Other Liabilities Disclosure [Abstract] Accrued Liabilities and Other Other Liabilities Disclosure [Text Block] Oil and Gas Exploration and Production Industries Disclosures [Abstract] Proved Developed and Undeveloped Oil and Gas Reserve Quantities [Table] Proved Developed and Undeveloped Oil and Gas Reserve Quantities [Table] Petroleum Reserves [Axis] Petroleum Reserves [Axis] Type of Reserve [Domain] Type of Reserve [Domain] Crude Oil Oil [Member] Natural Gas Liquids Natural Gas Liquids [Member] Natural Gas Natural Gas [Member] Estimated Net Quantities of Proved Oil and Natural Gas Reserves Reserve Quantities [Line Items] Estimated quantities of proved oil and natural gas reserves and changes in quantities of proved developed and undeveloped reserves Proved Developed and Undeveloped Reserves [Roll Forward] Balance at the beginning of the period (in Bbls/Mcf) Proved Developed and Undeveloped Reserves, Net Revisions of previous estimates (in Bbls/Mcf) Proved Developed and Undeveloped Reserves, Revisions of Previous Estimates Improved recovery, extensions and discoveries (in Bbls/Mcf) Proved Developed and Undeveloped Reserves, Recovery Extensions and Discoveries Changes in proved reserve estimates resulting from application of improved recovery, extensions and discovery techniques. Sales of minerals in place (in Bbls/Mcf) Proved Developed and Undeveloped Reserves, Sales of Minerals in Place Production (sales volumes) (in Bbls/Mcf) Proved Developed and Undeveloped Reserves, Production Balance at the end of the period (in Bbls/Mcf) Estimated quantities of proved oil and natural gas reserves and changes in quantities of proved developed and undeveloped reserves Proved Developed and Undeveloped Reserve (Energy) [Roll Forward] Balance at the beginning of the period (in BOE) Proved Developed and Undeveloped Reserve, Net (Energy) Revisions of previous estimates (in BOE) Proved Developed and Undeveloped Reserve, Revision of Previous Estimate (Energy) Improved recovery, extensions and discoveries (in BOE) Proved Developed and Undeveloped Reserves Energy Equivalents Improved Recovery Extensions Discoveries and Additions Additions to proved reserves, measured in energy equivalents, that result from (1) improved recovery (2) extension of the proved acreage of previously discovered (old) reservoirs through additional drilling in periods after discovery and (3) discovery of new fields with proved reserves or of new reservoirs of proved reserves in old fields. Sales of minerals in place (in BOE) Proved Developed and Undeveloped Reserves, Sale of Mineral in Place (Energy) Production (sales volumes) (in BOE) Proved Developed and Undeveloped Reserve, Production (Energy) Balance at the end of the period (in BOE) Proved developed reserves (in Bbls/Mcf) Proved Developed Reserves (Volume) Proved developed reserves (in BOE) Proved Developed Reserves (Energy) Proved undeveloped reserves (in Bbls/Mcf) Proved Undeveloped Reserve (Volume) Proved undeveloped reserves (in BOE) Proved Undeveloped Reserves (Energy) Standardized measure of discounted future net cash flows Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Net Cash Flows [Abstract] Future cash inflows Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Cash Inflows Future production costs and severance taxes Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Production Costs Future development costs Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Development Costs Future income tax expenses Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Income Tax Expense Future net cash flows Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Net Cash Flows 10% annual discount for estimated timing of cash flows Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Ten Percent Annual Discount for Estimated Timing of Cash Flows Standardized measure of discounted future net cash flows Standardized Measure of Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves Debt Disclosure [Abstract] Credit Agreements Debt Disclosure [Text Block] Equity [Abstract] Class of Treasury Stock [Table] Class of Treasury Stock [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Stock Common Stock [Member] Share Repurchase Program [Axis] Share Repurchase Program [Axis] Share Repurchase Program [Domain] Share Repurchase Program [Domain] 2015 Share Repurchase Program 2015 Share Repurchase Program [Member] 2015 Share Repurchase Program [Member] Equity, Class of Treasury Stock [Line Items] Equity, Class of Treasury Stock [Line Items] Number of treasury shares acquired (shares) Treasury Stock, Shares, Acquired Average cost per share (in USD per share) Treasury Stock Acquired, Average Cost Per Share Total cost of treasury shares acquired Treasury Stock, Value, Acquired, Cost Method Income Tax Disclosure [Abstract] Schedule of components of income tax provision (benefit) Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Schedule of reconciliation of statutory income tax expense to income tax provision Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Schedule of components of deferred taxes Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Operating Loss Carryforwards [Table] Operating Loss Carryforwards [Table] Income Tax Authority [Axis] Income Tax Authority [Axis] Income Tax Authority [Domain] Income Tax Authority [Domain] Federal Domestic Tax Authority [Member] Tax Credit Carryforward [Axis] Tax Credit Carryforward [Axis] Tax Credit Carryforward, Name [Domain] Tax Credit Carryforward, Name [Domain] Mineral Property Depletion Mineral Property Depletion [Member] Mineral Property Depletion [Member] Operating Loss Carryforwards [Line Items] Operating Loss Carryforwards [Line Items] Tax rate one time excluding adjustment Effective Income Tax Rate Reconciliation, Percent, Excluding One Time Adjustment Effective Income Tax Rate Reconciliation, Percent, Excluding One Time Adjustment Statutory tax rate Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Blended income tax rate Effective Income Tax Rate Reconciliation, At Blended Income Tax Rate, Percent Effective Income Tax Rate Reconciliation, At Blended Income Tax Rate, Percent Deferred tax benefit Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Change In Tax Rate, Deferred Tax Asset, Provisional Income Tax Expense (Benefit) Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Change In Tax Rate, Deferred Tax Asset, Provisional Income Tax Expense (Benefit) Income tax rate percentage Effective Income Tax Rate Reconciliation, Percent Unrecognized tax benefits Unrecognized Tax Benefits Tax loss carryforward from reverse merger Tax Credit Carryforward, Amount, Due to Reverse Merger Tax Credit Carryforward, Amount, Due to Reverse Merger Carryforward from