Statement of Stockholders' Equity [Abstract]
Dividends declared per share (in dollars per share)
Common Stock, Dividends, Per Share, Declared
Common stock issued (in shares)
Stock Issued During Period, Shares, New Issues
Debt Disclosure [Abstract]
Schedule of Long-Term Debt
Schedule of Long-term Debt Instruments [Table Text Block]
Long-Term Debt
Long-term Debt [Text Block]
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue
Disaggregation of Revenue [Table Text Block]
Schedule of Customer Accounts Receivable
Contract with Customer, Asset and Liability [Table Text Block]
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies
Commitments and Contingencies Disclosure [Text Block]
Statement [Table]
Statement [Table]
Equity Components [Axis]
Equity Components [Axis]
Equity Component [Domain]
Equity Component [Domain]
Common Stock
Common Stock [Member]
Capital in Excess of Par Value
Additional Paid-in Capital [Member]
Retained Earnings
Retained Earnings [Member]
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent [Member]
Statement [Line Items]
Statement [Line Items]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period
Stockholders' Equity Attributable to Parent
Net income
Net Income (Loss) Attributable to Parent
Other comprehensive income (loss)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent
Cash dividends declared
Dividends, Common Stock, Cash
Issuance of common stock
Stock Issued During Period, Value, New Issues
Balance at end of period
Statement of Comprehensive Income [Abstract]
NET INCOME
Other comprehensive income (loss), net of tax:
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract]
Interest rate swaps
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax, Parent
Interest rate swaps
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax
Defined benefit plans
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent
Other comprehensive income (loss), net of tax
COMPREHENSIVE INCOME
Comprehensive Income (Loss), Net of Tax, Attributable to Parent
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation
Basis of Accounting, Policy [Policy Text Block]
Recently Issued or Adopted Accounting Standards
New Accounting Pronouncements, Policy [Policy Text Block]
Number of pipelines serving Roanoke Gas
Number Of Pipelines
Number Of Pipelines
Income Tax Disclosure [Abstract]
Income Taxes
Income Tax Disclosure [Text Block]
Equity Method Investments and Joint Ventures [Abstract]
Schedule of Other Investments
Investment [Table Text Block]
Summary Unaudited Financial Statements - Equity Method Investment
Equity Method Investments [Table Text Block]
Equity [Abstract]
Other Comprehensive Income
Comprehensive Income (Loss) Note [Text Block]
Schedule of Long-term Debt Instruments [Table]
Schedule of Long-term Debt Instruments [Table]
Legal Entity [Axis]
Legal Entity [Axis]
Entity [Domain]
Entity [Domain]
Roanoke Gas Company [Member]
Roanoke Gas Company [Member]
Roanoke Gas Company [Member]
RGC Midstream LLC [Member]
RGC Midstream, LLC [Member]
RGC Midstream, LLC [Member]
Long-term Debt, Type [Axis]
Long-term Debt, Type [Axis]
Long-term Debt, Type [Domain]
Long-term Debt, Type [Domain]
Unsecured Senior Notes [Member]
Senior Notes [Member]
Unsecured Term Notes [Member]
Unsecured Debt [Member]
Notes Payable [Member]
Notes Payable, Other Payables [Member]
Line of Credit [Member]
Line of Credit [Member]
Debt Instrument [Axis]
Debt Instrument [Axis]
Debt Instrument, Name [Domain]
Debt Instrument, Name [Domain]
Unsecured Senior Notes Payable, at 4.26%, due on September 18, 2034 [Member]
Unsecured Senior Notes, at 4.26%, due on September 18, 2034 [Member]
Unsecured Senior Notes, at 4.26%, due on September 18, 2034 [Member]
Unsecured Term Notes Payable, at 30-day LIBOR plus 0.90%, due November 1, 2021 [Member]
Unsecured term notes payable, at 30-day LIBOR plus 0.90%, due November 1, 2021 [Member]
Unsecured term notes payable, at 30-day LIBOR plus 0.90%, due November 1, 2021 [Member]
Unsecured Term Notes Payable, at 3.58%, due October 2, 2027 [Member]
Unsecured term notes payable, at 3.58%, due October 2, 2027 [Member]
Unsecured term notes payable, at 3.58%, due October 2, 2027 [Member]
Unsecured Term Notes Payable, at 4.41%, due March 28, 2031 [Member]
Unsecured term notes payable, at 4.41%, due March 28, 2031 [Member]
Unsecured term notes payable, at 4.41%, due March 28, 2031.
Unsecured Term Notes Payable, at 3.60%, due December 6, 2029 [Member]
Unsecured Term Notes Payable, at 3.60%, due December 6, 2029 [Member]
Unsecured Term Notes Payable, at 3.60%, due December 6, 2029 [Member]
Unsecured Term Notes Payable, at 30-day LIBOR plus 1.35%, due December 29, 2022 [Member]
Unsecured term notes payable, at 30-day LIBOR plus 1.35%, due December 29, 2022 [Member]
Unsecured term notes payable, at 30-day LIBOR plus 1.35%, due December 29, 2022 [Member]
Unsecured Term Notes Payable, at 30-day LIBOR plus 1.15%, due June 12, 2026 [Member]
Unsecured term notes payable, at 30-day LIBOR plus 1.15%, due June 12, 2026 [Member]
Unsecured term notes payable, at 30-day LIBOR plus 1.15%, due June 12, 2026 [Member]
Unsecured Term Notes Payable, at 30-day LIBOR plus 1.20%, due June 1, 2024 [Member]
Unsecured term notes payable, at 30-day LIBOR plus 1.20%, due June 1, 2024 [Member]
Unsecured term notes payable, at 30-day LIBOR plus 1.20%, due June 1, 2024 [Member]
Line of Credit, at 30-day LIBOR plus 1.00%, due March 31, 2022 [Member]
Line of Credit, at 30-day LIBOR plus 1.00%, due March 31, 2022 [Member]
Line of Credit, at 30-day LIBOR plus 1.00%, due March 31, 2022 [Member]
Variable Rate [Axis]
Variable Rate [Axis]
Variable Rate [Domain]
Variable Rate [Domain]
30-day LIBOR [Member]
London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Debt Instrument [Line Items]
Notes payable
Unsecured Long-term Debt, Noncurrent
Line-of-credit
Long-term Line of Credit
Principal
Long-term Debt, Gross
Unamortized Debt Issuance Costs
Unamortized Debt Issuance Expense
Stated percentage rate
Debt Instrument, Interest Rate, Stated Percentage
Variable rate basis points (as a percent)
Debt Instrument, Basis Spread on Variable Rate
Earnings Per Share [Abstract]
Schedule of Basic and Diluted Earnings Per Share Reconciliation
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]
New Accounting Pronouncements or Change in Accounting Principle [Table]
New Accounting Pronouncements or Change in Accounting Principle [Table]
Adjustments for New Accounting Pronouncements [Axis]
Adjustments for New Accounting Pronouncements [Axis]
Type of Adoption [Domain]
Type of Adoption [Domain]
ASU 2016-02
Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of operating leases
Lessee, Operating Lease, Number Of Contracts
Number of operating leases
Quarterly operating lease obligation
Lessee, Operating Lease, Contractual Quarterly Payments
Amount of contractual obligation due quarterly, including but not limited to, long-term debt, capital lease obligations, operating lease obligations, purchase obligations, and other commitments.
Basis of Presentation
Significant Accounting Policies [Text Block]
Disaggregation of Revenue [Table]
Disaggregation of Revenue [Table]
Regulation Status [Axis]
Regulation Status [Axis]
Regulated and Unregulated Operation [Domain]
Regulated and Unregulated Operation [Domain]
Gas Utility [Member]
Regulated Operation [Member]
Non Utility [Member]
Unregulated Operation [Member]
Product and Service [Axis]
Product and Service [Axis]
Product and Service [Domain]
Product and Service [Domain]
Natural Gas [Member]
Oil and Gas [Member]
Other [Member]
Product and Service, Other [Member]
Customer [Axis]
Customer [Axis]
Customer [Domain]
Customer [Domain]
Residential [Member]
Residential Customers [Member]
Residential Customers [Member]
Commercial [Member]
Commercial Customers [Member]
Commercial Customers [Member]
Industrial and Transportation [Member]
Industrial And Transportation Customers [Member]
Industrial And Transportation Customers [Member]
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue [Line Items]
Total contracts with customers
Revenue from Contract with Customer, Excluding Assessed Tax
Revenue reductions (TCJA)
Tax Cuts And Jobs Act Of 2017 Effect On Revenues From Contract With Customer
Tax Cuts And Jobs Act Of 2017 Effect On Revenues From Contract With Customer
Alternative Revenue Programs
Revenue From Alternative Revenue Programs
Revenue From Alternative Revenue Programs
Operating revenues
Revenues
Regulatory Assets and Liabilities [Abstract]
Regulatory Assets and Liabilities [Abstract]
Remaining amount of regulatory assets that did not earn a return during the recovery period
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided
Other Investments
Equity Method Investments and Joint Ventures Disclosure [Text Block]
Regulated Operations [Abstract]
Rates and Regulatory Matters
Public Utilities Disclosure [Text Block]
Retirement Benefits [Abstract]
Schedule of Defined Benefit Plans Disclosures [Table]
Schedule of Defined Benefit Plans Disclosures [Table]
Retirement Plan Type [Axis]
Retirement Plan Type [Axis]
Retirement Plan Type [Domain]
Retirement Plan Type [Domain]
Defined Benefit Pension Plan [Member]
Pension Plan [Member]
Postretirement Medical Plan [Member]
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Disclosure [Line Items]
Fiscal Year-to-Date Contributions
Defined Benefit Plan, Plan Assets, Contributions by Employer
Remaining Fiscal Year Contributions
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year
Summary of Other Comprehensive Income and Loss
Comprehensive Income (Loss) [Table Text Block]
Reconciliation of Other Accumulated Other Comprehensive Income (Loss)
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]
Pension Plan [Member]
Postretirement Plan [Member]
Service cost
Defined Benefit Plan, Service Cost
Interest cost
Defined Benefit Plan, Interest Cost
Expected return on plan assets
Defined Benefit Plan, Expected Return (Loss) on Plan Assets
Recognized loss
Defined Benefit Plan, Amortization of Gain (Loss)
Net periodic/postretirement pension/benefit cost
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)
Employee Benefit Plans
Pension and Other Postretirement Benefits Disclosure [Text Block]
Segment Reporting [Abstract]
Segment Information
Segment Reporting Disclosure [Text Block]
Schedule of Equity Method Investments [Table]
Schedule of Equity Method Investments [Table]
Mountain Valley Pipeline LLC (Unconsolidated Entity)
Mountain Valley Pipeline LLC (Unconsolidated Entity) [Member]
Mountain Valley Pipeline LLC (Unconsolidated Entity) [Member]
Schedule of Equity Method Investments [Line Items]
Schedule of Equity Method Investments [Line Items]
Income Statement
Equity Method Investment, Summarized Financial Information, Income Statement [Abstract]
AFUDC
Equity Method Investment Summarized Financial Information Allowance For Funds Used During Construction
Equity Method Investment, Summarized Financial Information ,Allowance For Funds Used During Construction
Other Income (Expense), net
Equity Method Investment Summarized Financial Information Net Other Income
Equity Method Investment, Summarized Financial Information, Net Other Income
Net Income
Equity Method Investment, Summarized Financial Information, Net Income (Loss)
Balance Sheet
Equity Method Investment, Summarized Financial Information [Abstract]
Assets:
Equity Method Investment, Summarized Financial Information, Assets [Abstract]
Current Assets
Equity Method Investment, Summarized Financial Information, Current Assets
Construction Work in Progress
Equity Method Investment Summarized Financial Information Construction Work In Progress
Equity Method Investment, Summarized Financial Information, Construction Work In Progress
Other Assets
Equity Method Investment Summarized Financial Information Other Assets
Equity Method Investment, Summarized Financial Information, Other Assets
Total Assets
Equity Method Investment, Summarized Financial Information, Assets
Liabilities and Equity:
Equity Method Investment, Summarized Financial Information, Liabilities and Equity [Abstract]
Current Liabilities
Equity Method Investment, Summarized Financial Information, Current Liabilities
Noncurrent Liabilities
Equity Method Investment, Summarized Financial Information, Noncurrent Liabilities
Capital
Equity Method Investment Summarized Financial Information, Equity
Total Liabilities and Equity
Equity Method Investment, Summarized Financial Information, Liabilities and Equity
Regulatory Assets and Liabilities
Schedule of Regulatory Assets and Liabilities [Text Block]
Net Income
Weighted average common shares (in shares)
Weighted Average Number of Shares Outstanding, Basic
Effect of dilutive securities:
Dilutive Securities, Effect on Basic Earnings Per Share [Abstract]
Options to purchase common stock (in shares)
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements
Diluted average common shares (in shares)
Weighted Average Number of Shares Outstanding, Diluted
Earnings Per Share of Common Stock:
Earnings Per Share, Basic and Diluted [Abstract]
Basic (in dollars per share)
