XML 115 R91.htm IDEA: XBRL DOCUMENT
v3.25.3

Note 14 - Commitments and Contingencies (Details Textual) | 12 Months Ended
--- | ---
Sep. 30, 2025 USD ($) BTU $ / item | Sep. 30, 2024 USD ($)
Asset Management Contract Term (Year) | 3 years |
Energy Purchase Obligation Due In Next Twelve Months (British Thermal Unit) | BTU | 2,071,061 |
Energy Purchase Obligation Due In Third Year (British Thermal Unit) | BTU | 295,721 |
Purchase Commitment Minimum Volume Required | $ 1,360,000 |
Franchise Agreement Term (Year) |  | 20 years
Franchise Fee Annual Increase |  | 3.00%
Franchise Fee Total Cost Through End of Agreement | $ 1,690,215 |
Energy Purchase Obligation Due In Second Year (British Thermal Unit) | BTU | 2,071,061 |
Natural Gas Pipeline And Storage Capacity [Member] |  |
Cost of Product and Service Sold | $ 40,843,000 | $ 30,880,000
Natural Gas Pipeline And Storage Capacity [Member] | Asset Management Arrangement [Member] |  |
Cost of Product and Service Sold | $ 4,180,000 | $ 1,048,000
Minimum [Member] |  |
Purchase Commitment Purchase Price Per Energy Volume (in USD per Per Share) | $ / item | 2.92 |
Maximum [Member] |  |
Purchase Commitment Purchase Price Per Energy Volume (in USD per Per Share) | $ / item | 4.13 |

X
- Definition Represents asset management contract term. + References No definition available. + Details
Name: | rgco_AssetManagementContractTerm
Namespace Prefix: | rgco_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents energy purchase obligation due in next twelve months. + References No definition available. + Details
Name: | rgco_EnergyPurchaseObligationDueInNextTwelveMonths
Namespace Prefix: | rgco_
Data Type: | dtr-types:energyItemType
Balance Type: | na
Period Type: | instant

X
- Definition Represents energy purchase obligation due in second year. + References No definition available. + Details
Name: | rgco_EnergyPurchaseObligationDueInSecondYear
Namespace Prefix: | rgco_
Data Type: | dtr-types:energyItemType
Balance Type: | na
Period Type: | instant

X
- Definition Represents energy purchase obligation due in third year. + References No definition available. + Details
Name: | rgco_EnergyPurchaseObligationDueInThirdYear
Namespace Prefix: | rgco_
Data Type: | dtr-types:energyItemType
Balance Type: | na
Period Type: | instant

X
- Definition Represents franchise agreement term. + References No definition available. + Details
Name: | rgco_FranchiseAgreementTerm
Namespace Prefix: | rgco_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents franchise fee annual increase. + References No definition available. + Details
Name: | rgco_FranchiseFeeAnnualIncrease
Namespace Prefix: | rgco_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents franchise fee total cost through end of agreement. + References No definition available. + Details
Name: | rgco_FranchiseFeeTotalCostThroughEndOfAgreement
Namespace Prefix: | rgco_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Represents purchase commitment minimum volume required. + References No definition available. + Details
Name: | rgco_PurchaseCommitmentMinimumVolumeRequired
Namespace Prefix: | rgco_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition represents purchase commitment purchase price per energy volume. + References No definition available. + Details
Name: | rgco_PurchaseCommitmentPurchasePricePerEnergyVolume
Namespace Prefix: | rgco_
Data Type: | srt-types:perUnitItemType
Balance Type: | na
Period Type: | instant

X
- Definition The aggregate costs related to goods produced and sold and services rendered by an entity during the reporting period. This excludes costs incurred during the reporting period related to financial services rendered and other revenue generating activities. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 4A -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480434/815-10-50-4A Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 220 -SubTopic 40 -Name Accounting Standards Codification -Section 55 -Paragraph 11 -Publisher FASB -URI https://asc.fasb.org/1943274/2147476153/220-40-55-11 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 220 -SubTopic 40 -Name Accounting Standards Codification -Section 55 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org/1943274/2147476153/220-40-55-4 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 220 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03(2)(d)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2 Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 220 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03(2)(a)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 924 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 11.L) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479941/924-10-S99-1 Reference 7: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 220 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147476148/220-40-50-6 + Details
Name: | us-gaap_CostOfGoodsAndServicesSold
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | srt_ProductOrServiceAxis=rgco_NaturalGasPipelineAndStorageCapacityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionAxis=us-gaap_AssetManagementArrangementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |