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Financial Instruments (Tables) | 12 Months Ended
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Sep. 30, 2025
Derivative Instruments and Hedging Activities Disclosure [Abstract] |
Schedule of Financial Instruments on the Balance Sheet | The following tables present the fair value and balance sheet classification of our financial instruments as of September 30, 2025 and 2024. As discussed in Note 2 to the consolidated financial statements, we report our financial instruments as risk management assets and liabilities, each of which is classified as current or noncurrent based upon the anticipated settlement date of the underlying financial instrument. The gross amounts of recognized assets and liabilities are netted within our consolidated balance sheets to the extent that we have netting arrangements with the counterparties. However, as of September 30, 2025 and 2024, no gross amounts and no cash collateral were netted within our consolidated balance sheet.
| Balance Sheet Location |  | Assets |  | Liabilities
|  |  | (In thousands)
September 30, 2025 |  |  |  |  |
Not Designated As Hedges: |  |  |  |  |
Commodity contracts | Other current assets / Other current liabilities |  | $ | 5,303 |  |  | $ | (6,339) |
Commodity contracts | Deferred charges and other assets / Deferred credits and other liabilities |  | 4,594 |  |  | (146) |
Total |  |  | 9,897 |  |  | (6,485) |
Gross / Net Financial Instruments |  |  | $ | 9,897 |  |  | $ | (6,485) |
| Balance Sheet Location |  | Assets |  | Liabilities
|  |  | (In thousands)
September 30, 2024 |  |  |  |  |
Designated As Hedges: |  |  |  |  |
Interest rate contracts | Deferred charges and other assets / Deferred credits and other liabilities |  | $ | 91,981 |  |  | $ | — |
Total |  |  | 91,981 |  |  | — |
Not Designated As Hedges: |  |  |  |  |
Commodity contracts | Other current assets / Other current liabilities |  | 2,091 |  |  | (7,324) |
Commodity contracts | Deferred charges and other assets / Deferred credits and other liabilities |  | 2,216 |  |  | (313) |
Total |  |  | 4,307 |  |  | (7,637) |
Gross / Net Financial Instruments |  |  | $ | 96,288 |  |  | $ | (7,637) |
Schedule of Cash Flow Hedges Included in Accumulated Other Comprehensive Income (Loss) | The following table summarizes the gains and losses arising from hedging transactions that were recognized as a component of other comprehensive income, net of taxes, for the years ended September 30, 2025 and 2024.
| Fiscal Year Ended September 30
| 2025 |  | 2024
| (In thousands)
Increase (decrease) in fair value: |  |  |
Interest rate agreements | $ | 24,208 |  |  | $ | (43,430) |
Recognition of gains in earnings due to settlements: |  |  |
Interest rate agreements | (14,904) |  |  | (9,965) |
Total other comprehensive income (loss) from hedging, net of tax | $ | 9,304 |  |  | $ | (53,395) |
Schedule of Expected Recognition in Earnings of the Deferred Net Gains Recorded in AOCI | The following amounts, net of deferred taxes, represent the expected recognition in earnings of the deferred net gains recorded in AOCI associated with our interest rate agreements, based upon the fair values of these agreements at the date of settlement. The remaining amortization periods for these settled amounts extend through fiscal 2056.
|  | Interest Rate Agreements
|  | (In thousands)
2026 |  | $ | 19,093 |
2027 |  | 19,093 |
2028 |  | 19,093 |
2029 |  | 19,093 |
2030 |  | 19,093 |
Thereafter |  | 379,341 |
Total |  | $ | 474,806 |

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