Summary of Significant Accounting Policies (Schedule of Components of Other Current Assets) (Details) - USD ($) $ in Thousands |
Jun. 30, 2026 |
Sep. 30, 2025 |
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| Summary Of Significant Accounting Policies [Line Items] | ||
| Prepayments | $ 23,159 | $ 16,477 |
| Prepaid Property and Other Taxes | 10,586 | 13,920 |
| Regulatory Assets | 33,915 | 35,362 |
| Other Current Assets | 67,660 | 80,759 |
| Federal Income Taxes Receivable | ||
| Summary Of Significant Accounting Policies [Line Items] | ||
| Income Taxes Receivable | 0 | 14,511 |
| State Income Taxes Receivable | ||
| Summary Of Significant Accounting Policies [Line Items] | ||
| Income Taxes Receivable | $ 0 | $ 489 |
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- Definition Summary Of Significant Accounting Policies [Line Items] No definition available.
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- Definition Carrying amount as of the balance sheet date of income taxes previously overpaid to tax authorities (such as U.S. Federal, state and local tax authorities) representing refunds of overpayments or recoveries based on agreed-upon resolutions of disputes. Also called income tax refund receivable. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Amount of current assets classified as other. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of asset related to consideration paid in advance for other costs that provide economic benefits within a future period of one year or the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Amount of asset related to consideration paid in advance for income and other taxes that provide economic benefits within a future period of one year or the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Carrying amount as of the balance sheet date of capitalized costs of regulated entities that are expected to be recovered through revenue sources within one year or the normal operating cycle, if longer. Such costs are capitalized if they meet both of the following criteria: a. It is probable that future revenue in an amount at least equal to the capitalized cost will result from inclusion of that cost in allowable costs for rate-making purposes. b. Based on available evidence, the future revenue will be provided to permit recovery of the previously incurred cost rather than to provide for expected levels of similar future costs. If the revenue will be provided through an automatic rate-adjustment clause, this criterion requires that the regulator's intent clearly be to permit recovery of the previously incurred cost. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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