v3.26.1
Summary of Significant Accounting Policies (Schedule of Reclassification Out of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Reclassification Adjustments out of Accumulated Other Comprehensive Income (Loss) [Line Items]        
Operating Revenues $ 537,497 $ 531,830 $ 2,047,377 $ 1,811,262
Total Before Income Tax 184,794 200,897 756,179 544,791
Income Tax Expense [1] (46,173) (51,079) (188,245) (133,629)
Net Income Available for Common Stock 138,621 149,818 567,934 411,162
Amount of Gain or (Loss) Reclassified from Accumulated Other Comprehensive Income (Loss)        
Reclassification Adjustments out of Accumulated Other Comprehensive Income (Loss) [Line Items]        
Total Before Income Tax 58,170 2,258 22,684 23,601
Income Tax Expense (15,575) (608) (6,074) (6,352)
Net Income Available for Common Stock 42,595 1,650 16,610 17,249
Amount of Gain or (Loss) Reclassified from Accumulated Other Comprehensive Income (Loss) | Gains and Losses on Derivative Financial Instruments | Commodity Contracts        
Reclassification Adjustments out of Accumulated Other Comprehensive Income (Loss) [Line Items]        
Operating Revenues 58,258 2,515 22,959 24,409
Amount of Gain or (Loss) Reclassified from Accumulated Other Comprehensive Income (Loss) | Gains and Losses on Derivative Financial Instruments | Foreign Currency Contracts        
Reclassification Adjustments out of Accumulated Other Comprehensive Income (Loss) [Line Items]        
Operating Revenues $ (88) $ (257) $ (275) $ (808)
[1] The Company considers this line to be a significant expense.