Debt Instrument, Number of Instruments

No definition available.

Name:	rgco_DebtInstrumentNumberofInstruments
Namespace Prefix:	rgco_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

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

- Definition

Fixed interest rate related to the interest rate derivative.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeFixedInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

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

- Definition

Number of interest rate derivative instruments held by the entity at the reporting date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5579245-113959

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5580258-113959

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Details

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

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_UnsecuredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=rgco_Unsecuredtermnotespayableat30dayLIBORplus0.90dueNovember12021Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=rgco_Unsecuredtermnotespayableat30dayLIBORplus1.15dueJune122026Member
Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

Name:	us-gaap_DebtInstrumentAxis=rgco_Unsecuredtermnotespayableat30dayLIBORplus1.20dueJune12024Member
Namespace Prefix:
Data Type:	na
Balance Type:
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Derivatives and Hedging (Details)	Jun. 30, 2020 USD ($) debt_instrument instrument_held	Jun. 13, 2019 USD ($)	Jun. 12, 2019 USD ($) instrument_held
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of interest rate swaps associated with note(s) \| instrument_held	3
Roanoke Gas Company [Member] \| Unsecured Term Notes [Member] \| Unsecured Term Notes Payable, at 30-day LIBOR plus 0.90%, due November 1, 2021 [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Debt instrument, borrowing amount	$ 7,000,000
Effective interest rate	2.30%
RGC Midstream LLC [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of interest rate swaps associated with note(s) \| instrument_held	2
Debt instrument, number of instruments	2		2
RGC Midstream LLC [Member] \| Unsecured Term Notes [Member] \| Unsecured Term Notes Payable, at 30-day LIBOR plus 1.15%, due June 12, 2026 [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Debt instrument, borrowing amount	$ 14,000,000		$ 14,000,000
Effective interest rate	3.24%		3.24%
RGC Midstream LLC [Member] \| Unsecured Term Notes [Member] \| Unsecured Term Notes Payable, at 30-day LIBOR plus 1.20%, due June 1, 2024 [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Debt instrument, borrowing amount	$ 10,000,000	$ 10,000,000
Effective interest rate	3.14%	3.14%