reverse merger Deferred Taxes Business Combination Operating Loss Carryforwards Amount Available to Use Amount of operating loss carry-forwards recorded in a business combination which is available in equal amounts to reduce future taxable income under enacted tax laws. Annual amount of carryforward from reverse merger through 2023 Deferred Taxes Business Combination Operating Loss Carryforwards Annual Amount Available to Use Deferred Taxes Business Combination Operating Loss Carryforwards Annual Amount Available to Use Tax loss carryforwards from exercise of options and warrants Tax Credit Carryforward, Amount, Due to Exercise of Options and Warrants Tax Credit Carryforward, Amount, Due to Exercise of Options and Warrants Tax benefits related to stock-based compensation Excess Tax Benefit from Share-based Compensation, Financing Activities Tax carryforward Tax Credit Carryforward, Amount Statement of Financial Position [Abstract] Assets Assets [Abstract] Current assets Assets, Current [Abstract] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Restricted cash Restricted Cash, Current Receivables Receivables, Net, Current Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current Total current assets Assets, Current Property and equipment, net of depreciation, depletion, and amortization Property, Plant and Equipment, Net [Abstract] Oil and natural gas properties—full-cost method of accounting, of which none were excluded from amortization Oil and Gas Property, Full Cost Method, Net Other property and equipment, net Property, Plant and Equipment, Other, Net Total property and equipment, net Property, Plant and Equipment, Net Other assets, net Other Assets, Noncurrent Total assets Assets Liabilities and Stockholders' Equity Liabilities and Equity [Abstract] Current liabilities Liabilities, Current [Abstract] Accounts payable Accounts Payable, Current Accrued liabilities and other Other Liabilities, Current State and federal taxes payable Taxes Payable, Current Total current liabilities Liabilities, Current Long term liabilities Long-term Debt, Excluding Current Maturities [Abstract] Deferred income taxes Deferred Tax Liabilities, Net, Noncurrent Asset retirement obligations Asset Retirement Obligations, Noncurrent Total liabilities Liabilities Commitments and contingencies (Note 16) Commitments and Contingencies Stockholders' equity Stockholders' Equity Attributable to Parent [Abstract] Common stock; par value $0.001; 100,000,000 shares authorized: issued and outstanding 33,080,543 and 33,087,308 shares as of June 30, 2018 and 2017, respectively Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital Retained earnings Retained Earnings (Accumulated Deficit) Total stockholders' equity Stockholders' Equity Attributable to Parent Total liabilities and stockholders' equity Liabilities and Equity Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Preferred Preferred Stock [Member] Additional Paid-in Capital Additional Paid-in Capital [Member] Retained Earnings Retained Earnings [Member] Treasury Stock Treasury Stock [Member] Statement [Line Items] Statement [Line Items] Increase (Decrease) in Stockholders' Equity Increase (Decrease) in Stockholders' Equity [Roll Forward] Balance Balance (shares) Shares, Outstanding Issuance of restricted common stock Stock Issued During Period, Value, Restricted Stock Award, Gross Issuance of restricted common stock (shares) Stock Issued During Period, Shares, Restricted Stock Award, Gross Exercise of stock options Stock Issued During Period, Value, Stock Options Exercised Exercise of stock options (shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Forfeiture of restricted stock Stock Issued During Period, Value, Share-based Compensation, Forfeited Forfeiture of restricted stock (shares) Stock Issued During Period, Shares, Share-based Compensation, Forfeited Common share repurchases, including shares surrendered for tax withholding Common share repurchases, including shares surrendered for tax withholding (shares) Retirements of treasury stock Treasury Stock, Retired, Cost Method, Amount Stock-based compensation Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Redemption of preferred shares Stock Redeemed or Called During Period, Value Redemption of preferred shares (shares) Stock Redeemed or Called During Period, Shares Tax benefits related to stock-based compensation Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation Net income Net Income (Loss) Attributable to Parent Common stock cash dividends Dividends, Common Stock Preferred stock cash dividends Dividends, Preferred Stock Balance Balance (shares) Supplemental Cash Flow Elements [Abstract] Schedule of supplemental disclosures of cash flow information Schedule of Cash Flow, Supplemental Disclosures [Table Text Block] Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract] Royalty rights Royalty Rights Royalty Rights Less: Accumulated amortization of royalty rights Accumulated Amortization, Royalty Rights Accumulated Amortization, Royalty Rights Investment in Well Lift Inc., at cost Cost Method Investments Deferred loan costs Debt Issuance Costs, Gross Less: Accumulated amortization of deferred loan costs Accumulated Amortization, Debt Issuance Costs Software license Capitalized Computer Software, Gross Less: Accumulated amortization of software license Capitalized Computer Software, Accumulated Amortization Other assets, net Deferred Costs and Other Assets Accounting Policies [Abstract] Allowance for doubtful accounts Allowance for Doubtful Accounts Receivable, Current Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Measurement Input Type [Axis] Measurement Input Type [Axis] Measurement Input Type [Domain] Measurement Input Type [Domain] Discount rate Measurement Input, Discount Rate [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 natural gas properties Oil and Gas Properties [Member] Other Property and Equipment Other Capitalized Property Plant and Equipment [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Summary of Significant Accounting Policies Property, Plant and Equipment [Line Items] Limitation on Capitalized Costs Limitation on Capitalized Costs [Abstract] Discount rate for present value (as a percent) Alternative Investment, Measurement Input Period considered for computing unweighted arithmetic average of oil and natural gas prices (in months) Period Considered for Unweighted Arithmetic Average for Determining Oil and Natural Gas Prices Represents the period considered for calculating unweighted arithmetic average which is used to compute oil and natural gas prices. Other Property and Equipment Property, Plant and Equipment, Other, Net [Abstract] Expected lives of the