Earnings Per Share [Abstract]
Weighted-average shares - basic
Weighted Average Number of Shares Outstanding, Basic
Dilution effect of stock appreciation rights and stock awards at end of period
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements
Weighted-average shares - diluted
Weighted Average Number of Shares Outstanding, Diluted
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Outstanding commodity derivatives
Schedule of Derivative Instruments [Table Text Block]
Effect of derivative instruments on the condensed consolidated balance sheet
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block]
Schedule of offsetting of derivative liabilities in the condensed consolidated balance sheet
Offsetting Liabilities [Table Text Block]
Schedule of offsetting of derivative assets in the condensed consolidated balance sheet
Offsetting Assets [Table Text Block]
Effect of derivatives on the condensed consolidated statement of operations
Schedule of Derivatives Instruments Statements of Financial Performance and Financial Position, Location [Table Text Block]
Equity Method Investments and Joint Ventures [Abstract]
Summary of Information Related to the Company's Equity Method Investments
Equity Method Investments [Table Text Block]
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments [Table]
Schedule of Long-term Debt Instruments [Table]
Credit Facility [Axis]
Credit Facility [Axis]
Credit Facility [Domain]
Credit Facility [Domain]
Revolving credit facility
Line of Credit [Member]
Debt Instrument [Axis]
Debt Instrument [Axis]
Debt Instrument, Name [Domain]
Debt Instrument, Name [Domain]
6.51% weighted-average senior notes
Six Point Five One Percentage Weighted Average Fixed Rate Notes [Member]
6.51% Weighted Average Fixed Rate Notes.
9.78% senior notes
Nine Point Seven Eight Percentage Notes [Member]
9.78% Notes.
5.58% weighted-average senior notes
Five Point Five Eight Percentage Weighted Average Fixed Rate Notes [Member]
5.58% Weighted Average Fixed Rate Notes.
3.65% weighted-average senior notes
Three Point Sixty Five Percentage Weighted Average Fixed Rate Note [Member]
3.65% Weighted Average Fixed Rate Note
Debt Instrument [Line Items]
Debt Instrument [Line Items]
Total debt
Long-term Debt, Gross
Unamortized debt issuance costs
Debt Issuance Costs, Net
Long-term debt, net
Long-term Debt
Weighted average interest rate
Long-term Debt, Weighted Average Interest Rate, at Point in Time
Long-term debt, interest rate, stated percentage
Debt Instrument, Interest Rate, Stated Percentage
Current maturities
Long-term Debt, Current Maturities
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies
Commitments and Contingencies Disclosure [Text Block]
Fair Value Disclosures [Abstract]
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
Portion at Fair Value Measurement [Member]
Carrying Amount
Reported Value Measurement [Member]
Estimated Fair Value
Estimate of Fair Value Measurement [Member]
Fair value disclosures
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt
Current maturities
Long-term debt, excluding current maturities
Long-term Debt, Excluding Current Maturities
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligations
Asset Retirement Obligation Disclosure [Text Block]
Calculation of basic and diluted weighted-average shares outstanding
Schedule of Weighted Average Number of Shares [Table Text Block]
Calculation of weighted-average shares excluded from diluted EPS due to the anti-dilutive effect
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]
Derivative [Table]
Derivative [Table]
Balance Sheet Location [Axis]
Balance Sheet Location [Axis]
Balance Sheet Location [Domain]
Balance Sheet Location [Domain]
Derivative instruments (current)
Derivative Instruments (current) [Member]
Derivative Instruments (current) [Member]
Derivative instruments (non-current)
Derivative Instruments [Member]
Derivative Instruments [Member]
Hedging Designation [Axis]
Hedging Designation [Axis]
Hedging Designation [Domain]
Hedging Designation [Domain]
Derivatives Not Designated as Hedges
Not Designated as Hedging Instrument [Member]
Derivative Instrument [Axis]
Derivative Instrument [Axis]
Derivative Contract [Domain]
Derivative Contract [Domain]
Commodity contracts
Commodity Contract [Member]
Effect of derivative instruments on the Consolidated Balance Sheet
Derivatives, Fair Value [Line Items]
Derivative Assets
Derivative Asset
Derivative Liabilities
Derivative Liability
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table]
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table]
Antidilutive Securities [Axis]
Antidilutive Securities [Axis]
Antidilutive Securities, Name [Domain]
Antidilutive Securities, Name [Domain]
Stock appreciation rights and stock awards
Stock Compensation Plan [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-average stock appreciation rights and stock awards excluded from diluted EPS due to the anti-dilutive effect calculated using the treasury stock method
Antidilutive Securities Excluded from Computation of EPS, Amount, Treasury Stock Method
Antidilutive Securities Excluded from Computation of EPS, Amount, Treasury Stock Method
Fair Value Measurements, Recurring and Nonrecurring [Table]
Fair Value Measurements, Recurring and Nonrecurring [Table]
Fair Value, Hierarchy [Axis]
Fair Value, Hierarchy [Axis]
Fair Value Hierarchy [Domain]
Fair Value Hierarchy [Domain]
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Inputs, Level 1 [Member]
Significant Other Observable Inputs (Level 2)
Fair Value, Inputs, Level 2 [Member]
Significant Unobservable Inputs (Level 3)
Fair Value, Inputs, Level 3 [Member]
Measurement Frequency [Axis]
Measurement Frequency [Axis]
Fair Value, Measurement Frequency [Domain]
Fair Value, Measurement Frequency [Domain]
Recurring basis
Fair Value, Measurements, Recurring [Member]
Financial Assets and Liabilities Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets
Assets, Fair Value Disclosure [Abstract]
Deferred compensation plan
Deferred Compensation Plan Assets
Derivative instruments
Derivative Asset, Fair Value, Gross Asset
Total assets
Assets, Fair Value Disclosure
Liabilities
Liabilities, Fair Value Disclosure [Abstract]
Deferred compensation plan
Deferred Compensation Liability, Classified, Noncurrent
Derivative instruments
Total liabilities
Financial and Nonfinancial Liabilities, Fair Value Disclosure
Statement of Financial Position [Abstract]
Common stock, authorized (shares)
Common Stock, Shares Authorized
Common stock, par value (in dollars per share)
Common Stock, Par or Stated Value Per Share
Common stock, issued (shares)
Common Stock, Shares, Issued
Treasury stock (shares)
Treasury Stock, Shares
Balance Sheet Related Disclosures [Abstract]
Additional Balance Sheet Information
Supplemental Balance Sheet Disclosures [Text Block]
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Unsatisfied performance obligations
Revenue, Remaining Performance Obligation
Unsatisfied performance obligations, expected period of satisfaction
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period
Contracts with customers
Contract with Customer, Asset, Net
Statement of Cash Flows [Abstract]
CASH FLOWS FROM OPERATING ACTIVITIES
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net income
Net Income (Loss) Attributable to Parent
Adjustments to reconcile net income to cash provided by operating activities:
Adjustments, Noncash Items, to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract]
Depreciation, depletion and amortization
Depreciation, Depletion and Amortization
Impairment of oil and gas properties and other assets
Impairment of Oil and Gas Properties
Deferred income tax expense
Deferred Income Tax Expense (Benefit)
Loss on sale of assets
Gain (Loss) on Disposition of Property Plant Equipment
Exploratory dry hole cost
Results of Operations, Dry Hole Costs
Gain on derivative instruments
Derivative, Gain (Loss) on Derivative, Net
Net cash paid in settlement of derivative instruments
Proceeds from (Payments for) Derivative Instrument, Operating Activities
Proceeds from (Payments for) Derivative Instrument, Operating Activities
Loss on equity method investments
Income (Loss) from Equity Method Investments
Amortization of debt issuance costs
Amortization of Debt Issuance Costs
Stock-based compensation and other
Stock Based Compensation Expense and Other
The aggregate amount of noncash, equity-based employee remuneration and non-cash share-based compensation expense. This may include the value of stock options, amortization of restricted stock, and adjustments for officers compensation, as well as other non-cash expenses. As noncash, this element is an add back when calculating net cash generated by operating activities using the indirect method.
Changes in assets and liabilities:
Increase (Decrease) in Operating Capital [Abstract]
Accounts receivable, net
Increase (Decrease) in Receivables
Income taxes
Increase (Decrease) in Income Taxes Payable, Net of Income Taxes Receivable
Inventories
Increase (Decrease) in Inventories
Other current assets
Increase (Decrease) in Prepaid Expense and Other Assets
Accounts payable and accrued liabilities
Increase (Decrease) in Accounts Payable and Accrued Liabilities
Interest payable
Increase (Decrease) in Interest Payable, Net
Other assets and liabilities
Increase (Decrease) in Other Operating Assets and Liabilities, Net
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]
Capital expenditures
Payments to Explore and Develop Oil and Gas Properties
Proceeds from sale of assets
Proceeds from Sale of Property, Plant, and Equipment
Investment in equity method investments
Payments to Acquire Equity Method Investments
Net cash provided by (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]
Treasury stock repurchases
Payments for Repurchase of Equity
Dividends paid
Payments of Ordinary Dividends, Common Stock
Tax withholdings on vesting of stock awards
Payments Related to Tax Withholding for Share-based Compensation
Other
Proceeds from (Payments for) Other Financing Activities
Net cash used in financing activities
Net Cash Provided by (Used in) Financing Activities
Net increase in cash and cash equivalents
Cash and Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect
Cash and cash equivalents, beginning of period
Cash and Cash Equivalents, at Carrying Value
Cash and cash equivalents, end of period
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-based Compensation
Disclosure of Compensation Related Costs, Share-based Payments [Text Block]
Additional Balance Sheet Information
Additional Balance Sheet Information [Table Text Block]
Tabular disclosure of supplemental balance sheet disclosures for assets and liabilities.
Fair value assets, level 1 to level 2
Fair Value, Assets, Level 1 to Level 2 Transfers, Amount
Fair value liabilities, level 1 to level 2
Fair Value, Liabilities, Level 1 to Level 2 Transfers, Amount
Fair value assets, level 2 to level 1
Fair Value, Assets, Level 2 to Level 1 Transfers, Amount
Fair value liabilities, level 2 to level 1
Fair Value, Liabilities, Level 2 to Level 1 Transfers, Amount
Number of non-financial assets and liabilities impaired
Number of Non Financial Assets and Liabilities Impaired
Represents the number of non-financial assets and liabilities that were impaired during the period.
Financial assets and liabilities measured at fair value on a recurring basis
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]
Reconciliation of changes in the fair value of financial assets and liabilities classified as level 3
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]
Carrying amounts and fair values of debt
Fair Value, by Balance Sheet Grouping [Table Text Block]
Accounts receivable, net
Accounts and Notes Receivable, Net [Abstract]
Trade accounts
Accounts Receivable, Gross, Current
Joint interest accounts
Oil and Gas Joint Interest Billing Receivables
Other accounts
Other Receivables
Accounts receivable, net
Receivables Gross Current
The total amount due to the entity within one year of the balance sheet date (or one operating cycle, if longer) from outside sources, including trade accounts receivable, notes and loans receivable, as well as any other types of receivables.
