Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Abstract]
Fair Value Measurements, Recurring And Nonrecurring Basis [Table]
Fair Value Measurements, Recurring and Nonrecurring [Table]
Fair Value By Fair Value Hierarchy Level [Axis]
Fair Value Hierarchy and NAV [Axis]
Fair Value Measurements Fair Value Hierarchy [Domain]
Fair Value Hierarchy and NAV [Domain]
Quoted Prices in Active Markets (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]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Oil derivative contracts - current assets
Derivative Asset, Current
Oil derivative contracts - long-term assets
Derivative Asset, Noncurrent
Total Assets
Derivative Asset
Oil derivative contracts - current liabilities
Derivative Liability, Current
Oil derivative contracts - long-term liabilities
Derivative Liability, Noncurrent
Total Liabilities
Derivative Liability
Leases [Abstract]
2019
Operating Leases, Future Minimum Payments Due, Next Twelve Months
2020
Operating Leases, Future Minimum Payments, Due in Two Years
2021
Operating Leases, Future Minimum Payments, Due in Three Years
2022
Operating Leases, Future Minimum Payments, Due in Four Years
2023
Operating Leases, Future Minimum Payments, Due in Five Years
Thereafter
Operating Leases, Future Minimum Payments, Due Thereafter
Total minimum lease payments
Operating Leases, Future Minimum Payments Due
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents
Cash and Cash Equivalents, at Carrying Value
Restricted cash included in other assets
Restricted Cash and Cash Equivalents
Total cash, cash equivalents, and restricted cash shown in the unaudited condensed consolidated statement of cash flows
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents
Accounting Policies [Abstract]
Restricted cash
Statement [Table]
Statement [Table]
Adjustments for Error Corrections [Axis]
Adjustments for Error Corrections [Axis]
Adjustments for Error Correction [Domain]
Adjustments for Error Correction [Domain]
Previously Reported
Previously Reported [Member]
Adjustments
Scenario, Adjustment [Member]
Statement [Line Items]
Statement [Line Items]
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents
Net Cash Used in Investing Activities
Net Cash Provided by (Used in) Investing Activities
Debt Instrument, Convertible, Number of Equity Instruments
Debt Instrument, Convertible, Number of Equity Instruments
Earnings Per Share Reconciliation [Abstract]
Numerator
Numerator [Abstract]
The reconciliation of the numerator in the diluted EPS calculation.
Net income - basic
Net Income (Loss) Attributable to Parent
Interest on convertible senior notes including amortization of discount, net of tax
Interest on Convertible Debt, Net of Tax
Net income - diluted
Net Income (Loss) Available to Common Stockholders, Diluted
Denominator
Weighted Average Number of Shares Outstanding Reconciliation [Abstract]
Weighted average common shares outstanding - basic
Weighted Average Number of Shares Outstanding, Basic
Restricted stock and performance-based equity awards
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements
Convertible senior notes
Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities
Weighted average common shares outstanding - diluted
Weighted Average Number of Shares Outstanding, Diluted
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies
Commitments and Contingencies Disclosure [Text Block]
Revenue from Contract with Customer [Abstract]
Accrued production receivable
Other Receivables
Statement of Financial Position [Abstract]
Assets
Assets [Abstract]
Current assets
Assets, Current [Abstract]
Cash and cash equivalents
Trade and other receivables, net
Receivables, Net, Current
Derivative assets
Other current assets
Other Assets, Current
Total current assets
Assets, Current
Property and equipment
Property, Plant and Equipment, Net [Abstract]
Oil and natural gas properties (using full cost accounting)
Capitalized Costs, Oil and Gas Producing Activities, Gross [Abstract]
Proved properties
Capitalized Costs, Proved Properties
Unevaluated properties
Capitalized Costs, Unproved Properties
CO2 properties
Co2 Properties
Capitalized costs of natural CO2 properties including field support equipment and facilities.
Pipelines and plants
Pipelines And Plants
Capitalized costs of Pipelines and Plants
Other property and equipment
Property, Plant and Equipment, Other, Gross
Less accumulated depletion, depreciation, amortization and impairment
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment
Net property and equipment
Property, Plant and Equipment, Net
Operating lease right-of-use assets
Operating Lease, Right-of-Use Asset
Derivative assets
Other assets
Other Assets, Noncurrent
Total assets
Assets
Liabilities and Stockholders' Equity
Liabilities and Equity [Abstract]
Current liabilities
Liabilities, Current [Abstract]
Accounts payable and accrued liabilities
Accounts Payable and Accrued Liabilities, Current
Oil and gas production payable
Accounts Payable, Other, Current
Derivative liabilities
Current maturities of long-term debt (including future interest payable of $85,677 and $85,303, respectively - see Note 4)
Long-term Debt and Capital Lease Obligations, Current
Operating lease liabilities
Operating Lease, Liability, Current
Total current liabilities
Liabilities, Current
Long-term liabilities
Liabilities, Noncurrent [Abstract]
Long-term debt, net of current portion (including future interest payable of $121,982 and $164,914, respectively - see Note 4)
Long-term Debt and Capital Lease Obligations
Asset retirement obligations
Asset Retirement Obligations, Noncurrent
Derivative liabilities
Deferred tax liabilities, net
Deferred Tax Liabilities, Net, Noncurrent
Operating lease liabilities
Operating Lease, Liability, Noncurrent
Other liabilities
Other Liabilities, Noncurrent
Total long-term liabilities
Liabilities, Noncurrent
Commitments and contingencies (Note 7)
Commitments and Contingencies
Stockholders' equity
Stockholders' Equity Attributable to Parent [Abstract]
Preferred stock, $.001 par value, 25,000,000 shares authorized, none issued and outstanding
Preferred Stock, Value, Issued
Common stock, $.001 par value, 750,000,000 shares authorized; 464,166,479 and 462,355,725 shares issued, respectively
Common Stock, Value, Issued
Paid-in capital in excess of par
Additional Paid in Capital, Common Stock
Accumulated deficit
Retained Earnings (Accumulated Deficit)
Treasury stock, at cost, 2,474,904 and 1,941,749 shares, respectively
Treasury Stock, Value
Total stockholders' equity
Stockholders' Equity Attributable to Parent
Total liabilities and stockholders' equity
Liabilities and Equity
Organization and Nature of Operations
Nature of Operations [Text Block]
Interim Financial Statements - Basis of Accounting, Policy
Basis of Accounting, Policy [Policy Text Block]
Interim Financial Statements - Use of Estimates
Use of Estimates, Policy [Policy Text Block]
Reclassifications
Reclassification, Policy [Policy Text Block]
Cash, Cash Equivalents, and Restricted Cash
Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block]
Net Income per Common Share
Earnings Per Share, Policy [Policy Text Block]
Recent Accounting Pronouncements
New Accounting Pronouncements, Policy [Policy Text Block]
Revenue Recognition
Revenue Recognition, Policy [Policy Text Block]
Leases
Lessee, Leases [Policy Text Block]
Commodity Derivative Contracts
Derivatives, Policy [Policy Text Block]
Fair Value Measurements
Fair Value of Financial Instruments, Policy [Policy Text Block]
Effect of the Adoption of ASC Topic 842 (Leases) [Abstract]
Effect of the Adoption of ASC Topic 842 (Leases) [Abstract]
Leases [Table]
Leases [Table]
Leases [Table]
Lease Arrangement, Type [Axis]
Lease Arrangement, Type [Axis]
Lease Arrangement, Type [Domain]
Lease Arrangement, Type [Domain]
Pre-Existing Lease Liability [Member]
Pre-Existing Lease Liability [Member]
Pre-Existing Lease Liability [Member]
Lease Assets and Liabilities [Line Items]
Lessee, Lease, Description [Line Items]
Operating Lease, Liability
Operating Lease, Liability
Operating Lease, Right-of-Use Asset
Fair Value Disclosures [Abstract]
Fair value hierarchy of financial assets and liabilities
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]
Changes in fair value of Level 3 assets and liabilities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]
Qualitative valuation techniques for assets and liabilities measured on a recurring basis (Level 3)
Fair Value Measurement Inputs and Valuation Techniques [Table Text Block]
Basis of Presentation and Significant Accounting Policies
Basis of Presentation and Significant Accounting Policies [Text Block]
Operating Leases
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year
Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year
2020
Lessee, Operating Lease, Liability, Payments, Due Year Two
2021
Lessee, Operating Lease, Liability, Payments, Due Year Three
2022
Lessee, Operating Lease, Liability, Payments, Due Year Four
2023
Lessee, Operating Lease, Liability, Payments, Due Year Five
Thereafter
Lessee, Operating Lease, Liability, Payments, Due after Year Five
Total minimum lease payments
Lessee, Operating Lease, Liability, Payments, Due
Less: Amount representing interest
Lessee, Operating Lease, Liability, Undiscounted Excess Amount
Present value of minimum lease payments
Finance Leases
Finance Lease Liabilities, Payments, Due [Abstract]
2019
Finance Lease, Liability, Payments, Remainder of Fiscal Year
2020
Finance Lease, Liability, Payments, Due Year Two
2021
Finance Lease, Liability, Payments, Due Year Three
2022
Finance Lease, Liability, Payments, Due Year Four
2023
Finance Lease, Liability, Payments, Due Year Five
Thereafter
Finance Lease, Liability, Payments, Due after Year Five
Total minimum lease payments
Finance Lease, Liability, Payments, Due
Less: Amount representing interest
Finance Lease, Liability, Undiscounted Excess Amount
Present value of minimum lease payments
Finance Lease, Liability
Revenue Recognition
Revenue from Contract with Customer [Text Block]
Loss Contingencies [Table]
Loss Contingencies [Table]
Loss Contingency Nature [Axis]
Loss Contingency Nature [Axis]
Loss Contingency, Nature [Domain]
Loss Contingency, Nature [Domain]
Total liquidated damages
TotalLiquidatedDamages [Member]
Total liquidated damages
Other costs associated with the settlement
Other Costs Associated With Settlement [Member]
Other costs associated with settlement [Member]
Liquidated damages for contract years ending July 31, 2018 and July 31, 2019
Liquidated Damages For Remaining Contract Years [Member]
Liquidated damages for remaining contract years [Member]
Loss Contingencies [Line Items]
Loss Contingencies [Line Items]
Estimated Litigation Liability
Estimated Litigation Liability, Noncurrent
Fair Value Measurement Inputs and Valuation Techniques [Table]
Fair Value Measurement Inputs and Valuation Techniques [Table]
Valuation Approach and Technique [Axis]
Valuation Approach and Technique [Axis]
Valuation Approach and Technique [Domain]
Valuation Approach and Technique [Domain]
Income Approach Valuation Technique
Valuation, Income Approach [Member]
Range [Axis]
Range [Axis]
Range [Domain]
Range [Domain]
Minimum
Minimum [Member]
Maximum
Maximum [Member]
Fair Value Measurements, Recurring and nonrecurring, Valuation Techniques [Line Items]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs
Expected Volatility Range
Fair Value Assumptions, Expected Volatility Rate for a Commodity
Fair Value Assumptions, Expected Volatility Rate for a Commodity
Subsequent Events [Abstract]
Subsequent Event
Subsequent Events [Text Block]
Schedule of Lease Assets and Liabilities
Leases [Table Text Block]
[Table Text Block] for Schedule Of Supplemental Balance Sheet Information Related to Leases [Table]
Schedule of Weighted Average Lease Terms and Discount Rates
Schedule of Lease Terms and Discount Rates [Table Text Block]
[Table Text Block] for Schedule of Lease Terms and Discount Rates [Table]
Schedule of Lease Costs
Lease, Cost [Table Text Block]
Supplemental Cash Flow Information Related to Leases
Schedule Of Supplemental Cash Flow Information Related to Leases [Table Text Block]
Schedule of supplemental cash flow information related to leases[Table Text Block]
Schedule of Maturities of Operating and Finance Lease Liabilities
Schedule Of Maturities Of Operating And Finance Lease Liabilities
Schedule Of Maturities Of Operating And Finance Lease Liabilities [Table Text Block]
Schedule of operating long-term commitments which require future minimum lease payments
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]
Operating lease cost
Operating Lease, Cost
Finance lease cost
Finance Lease, Cost [Abstract]
Amortization of right-of-use assets
Finance Lease, Right-of-Use Asset, Amortization
Interest on lease liabilities
Finance Lease, Interest Expense
Total finance lease cost
Lease, Cost
Sublease income
Sublease Income
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]
Award Type [Axis]
Award Type [Axis]
Equity Award [Domain]
Equity Award [Domain]
Restricted Stock
Restricted Stock [Member]
Cash Settled Restricted Stock Units
Restricted Stock Units (RSUs) [Member]
Subsequent Event [Line Items]
Subsequent Event [Line Items]
Grants during period
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period
Value (per share) of restricted stock granted
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 floor
Stock Price Floor
Stock price floor
Equity award vesting percentage
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period
Schedule of cash, cash equivalents, and restricted cash
Schedule of Cash and Cash Equivalents [Table Text Block]
Schedule of earnings per share, basic and diluted reconciliation
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]
Commitments and contingencies (Note 7)
Debt and Capital Lease Obligations [Abstract]
Debt and Capital Lease Obligations [Abstract]
Schedule of Long-term Debt Instruments [Table]
Schedule of Long-term Debt Instruments [Table]
Long-term Debt, Type [Axis]
Long-term Debt, Type [Axis]
Long-term Debt, Type [Domain]
Long-term Debt, Type [Domain]
Future interest payable on senior secured notes
Future Interest Payable On Senior Secured Notes [Member]
Future Interest Payable On Senior Secured Notes
Debt Instrument [Line Items]
Debt Instrument [Line Items]
Future interest payable - current
Future interest payable - long-term
Preferred stock, par value
Preferred Stock, Par or Stated Value Per Share
Preferred stock, shares authorized
Preferred Stock, Shares Authorized
Preferred stock, shares issued
Preferred Stock, Shares Issued
Preferred stock, shares outstanding
Preferred Stock, Shares Outstanding
Common stock, par value
Common Stock, Par or Stated Value Per Share
Common stock, shares authorized
Common Stock, Shares Authorized
Common stock, shares issued
Common Stock, Shares, Issued
Treasury stock, shares
Treasury Stock, Shares
Statement of Stockholders' Equity [Abstract]
Equity Components [Axis]
Equity Components [Axis]
Equity Component [Domain]
Equity Component [Domain]
Common Stock ($.001 Par Value)
Common Stock [Member]
Paid-In Capital in Excess of Par
Additional Paid-in Capital [Member]
Retained Earnings (Accumulated Deficit)
Retained Earnings [Member]
Treasury Stock (at cost)
Treasury Stock [Member]
Beginning balance, shares
Beginning balance
Issued or purchased pursuant to stock compensation plans, shares
Stock Issued During Period, Shares, Share-based Compensation, Gross
Issued or purchased pursuant to stock compensation plans, value
Stock Issued During Period, Value, Share-based Compensation, Gross
Issued pursuant to notes conversion, shares
Stock Issued During Period, Shares, New Issues
Issued pursuant to directors' compensation plan, shares
Stock Issued During Period, Shares, Other
Issued pursuant to notes conversion, value
Stock Issued During Period, Value, New Issues
Stock-based compensation, value
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition
Tax withholding - stock compensation, shares
Shares Paid for Tax Withholding for Share Based Compensation
Tax withholding - stock compensation, value
Adjustments Related to Tax Withholding for Share-based Compensation
Net income (loss)
Ending balance, shares
Ending balance
Term of long term supply arrangement
Term of Long Term Supply Arrangement
Term of long-term supply agreement, expressed in years.
Maximum annual payment in event of shortfall
Maximum Annual Payment In Event Of Shortfall
Maximum amount to be paid each year in the event of a shortfall in volume on a supply commitment.
Maximum payment in event of shortfall
Maximum Payment In Event Of Shortfall
Maximum amount over the term of the contract that can be paid in the event of a shortfall in volume on a supply commitment.
Earnings Per Share [Abstract]
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
Stock Appreciation Rights (SARs) [Member]
Restricted Stock and Performance-Based Equity Awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Abstract]
Fair Value, Net Derivative Asset Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Fair value of Level 3 instruments, beginning of period
Fair value gains (losses) on commodity derivatives
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings
Receipts on settlements of commodity derivatives
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Settlements
Fair value of Level 3 instruments, end of period
The amount of total gains (losses) for the period included in earnings attributable to the change in unrealized gains (losses) relating to assets or liabilities still held at the reporting date
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)
Weighted Average Remaining Lease Term
Weighted Average Remaining Lease Term (years) [Abstract]
Weighted average remaining lease term (in years)
Operating leases
Operating Lease, Weighted Average Remaining Lease Term
Finance leases
Finance Lease, Weighted Average Remaining Lease Term
Weighted Average Discount Rate
Weighted Average Discount Rate [Abstract]
Weighted average discount rate
Operating leases
Operating Lease, Weighted Average Discount Rate, Percent
Finance leases
Finance Lease, Weighted Average Discount Rate, Percent
Debt Instrument [Axis]
Debt Instrument [Axis]
Debt Instrument, Name [Domain]
Debt Instrument, Name [Domain]
9% Senior Secured Second Lien Notes due 2021
9% Senior Secured Second Lien Notes Due 2021 [Member]
9% Senior Secured Second Lien Notes Due 2021
9 1/4% Senior Secured Second Lien Notes due 2022
9 1/4% Senior Secured Second Lien Notes Due 2022 [Member]
9 1/4% Senior Secured Second Lien Notes Due 2022 [Member]
7 3/4% Senior Secured Second Lien Notes due 2024
7 3/4% Senior Secured Second Lien Notes Due 2024 [Member]
7 3/4% Senior Secured Second Lien Notes Due 2024 [Member]
7 1/2% Senior Secured Second Lien Notes due 2024
7 1/2% Senior Secured Second Lien Notes due 2024 [Member]
7 1/2% Senior Secured Second Lien Notes due 2024 [Member]
6 3/8% Convertible Senior Notes due 2024
6 3/8% Convertible Senior Notes Due 2024 [Member]
6 3/8% Convertible Senior Notes Due 2024 [Member]
6 3/8% Senior Subordinated Notes due 2021
Senior Subordinated Notes Due 2021 [Member]
Senior Subordinated Notes Due 2021.
5 1/2% Senior Subordinated Notes due 2022
5.5% Senior Subordinated Notes Due 2022 [Member]
5.5% Senior Subordinated Notes Due 2022 [Member]
4 5/8% Senior Subordinated Notes due 2023
Senior Subordinated Notes Due 2023 [Member]
Senior Subordinated Notes Due 2023
Senior Secured Bank Credit Agreement
Long-term Line of Credit
Long-term Debt, Gross
Long-term Debt, Gross
Pipeline financings
Financing Lease Obligations
Financing Lease Obligations
Capital lease obligations
Capital Lease Obligations
Total debt principal balance
Debt and Capital Lease Obligations
Debt discount
Debt Instrument, Unamortized Discount
Future interest payable
Future Interest Payable on Senior Secured Notes
Future interest payable on senior secured notes
Debt issuance costs
Debt Issuance Costs, Net
Total debt, net of debt issuance costs and discount
Total Debt, Net Of Debt Issuance Costs
Amount of long-term debt and capital lease obligations due after one year or beyond the normal operating cycle, if longer, net of debt issuance costs on senior secured and senior subordinated notes.
Less: current maturities of long-term debt
Debt Instrument, Interest Rate, Stated Percentage
Debt Instrument, Interest Rate, Stated Percentage
Disaggregation of Revenue [Table]
Disaggregation of Revenue [Table]
Product and Service [Axis]
Product and Service [Axis]
Product and Service [Domain]
Product and Service [Domain]
Oil sales
Oil Sales [Member]
Revenue from the sale of oil and NGL products.
Natural gas sales
Natural Gas Sales [Member]
Revenue from the sale of natural gas.
CO2 sales and transportation fees
CO2 Sales And Transportation Fees [Member]
Revenue generated from CO2 sales and transportation fees.
Purchased oil sales
Oil and Gas, Purchased [Member]
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue [Line Items]
Revenues
Revenue from Contract with Customer, Excluding Assessed Tax
Debt Disclosure [Abstract]
Long-Term Debt
Debt Disclosure [Text Block]
Disaggregation of Revenue
Disaggregation of Revenue [Table Text Block]
Income Statement [Abstract]
Expenses
Costs and Expenses [Abstract]
Capitalized interest
Interest Costs Capitalized
Cash paid for amounts included in the measurement of lease liabilities
Cash Paid For Amounts Included In The Measurement Of Lease Liabilities [Abstract]
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows from operating leases
Operating Lease, Payments
Operating cash flows from interest on finance leases
Finance Lease, Interest Payment on Liability
Financing cash flows from finance leases
Finance Lease, Principal Payments
Right-of-use assets obtained in exchange for lease obligations
Right-Of-Use Assets Obtained In Exchange For Lease Obligations [Abstract]
Right-of-use assets obtained in exchange for lease obligations
Operating leases
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability
Finance leases
Right-of-Use Asset Obtained in Exchange for Finance Lease Liability
Oil, natural gas, and related product sales
Oil and Gas [Member]
CO2
Carbon dioxide [Member]
Carbon dioxide
Income Statement Location [Axis]
Income Statement Location [Axis]
Income Statement Location [Domain]
Income Statement Location [Domain]
Other income
Other Income [Member]
Transportation and marketing
Oil and Gas, Refining and Marketing [Member]
Revenues and other income
Revenues
Operating expenses
Operating Costs and Expenses
Taxes other than income
Taxes, Other
General and administrative expenses
General and Administrative Expense
Interest, net of amounts capitalized of $8,238, $8,851, $18,772 and $17,303, respectively
Interest Expense
Depletion, depreciation, and amortization
Depreciation, Depletion and Amortization
Commodity derivatives expense (income)
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net
Gain on debt extinguishment
Gain (Loss) on Extinguishment of Debt
Other expenses
Other Expenses
Total expenses
Costs and Expenses
Income tax provision
Income Tax Expense (Benefit)
Net income
Net income per common share
Basic
Earnings Per Share, Basic
Diluted
Earnings Per Share, Diluted
Weighted average common shares outstanding
Earnings Per Share, Basic and Diluted, Other Disclosures [Abstract]
Basic
Diluted
Sensitivity Analysis of Fair Value, Impact of 100 Basis Point Increase or Decrease in Level 3 Inputs
Sensitivity Analysis of Fair Value, Impact of 100 Basis Point Increase or Decrease in Level 3 Inputs
The financial impact of a 100 basis point increase or decrease in volatility of a level 3 input as of the balance sheet date.