individual assets or group of assets Property, Plant and Equipment, Useful Life Statement of Cash Flows [Abstract] Cash Flows From Operating Activities Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract] Net income attributable to the Company 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, depletion and amortization Depreciation Depletion and Amortization Cash Flows Impact The net cash impact recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets. Impairments included in restructuring charge Asset Impairment Charges Stock-based compensation Share-based Compensation Accretion of discount on asset retirement obligations Asset Retirement Obligation, Accretion Expense Settlement of asset retirement obligations Asset Retirement Obligation, Cash Paid to Settle Deferred income taxes Deferred Income Tax Expense (Benefit) Gain on derivative instruments, net Gain (Loss) on Derivative Instruments, Net, Pretax Noncash gain on Delhi field litigation settlement Noncash Gain (Loss) on Litigation Settlement, Fair Value Noncash Gain (Loss) on Litigation Settlement, Fair Value Write-off of deferred loan costs Write off of Deferred Debt Issuance Cost Changes in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Receivables Increase (Decrease) in Receivables Prepaid expenses and other current assets Increase (Decrease) in Prepaid Expense and Other Assets Accounts payable and accrued expenses Increase (Decrease) in Accounts Payable and Accrued Liabilities Income taxes payable Increase (Decrease) in Accrued Taxes Payable 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] Derivative settlements received (paid) Payments for (Proceeds from) Derivative Instrument, Investing Activities Development of oil and natural gas properties Payment for Development of Oil and Gas Properties Represents the cash outflow in relation to the development of oil and gas properties during the reporting period. Capital expenditures for other property and equipment Payments to Acquire Other Property, Plant, and Equipment Other assets Payments for (Proceeds from) Other Investing Activities Net cash used by 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] Proceeds from the exercise of stock options Proceeds from Stock Options Exercised Common share repurchases, including shares surrendered for tax withholding Payments for Repurchase of Common Stock Common stock dividends paid Payments of Ordinary Dividends, Common Stock Preferred stock dividends paid Payments of Ordinary Dividends, Preferred Stock and Preference Stock Redemption of preferred shares Payments Of Deemed Dividends, Preferred Stock And Preference Stock Payments Of Deemed Dividends, Preferred Stock And Preference Stock Deferred loan costs Payments of Debt Issuance Costs Other Proceeds from (Payments for) Other Financing Activities Net cash provided (used) by 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, beginning of year Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Cash, cash equivalents and restricted cash, end of year Receivables [Abstract] Schedule of receivables Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] 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, issued shares Common Stock, Shares, Issued Common stock, outstanding shares Common Stock, Shares, Outstanding Restricted cash included in current assets Restricted Cash Total cash, cash equivalents and restricted cash shown in the statements of cash flows Income taxes paid Income Taxes Paid Income tax refunds Proceeds from Income Tax Refunds Non-cash transactions: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Increase (decrease) in accrued purchases of property and equipment Increase (Decrease) in Accounts Payable Used to Acquire Property and Equipment Increase (Decrease) in Accounts Payable Used to Acquire Property and Equipment Deferred loan costs charged to oil and gas property costs Deferred Loan Costs Reclassified to Oil and Gas Property Cost Deferred Loan Costs Reclassified to Oil and Gas Property Cost Oil and natural gas property costs attributable to the recognition of asset retirement obligations Asset Retirement Obligation Liabilities Incurred Net Amount of asset retirement obligations incurred during the period, net of certain increases or decreases in the amount of the asset retirement obligation during the current period that may include changes in the amount or timing of the estimated cash flows associated with the settlement of the obligation. Mengel working interest acquired in Delhi Field litigation settlement Royalty rights acquired through non-monetary exchange of patent and trademark assets Non Cash Transaction, Royalty Rights Acquired Through Non-Monetary Exchange of Assets Non Cash Transaction, Royalty Rights Acquired Through Non-Monetary Exchange of Assets Previously acquired Company shares swapped by holders to pay stock option exercise price Noncash Settlement Related to Tax Withholding for Share-based Compensation Value of shares swapped by option holders in lieu of tax payments for exercise of option. Accrued purchases of treasury stock Non Cash Transaction, Accrued Purchases of Treasury Stock Non Cash Transaction, Accrued Purchases of Treasury Stock Fair Value Disclosures [Abstract] Fair Value Measurement Fair Value Disclosures [Text Block] Other Current Liabilities Other Current Liabilities [Table Text Block] 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] Line of Credit Line of Credit [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Senior Secured Reserve-Based Credit Facility Senior Secured Reserve-Based Credit Facility [Member] Senior Secured Reserve-Based Credit Facility [Member] Debt Instrument, Variable Rate Base [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] LIBOR London Interbank Offered Rate (LIBOR) [Member] Prime Rate Prime Rate [Member] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Revolving Credit Facility Revolving Credit Facility [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Term of debt instrument Debt Instrument, Term Maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Initial borrowing base Line of Credit Facility, Initial Borrowing Base Line of Credit Facility, Initial Borrowing Base Placement fee percentage Line of Credit Facility, Placement Fee Percentage Line of Credit Facility, Placement Fee Percentage Placement fee amount Debt Instrument, Fee Amount Commitment fee percentage Line of Credit Facility, Commitment Fee Percentage Basis spread on variable rate Debt Instrument, Basis Spread on Variable Rate Maximum total leverage ratio Debt Covenant, Maximum Total Leverage Ratio Debt Covenant, Maximum Total Leverage Ratio Debt service coverage ratio Debt Service Coverage Ratio Debt Service Coverage Ratio Minimum consolidated tangible net worth Line of Credit Facility, Covenant Compliance, Minimum Consolidated Tangible Net Worth Line of Credit Facility, Covenant Compliance, Minimum Consolidated Tangible Net Worth Debt issuance costs Debt Issuance Costs, Net Unamortized debt issuance costs Unamortized Debt Issuance Expense Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Contingent Restricted Stock, Performance Based [Member] Contingent Restricted Stock, Performance Based [Member] Contingent Restricted Stock, Performance Based [Member] Contingent Restricted Stock, Market Based [Member] Contingent Restricted Stock, Market Based [Member] Contingent Restricted Stock, Market Based [Member] Contingent Restricted Stock Grants Contingent Restricted Stock Grants [Member] Contingent Restricted Stock Grants [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Number of Restricted Stock Units Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Nonvested, beginning of period (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Forfeited (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Vested (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Nonvested, end of period (shares) Weighted Average Grant-Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Weighted average grant date fair value, beginning of period (in USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Forfeited, weighted average grant date fair value (in USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Vested, weighted average grant date fair value (in USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Weighted average grant date fair value, end of period (in USD per share) Unamortized compensation expense Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options Weighted Average Remaining Amortization Period (in years) Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Potential future compensation expense Share-based Compensation Arrangement by Share-based Payment Award, Potential Future Allocated Share based Compensation Expense Not Probable Share-based Compensation Arrangement by Share-based Payment Award, Potential Future Allocated Share based Compensation Expense Not Probable Schedule of other assets Schedule of Other Assets [Table Text Block] Property, Plant and Equipment [Abstract] Property and Equipment Property, Plant and Equipment Disclosure [Text Block] Commitments and Contingencies Disclosure [Abstract] Schedule of future minimum lease commitments under the operating lease Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Risks and Uncertainties [Abstract] Concentrations of Credit Risk Concentration Risk Disclosure [Text Block] Receivables Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Stockholders' Equity Stockholders' Equity Note Disclosure [Text Block] Earnings Per Share [Abstract] Schedule of computation of basic and diluted income (loss) per share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule of outstanding potentially dilutive securities Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Property acquisition costs: Costs Incurred, Acquisition of Oil and Gas Properties [Abstract] Proved property Costs Incurred, Acquisition of Oil and Gas Properties with Proved Reserves Unproved property Costs Incurred, Acquisition of Unproved Oil and Gas Properties Exploration costs Costs Incurred, Exploration Costs Development costs Costs Incurred, Development Costs Total costs incurred for oil and natural gas activities Costs Incurred, Acquisition of Oil and Gas Properties Including Exploration and Development Cost Represents the cost incurred, including capitalized costs and costs charged to expense, in acquisition of oil and gas properties, exploration and development costs. Quarterly Financial Information Disclosure [Abstract] Selected Quarterly Financial Data (Unaudited) Quarterly Financial Information [Text Block] Dehli Field Litigation Settlement Legal Matters and Contingencies [Text Block] Supplemental Disclosure of Cash Flow Information Cash Flow, Supplemental Disclosures [Text Block] Prepaid insurance Prepaid Insurance Prepaid federal and state income taxes Prepaid Taxes Retainers and deposits Retainage Deposit Other prepaid expenses Other Prepaid Expense, Current Prepaid expenses and other current assets Accrued incentive and other compensation Accrued Salaries Accrued severance (for two former employees) Restructuring Reserve, Current Asset retirement obligations due within one year Asset Retirement Obligation, Current Accrued royalties, including suspended accounts Accrued Royalties, Current Accrued franchise taxes Accrual for Taxes Other than Income Taxes, Current Accrued ad valorem taxes Sales and Excise Tax Payable Accrued liabilities and other Effective Income Tax Rate Reconciliation, Amount [Abstract] Effective Income Tax Rate Reconciliation, Amount [Abstract] Income tax provision (benefit) computed at the statutory federal rate Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount Adjustment of deferred income liability for lower statutory federal tax rate Change in valuation allowance due to newly enacted tax legislation Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount Depletion in excess of tax basis Effective Income Tax Rate Reconciliation, Nondeductible Expense, Depletion, Amount State income taxes, net of federal tax benefit Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount Permanent differences related to stock-based compensation Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Compensation Cost, Amount Other Effective Income Tax Rate Reconciliation, Other Adjustments, Amount Total income tax provision Income Tax Expense (Benefit) Effective Income Tax Rate Reconciliation, Percent [Abstract] Effective Income Tax Rate Reconciliation, Percent [Abstract] Income tax (benefit) provision computed at the statutory federal rate Adjustment of deferred income liability for lower statutory federal tax rate Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Change In Tax Rate, Deferred Tax Asset, Provisional Income Tax Expense (Benefit), Percent Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Change In Tax Rate, Deferred Tax Asset, Provisional Income Tax Expense (Benefit), Percent Change in valuation allowance due to newly enacted tax legislation Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Percent Depletion in excess of tax basis Effective Income Tax Rate Reconciliation, Nondeductible Expense, Depletion, Percent State income taxes, net of federal tax benefit Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent Permanent differences related to stock-based compensation Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Compensation Cost, Percent Other