Earnings Per Share, Basic
Diluted (in dollars per share)
Earnings Per Share, Diluted
Schedule of Regulatory Assets [Table]
Schedule of Regulatory Assets [Table]
Regulatory Asset [Axis]
Regulatory Asset [Axis]
Regulatory Asset [Domain]
Regulatory Asset [Domain]
WNA
WNA [Member]
WNA [Member]
ESAC Assets
ESAC Assets [Member]
ESAC Assets [Member]
Accrued pension and postretirement medical
Pension Costs [Member]
Other deferred expenses
Other Assets [Member]
Premium on early retirement of debt
Deferred Gain (Loss) on Early Extinguishment of Debt [Member]
Regulatory Assets [Line Items]
Regulatory Assets [Line Items]
Current regulatory assets
Regulatory Assets, Current
Utility property in service, other
Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment
Construction work in progress - AFUDC
Public Utilities, Property, Plant and Equipment, Construction Work In Progress, Allowance For Funds Used During Construction
Public Utilities, Property, Plant and Equipment, Construction Work In Progress, Allowance For Funds Used During Construction
Noncurrent regulatory assets
Regulatory Assets, Noncurrent
Total regulatory assets
Regulatory Assets
Statement of Financial Position [Abstract]
Accounts receivable, allowance for uncollectibles
Accounts Receivable, Allowance for Credit Loss, Current
Common stock, par value (in dollars per share)
Common Stock, Par or Stated Value Per Share
Common stock, shares authorized
Common Stock, Shares Authorized
Common stock, shares issued
Common Stock, Shares, Issued
Common stock, shares outstanding
Common Stock, Shares, Outstanding
Preferred stock, par value (in dollars per share)
Preferred Stock, No Par Value
Preferred stock, shares authorized
Preferred Stock, Shares Authorized
Preferred stock, shares issued
Preferred Stock, Shares Issued
Preferred stock, shares outstanding
Preferred Stock, Shares Outstanding
Revenue
Revenue from Contract with Customer [Text Block]
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives and Hedging
Derivative Instruments and Hedging Activities Disclosure [Text Block]
Fair Value Disclosures [Abstract]
Fair Value Measurements
Fair Value Disclosures [Text Block]
Schedule of Regulatory Liabilities [Table]
Schedule of Regulatory Liabilities [Table]
Public Utilities, Regulatory Proceeding [Axis]
Public Utilities, Regulatory Proceeding [Axis]
Public Utilities, Regulatory Proceeding [Domain]
Public Utilities, Regulatory Proceeding [Domain]
General Rate Case [Member]
General Rate Case [Member]
General Rate Case [Member]
Regulatory Agency [Axis]
Regulatory Agency [Axis]
Regulatory Agency [Domain]
Regulatory Agency [Domain]
Virginia State Corporate Commission (SCC) [Member]
Virginia State Corporate Commission (SCC) [Member]
Virginia State Corporate Commission (SCC) [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities [Line Items]
Approved non-gas rate increase
Public Utilities, Approved Rate Increase (Decrease), Amount
Additional write down of ESAC regulatory assets
Amount of Impairment to Carrying Amount of Regulatory Assets
Rate refund paid
Contract with Customer, Liability, Cumulative Catch-up Adjustment to Revenue, Change in Estimate of Transaction Price
Regulatory liability, refund period (in years)
Regulatory Liability Refund Period
Period of time over which the regulatory liability will be refunded.
Regulatory Liability [Axis]
Regulatory Liability [Axis]
Regulatory Liability [Domain]
Regulatory Liability [Domain]
Over-recovery of gas costs
Over Recovery Of Gas Costs [Member]
Over-Recovery Of Gas Costs [Member]
Over-recovery of SAVE Plan revenues
Over-recovery of SAVE Plan revenues [Member]
Over-recovery of SAVE Plan revenues [Member]
Rate Refund
Revenue Subject to Refund [Member]
Excess deferred income taxes
TaxCutsandJobsActof2017EstimatedAccountingChangeinTaxRateRegulatoryLiability [Member]
Amount of deferred tax liability that was reclassified to a regulatory liability due to the Tax Cuts and Jobs Act of 2017 change in federal tax rate
Other deferred liabilities
Other Liabilities [Member]
Current regulatory liabilities
Regulatory Liability, Current
Deferred Credits and Other Liabilities:
Regulatory Liabilities And Asset Retirement Obligations, Noncurrent [Abstract]
Regulatory Liabilities And Asset Retirement Obligations, Noncurrent [Abstract]
Asset retirement obligations
Asset Retirement Obligations, Noncurrent
