Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative [Table] Derivative [Table] Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract [Domain] Derivative Contract [Domain] Oil contracts Oil contracts [Member] Oil contracts [Member] Oil contracts, price per bbl Oil contracts, price per bbl [Member] Oil contracts, price per bbl [Member] Short put Short Put [Member] Short Put [Member] Trading Activity [Axis] Trading Activity [Axis] Trading Activity, by Type [Domain] Trading Activity, by Type [Domain] Collar contract for Q2 Collar Contract For Second Quarter of Year One [Member] Collar Contract For Second Quarter of Year One [Member] Collar contract for Q3 Collar Contract For Third Quarter of Year One [Member] Collar Contract For Third Quarter of Year One [Member] Collar contract for Q4 Collar Contract For Fourth Quarter of Year One [Member] Collar Contract For Fourth Quarter of Year One [Member] Collar Contracts for next year Collar Contracts for Year 2 [Member] Collar Contracts for Year 2 [Member] Collar contracts with short puts for Q2 Collar Contracts With Short Puts For Second Quarter of Year One [Member] Collar Contracts With Short Puts For Second Quarter of Year One [Member] Collar contracts with short puts for Q3 Collar Contracts With Short Puts For Third Quarter of Year One [Member] Collar Contracts With Short Puts For Third Quarter of Year One [Member] Collar contracts with short puts for Q4 Collar Contracts With Short Puts For Fourth Quarter of Year One [Member] Collar Contracts With Short Puts For Fourth Quarter of Year One [Member] Collar contracts with short puts for next year Collar Contracts With Short Puts for Year 2 [Member] Collar Contracts With Short Puts for Year 2 [Member] Derivative [Line Items] Derivative [Line Items] Volume, barrels per day Derivative, Nonmonetary Notional Amount Ceiling, price per barrel Derivative, Average Cap Price Floor, price per barrel Derivative, Average Floor Price Short put, price per barrel Derivative, Notional Amount, Price Per Unit The price per unit of the notional amount of the derivative contract expressed in nonmonetary units. For example, the price per barrel specified in a fuel oil forward purchase contract. Subsequent Events [Abstract] Subsequent Events Subsequent Events [Text Block] Income Tax Disclosure [Abstract] Effective tax rate Effective Income Tax Rate Reconciliation, Percent U.S. statutory rate Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Recognizing excess tax benefits associated with the adoption of ASU 2016-09 Effective Income Tax Rate Reconciliation, Other Adjustments, Amount Unrecognized Tax Benefits Unrecognized Tax Benefits Income Taxes Income Tax Disclosure [Text Block] Interest and Other Income [Abstract] Interest and Other Income Other Income and Other Expense Disclosure [Text Block] Revenue from Contract with Customer [Abstract] Revenue Recognition Revenue from Contract with Customer [Text Block] Other Income and Expenses [Abstract] Schedule of components of other expense Schedule of Other Nonoperating Expense, by Component [Table Text Block] Fair Value Disclosures [Abstract] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Impaired Long-Lived Assets Held and Used by Type [Axis] Impaired Long-Lived Assets Held and Used by Type [Axis] Impaired Long-Lived Assets Held and Used, Asset Name [Domain] Impaired Long-Lived Assets Held and Used, Asset Name [Domain] Raton Raton Field [Member] Raton Field [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] Impairment of oil and gas properties Impairment of Oil and Gas Properties Estimated fair value Fair Value of Asset Group Fair Value of Asset Group Management oil price outlook per barrel Management oil price outlook Management oil price outlook Management gas price outlook per millions of BTU Management gas price outlook Management gas price outlook Discount rate Fair Value Inputs, Discount Rate Fair Value, by Balance Sheet Grouping, Disclosure Item Amounts [Axis] Measurement Basis [Axis] Fair Value, Disclosure Item Amounts [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement [Member] Portion at Fair Value Measurement [Member] Carrying Value Reported Value Measurement [Member] Fair Value Estimate of Fair Value Measurement [Member] Commercial paper, corporate bonds and time deposits Investments Current portion of long-term debt Long-term Debt, Current Maturities Long-term debt Long-term Debt, Excluding Current Maturities Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Stock Common Stock [Member] Additional Paid-in Capital Additional Paid-in Capital [Member] Treasury Stock Treasury Stock [Member] Retained Earnings Retained Earnings [Member] Noncontrolling Interests Noncontrolling Interest [Member] Statement [Line Items] Statement [Line Items] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Beginning Balance, shares Shares, Outstanding Beginning Balance Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Dividends declared ($0.16 per share) Dividends, Cash Purchases of treasury stock, shares Treasury Stock, Shares, Acquired Purchases of treasury stock Treasury Stock, Value, Acquired, Cost Method Compensation costs: Share-based Compensation [Abstract] Vested compensation awards, shares Stock Issued Or Vested During Period Shares Stock Awards Number of common stock issued as a result of granting or vesting of employee stock awards (including income tax benefits), and the shares of treasury stock purchases related to withholding taxes. Vested compensation awards Stock Issued Or Vested During Period Value Stock Awards Par value of share-based payments that vest or lapse during the period. Compensation costs included in net income Allocated Share-based Compensation Expense Net income Net Income (Loss) Attributable to Parent Ending Balance, shares Ending Balance Schedule of Marketing Derivative Contracts Volume and Price [Table] Schedule of Marketing Derivative Contracts Volume and Price [Table] Schedule of Marketing Derivative Contracts Volume and Price [Table] Oil index swap contracts Oil Index Swap Contracts [Member] Oil Index Swap Contracts [Member] Asset Area [Axis] Asset Area [Axis] Asset Area [Axis] Asset Area [Domain] Asset Area [Domain] [Domain] for Asset Area [Axis] Louisiana Light Sweet Louisiana Light Sweet [Member] Louisiana Light Sweet [Member] Magellan East Houston Magellan East Houston [Member] Magellan East Houston [Member] Second Quarter Basis Swap Contracts for First Quarter of Year One [Member] Basis Swap Contracts for First Quarter of Year One [Member] Third Quarter Basis Swap Contracts for Second Quarter of Year One [Member] Basis Swap Contracts for Second Quarter of Year One [Member] Index Swap Contracts for June 2018 Through August 2018 Index Swap Contracts for June 2018 Through August 2018 [Member] Index Swap Contracts for June 2018 Through August 2018 [Member] Schedule of Marketing Derivative Contracts Volume and Price [Line Items] Schedule of Marketing Derivative Contracts Volume and Price [Line Items] [Line Items] for Schedule of Marketing Derivative Contracts Volume and Price [Table] Price differential, dollars per barrel Derivative, Swap Type, Price Differential Derivative, Swap Type, Price Differential Debt Disclosure [Abstract] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent event Subsequent Event [Member] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] 6.65% Senior notes Six Point Six Five Percent Senior Notes Due Two Thousand Seventeen [Member] Six Point Six Five Percent Senior Notes Due Two Thousand Seventeen [Member] 6.875% Senior notes Six Point Eight Seven Five Percent Senior Notes Due Two Thousand Eighteen [Member] Six Point Eight Seven Five Percent Senior Notes Due Two Thousand Eighteen [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Aggregate loan commitments Line of Credit Facility, Maximum Borrowing Capacity Outstanding borrowing Long-term Line of Credit Stated interest rate Debt Instrument, Interest Rate, Stated Percentage Repayments Repayments of Long-term Debt Fair Value Measurements Fair Value Disclosures [Text Block] Document And Entity Information [Abstract] Document and Entity Information [Abstract] Document Type Document Type Amendment Flag Amendment Flag Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Trading Symbol Trading Symbol 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 Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Products and Services [Axis] Products and Services [Axis] Products and Services [Domain] Products and Services [Domain] Oil sales Oil Sales [Member] Oil Sales [Member] NGL sales NGL Sales [Member] NGL Sales [Member] Gas sales Gas Sales [Member] Gas Sales [Member] Total oil and gas sales Total Oil and Gas Sales [Member] Total Oil and Gas Sales [Member] Sales of purchased oil and gas Sales of Purchased Oil and Gas [Member] Sales of Purchased Oil and Gas [Member] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Total revenue derived from contracts with purchasers Revenue from Contract with Customer, Including Assessed Tax Business Combinations [Abstract] Disposal Groups, Including Discontinued Operations [Table] Disposal Groups, Including Discontinued Operations [Table] Disposal Group Name [Axis] Disposal Group Name [Axis] Disposal Group Name [Domain] Disposal Group Name [Domain] West Eagle Ford Shale West Eagle Ford Shale [Member] West Eagle Ford Shale [Member] Permian Basin Permian Basin [Member] Permian Basin [Member] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Net acres Area of Land Cash proceeds, before normal closing adjustments Disposal Group, Including Discontinued Operation, Consideration Cash proceeds Proceeds from Sale of Productive Assets Gain on disposition of assets, net Gain (Loss) on Disposition of Property Plant Equipment Compensation Related Costs [Abstract] Stock-based compensation expense Deferred Compensation Arrangement with Individual, Compensation Expense Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Restricted Stock Liability Awards Restricted Stock Liability Awards [Member] Restricted Stock Liability Awards [Member] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] Affiliates Affiliated Entity [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Unrecognized stock-based compensation expense Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized Remaining vesting period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Due to affiliates Accounts Payable, Current Components of interest and other income Interest and Other Income [Table Text Block] Incentive Plans Compensation and Employee Benefit Plans [Text Block] Earnings Per Share [Abstract] Net Income (Loss) Per Share Earnings Per Share [Text Block] Schedule of Held-to-maturity Securities [Table] Schedule of Held-to-maturity Securities [Table] Debt Security [Axis] Debt Security [Axis] Major Types of Debt Securities [Domain] Major Types of Debt Securities [Domain] Cash Cash and Cash Equivalents [Member] Commercial Paper Commercial Paper [Member] Corporate Bonds Corporate Bond Securities [Member] Time Deposits Bank Time Deposits [Member] Schedule of Held-to-maturity Securities [Line Items] Schedule of Held-to-maturity Securities [Line Items] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Short-term investments Short-term Investments Long-term investments Long-term Investments Total cash and cash equivalents and investments Cash, Cash Equivalents, and Short-term Investments Statement of Financial Position [Abstract] Common stock, par value (usd per share) Common Stock, Par or Stated Value Per Share Common stock, shares authorized Common Stock, Shares Authorized Common stock, shares issued Common Stock, Shares, Issued Treasury stock, shares Treasury Stock, Shares Derivative Financial Instruments Derivative Instruments and Hedging Activities Disclosure [Text Block] Extractive Industries [Abstract] Exploratory Costs Oil and Gas Exploration and Production Industries Disclosures [Text Block] Asset Retirement Obligation [Abstract] Asset Retirement Obligations Asset Retirement Obligation Disclosure [Text Block] Increase (Decrease) in Capitalized Exploratory Well Costs that are Pending Determination of Proved Reserves [Roll Forward] Increase (Decrease) in Capitalized Exploratory Well Costs that are Pending Determination of Proved Reserves [Roll Forward] Beginning capitalized exploratory well costs Capitalized Exploratory Well Costs Additions to exploratory well costs pending the determination of proved reserves Capitalized Exploratory Well Cost, Additions Pending Determination of Proved Reserves Reclassification due to determination of proved reserves Reclassification to Well, Facilities, and Equipment Based on Determination of Proved Reserves Exploratory well costs charged to exploration and abandonment expense Capitalized Exploratory Well Cost, Charged to Expense Ending capitalized exploratory well costs Authorized amount Stock Repurchase Program, Authorized Amount Remaining authorized amount Stock Repurchase Program, Remaining Authorized Repurchase Amount Common stock purchased Treasury Stock, Common, Value Net income (loss) attributable to common stockholders Participating share-based earnings Participating Securities, Distributed and Undistributed Earnings (Loss), Basic Basic income (loss) from continuing operations attributable to common stockholders Net Income (Loss) Available to Common Stockholders, Basic Diluted income (loss) from continuing operations attributable to common stockholders Net Income (Loss) Available to Common Stockholders, Diluted Projects with Exploratory Well Costs Capitalized for More than One Year [Table] Projects with Exploratory Well Costs Capitalized for More than One Year [Table] Project [Axis] Project [Axis] Project [Domain] Project [Domain] Eagle Ford Shale area Eagle Ford Shale [Member] Eagle Ford Shale [Member] Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items] Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items] Number of wells or projects with exploratory well costs that have been suspended for a period greater than one year Projects that have Exploratory Well Costs that have been Capitalized for Period Greater than One Year, Number of Projects Commodity derivatives Commodity [Member] Interest rate derivatives Interest Rate Contract [Member] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Quoted Prices in Active Markets for Identical Assets (Level 1) Fair Value, Inputs, Level 1 [Member] Significant Other Observable Inputs (Level 2) Fair Value, Inputs, Level 2 [Member] Significant Unobservable Inputs (Level 3) Fair Value, Inputs, Level 3 [Member] Assets: Assets, Fair Value Disclosure [Abstract] Derivative assets Derivative Asset, Fair Value, Amount Not Offset Against Collateral Deferred compensation plan assets Deferred Compensation Plan Assets Total assets Assets, Fair Value Disclosure Liabilities: Liabilities, Fair Value Disclosure [Abstract] Commodity derivatives Derivative Liability, Fair Value, Amount Not Offset Against Collateral Total liabilities Financial and Nonfinancial Liabilities, Fair Value Disclosure Total recurring fair value measurements Recurring Measurements, (Fair Value, Net) Recurring Measurements, (Fair Value, Net). Transportation commitment charges Transportation Commitment Loss Transportation Commitment Loss Loss from vertical integration services Third-party vertical integration services Third-party vertical integration services (b) Other Other General Expense Total other expense Other Nonoperating Expense Vertical integration net margins, revenue Gross Revenues Included In Third Party Loss From Vertical Integration Services Gross Revenues Included In Third Party Loss From Vertical Integration Services Vertical integration net margins, costs and expenses Gross Expenses Included In Third Party Loss From Vertical Integration Services Gross Expenses Included In Third Party Loss From Vertical Integration Services Organization, Consolidation and Presentation of Financial Statements [Abstract] Presentation Consolidation, Policy [Policy Text Block] New accounting pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Statement of Cash Flows [Abstract] Cash flows from operating activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Net income (loss) Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Adjustments to reconcile net income (loss) to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depletion, depreciation and amortization Depreciation, Depletion and Amortization Impairment of oil and gas properties Exploration expenses, including dry holes Dry Hole Expense The amount of noncash dry hole and unproved property abandonment expense during the period. Deferred income taxes Deferred Income Tax Expense (Benefit) Gain on disposition of assets, net Accretion of discount on asset retirement obligations Asset Retirement Obligation, Accretion Expense Interest expense Amortization of Debt Issuance Costs and Discounts Derivative related activity Noncash Gain Loss On Derivative Instruments Aggregate net noncash gain (loss) on commodity and interest rate derivative instruments. Amortization of stock-based compensation Amortization Stock Based Compensation Non-cash amortization of unvested stock-based compensation during the operating period. Other Other Operating Activities, Cash Flow Statement Change in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Accounts receivable Increase (Decrease) in Accounts Receivable Inventories Increase (Decrease) in Inventories Investments Increase Decrease in Investments Increase Decrease in Investments Other current assets Increase (Decrease) in Other Current Assets Accounts payable Increase (Decrease) in Accounts Payable Interest payable Increase (Decrease) in Interest Payable, Net Income taxes payable Increase (Decrease) in Income Taxes Payable Other current liabilities Increase (Decrease) in Other Current Liabilities Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Proceeds from disposition of assets Proceeds from investments Proceeds from Sale and Maturity of Held-to-maturity Securities Purchase of investments Payments to Acquire Held-to-maturity Securities Additions to oil and gas properties Payments to Acquire Oil and Gas Property Additions to other assets and other property and equipment, net Payments to Acquire Other Productive Assets Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Principal payments on long-term debt Purchases of treasury stock Payments for Repurchase of Common Stock Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities Net increase (decrease) in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents, beginning of period Cash and cash equivalents, end of period Divestitures Mergers, Acquisitions and Dispositions Disclosures [Text Block] Assets and Liabilities Held for Sale Disposal Groups, Including Discontinued Operations [Table Text Block] Organization And Nature Of Operations Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Long-term Debt Long-term Debt [Text Block] Oil and Gas Production Type [Axis] Oil and Gas Production Type [Axis] Production Type [Domain] Production Type [Domain] Ethane Ethane [Member] Ethane [Member] NGL contract, MMBtu Equivalent NGL contract, MMBtu Equivalent [Member] NGL contract, in MMBtu [Member] NGL contract, price per MMBtu Equivalent NGL contract, price per MMBtu Equivalent [Member] NGL contract, price per MMBtu Equivalent [Member] NGL contract, in BBLS NGL contract, in BBLS [Member] NGL contract, in BBLS [Member] Basis Swap Contracts for Q2 Basis Swap Contracts for Q3 Basis Swap Contracts for Third Quarter of Year One [Member] Basis Swap Contracts for Third Quarter of Year One [Member] Basis swap contracts for Q4 Basis Swap Contracts for Fourth Quarter of Year One [Member] Basis Swap Contracts for Fourth Quarter of Year One [Member] Basis swap contracts for next year Basis Swap Contracts for Year 2 [Member] Basis Swap Contracts for Year 2 Schedule of share based incentive award activity Schedule of Other Share-based Compensation, Activity [Table Text Block] Capitalized exploratory well costs that have been suspended: Capitalized Exploratory Well Costs [Abstract] One year or less Capitalized Exploratory Well Costs that Have Been Capitalized for Period of One Year or Less More than one year Capitalized Exploratory Well Costs that Have Been Capitalized for Period Greater than One Year Total Restricted Stock Equity Awards Restricted Stock [Member] Performance Units Performance Shares [Member] Stock Options Employee Stock Option [Member] Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Beginning balance outstanding, shares Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Awards granted, shares Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Awards forfeited, shares Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Awards vested, shares Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Ending balance outstanding, shares Stock options outstanding, shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Exercise of stock options, shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Schedule of asset retirement obligations Schedule of Asset Retirement Obligations [Table Text Block] Reconciliation of Basic Weighted Average Shares to Diluted Weighted Average Shares [Table] Reconciliation of Basic Weighted Average Shares to Diluted Weighted Average Shares [Table] Reconciliation of Basic Weighted Average Shares to Diluted Weighted Average Shares [Table] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Weighted average shares, basic Weighted Average Number of Shares Outstanding, Basic Incremental Common Shares Attributable to Dilutive Effect of Call Options and Warrants Incremental Common Shares Attributable to Dilutive Effect of Call Options and Warrants Weighted average shares, diluted Weighted Average Number of Shares Outstanding, Diluted Schedule of Adoption of ASC 606 Schedule of Prospective Adoption of New Accounting Pronouncements [Table Text Block] Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] Swap contracts for Q2 Swap Contracts For Second Quarter of Year One [Member] Swap Contracts For Second Quarter of Year One [Member] Swap contracts for Q3 Swap Contracts For Third Quarter of Year One [Member] Swap Contracts For Third Quarter of Year One [Member] Swap contracts for Q4 Swap Contracts For Fourth Quarter of Year One [Member] Swap Contracts For Fourth Quarter of Year One [Member] Swap contracts for next year Swap Contracts for Year 2 [Member] Swap Contracts for Year 2 [Member] Basis Swap Contracts for July 2018 Through September 2019 Basis Swap Contracts for July 2018 Through September 2019 [Member] Basis Swap Contracts for July 2018 Through September 2019 [Member] Basis Swap Contracts for January 2019 Through September 2019 Basis Swap Contracts for January 2019 Through September 2019 [Member] Basis Swap Contracts for January 2019 Through September 