Effective Income Tax Rate Reconciliation, Other Adjustments, Percent Income tax (benefit) provision Retirement Benefits [Abstract] Employer match of employee contributions of first 6% of eligible compensation (as a percent) Defined Contribution Plan, Employer Matching Contribution, Percent of Match Percentage of eligible compensation, matched 100% by employer Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay Matching contribution to the plan Defined Contribution Plan, Employer Discretionary Contribution Amount Average Sales Price and Production Costs Per Unit of Production [Table] Average Sales Price and Production Costs Per Unit of Production [Table] Oil and Gas Production Type [Axis] Oil and Gas Production Type [Axis] Production Type [Domain] Production Type [Domain] Oil (per barrel) Oil Per Barrel [Member] Represents the petroleum extracted from the ground. Gas (per million BTU) Gas Per Millions of B T U [Member] Methane gas extracted from the ground and sold by oil industry companies that are measured in million british thermal units (MMBtu). Average Sales Price and Production Costs Per Unit of Production [Line Items] Average Sales Price and Production Costs Per Unit of Production [Line Items] Commodity Prices Used in Determining Future Cash Flows Commodity Prices Used in Determining Future Cash Flows Represents the unweighted arithmetic average first-day-of-the-month commodity prices used in determining future cash flows. Restructuring and Related Activities [Abstract] Schedule of Restructuring and Related Costs [Table] Schedule of Restructuring and Related Costs [Table] Disposal Group Classification [Axis] Disposal Group Classification [Axis] Disposal Group Classification [Domain] Disposal Group Classification [Domain] Exchange of Assets Disposal Group, Disposed of by Means Other than Sale, Not Discontinued Operations, Exchange [Member] Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] Well Lift Inc. Well Lift Inc. [Member] Well Lift Inc. [Member] Disposal Group Name [Axis] Disposal Group Name [Axis] Disposal Group Name [Domain] Disposal Group Name [Domain] GARP GARP Assets [Member] GARP Assets [Member] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Restructuring charges Restructuring Charges [Member] Restructuring Cost and Reserve [Line Items] Restructuring Cost and Reserve [Line Items] Restructuring charges Restructuring Charges Restructuring reserve Restructuring Reserve Total impairments Disposal Group, Including Discontinued Operation, Depreciation and Amortization Adjustment to Cost Restructuring Reserve, Accrual Adjustment Ownership percentage Cost Method Investment, Ownership Percentage Cost Method Investment, Ownership Percentage Ownership percentage after conversion of preferred stock into common stock Cost Method Investment, Ownership Percentage After Conversion of Preferred Stock Cost Method Investment, Ownership Percentage After Conversion of Preferred Stock Perpetual royalty percentage Perpetual Royalty Revenue, Percentage Perpetual Royalty Revenue, Percentage Discounted net present value of assets Disposal Group, Including Discontinued Operation, Discounted Net Present Value of Assets Disposal Group, Including Discontinued Operation, Discounted Net Present Value of Assets Asset Retirement Obligation Disclosure [Abstract] Asset Retirement Obligations Asset Retirement Obligation Disclosure [Text Block] Schedule of costs incurred and capitalized in oil and natural gas property acquisition, exploration and development activities Cost Incurred in Oil and Gas Property Acquisition, Exploration, and Development Activities Disclosure [Table Text Block] Schedule of estimated quantities of proved oil and natural gas reserves and changes in quantities of proved developed and undeveloped reserves Schedule of Proved Developed and Undeveloped Oil and Gas Reserve Quantities [Table Text Block] Schedule of standardized measure of discounted future net cash flows related to proved oil and natural gas reserves Standardized Measure of Discounted Future Cash Flows Relating to Proved Reserves Disclosure [Table Text Block] Schedule of NYMEX prices used in determining future cash flows Oil and Gas Net Production, Average Sales Price and Average Production Costs Disclosure [Table Text Block] Schedule of changes in the standardized measure of discounted future net cash flows applicable to proved crude oil, natural gas liquids, and natural gas reserves Schedule of Changes in Standardized Measure of Discounted Future Net Cash Flows [Table Text Block] Prepaid Expenses and Other Current Assets Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Table Text Block] Schedule of reconciliation of the beginning and ending asset retirement obligation Schedule of Change in Asset Retirement Obligation [Table 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 Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Voluntary Filers Entity Current Reporting Status Entity Current Reporting Status Entity Public Float Entity Public Float Schedule of prepaid expenses and other current assets Schedule of Other Current Assets [Table Text Block] Reconciliation of the beginning and ending asset retirement obligation Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] Asset retirement obligations—beginning of period Asset Retirement Obligation Liabilities incurred Asset Retirement Obligation, Liabilities Incurred Liabilities settled Asset Retirement Obligation, Liabilities Settled Liabilities sold Asset Retirement Obligation Liabilities Sold Amount of asset retirement obligations sold, or otherwise disposed of, during the period. This may include asset retirement obligations transferred to third parties associated with the sale of a long-lived asset. Accretion of discount Revisions to previous estimates Asset Retirement Obligation, Revision of Estimate Asset retirement obligations—ending of period Less: current asset retirement obligations Long-term portion of asset retirement obligations Receivables from oil and gas sales Accounts Receivable, Net, Current Other Other Receivables, Net, Current Total receivables Current deferred tax asset Deferred Tax Assets, Net, Current Non-current deferred tax liability Net liability Deferred Tax Liabilities, Net Derivative Instruments and Hedging Activities Disclosure [Abstract] Net asset position of derivatives with counterparty Derivative Assets (Liabilities), at Fair Value, Net Gain on derivatives Derivative, Gain on Derivative Gain on settled derivatives Derivative, Gain on Settled Derivatives Derivative, Gain on Settled Derivatives Unrealized gain (loss) on derivatives Unrealized Gain (Loss) on Derivatives Restricted Stock Restricted Stock [Member] Restricted Stock, Service Based