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v3.25.3

Note 1 - Summary of Significant Accounting Policies (Details Textual) | 12 Months Ended |  |  |
--- | --- | --- | --- | ---
Sep. 30, 2025 USD ($) shares | Sep. 30, 2024 USD ($) shares | Sep. 24, 2021 USD ($) | Aug. 20, 2021 USD ($) | Jun. 30, 2019
Number of Major Customers | 62,500 |  |  |  |
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided | $ 5,897,920 |  |  |  |
Regulatory Utility Assets Provision, Period (Year) | 5 years |  |  |  |
Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service | 3.26% | 3.26% |  |  |
Unbilled Receivables, Current | $ 1,373,512 | $ 1,294,798 |  |  |
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares) | shares | 1,926 | 2,542 |  |  |
Number of Pipelines | 3 |  |  |  |
Number of States in which Entity Operates | 2 |  |  |  |
Unsecured Term Notes Payable, at 30-day SOFR Average 1.20% Due August 20, 2026 [Member] |  |  |  |  |
Debt Instrument, Face Amount |  |  |  | $ 15,000,000 |
Subsequent Letter of Commitment to Refinance [Member] |  |  |  |  |
Debt Instrument, Face Amount | $ 53,600,000 |  |  |  |
Roanoke Gas Company [Member] | Unsecured Debt [Member] | Unsecured Term Notes Payable, at 30-day SOFR Average 1.20% Due August 20, 2026 [Member] |  |  |  |  |
Debt Instrument, Face Amount |  |  |  | $ 15,000,000 |
Derivative, Fixed Interest Rate |  |  |  | 2.00% |
Roanoke Gas Company [Member] | Unsecured Debt [Member] | Unsecured Term Notes Payable, at 30-day LIBOR Plus 100 Basis Points, Due October 1, 2028 [Member] |  |  |  |  |
Debt Instrument, Face Amount |  |  | $ 10,000,000 |  |
Derivative, Fixed Interest Rate |  |  | 2.49% |  |
RGC Midstream LLC [Member] | Unsecured Term Notes [Member] | Variable Rate Term Note 1 [Member] |  |  |  |  |
Debt Instrument, Face Amount | 14,000,000 |  |  |  |
Derivative, Fixed Interest Rate |  |  |  |  | 3.24%
RGC Midstream LLC [Member] | Unsecured Term Notes [Member] | Variable Rate Term Note 2 [Member] |  |  |  |  |
Debt Instrument, Face Amount | 4,000,000 |  |  |  |
Derivative, Fixed Interest Rate |  |  |  |  | 2.443%
RGC Midstream LLC [Member] | Unsecured Term Notes [Member] | Variable Rate Term Note 3 [Member] |  |  |  |  |
Debt Instrument, Face Amount | 20,600,000 |  |  |  |
Derivative, Fixed Interest Rate |  |  |  |  | 5.061%
RGC Midstream LLC [Member] | Unsecured Term Notes [Member] | Variable Rate Term Note 4 [Member] |  |  |  |  |
Debt Instrument, Face Amount | 15,000,000 |  |  |  |
Derivative, Fixed Interest Rate |  |  |  |  | 5.061%
RGC Midstream LLC [Member] | Unsecured Term Notes [Member] | Subsequent Letter of Commitment to Refinance [Member] |  |  |  |  |
Debt Instrument, Face Amount | $ 53,600,000 |  |  |  |
Energy Related Derivative [Member] |  |  |  |  |
Derivative, Number of Instruments Held | 0 | 0 |  |  |
Interest Rate Swap [Member] |  |  |  |  |
Derivative, Number of Instruments Held | 6 |  |  |  |
Interest Rate Swap [Member] | Roanoke Gas Company [Member] |  |  |  |  |
Derivative, Number of Instruments Held | 2 |  |  |  |
Interest Rate Swap [Member] | RGC Midstream LLC [Member] |  |  |  |  |
Derivative, Number of Instruments Held | 4 |  |  |  |
Customer Concentration Risk [Member] | Revenue from Contract with Customer Benchmark [Member] |  |  |  |  |
Number of Major Customers | 0 | 0 |  |  |
Customer Concentration Risk [Member] | Revenue from Contract with Customer Benchmark [Member] | Minimum [Member] |  |  |  |  |
Concentration Risk, Percentage | 5.00% | 5.00% |  |  |
Operations and Maintenance Expense [Member] |  |  |  |  |
Amortization of Regulatory Asset | $ 101,141 | $ 116,085 |  |  |
Other Income [Member] |  |  |  |  |
Amortization of Regulatory Asset | 131,673 | 211,863 |  |  |
Interest Expense [Member] |  |  |  |  |
Amortization of Regulatory Asset | $ 114,187 | $ 114,187 |  |  |

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