2019 [Member] Gas contracts, in MMBTU Gas contracts, in MMBTU [Member] Gas contracts, in MMBTU [Member] Gas contracts, price per MMBTU Gas contracts, price per MMBTU [Member] Gas contracts, price per MMBTU [Member] Southern California Southern California [Member] Southern California [Member] Price per MMBtu in usd Derivative, Average Forward Price Schedule of oil derivative contracts volume and weighted average price Schedule of Oil Derivative Contracts volume and weighted average price [Table Text Block] Schedule of Oil Derivative Contracts Volume and Weighted Average Price [Text Block] Schedule of NGL derivative volumes and weighted average prices Schedule of NGL Derivative Volumes and Weighted Average Prices [Table Text Block] Schedule of NGL Derivative Volumes and Weighted Average Prices [Table Text Block] Schedule of gas derivative volume and weighted average prices Schedule Of Gas Volume And Weighted Average Prices [Table Text Block] Schedule Of Gas Volume And Weighted Average Prices [Table Text Block] Schedule of Marketing Derivative Contracts Volume and Price Schedule of Marketing Derivative Contracts Volume and Price [Table Text Block] Schedule of Marketing Derivative Contracts Volume and Price [Table Text Block] Offsetting asset and liability Offsetting Asset and Liability [Table Text Block] Offsetting Asset and Liability [Table Text Block] Schedule of derivative gains and losses recognized on statement of operations Schedule of Derivative Gains and Losses Recognized on Statement of Operations [Table Text Block] Schedule of Derivative Gains and Losses Recognized on Statement of Operations [Text Block] Subsequent Event [Table] Subsequent Event [Table] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Forecast Scenario, Forecast [Member] Subsequent Event [Line Items] Subsequent Event [Line Items] Gain on disposal Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal Principal payments on long-term debt Income Statement [Abstract] Revenues and other income: Revenues [Abstract] Sales of purchased oil and gas Revenue from Purchased Oil and Gas Interest and other Other Nonoperating Income Derivative gains (losses), net Gain (Loss) on Derivative Instruments, Net, Pretax Total revenues and other income Revenues Costs and expenses: Costs and Expenses [Abstract] Oil and gas Oil and Gas Revenue Oil and gas production Oil and Gas Production Expense Production and ad valorem taxes Taxes, Miscellaneous Purchased oil and gas Cost of Purchased Oil and Gas Exploration and abandonments Exploration Abandonment and Impairment Expense General and administrative General and Administrative Expense Interest Interest Expense Other Costs and Expenses Costs and Expenses Income (loss) before income taxes Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Income tax benefit (provision) Income Tax Expense (Benefit) Net income (loss) attributable to common stockholders Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Basic and diluted net income (loss) per share attributable to common stockholders (usd per share) Earnings Per Share, Basic and Diluted Weighted average shares outstanding: Dividends declared per share (usd per share) Common Stock, Dividends, Per Share, Declared ASSETS Assets [Abstract] Current assets: Assets, Current [Abstract] Accounts receivable: Accounts Receivable, Net, Current [Abstract] Trade, net Accounts Receivable, Net, Current Due from affiliates Due from Affiliate, Current Income taxes receivable Income Taxes Receivable, Current Inventories Inventory, Net Assets held for sale Disposal Group, Including Discontinued Operation, Assets Derivatives Derivative Asset, Current Other Other Assets, Current Total current assets Assets, Current Property, plant and equipment, at cost: Property, Plant and Equipment, Net [Abstract] Oil and gas properties, using the successful efforts method of accounting: Oil and Gas Property, Successful Effort Method, Net [Abstract] Proved properties Proved Oil and Gas Property, Successful Effort Method Unproved properties Unproved Oil and Gas Property, Successful Effort Method Accumulated depletion, depreciation and amortization Oil and Gas Property, Successful Effort Method, Accumulated Depreciation, Depletion and Amortization Total property, plant and equipment Oil and Gas Property, Successful Effort Method, Net Goodwill Goodwill Other property and equipment, net Property, Plant and Equipment, Net Other assets, net Other Assets, Noncurrent Total Assets Assets LIABILITIES AND EQUITY Liabilities and Equity [Abstract] Current liabilities: Liabilities, Current [Abstract] Accounts