Regulatory cost of retirement obligations
Regulatory cost of retirement obligations
Regulatory cost of retirement obligations not otherwise included in ARO
Noncurrent regulatory liabilities - excess deferred income taxes
Regulatory Liability, Noncurrent
Total non-current
Regulatory Liabilities And Asset Retirement Obligations, Noncurrent
Regulatory Liabilities And Asset Retirement Obligations, Noncurrent
Total regulatory liabilities
Regulatory Liabilities
Schedule of Segment Reporting Information, by Segment [Table]
Schedule of Segment Reporting Information, by Segment [Table]
Consolidation Items [Axis]
Consolidation Items [Axis]
Consolidation Items [Domain]
Consolidation Items [Domain]
Operating Segments
Operating Segments [Member]
Parent and Other
Corporate, Non-Segment [Member]
Segments [Axis]
Segments [Axis]
Segments [Domain]
Segments [Domain]
Gas Utility
Gas Utility Segment [Member]
Gas Utility Segment [Member]
Investment In Affiliates
Investment In Affiliates Segment [Member]
Investment In Affiliates Segment [Member]
Segment Reporting Information [Line Items]
Segment Reporting Information [Line Items]
Operating revenues
Depreciation
Depreciation, Depletion and Amortization, Nonproduction
Operating income (loss)
Operating Income (Loss)
Equity in earnings
Income (Loss) from Equity Method Investments
Interest expense
Interest Expense
Total assets
Assets
ASSETS
Assets [Abstract]
CURRENT ASSETS:
Assets, Current [Abstract]
Cash and cash equivalents
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents
Accounts receivable (less allowance for uncollectibles of $493,823 and $110,743, respectively)
Accounts Receivable, after Allowance for Credit Loss, Current
Materials and supplies
Other Inventory, Gross
Gas in storage
Energy Related Inventory, Natural Gas in Storage
Prepaid income taxes
Prepaid Taxes
Regulatory assets
Other
Other Assets, Current
Total current assets
Assets, Current
UTILITY PROPERTY:
Public Utilities, Property, Plant and Equipment, Net [Abstract]
In service
Public Utilities, Property, Plant and Equipment, Plant in Service
Accumulated depreciation and amortization
Public Utilities, Property, Plant and Equipment, Accumulated Depreciation
In service, net
Public Utilities Property Plant and Equipment in Service Net
Period end net book value of property, plant and equipment that is in service and owned by the regulated operations of the public utility.
Construction work in progress
Public Utilities, Property, Plant and Equipment, Construction Work in Progress
Utility plant, net
Public Utilities, Property, Plant and Equipment, Net
OTHER ASSETS:
Other Assets, Noncurrent [Abstract]
Regulatory assets
Investment in unconsolidated affiliates
Long-term Investments
Other
Other Assets, Miscellaneous, Noncurrent
Other
Other Assets, Noncurrent
TOTAL ASSETS
LIABILITIES AND STOCKHOLDERS’ EQUITY
Liabilities and Equity [Abstract]
CURRENT LIABILITIES:
Liabilities, Current [Abstract]
Dividends payable
Dividends Payable, Current
Accounts payable
Accounts Payable, Current
Capital contributions payable
Capital Contributions Payable
Capital contributions remaining to be paid pursuant to the capital call notice.
Customer credit balances
Contract with Customer, Liability, Current
Income taxes payable
Accrued Income Taxes, Current
Customer deposits
Contract with Customer, Refund Liability, Current
Accrued expenses
Accrued Liabilities, Current
Interest rate swaps
Derivative Liability, Current
Regulatory liabilities
Total current liabilities
Liabilities, Current
LONG-TERM DEBT:
Long-term Debt, Excluding Current Maturities [Abstract]
Line-of-credit
Long-term Line of Credit, Noncurrent
Less unamortized debt issuance costs
Long-term debt, net
Long-term Debt, Excluding Current Maturities
DEFERRED CREDITS AND OTHER LIABILITIES:
Deferred Credits and Other Liabilities [Abstract]
Interest rate swaps
Derivative Liability, Noncurrent
Benefit plan liabilities
Liability, Defined Benefit Plan, Noncurrent
Deferred income taxes
Deferred Income Tax Liabilities, Net
Regulatory liabilities
Total deferred credits and other liabilities
Other Liabilities, Noncurrent
STOCKHOLDERS’ EQUITY:
Stockholders' Equity Attributable to Parent [Abstract]
Common stock, $5 par value; authorized 20,000,000 and 10,000,000 shares; issued and outstanding 8,136,945 and 8,073,264 shares, respectively
Common Stock, Value, Issued
