Period of time over which the regulatory liability will be refunded.

No definition available.

Name:	rgco_RegulatoryLiabilityRefundPeriod
Namespace Prefix:	rgco_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Discloses the amount of any reduction to the carrying amounts of regulated assets that result from impairment (for example, rate actions of a regulator).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 340
-Section 35
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6066304&loc=d3e44026-110379

+ Details

Name:	us-gaap_AmountOfImpairmentToCarryingAmountOfRegulatoryAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of increase (decrease) in revenue recognized for cumulative catch-up adjustment from change in estimate of transaction price which (increases) decreases obligation to transfer good or service to customer for which consideration from customer has been received or is due. Includes, but is not limited to, change in assessment of whether estimate of variable consideration is constrained.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130551-203045

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of public utility's approved rate increase (decrease) by regulatory agency.

+ References

No definition available.

+ Details

Name:	us-gaap_PublicUtilitiesApprovedRateIncreaseDecreaseAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_RegulatoryLiabilitiesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	dei_LegalEntityAxis=rgco_RoanokeGasCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PublicUtilitiesRegulatoryProceedingAxis=rgco_GeneralRateCaseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RegulatoryAgencyAxis=rgco_VirginiaStateCorporateCommissionSCCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Rates and Regulatory Matters (Details) - Roanoke Gas Company [Member] - USD ($)		1 Months Ended	6 Months Ended
	Jan. 24, 2020	Mar. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Regulatory Liabilities [Line Items]
Additional write down of ESAC regulatory assets				$ 317,191
Rate refund paid		$ (3,800,000)
Regulatory liability, refund period (in years)			28 years
General Rate Case [Member] \| Virginia State Corporate Commission (SCC) [Member]
Regulatory Liabilities [Line Items]
Approved non-gas rate increase	$ 7,250,000