v3.22.2.2
Long-term Debt and Finance Lease Obligations, Lines of Credit and Fair Value Disclosure - Narrative (Details) - USD ($)
3 Months Ended
Jul. 31, 2022
Apr. 30, 2022
Debt Instrument    
Fair value of long-term debt $ 1,509,000,000 $ 1,508,000,000
Finance lease obligations 73,890,000 74,234,000
Unsecured Revolving Credit Facility Due January 2024 | Revolving Credit Facility    
Debt Instrument    
Maximum borrowing capacity 450,000,000  
Fair value of amount outstanding $ 0 0
Unsecured Revolving Credit Facility Due January 2024 | Revolving Credit Facility | Federal Funds    
Debt Instrument    
Effective percentage 0.50%  
Unsecured Revolving Credit Facility Due January 2024 | Revolving Credit Facility | Alternate Base Rate    
Debt Instrument    
Effective percentage 1.00%  
Unsecured Revolving Credit Facility Due January 2024 | Minimum | Revolving Credit Facility    
Debt Instrument    
Facility fee percentage 0.20%  
Unsecured Revolving Credit Facility Due January 2024 | Minimum | Revolving Credit Facility | LIBOR    
Debt Instrument    
Effective percentage 0.50%  
Basis spread on variable rate 1.05%  
Unsecured Revolving Credit Facility Due January 2024 | Minimum | Revolving Credit Facility | Alternate Base Rate    
Debt Instrument    
Basis spread on variable rate 0.05%  
Unsecured Revolving Credit Facility Due January 2024 | Maximum | Revolving Credit Facility    
Debt Instrument    
Facility fee percentage 0.40%  
Unsecured Revolving Credit Facility Due January 2024 | Maximum | Revolving Credit Facility | LIBOR    
Debt Instrument    
Basis spread on variable rate 1.85%  
Unsecured Revolving Credit Facility Due January 2024 | Maximum | Revolving Credit Facility | Alternate Base Rate    
Debt Instrument    
Basis spread on variable rate 0.85%  
Unsecured Revolving Line of Credit | Line of Credit    
Debt Instrument    
Maximum borrowing capacity $ 25,000,000  
Fair value of amount outstanding 0 $ 0
Unsecured Revolving Line of Credit | Letter of Credit    
Debt Instrument    
Maximum borrowing capacity $ 5,924,000