Preferred stock, no par, authorized 5,000,000 shares; no shares issued and outstanding
Preferred Stock, Value, Issued
Capital in excess of par value
Additional Paid in Capital, Common Stock
Retained earnings
Retained Earnings (Accumulated Deficit)
Accumulated other comprehensive loss
Accumulated Other Comprehensive Income (Loss), Net of Tax
Total stockholders’ equity
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY
Liabilities and Equity
Fair Value, by Balance Sheet Grouping [Table]
Fair Value, by Balance Sheet Grouping [Table]
Measurement Basis [Axis]
Measurement Basis [Axis]
Fair Value Measurement [Domain]
Fair Value Measurement [Domain]
Portion at Fair Value Measurement [Member]
Portion at Fair Value Measurement [Member]
Carrying Value [Member]
Reported Value Measurement [Member]
Fair Value [Member]
Estimate of Fair Value Measurement [Member]
Fair Value Hierarchy and NAV [Axis]
Fair Value Hierarchy and NAV [Axis]
Fair Value Hierarchy and NAV [Domain]
Fair Value Hierarchy and NAV [Domain]
Quoted Prices in Active Markets (Level 1) [Member]
Fair Value, Inputs, Level 1 [Member]
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Inputs, Level 2 [Member]
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities:
Liabilities, Fair Value Disclosure [Abstract]
Notes payable
Notes Payable, Fair Value Disclosure
Total
Financial and Nonfinancial Liabilities, Fair Value Disclosure
Reclassification out of Accumulated Other Comprehensive Income [Table]
Reclassification out of Accumulated Other Comprehensive Income [Table]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Increase (Decrease) in Other Accumulated Comprehensive Income (Loss) [Roll Forward]
Other comprehensive loss
Schedule of Components of Net Periodic Pension and Postretirement Benefit Cost
Schedule of Net Benefit Costs [Table Text Block]
Summary of Employer Contributions to Defined Benefit Plans
Summary of Employer Contributions to Defined Benefit Plans [Table Text Block]
Summary of Employer Contributions to Defined Benefit Plans [Table Text Block]
Corporate federal tax rate
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent
Income tax expense computed at the federal statutory rate
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount
State income taxes, net of federal tax benefit
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount
Net amortization of excess deferred taxes on regulated operations
Net Amortization Of Excess Deferred Taxes On Regulated Operations
Net Amortization Of Excess Deferred Taxes On Regulated Operations
Other, net
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount
Total income tax expense
Income Tax Expense (Benefit)
Effective tax rate
Effective Income Tax Rate Reconciliation, Percent
Investment, Name [Axis]
Investment, Name [Axis]
Investment, Name [Domain]
Investment, Name [Domain]
MVP [Member]
MVP Investment [Member]
MVP Investment [Member]
Southgate [Member]
MVP Southgate Investment [Member]
MVP Southgate Investment [Member]
Statistical Measurement [Axis]
Statistical Measurement [Axis]
Statistical Measurement [Domain]
Statistical Measurement [Domain]
Minimum [Member]
Minimum [Member]
Maximum [Member]
Maximum [Member]
Ownership [Axis]
Ownership [Axis]
Ownership [Domain]
Ownership [Domain]
Southgate [Member]
Equity interest percentage
Equity Method Investment, Ownership Percentage
Pipeline capacity per day (in bcf)
Transportation and Delivery Capacity Per Day
Transportation and delivery capacity for pipeline deals per day
Total project cost
Estimated Total Mountain Valley Pipeline Cost Projection
Estimated total cost of construction of the Mountain Valley Pipeline.
Total estimated investment
Estimated Investment in Mountain Valley Pipeline
Estimated total cash investment by the Company in Mountain Valley Pipeline at completion of project.
Length of planned natural gas pipeline (in miles)
Length Of Planned Natural Gas Pipeline
Length of planned natural gas pipeline in miles
Ownership percentage (less than)
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners
Estimated total MVP Southgate pipeline cost projection
Estimated Total MVP Southgate Pipeline Cost Projection
Estimated total of construction for the MVP Southgate Pipeline.
Estimated investment in MVP Southgate
Estimated Investment In MVP Southgate
Estimated total cash investment by the Company in MVP Southgate Pipeline at completion of project.
