Percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

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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

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

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

+ Details

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

- Definition

The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Carrying value as of the balance sheet date of uncollateralized debt obligation (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion.

+ References

+ Details

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

Long-Term Debt (Schedule of Long-Term Debt) (Details) - USD ($)			6 Months Ended
	Mar. 26, 2020	Dec. 23, 2019	Mar. 31, 2020	Dec. 06, 2019	Sep. 30, 2019
Debt Instrument [Line Items]
Notes payable			$ 112,575,200		$ 95,512,200
Principal			112,575,200		103,684,673
Unamortized Debt Issuance Costs			343,551		313,315
Notes Payable [Member]
Debt Instrument [Line Items]
Notes payable			112,575,200		95,512,200
Unamortized Debt Issuance Costs			343,551		313,315
Roanoke Gas Company [Member] \| Unsecured Senior Notes [Member] \| Unsecured Senior Notes Payable, at 4.26%, due on September 18, 2034 [Member]
Debt Instrument [Line Items]
Notes payable			30,500,000		30,500,000
Unamortized Debt Issuance Costs			$ 139,984		144,811
Stated percentage rate			4.26%
Roanoke Gas Company [Member] \| Unsecured Term Notes [Member] \| Unsecured Term Notes Payable, at 30-day LIBOR plus 0.90%, due November 1, 2021 [Member]
Debt Instrument [Line Items]
Notes payable			$ 7,000,000		7,000,000
Unamortized Debt Issuance Costs			$ 5,280		6,948
Roanoke Gas Company [Member] \| Unsecured Term Notes [Member] \| Unsecured Term Notes Payable, at 30-day LIBOR plus 0.90%, due November 1, 2021 [Member] \| 30-day LIBOR [Member]
Debt Instrument [Line Items]
Variable rate basis points (as a percent)			0.90%
Roanoke Gas Company [Member] \| Unsecured Term Notes [Member] \| Unsecured Term Notes Payable, at 3.58%, due October 2, 2027 [Member]
Debt Instrument [Line Items]
Notes payable			$ 8,000,000		8,000,000
Unamortized Debt Issuance Costs			$ 36,120		38,528
Stated percentage rate			3.58%
Roanoke Gas Company [Member] \| Unsecured Term Notes [Member] \| Unsecured Term Notes Payable, at 4.41%, due March 28, 2031 [Member]
Debt Instrument [Line Items]
Notes payable			$ 10,000,000		10,000,000
Unamortized Debt Issuance Costs			$ 34,459		36,272
Stated percentage rate			4.41%
Roanoke Gas Company [Member] \| Unsecured Term Notes [Member] \| Unsecured Term Notes Payable, at 3.60%, due December 6, 2029 [Member]
Debt Instrument [Line Items]
Notes payable			$ 10,000,000		0
Unamortized Debt Issuance Costs			$ 34,346		0
Stated percentage rate			3.60%	3.60%
Roanoke Gas Company [Member] \| Line of Credit [Member] \| Line of Credit, at 30-day LIBOR plus 1.00%, due March 31, 2022 [Member]
Debt Instrument [Line Items]
Line-of-credit			$ 0		8,172,473
Unamortized Debt Issuance Costs			$ 0		0
Roanoke Gas Company [Member] \| Line of Credit [Member] \| Line of Credit, at 30-day LIBOR plus 1.00%, due March 31, 2022 [Member] \| 30-day LIBOR [Member]
Debt Instrument [Line Items]
Variable rate basis points (as a percent)	1.00%		1.00%
RGC Midstream LLC [Member] \| Unsecured Term Notes [Member] \| Unsecured Term Notes Payable, at 30-day LIBOR plus 1.35%, due December 29, 2022 [Member]
Debt Instrument [Line Items]
Notes payable			$ 23,075,200		16,012,200
Unamortized Debt Issuance Costs			$ 68,492		59,504
RGC Midstream LLC [Member] \| Unsecured Term Notes [Member] \| Unsecured Term Notes Payable, at 30-day LIBOR plus 1.35%, due December 29, 2022 [Member] \| 30-day LIBOR [Member]
Debt Instrument [Line Items]
Variable rate basis points (as a percent)		1.35%	1.35%
RGC Midstream LLC [Member] \| Unsecured Term Notes [Member] \| Unsecured Term Notes Payable, at 30-day LIBOR plus 1.15%, due June 12, 2026 [Member]
Debt Instrument [Line Items]
Notes payable			$ 14,000,000		14,000,000
Unamortized Debt Issuance Costs			$ 15,048		16,252
RGC Midstream LLC [Member] \| Unsecured Term Notes [Member] \| Unsecured Term Notes Payable, at 30-day LIBOR plus 1.15%, due June 12, 2026 [Member] \| 30-day LIBOR [Member]
Debt Instrument [Line Items]
Variable rate basis points (as a percent)			1.15%
RGC Midstream LLC [Member] \| Unsecured Term Notes [Member] \| Unsecured Term Notes Payable, at 30-day LIBOR plus 1.20%, due June 1, 2024 [Member]
Debt Instrument [Line Items]
Notes payable			$ 10,000,000		10,000,000
Unamortized Debt Issuance Costs			$ 9,822		$ 11,000
RGC Midstream LLC [Member] \| Unsecured Term Notes [Member] \| Unsecured Term Notes Payable, at 30-day LIBOR plus 1.20%, due June 1, 2024 [Member] \| 30-day LIBOR [Member]
Debt Instrument [Line Items]
Variable rate basis points (as a percent)			1.20%