Allowance for doubtful accounts
Allowance for Doubtful Accounts Receivable, Current
Accounts receivable, net
Receivables, Net, Current
Other assets
Other Assets, Noncurrent [Abstract]
Debt issuance costs
Debt Issuance Cost, Gross, Noncurrent
Other accounts
Other Assets, Miscellaneous, Noncurrent
Other assets
Other Assets, Noncurrent
Accounts payable
Accounts Payable, Current [Abstract]
Trade accounts
Accounts Payable, Trade, Current
Natural gas purchases
Gas Purchase Payable, Current
Royalty and other owners
Accrued Royalties, Current
Accrued transportation
Accrued Transportation Costs
Accrued Transportation Costs
Accrued capital costs
Accrued Capital Expenditures
Accrued Capital Expenditures
Taxes other than income
Accrual for Taxes Other than Income Taxes, Current
Deposits received for asset sales
Deposits
Other accounts
Accounts Payable, Other, Current
Accounts payable
Accounts Payable, Current
Accrued liabilities
Accrued Liabilities, Current [Abstract]
Employee benefits
Accrued Employee Benefits, Current
Taxes other than income
Accrual for Ad Valorem and Other Non Income Taxes Current
Carrying value as of the balance sheet date of obligations incurred and payable for advalorem taxes, franchise and other non-income taxes. Reflects the current portion of the liability (payable within one year or the normal operating cycle if longer).
Income taxes payable
Accrued Income Taxes, Current
Asset retirement obligations
Asset Retirement Obligation, Current
Other accounts
Other Accrued Liabilities, Current
Accrued liabilities
Accrued Liabilities, Current
Other liabilities
Other Liabilities, Noncurrent [Abstract]
Other accounts
Other Sundry Liabilities, Noncurrent
Other liabilities
Other Liabilities, Noncurrent
Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table]
Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table]
Range [Axis]
Range [Axis]
Range [Domain]
Range [Domain]
Minimum
Minimum [Member]
Maximum
Maximum [Member]
Award Type [Axis]
Award Type [Axis]
Equity Award [Domain]
Equity Award [Domain]
TSR Performance Share Awards
TSR Performance Shares [Member]
Represents the shares or units awarded to the employees based on the comparative performance of the reporting entity's common stock measured against fifteen to sixteen other entities in its peer group over a three year performance period.
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in dollars per share)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value
Stock price volatility
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate
Risk free rate of return
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate
Minimum expected volatility
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Minimum
Maximum expected volatility
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Maximum
Minimum risk free interest rate
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Minimum
Maximum risk free interest rate
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Maximum
Activity Related to Asset Retirement Obligations
Schedule of Change in Asset Retirement Obligation [Table Text Block]
Income Tax Disclosure [Abstract]
Income Taxes
Income Tax Disclosure [Text Block]
Fair Value Measurements
Fair Value Disclosures [Text Block]
ASSETS
Assets [Abstract]
Current assets
Assets, Current [Abstract]
Cash and cash equivalents
Accounts receivable, net
Income taxes receivable
Income Taxes Receivable, Current
Inventories
Inventory, Net
Derivative instruments
Derivative Asset, Current
Current assets held for sale
Disposal Group, Including Discontinued Operation, Assets, Current
Other current assets
Other Assets, Current
Total current assets
Assets, Current
Properties and equipment, net (Successful efforts method)
Property, Plant and Equipment, Net
Equity method investments
Equity Method Investments
Assets held for sale
Disposal Group, Including Discontinued Operation, Assets, Noncurrent
Derivative instruments
Derivative Asset, Noncurrent
Other assets
TOTAL ASSETS
Assets
LIABILITIES AND STOCKHOLDERS' EQUITY
Liabilities and Equity [Abstract]
Current liabilities
Liabilities, Current [Abstract]
Accounts payable
Current portion of long-term debt
