v3.25.2
Postretirement Benefits - Additional Information (Detail)
$ in Millions
May 31, 2025
USD ($)
Schedule of Pension and Other Postretirement Benefits Expected Benefit Payments [Line Items]  
Estimated benefits payable in the first year $ 75.3
Estimated benefits payable in the second year 77.5
Estimated benefits payable in the third year 81.5
Estimated benefits payable in the fourth year 89.2
Estimated benefits payable in the fifth year 89.1
Estimated benefits payable in the years thereafter 448.3
Postretirement Benefits  
Schedule of Pension and Other Postretirement Benefits Expected Benefit Payments [Line Items]  
Estimated benefits payable in the years thereafter 7.8
Minimum | Postretirement Benefits  
Schedule of Pension and Other Postretirement Benefits Expected Benefit Payments [Line Items]  
Estimated benefits payable in the first year 1.2
Estimated benefits payable in the second year 1.2
Estimated benefits payable in the third year 1.2
Estimated benefits payable in the fourth year 1.2
Estimated benefits payable in the fifth year 1.2
Maximum | Postretirement Benefits  
Schedule of Pension and Other Postretirement Benefits Expected Benefit Payments [Line Items]  
Estimated benefits payable in the first year 1.7
Estimated benefits payable in the second year 1.7
Estimated benefits payable in the third year 1.7
Estimated benefits payable in the fourth year 1.7
Estimated benefits payable in the fifth year $ 1.7