Restricted Stock, Service Based [Member] Restricted Stock, Service Based [Member] Restricted Stock, Performance Based Restricted Stock, Performance Based [Member] Restricted Stock, Performance Based [Member] Restricted Stock, Market Based Restricted Stock, Market Based [Member] Restricted Stock, Market Based [Member] Number of Restricted Shares Grants (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Weighted Average Grant-Date Fair Value Grants, weighted average grant date fair value (in USD 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 Forfeited, weighted average grant date fair value (in USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested Options Forfeited, Weighted Average Grant Date Fair Value Revenues Revenues Operating income Operating Income (Loss) Net income available to common shareholders Net Income (Loss) Available to Common Stockholders, Basic Basic net income per share (in dollars per share) Earnings Per Share, Basic Diluted net income per share (in dollars per share) Earnings Per Share, Diluted Asset Acquisition [Abstract] Asset Acquisition [Abstract] Enduro Purchase and Sale Agreement and Related Subsequent Events Asset Acquisition [Text Block] Asset Acquisition [Text Block] Line of Credit Facility [Table] Line of Credit Facility [Table] Ownership [Axis] Ownership [Axis] Ownership [Domain] Ownership [Domain] Line of Credit Facility [Line Items] Line of Credit Facility [Line Items] Ownership percentage Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners Schedule of oil and natural gas properties and other property and equipment Property, Plant and Equipment [Table Text Block] Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization and Basis of Preparation Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Schedule of customers from whom the entity derived 10 percent or more of net oil and natural gas revenues Schedules of Concentration of Risk, by Risk Factor [Table Text Block] Deferred tax assets: Deferred Tax Assets, Net [Abstract] Non-qualified stock-based compensation Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost Net operating loss carry-forwards Deferred Tax Assets, Operating Loss Carryforwards AMT credit carry-forward Deferred Tax Assets Tax Credit Carryforwards Alternative Minimum Tax Net Amount after allocation of valuation allowances of deferred tax asset attributable to deductible alternative minimum tax credit carry-forwards. Other Deferred Tax Assets, Other Gross deferred tax assets Deferred Tax Assets, Gross Valuation allowance Deferred Tax Assets, Valuation Allowance Total deferred tax assets Deferred Tax Assets, Net of Valuation Allowance Deferred tax liability: Deferred Tax Liabilities, Net [Abstract] Oil and natural gas properties Deferred Tax Liabilities, Property, Plant and Equipment Total deferred tax liability Deferred Tax Liabilities, Gross Net deferred tax liability Loss Contingencies [Table] Loss Contingencies [Table] Litigation Case [Axis] Litigation Case [Axis] Litigation Case [Domain] Litigation Case [Domain] Dehli Field Litigation Dehli Field Litigation [Member] Dehli Field Litigation [Member] Counterparty Name [Axis] Counterparty Name [Axis] Counterparty Name [Domain] Counterparty Name [Domain] Denbury Resources, Inc Denbury Resources, Inc [Member] Denbury Resources, Inc [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] Level 2 Fair Value, Inputs, Level 2 [Member] Loss Contingencies [Line Items] Loss Contingencies [Line Items] Delhi field litigation settlement gain Gain (Loss) Related to Litigation Settlement Proceeds from litigation Proceeds from Legal Settlements Working interest in Mengal Sand Interval Related Party Transactions, Percentage of Working Interest Related Party Transactions, Percentage of Working Interest Fair value of litigation settlement Overriding royalty interest in Holt-Bryant Loss Contingencies Percentage of Overriding Royalty Interest in Product Service Purchased Represents the percentage of overriding royalty interest in product service purchased by the entity. Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Income Statement [Abstract] Product and Service [Axis] Product and Service [Axis] Product and Service [Domain] Product and Service [Domain] Crude Oil Crude Oil [Member] Artificial Lift Technology Artificial Lift Technology [Member] Artificial Lift Technology [Member] Production Oil and Gas, Exploration and Production [Member] Revenues Revenues [Abstract] Total revenues Operating costs Operating Expenses [Abstract] Production costs Cost of Goods and Services Sold Depreciation, depletion and amortization Depreciation, Depletion and Amortization General and administrative expenses General and Administrative Expense Total operating costs Operating Expenses Income from operations Other Nonoperating Income (Expense) [Abstract] Gain on settled derivative instruments, net Gain (Loss) on Settled Derivative Instruments, Net, Pretax Gain (Loss) on Settled Derivative Instruments, Net, Pretax Gain (loss) on unsettled derivative instruments, net Gain (Loss) on Unsettled Derivative Instruments, Net, Pretax Gain (Loss) on Unsettled Derivative Instruments, Net, Pretax Delhi field litigation settlement Delhi field insurance recovery related to pre-reversion event Insurance Recoveries, Recovery Related to Pre-Reversion Event Insurance Recoveries, Recovery Related to Pre-Reversion Event Interest and other income Investment Income, Interest and Other Investment Income, Interest and Other Interest (expense) Interest Expense Income before income tax provision Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Income tax provision (benefit) Net income attributable to the Company Dividends on preferred stock Preferred Stock Dividends, Income Statement Impact Deemed dividend on redeemed preferred shares Preferred Stock Deemed Dividends, Income Statement Impact Preferred Stock Deemed Dividends, Income Statement Impact Net income attributable to common shareholders Earnings per common share Earnings Per Share, Basic and Diluted [Abstract] Basic (in dollars per share) Diluted (in dollars per share) Weighted average number of common shares outstanding Earnings Per Share, Basic and Diluted, Other Disclosures [Abstract] Basic (in shares) Weighted Average Number of Shares Outstanding, Basic Diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Current: Current Income Tax Expense (Benefit), Continuing Operations [Abstract] Federal Current Federal Tax Expense (Benefit) State Current State and Local Tax Expense (Benefit) Total current income tax provision Current Income Tax Expense (Benefit) Deferred: Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract] Federal Deferred Federal Income Tax Expense (Benefit) State