Debt, Fair Value
Notes Payable, Fair Value Disclosure
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative [Table]
Derivative [Table]
Derivative Instrument [Axis]
Derivative Instrument [Axis]
Derivative Contract [Domain]
Derivative Contract [Domain]
Swap
Swap [Member]
Three-way Collar
Three-way Collar [Member]
Three-way Collar [Member]
Derivative By Year [Axis]
Derivative By Year [Axis]
Derivative By Year.
Derivative By Year [Domain]
Derivative By Year [Domain]
Derivative By Year.
Year 2019
Year 2019 [Member]
Year 2019
Year 2020
Year 2020 [Member]
Year 2020 [Member]
Derivative by Period [Axis]
Derivative by Period [Axis]
Derivative By Period.
Derivative by Period [Domain]
Derivative by Period [Domain]
Derivative By Period.
Q1-Q2
Q1-Q2 [Member]
Q1-Q2 [Member]
Q3-Q4
Q3-Q4 [Member]
Q3-Q4
Derivative By Index [Axis]
Derivative by Index [Axis]
Derivative by Index [Axis]
Derivative By Name [Domain]
Derivative by Name [Domain]
[Domain] for Derivative by Nature [Axis]
NYMEX
NYMEX [Member]
NYMEX
LLS
LLS [Member]
LLS
Derivative [Line Items]
Derivative [Line Items]
Volume per day
Derivative, Nonmonetary Notional Amount
Derivative, Swap Type, Fixed Price
Derivative, Swap Type, Fixed Price
Weighted average swap price
Derivative, Swap Type, Average Fixed Price
Derivative, Floor Price
Derivative, Floor Price
Derivative, Cap Price
Derivative, Cap Price
Weighted average sold put price
Derivative, Average Price Risk Option Strike Price
Weighted average floor price
Derivative, Average Floor Price
Weighted average ceiling price
Derivative, Average Cap Price
Commodity derivative contracts not classified as hedging instruments
Schedule of Derivative Instruments [Table Text Block]
Components of Long-Term Debt
Schedule of Debt [Table Text Block]
Leases
Leases of Lessee Disclosure [Text Block]
Senior Subordinated Notes
Senior Subordinated Notes [Member]
Covenant By Year [Axis]
Covenant By Year [Axis]
Covenant By Year
Covenant By Year [Domain]
Covenant By Year [Domain]
[Domain] for Covenant By Year
Year 2021
Year 2021 [Member]
Year 2021 [Member]
Covenant By Period [Axis]
Covenant By Period [Axis]
Covenant By Period
Covenant By Period [Domain]
Covenant By Period [Domain]
[Domain] for Covenant By Period
Q1
Q1 [Member]
Quarter 1.
Q2
Q2 [Member]
Quarter 2.
Q3
Q3 [Member]
Quarter 3.