Accrued liabilities
Interest payable
Interest Payable, Current
Derivative instruments
Derivative Liability, Current
Current liabilities held for sale
Disposal Group, Including Discontinued Operation, Liabilities, Current
Total current liabilities
Liabilities, Current
Long-term debt, net
Deferred income taxes
Deferred Tax Liabilities, Net, Noncurrent
Asset retirement obligations
Asset Retirement Obligations, Noncurrent
Liabilities held for sale
Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent
Postretirement benefits
Liability, Defined Benefit Plan, Noncurrent
Other liabilities
Total liabilities
Liabilities
Commitments and contingencies
Commitments and Contingencies
Stockholders' equity
Stockholders' Equity Attributable to Parent [Abstract]
Common stock: Authorized - 960,000,000 shares of $0.10 par value in 2017 and 2016 Issued - 475,443,335 shares and 475,042,692 shares in 2017 and 2016, respectively
Common Stock, Value, Issued
Additional paid-in capital
Additional Paid in Capital, Common Stock
Retained earnings
Retained Earnings (Accumulated Deficit)
Accumulated other comprehensive income (loss)
Accumulated Other Comprehensive Income (Loss), Net of Tax
Less treasury stock, at cost: 12,935,926 and 9,892,680 shares in 2017 and 2016, respectively
Treasury Stock, Value
Total stockholders' equity
Stockholders' Equity Attributable to Parent
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY
Liabilities and Equity
Debt and Credit Agreements
Long-term Debt [Text Block]
Property, Plant and Equipment [Table]
Property, Plant and Equipment [Table]
Accrued Liabilities
Accrued Liabilities [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment [Line Items]
Borrowing base
Line of Credit Facility, Maximum Borrowing Capacity
Remaining borrowing capacity
Line of Credit Facility, Remaining Borrowing Capacity
Change in interest rate during period
Debt Instrument, Interest Rate, Change in Rate During Period
Debt Instrument, Interest Rate, Change in Rate During Period
Line of credit
Long-term Line of Credit
Schedule of Share-based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions
Schedule of Share-based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions [Table Text Block]
Debt and credit agreement components
Schedule of Long-term Debt Instruments [Table Text Block]
Offsetting of Derivative Assets and Liabilities in the Condensed Consolidated Balance Sheet
Offsetting [Abstract]
Derivative assets
Derivative Asset [Abstract]
Gross amounts of recognized assets
Gross amounts offset in the statement of financial position
Derivative Asset, Fair Value, Gross Liability
Net amounts of assets presented in the statement of financial position
Gross amounts of financial instruments not offset in the statement of financial position
Derivative Asset, Fair Value, Amount Offset Against Collateral
Net amount
Derivative Asset, Fair Value, Offset Against Collateral, Net of Not Subject to Master Netting Arrangement, Policy Election
Derivative liabilities
Offsetting Derivative Liabilities [Abstract]
Gross amounts of recognized liabilities
Derivative Liability, Fair Value, Gross Liability
Gross amounts offset in the statement of financial position
Derivative Liability, Fair Value, Gross Asset
Net amounts of liabilities presented in the statement of financial position
Derivative Liability, Fair Value, Amount Not Offset Against Collateral
Gross amounts of financial instruments not offset in the statement of financial position
Derivative Liability, Not Subject to Master Netting Arrangement
Net amount
Derivative Liability, Fair Value, Offset Against Collateral, Net of Not Subject to Master Netting Arrangement, Policy Election
Income Statement [Abstract]
OPERATING REVENUES
Revenues [Abstract]
Natural gas
Natural Gas Production Revenue
Crude oil and condensate
Oil and Condensate Revenue
Gain on derivative instruments
Gain (Loss) on Sale of Derivatives
Brokered natural gas
Brokered Natural Gas Margin Revenue
Other
Other Revenue, Net
TOTAL OPERATING REVENUES
Revenues
OPERATING EXPENSES
Operating Expenses [Abstract]
Direct operations
Direct Operating Costs
Transportation and gathering