Number of unsecured Promissory Notes funding the investment
Debt Instrument, Number of Instruments
Debt Instrument, Number of Instruments
Income Statement [Abstract]
OPERATING REVENUES:
Results of Operations, Revenue from Oil and Gas Producing Activities [Abstract]
OPERATING EXPENSES:
Utilities Operating Expense [Abstract]
Cost of gas and sales
Cost of Goods and Services Sold
Operations and maintenance
Utilities Operating Expense, Maintenance and Operations
General taxes
Taxes, Miscellaneous
Depreciation and amortization
Total operating expenses
Cost Of Revenue And Operating Expenses
Cost Of Revenue And Operating Expenses
OPERATING INCOME
Equity in earnings of unconsolidated affiliate
Other income, net
Other Nonoperating Income (Expense)
INCOME TAX EXPENSE
NET INCOME
BASIC EARNINGS PER COMMON SHARE (in dollars per share)
DILUTED EARNINGS PER COMMON SHARE (in dollars per share)
DIVIDENDS DECLARED PER COMMON SHARE (in dollars per share)
Information related to segments
Schedule of Segment Reporting Information, by Segment [Table Text Block]
Schedule of Fair Value of Financial Assets and Liabilities Measured on a Recurring Basis
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]
Summary of the Fair Value of Financial Assets and Liabilities Not Adjusted to Fair Value
Fair Value, by Balance Sheet Grouping [Table Text Block]
Derivative Instruments and Hedging Activities Disclosures [Table]
Derivative Instruments and Hedging Activities Disclosures [Table]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of interest rate swaps associated with note(s)
Number of Interest Rate Derivatives Held
Debt instrument, borrowing amount
Debt Instrument, Face Amount
Effective interest rate
Derivative, Fixed Interest Rate
Debt instrument, number of instruments
Accumulated Other Comprehensive Income (Loss) [Table]
Accumulated Other Comprehensive Income (Loss) [Table]
Interest rate swap [Member]
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
Interest rate swap [Member]
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Defined benefit plans [Member]
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Before-Tax Amount
Other Comprehensive Income (Loss), before Tax [Abstract]
Other comprehensive income (loss) before reclassifications
OCI, before Reclassifications, before Tax, Attributable to Parent
Reclassifications from accumulated other comprehensive income
Reclassification from AOCI, Current Period, before Tax, Attributable to Parent
Other comprehensive income (loss)
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent
Tax (Expense) or Benefit
Other Comprehensive Income (Loss), Tax [Abstract]
Other comprehensive income before reclassifications
Other Comprehensive Income (Loss) before Reclassifications, Tax
Reclassifications from accumulated other comprehensive income
Reclassification from AOCI, Current Period, Tax
Other comprehensive loss
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent
Net-of-Tax Amount
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Other comprehensive income (loss) before reclassifications
OCI, before Reclassifications, Net of Tax, Attributable to Parent
Reclassifications from accumulated other comprehensive income
Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent
Earnings Per Share
Earnings Per Share [Text Block]
Document And Entity Information [Abstract]
Document And Entity Information [Abstract]
Document Type
Document Type
Amendment Flag
Amendment Flag
Document Period End Date
Document Period End Date
Document Fiscal Year Focus
Document Fiscal Year Focus
Document Fiscal Period Focus
Document Fiscal Period Focus
Entity Registrant Name
Entity Registrant Name
Entity Central Index Key
Entity Central Index Key
Current Fiscal Year End Date
Current Fiscal Year End Date
Entity Current Reporting Status
Entity Current Reporting Status
Entity Filer Category
Entity Filer Category
Entity Small Business
Entity Small Business
Entity Emerging Growth Company
Entity Emerging Growth Company
Entity Shell Company
Entity Shell Company
Entity Common Stock, Shares Outstanding
Entity Common Stock, Shares Outstanding
Investments in and Advances to Affiliates [Table]
Investments in and Advances to Affiliates [Table]
Investments in and Advances to Affiliates [Line Items]
Investments in and Advances to Affiliates [Line Items]
Balance Sheet location of Other Investments:
Balance Sheet Related Disclosures [Abstract]
Other Assets:
Other Assets [Abstract]
MVP
Equity Method Investments
Southgate
Other Long-term Investments
Investment in unconsolidated affiliates
Current Liabilities:
Income Statement location of Other Investments:
Income Statement Related Disclosures [Abstract]
Undistributed earnings, net of income taxes, of MVP in retained earnings
Retained Earnings, Undistributed Earnings from Equity Method Investees
Change in investment in unconsolidated affiliate [Abstract]
Change in investment in unconsolidated affiliate [Abstract]
Change in investment in unconsolidated affiliate [Abstract]
Cash investment
Payments to Acquire Additional Interest in Subsidiaries
Change in accrued capital calls
Noncash Increase Decrease In Unconsolidated Affiliate
The noncash increase (decrease) in unconsolidated affiliate. The noncash change reflects the affect of fluctuations in capital contributions payable during the related period.
Change in investment in unconsolidated affiliates
Change in Investment in Unconsolidated Affiliate
Change in Investment in Unconsolidated Affiliate
Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis and Fair Value Measurement Inputs [Table]
Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis and Fair Value Measurement Inputs [Table]
Schedule of fair value assets and liabilities measured on recurring basis and fair value measurement inputs.
Measurement Frequency [Axis]
Measurement Frequency [Axis]
Measurement Frequency [Domain]
Measurement Frequency [Domain]
Recurring [Member]
Fair Value, Recurring [Member]
Fair Value Hierarchy and NAV [Axis]
Derivative Instrument [Axis]
Derivative Instrument [Axis]
Derivative Contract [Domain]
Derivative Contract [Domain]
Interest Rate Swap [Member]
Interest Rate Swap [Member]
Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis and Fair Value Measurement Inputs [Line Items]
Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis and Fair Value Measurement Inputs [Line Items]
Schedule of fair value assets and liabilities measured on recurring basis and fair value measurement inputs [line items].