Portion of exchange related to Senior Secured Notes
Portion Of Exchange Related To Senior Secured Notes [Member]
Portion Of Exchange Related To Senior Secured Notes [Member]
4 5/8% Senior Subordinated Notes due 2023
4 5/8% Senior Subordinated Notes Due 2023 [Member]
4 5/8% Senior Subordinated Notes Due 2023 [Member]
6 3/8% Convertible Senior Notes due 2024
5 1/2% Senior Subordinated Notes due 2022
5 1/2% Senior Subordinated Notes Due 2022 [Member]
5 1/2% Senior Subordinated Notes Due 2022 [Member]
Debt Instrument, Redemption, Period [Axis]
Debt Instrument, Redemption, Period [Axis]
Debt Instrument, Redemption, Period [Domain]
Debt Instrument, Redemption, Period [Domain]
Debt Instrument, Redemption, Period One
Debt Instrument, Redemption, Period One [Member]
Initial Redemption Period With Proceeds From Equity Offering
Initial Redemption Period With Proceeds From Equity Offering [Member]
Initial Redemption Period With Proceeds From Equity Offering
Debt Instrument, Redemption, Period Two
Debt Instrument, Redemption, Period Two [Member]
Initial Redemption Period With Make Whole Premium
Initial Redemption Period With Make Whole Premium [Member]
Initial Redemption Period With Make Whole Premium
Extinguishment of Debt [Axis]
Extinguishment of Debt [Axis]
Extinguishment of Debt, Type [Domain]
Extinguishment of Debt, Type [Domain]
Portion of notes exchange related to senior subordinated notes
Portion Of Exchange Related To Senior Subordinated Notes [Member]
Portion Of Exchange Related To Senior Subordinated Notes [Member]
Interest in guarantor subsidiaries
Interest In Guarantor Subsidiaries
Interest in entities which guarantee our debt issuances, expressed as a percentage
Borrowing base
Line of Credit Facility, Maximum Borrowing Capacity
Lender commitments
Line of Credit Facility, Current Borrowing Capacity
Line of Credit Facility, Interest Rate During Period
Line of Credit Facility, Interest Rate During Period
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage
Senior secured debt to consolidated EBITDAX
Senior Secured Debt to EBITDAX
Maximum permitted Senior Secured Debt to consolidated EBITDAX ratio.
Consolidated EBITDAX to consolidated interest charges
EBITDAX to Consolidated Interest
Minimum permitted consolidated EBITDAX to Consolidated Interest charges ratio.
Current ratio requirement
Current Ratio Requirement
Current Ratio Requirement
Long-Term Debt (Textual) [Abstract]
Debt Instruments [Abstract]
Debt Exchange, Amount
Debt Exchange, Amount
Amount of debt exchanged for other debt or securities during the period.
Debt Instrument, Face Amount
Debt Instrument, Face Amount
Debt Instrument, Percentage of Principal Amount Available To Be Redeemed
Debt Instrument, Percentage of Principal Amount Available To Be Redeemed
Debt Instrument, Percentage of Principal Amount Available To Be Redeemed
Cash paid in conjunction with debt exchange
Early Repayment of Subordinated Debt
Debt Instrument, Redemption Price, Percentage
Debt Instrument, Redemption Price, Percentage
Gain on debt extinguishment
Long-term Debt, Gross
Debt discount
Debt Instrument, Interest Rate, Effective Percentage
Debt Instrument, Interest Rate, Effective Percentage
Fair Value Issuance Percentage
Fair Value Percentage At Issuance Date
Fair Value Percentage At Issuance Date
Senior Secured Bank Credit Facility [Abstract]
Line of Credit Facility [Abstract]
Total Debt to Consolidated EBITDAX
TotalDebttoConsolidatedEBITDAX
Maximum permitted total debt to consolidated EBITDAX.
Convertible Debt [Abstract]
Share conversion rate per $1,000 principal
Debt Instrument, Convertible, Conversion Ratio
Volume weighted average stock price for automatic conversion
Debt Instrument, Convertible, Stock Price Trigger
Threshold trading days for automatic debt conversion
Debt Instrument, Convertible, Threshold Trading Days
Consecutive trading days threshold for automatic debt conversion
Debt Instrument, Convertible, Threshold Consecutive Trading Days
Document And Company Information [Abstract]
Document and Company Information.