Deferred State and Local Income Tax Expense (Benefit) Total deferred income tax provision Dividends declared and paid Dividends Declared [Table Text Block] Schedule of share repurchases Schedule Of Share Repurchases [Table Text Block] Schedule Of Share Repurchases [Table Text Block] Restructuring Restructuring and Related Activities Disclosure [Text Block] Retirement Plan Compensation and Employee Benefit Plans [Text Block] Delhi Field Delhi Field Property [Member] Represents the Delhi Field property in Northeast Louisiana. Property, Plant and Equipment [Line Items] Capital expenditures Capital Expenditures Incurred but Not yet Paid Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] 2016 Equity Incentive Plan 2016 Equity Incentive Plan [Member] 2016 Equity Incentive Plan [Member] 2004 Stock Plan Evolution Petroleum Corporation Amended and Restated 2004 Stock Plan [Member] Represents Evolution Petroleum Corporation Amended and Restated 2004 Stock Plan of the entity. Stock Options Employee Stock Option [Member] Restricted Stock and Contingent Restricted Stock Restricted Stock and Contingent Restricted Stock [Member] Restricted Stock and Contingent Restricted Stock [Member] Other Awards Restricted Stock and Contingent Restricted Stock, Other Awards [Member] Restricted Stock and Contingent Restricted Stock, Other Awards [Member] Service-Based Restricted Stock and Contingent Restricted Stock, Service-Based [Member] Restricted Stock and Contingent Restricted Stock, Service-Based [Member] Performance Shares Performance Shares [Member] Title of Individual [Axis] Title of Individual [Axis] Relationship to Entity [Domain] Relationship to Entity [Domain] Employees Employees [Member] Employees [Member] Director Director [Member] Shares authorized for granting (shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Shares available for grant (shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Stock options intrinsic value Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value Vesting period (in years) Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Number of shares forfeited (shares) Expiration period (in years) Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period Fair value at grant date, per share (in dollars per share) Shares granted (in shares) Option vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number Shares unexercised (shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Restricted stock, vested (shares) Non-cash stock-based compensation expense Allocated Share-based Compensation Expense Oil and natural gas properties: Oil and Gas Property [Abstract] Property costs subject to amortization Oil and Gas Property, Full Cost Method, Gross Less: Accumulated depreciation, depletion, and amortization Oil and Gas Property, Full Cost Method, Depletion Unproved properties not subject to amortization Capitalized Costs of Unproved Properties Excluded from Amortization, Cumulative Oil and natural gas properties, net Other property and equipment: Furniture, fixtures and office equipment, at cost Property, Plant and Equipment, Other, Gross Less: Accumulated depreciation Property, Plant and Equipment, Other, Accumulated Depreciation Other property and equipment, net Net Income Per Share Earnings Per Share [Text Block] 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] Contingent Restricted Stock grants Stock Options Equity Option [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 Exercise Price (in dollars per share) Antidilutive Securities Excluded from Computation of Earnings Per Share Weighted Average Exercise Price Represents the weighted average exercise price of securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented. Outstanding (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Term of operating lease (in years) Lessee, Operating Lease, Term of Contract Rent expense Operating Leases, Rent Expense, Net Schedule of Earnings Per Share, Basic, by Common Class, Including Two Class Method [Table] Schedule of Earnings Per Share, Basic, by Common Class, Including Two Class Method [Table] Contingent restricted stock grants Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items] Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items] Numerator Net Income (Loss) Available to Common Stockholders, Basic [Abstract] Net income attributable to common shareholders Denominator Weighted Average Number of Shares Outstanding, Diluted [Abstract] Weighted average number of common shares—Basic (in shares) Effect of dilutive securities: Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract] Weighted average dilutive securities (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Total weighted average dilutive securities (in shares) Weighted Average Number Diluted Shares Outstanding Adjustment Weighted average number of common shares and dilutive potential common shares used in diluted EPS (in shares) Net income per common share - Basic (in dollars per share) Net income per common share - Diluted (in dollars per share) Reserve Quantities [Line Items] Period Considered for Unweighted Arithmetic Average for Determining Reserve Volumes and Values Period Considered for Unweighted Arithmetic Average for Determining Reserve Volumes and Values Represents the period considered for calculating unweighted arithmetic average which is used to determine reserve volumes and values of oil and natural gas prices. Period Considered for Determining Unweighted Arithmetic Average of First Day of Month, Commodity Prices Period Considered for Determining Unweighted Arithmetic Average of First Day of Month, Commodity Prices Represents the period considered for determining unweighted arithmetic average of first-day-of-the-month commodity prices. Schedule of Valuation Assumptions Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Schedule of Restricted Stock transactions Schedule of Nonvested Share Activity [Table Text Block] Schedule of Restricted Stock Activity Schedule of Share-based Compensation, Restricted Stock Units Award Activity [Table Text Block] Derivatives Derivative Instruments and Hedging Activities Disclosure [Text Block] Concentration Risk [Table] Concentration Risk [Table] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Net revenue Sales [Member] Concentration Risk Type [Axis] Concentration Risk Type [Axis] Concentration Risk Type [Domain] Concentration Risk Type [Domain] Major Customers Customer Concentration Risk [Member] Major Customers [Axis] Customer [Axis] Name of Major Customer [Domain] Customer [Domain] Plains Marketing L.P. (Oil sales from Delhi) Plains Marketing L P [Member] Represents Plains Marketing L.P., a major customer of the entity. American Midstream Gas Solutions (NGL