Gas Gathering, Transportation, Marketing and Processing Costs
Brokered natural gas
Brokered Natural Gas Margin Costs
Taxes other than income
Taxes, Miscellaneous
Exploration
Exploration Expense
General and administrative
General and Administrative Expense
TOTAL OPERATING EXPENSES
Operating Expenses
Loss on equity method investments
Loss on sale of assets
INCOME FROM OPERATIONS
Operating Income (Loss)
Interest expense, net
Interest Income (Expense), Net
Other expense
Other Nonoperating Income (Expense)
Income tax expense
Income Tax Expense (Benefit)
NET INCOME
Earnings per share
Basic (in dollars per share)
Earnings Per Share, Basic
Diluted (in dollars per share)
Earnings Per Share, Diluted
Weighted-average common shares outstanding
Weighted Average Number of Shares Outstanding, Diluted [Abstract]
Basic (in shares)
Diluted (in shares)
Dividends per common share (in dollars per share)
Common Stock, Dividends, Per Share, Cash Paid
Property, Plant and Equipment [Abstract]
Properties and Equipment, Net
Property, Plant and Equipment Disclosure [Text Block]
Geographical [Axis]
Geographical [Axis]
Geographical [Domain]
Geographical [Domain]
East Texas
East Texas [Member]
East Texas [Member]
West Virginia, Virginia, and Ohio
West Virginia, Virginia, and Ohio [Member]
West Virginia, Virginia, and Ohio [Member]
Property, Plant and Equipment, Type [Axis]
Property, Plant and Equipment, Type [Axis]
Property, Plant and Equipment, Type [Domain]
Property, Plant and Equipment, Type [Domain]
Oil and Gas Properties, Proved and Unproved
Oil and Gas Properties, Proved and Unproved [Member]
Oil and Gas Properties, Proved and Unproved [Member]
Gain (loss) on sale of assets
Equity Method Investments
Equity Method Investments and Joint Ventures Disclosure [Text Block]
Derivative Instruments and Hedging Activities
Derivative Instruments and Hedging Activities Disclosure [Text Block]
Document and Entity Information
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 Filer Category
Entity Filer Category
Document Type
Document Type
Document Period End Date
Document Period End Date
Document Fiscal Year Focus
Document Fiscal Year Focus
Document Fiscal Period Focus
Document Fiscal Period Focus
Amendment Flag
Amendment Flag
Entity Common Stock, Shares Outstanding
Entity Common Stock, Shares Outstanding
Entity Current Reporting Status
Entity Current Reporting Status
Schedule of New Accounting Pronouncements and Changes in Accounting Principles
Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block]
Schedule of properties and equipment, net
Property, Plant and Equipment [Table Text Block]
Derivative, by Nature [Axis]
Derivative, Name [Domain]
Natural gas (Leidy)
Natural Gas Swap With Contract Period Of April 2018 To December 2018 [Member]
Natural Gas Swap With Contract Period Of April 2018 To December 2018 [Member]
Natural gas (Transco)
Natural Gas Swap1 With Contract Period Of April 2018 To December 2018 [Member]
Natural Gas Swap1 With Contract Period Of April 2018 To December 2018 [Member]
Natural gas (NYMEX)
Natural Gas Collar With Contract Period Of April 2018 To December 2018 [Member]
Natural Gas Collar With Contract Period Of April 2018 To December 2018 [Member]
Natural gas (NYMEX)
Natural Gas Collar With Contract Period Of April 2018 To October 2018 [Member]
Natural Gas Collar With Contract Period Of April 2018 To October 2018 [Member]
Natural gas purchase
Natural Gas Purchase With Contract Period Of April 2018 To October 2018 [Member]
Natural Gas Purchase With Contract Period Of April 2018 To October 2018 [Member]
Derivative [Line Items]
Derivative [Line Items]
Volume (in Bcf for gas and mmbbls for oil)
Derivative, Nonmonetary Notional Amount, Volume
Swaps Weighted Average (in usd per Mcf or usd per bbl)
Derivative, Swap Type, Average Fixed Price
Disaggregation of Revenue [Table]
Disaggregation of Revenue [Table]
Products and Services [Axis]
Products and Services [Axis]
Products and Services [Domain]
Products and Services [Domain]
Natural gas
Natural Gas [Member]
Crude oil and condensate
Crude Oil and Condensate Revenues [Member]
Represents the crude oil and condensate revenues line item in the statement of operations.