Document Type
Document Type
Document Quarterly Report
Document Quarterly Report
Document Period End Date
Document Period End Date
Document Transition Report
Document Transition Report
Entity File Number
Entity File Number
Entity Registrant Name
Entity Registrant Name
Entity Incorporation, State or Country Code
Entity Incorporation, State or Country Code
Entity Tax Identification Number
Entity Tax Identification Number
Entity Address, Address Line One
Entity Address, Address Line One
Entity Address, City or Town
Entity Address, City or Town
Entity Address, State or Province
Entity Address, State or Province
Entity Address, Postal Zip Code
Entity Address, Postal Zip Code
City Area Code
City Area Code
Local Phone Number
Local Phone Number
Title of 12(b) Security
Title of 12(b) Security
Trading Symbol
Trading Symbol
Security Exchange Name
Security Exchange Name
Entity Current Reporting Status
Entity Current Reporting Status
Entity Interactive Data Current
Entity Interactive Data Current
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
Entity Central Index Key
Entity Central Index Key
Current Fiscal Year End Date
Current Fiscal Year End Date
Document Fiscal Year Focus
Document Fiscal Year Focus
Document Fiscal Period Focus
Document Fiscal Period Focus
Amendment Flag
Amendment Flag
Operating Leases
Leases, Operating [Abstract]
Operating lease liabilities - current
Operating lease liabilities - long-term
Total operating lease liabilities
Finance leases
Other property and equipment
FinanceLeaseRightOfUseAssetGross
Gross amount of lessee's right to use underlying asset under finance lease.
Accumulated depreciation
Finance Lease Right Of Use Asset Accumulated Depreciation
Amount of accumulated depreciation related to finance lease right-of-use assets.
Other property and equipment, net
Finance Lease, Right-of-Use Asset
Current maturities of long-term debt
Finance Lease, Liability, Current
Long-term debt, net of current portion
Finance Lease, Liability, Noncurrent
Total finance lease liabilities
Commodity Derivative Contracts
Derivative Instruments and Hedging Activities Disclosure [Text Block]
Fair Value Measurements
Fair Value Disclosures [Text Block]
Statement of Cash Flows [Abstract]
Cash flows from operating activities
Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract]
Adjustments to reconcile net income to cash flows from operating activities
Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract]
Deferred income taxes
Deferred Income Tax Expense (Benefit)
Stock-based compensation
Share-based Compensation
Receipt (payment) on settlements of commodity derivatives
Receipt (Payment) On Settlements of Commodity Derivatives
Receipt (payment) on settlements of commodity derivatives
Debt issuance costs and discounts
Amortization of Debt Issuance Costs and Discounts
Other, net
Other Noncash Income (Expense)
Changes in assets and liabilities, net of effects from acquisitions
Increase (Decrease) in Operating Capital [Abstract]
Accrued production receivable
Increase (Decrease) in Other Receivables
Trade and other receivables
Increase (Decrease) in Receivables
Other current and long-term assets
Increase (Decrease) in Other Operating Assets
Accounts payable and accrued liabilities
Increase (Decrease) in Accounts Payable and Accrued Liabilities
Oil and natural gas production payable
Increase (Decrease) in Other Accounts Payable
Other liabilities
Increase (Decrease) in Other Operating Liabilities
Net cash provided by operating activities
Net Cash Provided by (Used in) Operating Activities, Continuing Operations
Cash flows from investing activities
Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract]
Oil and natural gas capital expenditures
Payments to Explore and Develop Oil and Gas Properties
Pipelines and plants capital expenditures
Payments To Construct And Develop Pipelines And Plants
Capital expenditures to construct and develop CO2 pipelines and capital expenditures related to plants.
Net proceeds from sales of oil and natural gas properties and equipment
Proceeds from Sale of Oil and Gas Property and Equipment
Other
Payments for (Proceeds from) Other Investing Activities
Net cash used in investing activities
Net Cash Provided by (Used in) Investing Activities, Continuing Operations
Cash flows from financing activities
Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract]
Bank repayments
Repayments of Long-term Lines of Credit
Bank borrowings
Proceeds from Long-term Lines of Credit
Interest payments treated as a reduction of debt
Interest payments treated as a reduction of debt
Interest payments treated as a reduction of debt
Cash paid in conjunction with debt exchange
Costs of debt financing
Payments of Debt Issuance Costs
Pipeline financing and capital lease debt repayments
Payments to Acquire Equipment on Lease
Other
Proceeds from (Payments for) Other Financing Activities
Net cash used in financing activities
Net Cash Provided by (Used in) Financing Activities, Continuing Operations
Net increase (decrease) in cash, cash equivalents, and restricted cash
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect
Cash, cash equivalents, and restricted cash at beginning of period
Cash, cash equivalents, and restricted cash at end of period