Natural gas purchases
Natural Gas Purchases Fair Value Disclosure
Fair market value estimated at the corresponding first of month index prices for which the obligation, the timing difference between the payment for natural gas purchases and the actual receipt of such purchases under the current asset management contract, is expected to be settled.
Interest rate swap
Derivative Liability
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]
Statement of Cash Flows [Abstract]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Cash Provided by (Used in) Operating Activities [Abstract]
Adjustments to reconcile net income to net cash provided by operating activities:
Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract]
Depreciation and amortization
Depreciation, Depletion and Amortization
Cost of retirement of utility plant, net
Cost of Plant Retirement
Cost incurred to retire and remove from service property of the entity including amount to settle asset retirement obligations.
Equity in earnings of unconsolidated affiliate
Allowance for funds used during construction
Public Utilities, Allowance for Funds Used During Construction, Additions
Changes in assets and liabilities which provided cash, exclusive of changes and noncash transactions shown separately
Increase (Decrease) in Operating Capital
Net cash provided by operating activities
Net Cash Provided by (Used in) Operating Activities
CASH FLOWS FROM INVESTING ACTIVITIES:
Net Cash Provided by (Used in) Investing Activities [Abstract]
Expenditures for utility property
Payments to Acquire Property, Plant, and Equipment
Investment in unconsolidated affiliates
Proceeds from disposal of utility property
Proceeds from Sale of Property, Plant, and Equipment
Net cash used in investing activities
Net Cash Provided by (Used in) Investing Activities
CASH FLOWS FROM FINANCING ACTIVITIES:
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from issuance of unsecured notes
Proceeds from Issuance of Unsecured Debt
Borrowings under line-of-credit
Proceeds from Lines of Credit
Repayments under line-of-credit
Repayments of Lines of Credit
Debt issuance expenses
Payments of Debt Issuance Costs
Proceeds from issuance of stock
Proceeds from Issuance of Common Stock
Cash dividends paid
Payments of Ordinary Dividends, Common Stock
Net cash provided by financing activities
Net Cash Provided by (Used in) Financing Activities
NET INCREASE IN CASH AND CASH EQUIVALENTS
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect
CASH AND CASH EQUIVALENTS AT BEGINNING OF YEAR
CASH AND CASH EQUIVALENTS AT END OF YEAR
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION:
Supplemental Cash Flow Information [Abstract]
Interest
Interest Paid, Excluding Capitalized Interest, Operating Activities
Income taxes
Income Taxes Paid, Net
Schedule of Regulatory Assets
Schedule of Regulatory Assets [Table Text Block]
Schedule of Regulatory Liabilities
Schedule of Regulatory Liabilities [Table Text Block]
Subsequent Events [Abstract]
Subsequent Events
Subsequent Events [Text Block]
Unbilled revenue
Contract with Customer, Asset, Net, Current
Increase (decrease) in Unbilled revenue
Increase (Decrease) in Contract with Customer, Asset
Increase (decrease) in Customer credit balances
Increase (Decrease) in Contract with Customer, Liability
Increase (decrease) in Customer deposits
Increase Decrease In Contract With Customer Refund Liability
Amount of increase (decrease) of liability for consideration received or receivable from customer which is not included in the transaction price, when considered is expected to be refunded to customer.
Capitalized Contract Cost [Table]
Capitalized Contract Cost [Table]
Receivable Type [Axis]
Receivable Type [Axis]
Receivable [Domain]
Receivable [Domain]
Trade Accounts Receivable [Member]
Trade Accounts Receivable [Member]
Capitalized Contract Cost [Line Items]
Capitalized Contract Cost [Line Items]
Trade accounts receivable
Increase (decrease) in Trade accounts receivable
Increase (Decrease) in Accounts Receivable
Roanoke Gas [Member]
Line of credit, maximum borrowing capacity
Line of Credit Facility, Current Borrowing Capacity
Debt term
Debt Instrument, Term
Availability fee (as a percent)
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage
Maximum percentage of Consolidated Long Term Indebtedness to Consolidated Total Capitalization
Debt Instrument, Debt Covenant, Ratio of Long-term Debt to Total Capitalization, Maximum
Debt Instrument, Debt Covenant, Ratio of Long-term Debt to Total Capitalization, Maximum
Maximum percentage of Priority Indebtedness to Consolidated Total Assets
Debt Instrument, Debt Covenant, Ratio of Priority Debt to Total Assets, Maximum
Debt Instrument, Debt Covenant, Ratio of Priority Debt to Total Assets, Maximum