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Fair Value Measurements - Recurring Fair Value Measures Of Assets And Liabilities (Details) - USD ($) $ in Thousands | Dec. 31, 2024 | Sep. 30, 2024
--- | --- | ---
Assets: |  |  |
Cash Equivalents – Money Market Mutual Funds | [1] | $ 41,745 | $ 29,238
Derivative Financial Instruments: |  |  |
Derivative Asset, Statement of Financial Position [Extensible Enumeration] |  | Fair Value of Derivative Financial Instruments | Fair Value of Derivative Financial Instruments
Total Assets | [1] | $ 90,962 | $ 154,040
Derivative Financial Instruments: |  |  |
Derivative Liability, Statement of Financial Position [Extensible Enumeration] |  | Fair Value of Derivative Financial Instruments | Fair Value of Derivative Financial Instruments
Total Liabilities | [1] | $ 20,893 | $ 4,735
Total Net Assets/(Liabilities) | [1] | 70,069 | 149,305
Over the Counter Swaps – Gas |  |  |
Derivative Financial Instruments: |  |  |
Derivative Asset | [1] | 12,717 | 58,811
Derivative Financial Instruments: |  |  |
Derivative Liability | [1] | 10,628 | 5,008
Over the Counter No Cost Collars – Gas |  |  |
Derivative Financial Instruments: |  |  |
Derivative Asset | [1] | 8,046 | 28,810
Derivative Financial Instruments: |  |  |
Derivative Liability | [1] | 8,886 | (273)
Contingent Consideration for Asset Sale |  |  |
Derivative Financial Instruments: |  |  |
Derivative Asset | [1] | 380 | 729
Foreign Currency Contracts |  |  |
Derivative Financial Instruments: |  |  |
Derivative Asset | [1] | (448) | (445)
Derivative Financial Instruments: |  |  |
Derivative Liability | [1] | 1,379 | 0
Balanced Equity Mutual Fund |  |  |
Derivative Financial Instruments: |  |  |
Other Investments | [1] | 12,241 | 19,523
Fixed Income Mutual Fund |  |  |
Derivative Financial Instruments: |  |  |
Other Investments | [1] | 16,281 | 17,374
Level 1 |  |  |
Assets: |  |  |
Cash Equivalents – Money Market Mutual Funds |  | 41,745 | 29,238
Derivative Financial Instruments: |  |  |
Total Assets |  | 70,267 | 66,135
Derivative Financial Instruments: |  |  |
Total Liabilities |  | 0 | 0
Total Net Assets/(Liabilities) |  | 70,267 | 66,135
Level 1 | Over the Counter Swaps – Gas |  |  |
Derivative Financial Instruments: |  |  |
Derivative Asset |  | 0 | 0
Derivative Financial Instruments: |  |  |
Derivative Liability |  | 0 | 0
Level 1 | Over the Counter No Cost Collars – Gas |  |  |
Derivative Financial Instruments: |  |  |
Derivative Asset |  | 0 | 0
Derivative Financial Instruments: |  |  |
Derivative Liability |  | 0 | 0
Level 1 | Contingent Consideration for Asset Sale |  |  |
Derivative Financial Instruments: |  |  |
Derivative Asset |  | 0 | 0
Level 1 | Foreign Currency Contracts |  |  |
Derivative Financial Instruments: |  |  |
Derivative Asset |  | 0 | 0
Derivative Financial Instruments: |  |  |
Derivative Liability |  | 0 | 0
Level 1 | Balanced Equity Mutual Fund |  |  |
Derivative Financial Instruments: |  |  |
Other Investments |  | 12,241 | 19,523
Level 1 | Fixed Income Mutual Fund |  |  |
Derivative Financial Instruments: |  |  |
Other Investments |  | 16,281 | 17,374
Level 2 |  |  |
Assets: |  |  |
Cash Equivalents – Money Market Mutual Funds |  | 0 | 0
Derivative Financial Instruments: |  |  |
Total Assets |  | 62,795 | 109,603
Derivative Financial Instruments: |  |  |
Total Liabilities |  | 62,993 | 26,433
Total Net Assets/(Liabilities) |  | (198) | 83,170
Level 2 | Over the Counter Swaps – Gas |  |  |
Derivative Financial Instruments: |  |  |
Derivative Asset |  | 43,937 | 76,009
Derivative Financial Instruments: |  |  |
Derivative Liability |  | 41,848 | 22,206
Level 2 | Over the Counter No Cost Collars – Gas |  |  |