Brokered natural gas
Brokered Natural Gas [Member]
Brokered Natural Gas [Member]
Other
Other Revenues [Member]
Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers
Revenue from Contract with Customer, Excluding Assessed Tax
Decrease in income taxes
Increase (Decrease) in Income Taxes
Effective tax rate
Effective Income Tax Rate Reconciliation, Percent
Restricted Stock Units
Restricted Stock Units (RSUs) [Member]
Performance Share Awards
Performance Shares [Member]
Performance Share Awards Based on Internal Performance Metrics
Internal Metrics Performance Share Awards [Member]
The portion of performance share-based compensation awards that have payouts based on performance against internal performance metrics established by the entity.
Employee Performance Share Awards
Employee Performance Shares [Member]
Represents the shares or units awarded to the employees for meeting certain performance targets.
Hybrid Performance Share Awards
Hybrid Performance Shares [Member]
Represents the shares or units awarded to the employees for meeting certain performance targets, if the entity does not meet the performance metric for the applicable period, then the portion of the performance shares that would have been issued on that anniversary date will be forfeited.
Performance Shares Based on Market Conditions
Market Based Performance Share Awards [Member]
The portion of performance share-based compensation awards that have payouts based on market conditions established by the entity.
Vesting [Axis]
Vesting [Axis]
Vesting [Domain]
Vesting [Domain]
Hybrid performance share awards, percentage vesting on the first anniversary
Share-based Compensation Award, Share Awards Percentage Vesting on the First Service Anniversary [Member]
Share-based Compensation Award, Share Awards Percentage Vesting on the First Service Anniversary [Member]
Hybrid performance share awards, percentage vesting on the second anniversary
Share-based Compensation Award, Share Awards Percentage Vesting on the Second Service Anniversary [Member]
Share-based Compensation Award, Share Awards Percentage Vesting on the Second Service Anniversary [Member]
Hybrid performance share awards, percentage vesting on the third anniversary
Share-based Compensation Award, Share Awards Percentage Vesting on the Third Service Anniversary [Member]
Share-based Compensation Award, Share Awards Percentage Vesting on the Third Service Anniversary [Member]
Stock-based Compensation arrangements
Stock based compensation expense
Allocated Share-based Compensation Expense
Granted (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period
Annual forfeiture rate assumption (as a percent)
Share Based Compensation Arrangement by Share Based Payment Award Fair Value Assumptions Expected Forfeitures
The rate of forfeitures assumptions that is used in calculating the fair values of a share-based compensation award.
Right to receive additional shares, maximum (as a percent)
Share Based Compensation Arrangement by Share Based Compensation Award Percentage Right to Receive Additional Shares
Represents the right of an employee to receive additional shares of common stock expressed as a percentage of award granted on satisfaction of either a service condition, market condition or a performance condition under an equity-based compensation plan.
Number of years over which performance criteria is to be met
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period
Award vesting rights (as a percent)
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage
Minimum operating cash flow for the year preceding the performance period
Share Based Compensation Arrangement by Share Based Payment Award, Equity Instruments Other than Options, Minimum Operating Cash Flow Requirement
Represents the minimum operating cash flow which the entity must achieve in the one-year period preceding the vesting date of share-based compensation awards with payout based on performance.
Right to receive shares (as a percent)
Share Based Compensation Arrangement by Share Based Compensation Award, Percentage Right to Receive Shares
Represents the right to receive shares under share-based compensation arrangement, expressed as a percentage.
Right to receive an additional award in cash (as a percent)
Share Based Compensation Arrangement By Share Based Compensation Award Percentage Right To Receive Cash
Represents the right to receive cash under share-based compensation arrangement, expressed as a percentage
Performance period
Share Based Compensation Arrangement by Share Based Payment Award Performance Period
Represents the performance period for awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.
Earnings per Common Share
Earnings Per Share [Text Block]
Cash received (paid) on settlement of derivative instruments, gain (loss) on derivative instruments
Realized Gain (Loss) on Derivatives
The realized gain (loss) on derivative instruments from the difference between the book value and the sale price of options, swaps, futures, forward contracts, and other derivative instruments. This element refers to the gain (loss) included in earnings.
