrument [Line Items]        
Applicable margin on variable interest rate   0.125%    
Credit Agreement | Minimum | Revolving Credit Facility        
Debt Instrument [Line Items]        
Quarterly commitment fee on average daily unused amount of Credit Facilities   0.175%    
Credit Agreement | Maximum        
Debt Instrument [Line Items]        
Leverage ratio to be attained for payment of dividends 4.25      
Credit Agreement | Maximum | London Interbank Offered Rate (LIBOR)        
Debt Instrument [Line Items]        
Applicable margin on variable interest rate   2.00%    
Credit Agreement | Maximum | Base Rate Loans        
Debt Instrument [Line Items]        
Applicable margin on variable interest rate   1.00%    
Credit Agreement | Maximum | Revolving Credit Facility        
Debt Instrument [Line Items]        
Quarterly commitment fee on average daily unused amount of Credit Facilities   0.35%