sales from Delhi) American Midstream Gas Solutions [Member] American Midstream Gas Solutions [Member] All others All Other Immaterial Customers [Member] All Other Immaterial Customers [Member] Concentrations of Credit Risk Concentration Risk [Line Items] Percent of Total Revenue Concentration Risk, Percentage General and Administrative Expense General and Administrative Expense [Member] Non-cash stock-based compensation expense Stock-Based Incentive Plan Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Principles of Consolidation and Reporting Consolidation, Policy [Policy Text Block] Use of Estimates Use of Estimates, Policy [Policy Text Block] Cash and Cash Equivalents Cash and Cash Equivalents, Policy [Policy Text Block] Restricted Cash Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] Accounts Receivable and Allowance for Doubtful Accounts Trade and Other Accounts Receivable, Policy [Policy Text Block] Oil and Natural Gas Properties Full Cost or Successful Efforts, Policy [Policy Text Block] Limitation on Capitalized Costs Exploratory Drilling Costs Capitalization and Impairment, Policy [Policy Text Block] Other Property and Equipment Property, Plant and Equipment, Policy [Policy Text Block] Deferred Financing Costs Deferred Charges, Policy [Policy Text Block] Asset Retirement Obligations Asset Retirement Obligation [Policy Text Block] Fair Value of Financial Instruments Fair Value of Financial Instruments, Policy [Policy Text Block] Stock-based Compensation Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block] Revenue Recognition Revenue Recognition, Policy [Policy Text Block] Derivative Instruments Derivatives, Policy [Policy Text Block] Depreciation, Depletion and Amortization Depreciation, Depletion, and Amortization [Policy Text Block] Income Taxes Income Tax, Policy [Policy Text Block] Earnings (Loss) Per Share Earnings Per Share, Policy [Policy Text Block] Recent Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] 2019 Operating Leases, Future Minimum Payments Due, Next Twelve Months Dividends Payable [Table] Dividends Payable [Table] Dividends [Axis] Dividends [Axis] Dividends [Domain] Dividends [Domain] Dividends Paid 1 Dividends Paid 1 [Member] Dividends Paid 1 [Member] Dividends Paid 2 Dividends Paid 2 [Member] Dividends Paid 2 [Member] Dividends Paid 3 Dividends Paid 3 [Member] Dividends Paid 3 [Member] Dividends Paid 4 Dividends Paid 4 [Member] Dividends Paid 4 [Member] Dividends Payable [Line Items] Dividends Payable [Line Items] Cash dividends paid (per common share) Common Stock, Dividends, Per Share, Cash Paid Income Taxes Income Tax Disclosure [Text Block] Changes in the standardized measure of discounted future net cash flows applicable to proved crude oil, natural gas liquids, and natural gas reserves Increase (Decrease) in Standardized Measure of Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves [Roll Forward] Balance, beginning of year Net changes in sales prices and production costs related to future production Net Increase (Decrease) in Sales and Transfer Prices and Production Costs Changes in estimated future development costs Changes in Estimated Future Development Costs Sales of oil and gas produced during the period, net of production costs Sales and Transfers of Oil and Gas Produced, Net of Production Costs Net change due to extensions, discoveries, and improved recovery Extensions, Discoveries, Additions and Improved Recovery, Less Related Costs Net change due to revisions in quantity estimates Revisions of Previous Quantity Estimates Net change due to sales of minerals in place Decrease Due to Sales of Minerals in Place Development costs incurred during the period Previously Estimated Development Costs Incurred Accretion of discount Standardized Measure of Discounted Future Net Cash Flow Relating to Proved Oil and Gas Reserves, Accretion of Discount Net change in discounted income taxes Changes in Future Income Tax Expense Estimates on Future Cash Flows Related to Proved Oil and Gas Reserves Net changes in timing of production and other Standardized Measure of Discounted Future Net Cash Flow of Proved Oil and Gas Reserves, Other Balance, end of year Summary of quarterly financial information Quarterly Financial Information [Table Text Block] Asset Acquisition [Table] Asset Acquisition [Table] Asset Acquisition [Table] Affiliate of Enduro Resource Partners LLC Affiliate Of Enduro Resource Partners LLC [Member] Affiliate Of Enduro Resource Partners LLC [Member] Asset Acquisition [Line Items] Asset Acquisition [Line Items] [Line Items] for Asset Acquisition [Table] Purchase price of oil and gas assets Payments to Acquire Oil and Gas Property and Equipment Escrow deposit Asset Acquisition, Contingent Consideration, Escrow Deposit Asset Acquisition, Contingent Consideration, Escrow Deposit Proceeds from break-up fee Asset Acquisition, Contingent Consideration, Proceeds From Break-Up Fee Asset Acquisition, Contingent Consideration, Proceeds From Break-Up Fee Third party due diligence expense Asset Acquisition, Third Party Due Diligence Expense Asset Acquisition, Third Party Due Diligence Expense Vesting-date intrinsic value of Restricted Stock Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Vested Grant-date fair value of vested Restricted Stock Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value Other Assets Other Assets Disclosure [Text Block] Supplemental Disclosures about Oil and Natural Gas Producing Properties (unaudited) Oil and Gas Exploration and Production Industries Disclosures [Text Block] Weighted average fair value of market-based awards granted (in dollars per share) Share Price Risk-free interest rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Expected life in years Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term Expected volatility Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate Dividend yield Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Series A Cumulative Preferred Stock Series A Preferred Stock [Member] Class of Stock [Line Items] Class of Stock [Line Items] Dividends paid Dividends, Common Stock, Cash Amount authorized to be repurchased Stock Repurchase Program, Authorized Amount Purchases of treasury stock (shares) Treasury stock acquired, average cost (in USD per share) Issuance of preferred stock (in shares) Stock Issued During Period, Shares, New Issues Preferred stock dividend rate (as a percent) Preferred Stock, Dividend Rate, Percentage Preferred stock, liquidation preference (in dollars per share) Preferred Stock, Liquidation Preference Per Share Aggregate redemption cost Deemed dividend Preferred Stock, Deemed Dividend Preferred Stock, Deemed Dividend Cash dividends to preferred stockholders