Non-cash gain (loss) on derivative instruments, gain (loss) on derivative instruments
Unrealized Gain (Loss) on Derivatives
Gain (loss) on derivative instruments
Financial Statement Presentation
Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Text Block]
Schedule of Equity Method Investments [Table]
Schedule of Equity Method Investments [Table]
Other Commitments [Axis]
Other Commitments [Axis]
Other Commitments [Domain]
Other Commitments [Domain]
Investment Commitment
Equity Method Investment Commitment [Member]
Equity Method Investment Commitment [Member]
Investment, Name [Axis]
Investment, Name [Axis]
Investment, Name [Domain]
Investment, Name [Domain]
Constitution
Constitution Pipeline Company, LLC [Member]
Constitution Pipeline Company, LLC [Member]
Meade
Meade Pipeline Co LLC [Member]
Represents information pertaining to the Meade Pipeline Co LLC.
Schedule of Equity Method Investments [Line Items]
Schedule of Equity Method Investments [Line Items]
Ownership percentage
Equity Method Investment, Ownership Percentage
Equity Method Investments
Equity Method Investments [Roll Forward]
Equity Method Investments [Roll Forward]
Balance at beginning of period
Contributions
Balance at end of period
Expected future contributions
Other Commitments, Future Minimum Payments, Remainder of Fiscal Year
Basis difference in investment
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity
Equity [Abstract]
Incremental shares authorized
Stock Repurchase Program, Incremental Number Of Shares Authorized To Be Repurchased
Stock Repurchase Program, Incremental Number Of Shares Authorized To Be Repurchased
Treasury stock
Shares authorized for repurchase
Stock Repurchase Program, Number of Shares Authorized to be Repurchased
Remaining shares available for repurchase (in shares)
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased
Subsequent Event [Table]
Subsequent Event [Table]
Subsequent Event Type [Axis]
Subsequent Event Type [Axis]
Subsequent Event Type [Domain]
Subsequent Event Type [Domain]
Subsequent Event
Subsequent Event [Member]
Subsequent Event [Line Items]
Subsequent Event [Line Items]
Shares repurchased
Treasury Stock, Shares, Acquired
Treasury stock repurchases (in usd)
Asset Retirement Obligation
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period(1)
Asset Retirement Obligation
Liabilities incurred
Asset Retirement Obligation, Liabilities Incurred
Liabilities settled
Asset Retirement Obligation, Liabilities Settled
Liabilities divested
Asset Retirement Obligation, Liabilities Divested
Amount of asset retirement obligations divested during the period.
Accretion expense
Asset Retirement Obligation, Accretion Expense
Balance at end of period(2)
Recent Accounting Pronouncements
New Accounting Pronouncements, Policy [Policy Text Block]
Capital Stock
Stockholders' Equity Note Disclosure [Text Block]
Proved oil and gas properties
Proved Oil and Gas Property, Successful Effort Method
Unproved oil and gas properties
Unproved Oil and Gas Property, Successful Effort Method
Gathering and pipeline systems
Gathering and Pipeline Systems
Carrying amount at the balance sheet date for gathering and pipeline assets used in the normal conduct of business and not intended for resale. Amount does not include depreciation.
Land, building and other equipment
Property, Plant and Equipment, Other, Gross
Properties and equipment, gross, total
Property, Plant and Equipment, Gross
Accumulated depreciation, depletion and amortization
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment
Properties and equipment, net
Reconciliation of changes in the fair value of financial assets and liabilities classified as Level 3 in the fair value hierarchy
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance at beginning of period
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs
Total gain (loss) included in earnings
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings
Settlement (gain) loss
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Purchases, Sales, Issues, Settlements
Transfers in and/or out of level 3
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Transfers, Net
Balance at end of period
Change in unrealized gains (losses) relating to assets and liabilities still held at the end of the period
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Change in Unrealized Gain (Loss)