v3.26.3
Benefit Plans - Components of Net Periodic Benefit Costs (Details) - USD ($)
$ in Thousands
 12 Months Ended
Aug. 31, 2026
Aug. 31, 2025
Aug. 31, 2024
Other Benefits      
Components of net periodic benefit costs:      
Service cost $ 840 $ 844 $ 650
Interest cost 1,125 1,140 1,144
Expected return on assets 0 0 0
Prior service cost (credit) amortization (445) (445) (445)
Amortization of actuarial (gain) loss (1,197) (1,192) (1,616)
Periodic benefit costs, net 323 347 (267)
Qualified Pension Benefits | Pension Benefits      
Components of net periodic benefit costs:      
Service cost 45,390 43,727 37,391
Interest cost 36,106 34,898 35,928
Expected return on assets (50,316) (46,977) (47,860)
Prior service cost (credit) amortization (595) 199 178
Amortization of actuarial (gain) loss 16,498 12,815 1,796
Periodic benefit costs, net 47,083 44,662 27,433
Nonqualified Pension Benefits | Pension Benefits      
Components of net periodic benefit costs:      
Service cost 3,325 3,027 1,968
Interest cost 1,340 1,154 1,043
Expected return on assets 0 0 0
Prior service cost (credit) amortization (30) (47) (114)
Amortization of actuarial (gain) loss 982 799 380
Periodic benefit costs, net $ 5,617 $ 4,933 $ 3,277