Derivative Financial Instruments: |  |  |
Derivative Asset |  | 18,426 | 32,584
Derivative Financial Instruments: |  |  |
Derivative Liability |  | 19,266 | 3,501
Level 2 | Contingent Consideration for Asset Sale |  |  |
Derivative Financial Instruments: |  |  |
Derivative Asset |  | 380 | 729
Level 2 | Foreign Currency Contracts |  |  |
Derivative Financial Instruments: |  |  |
Derivative Asset |  | 52 | 281
Derivative Financial Instruments: |  |  |
Derivative Liability |  | 1,879 | 726
Level 2 | Balanced Equity Mutual Fund |  |  |
Derivative Financial Instruments: |  |  |
Other Investments |  | 0 | 0
Level 2 | Fixed Income Mutual Fund |  |  |
Derivative Financial Instruments: |  |  |
Other Investments |  | 0 | 0
Level 3 |  |  |
Assets: |  |  |
Cash Equivalents – Money Market Mutual Funds |  | 0 | 0
Derivative Financial Instruments: |  |  |
Total Assets |  | 0 | 0
Derivative Financial Instruments: |  |  |
Total Liabilities |  | 0 | 0
Total Net Assets/(Liabilities) |  | 0 | 0
Level 3 | Over the Counter Swaps – Gas |  |  |
Derivative Financial Instruments: |  |  |
Derivative Asset |  | 0 | 0
Derivative Financial Instruments: |  |  |
Derivative Liability |  | 0 | 0
Level 3 | Over the Counter No Cost Collars – Gas |  |  |
Derivative Financial Instruments: |  |  |
Derivative Asset |  | 0 | 0
Derivative Financial Instruments: |  |  |
Derivative Liability |  | 0 | 0
Level 3 | Contingent Consideration for Asset Sale |  |  |
Derivative Financial Instruments: |  |  |
Derivative Asset |  | 0 | 0
Level 3 | Foreign Currency Contracts |  |  |
Derivative Financial Instruments: |  |  |
Derivative Asset |  | 0 | 0
Derivative Financial Instruments: |  |  |
Derivative Liability |  | 0 | 0
Level 3 | Balanced Equity Mutual Fund |  |  |
Derivative Financial Instruments: |  |  |
Other Investments |  | 0 | 0
Level 3 | Fixed Income Mutual Fund |  |  |
Derivative Financial Instruments: |  |  |
Other Investments |  | 0 | 0
Netting Adjustments |  |  |
Assets: |  |  |
Cash Equivalents – Money Market Mutual Funds | [1] | 0 | 0
Derivative Financial Instruments: |  |  |
Total Assets | [1] | (42,100) | (21,698)
Derivative Financial Instruments: |  |  |
Total Liabilities | [1] | (42,100) | (21,698)
Total Net Assets/(Liabilities) | [1] | 0 | 0
Netting Adjustments | Over the Counter Swaps – Gas |  |  |
Derivative Financial Instruments: |  |  |
Derivative Asset | [1] | (31,220) | (17,198)
Derivative Financial Instruments: |  |  |
Derivative Liability | [1] | (31,220) | (17,198)
Netting Adjustments | Over the Counter No Cost Collars – Gas |  |  |
Derivative Financial Instruments: |  |  |
Derivative Asset | [1] | (10,380) | (3,774)
Derivative Financial Instruments: |  |  |
Derivative Liability | [1] | (10,380) | (3,774)
Netting Adjustments | Contingent Consideration for Asset Sale |  |  |
Derivative Financial Instruments: |  |  |
Derivative Asset | [1] | 0 | 0
Netting Adjustments | Foreign Currency Contracts |  |  |
Derivative Financial Instruments: |  |  |
Derivative Asset | [1] | (500) | (726)
Derivative Financial Instruments: |  |  |
Derivative Liability | [1] | (500) | (726)
Netting Adjustments | Balanced Equity Mutual Fund |  |  |
Derivative Financial Instruments: |  |  |
Other Investments | [1] | 0 | 0
Netting Adjustments | Fixed Income Mutual Fund |  |  |
Derivative Financial Instruments: |  |  |
Other Investments | [1] | $ 0 | $ 0
[1] | Netting Adjustments represent the impact of legally-enforceable master netting arrangements that allow the Company to net gain and loss positions held with the same counterparties. The net asset or net liability for each counterparty is recorded as an asset or liability on the Company’s balance sheet.

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