payable: Accounts Payable, Current [Abstract] Trade Accounts Payable, Trade, Current Due to affiliates Due to Affiliate, Current Interest payable Interest Payable, Current Income taxes payable Accrued Income Taxes, Current Liabilities held for sale Disposal Group, Including Discontinued Operation, Liabilities Derivatives Derivative Liability, Current Other Other Liabilities, Current Total current liabilities Liabilities, Current Long-term debt Derivatives Derivative Liability, Noncurrent Deferred income taxes Deferred Tax Liabilities, Net, Noncurrent Other liabilities Other Liabilities, Noncurrent Equity: Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Common stock, $.01 par value Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital Treasury stock at cost Treasury Stock, Value Retained earnings Retained Earnings (Accumulated Deficit) Total equity attributable to common stockholders Stockholders' Equity Attributable to Parent Noncontrolling interests in consolidated subsidiaries Stockholders' Equity Attributable to Noncontrolling Interest Total equity Commitments and contingencies Commitments and Contingencies Total Liabilities and Equity Liabilities and Equity Reconciliation of earnings attributable to common stockholders, basic and diluted Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule of Weighted Average Number of Shares [Table Text Block] Schedule of Weighted Average Number of Shares [Table Text Block] Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] Beginning asset retirement obligations Asset Retirement Obligation New wells placed on production Asset Retirement Obligation, Liabilities Incurred Changes in estimates Asset Retirement Obligation, Revision of Estimate Obligations reclassified to liabilities held for sale Asset Retirement Obligation Liabilities Reclassified Asset Retirement Obligation Liabilities Reclassified Liabilities settled Asset Retirement Obligation, Liabilities Settled Accretion of discount Ending asset retirement obligations Asset retirement obligations, current portions Asset Retirement Obligation, Current Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Capitalized exploratory well and project activity Schedule of Aging of Capitalized Exploratory Well Costs [Table Text Block] Capitalized exploratory costs and the number of projects for which exploratory costs have been capitalized Schedule of Projects with Exploratory Well Costs Capitalized for More than One Year [Table Text Block] Other Expense Other Nonoperating Income and Expense [Text Block] Income tax (provisions) benefits attributable to income from continuing operations Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Interest income Other Interest and Dividend Income Deferred compensation plan income Deferred Compensation Plan Income Deferred Compensation Plan Income Seismic data sales Seismic Data Sales Seismic Data Sales Severance and sales tax refunds Income Tax Credits and Adjustments Other income Other Income Total interest and other income Hedging Designation [Axis] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Derivatives not designated as hedging instruments Not Designated as Hedging Instrument [Member] Commodity price derivatives Commodity Contract [Member] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Derivatives - current Derivative Current [Member] Derivative Current [Member] Derivatives - noncurrent Derivative Noncurrent [Member] Derivative Noncurrent [Member] Asset Derivatives, Fair Value Derivative Asset, Fair Value, Gross Asset Gross Amounts Offset in the Consolidated Balance Sheet, Assets Derivatives Derivative Assets Offset In Balance Sheet Derivative Assets Offset In Balance Sheet Net Fair Value Presented in the Consolidated Balance Sheet, Asset Derivatives - current Net Fair Value Presented in the Consolidated Balance Sheet, Asset Derivatives - noncurrent Derivative Asset, Noncurrent Net Fair Value Presented in the Consolidated Balance Sheet, Asset Derivatives Liability Derivatives, Fair Value Derivative Liability, Fair Value, Gross Liability Gross Amounts Offset in the Consolidated Balance Sheet. Liabilities Derivatives Derivative Liabilities Offset In Balance Sheet Derivative Liabilities Offset In Balance Sheet Net Fair Value Presented in the Consolidated Balance Sheet, Liabilities Derivatives - current Net Fair Value Presented in the Consolidated Balance Sheet, Liabilities Derivatives - noncurrent Net Fair Value Presented in the Consolidated Balance Sheet, Liabilities Derivatives Basis of Presentation Basis of Presentation and Significant Accounting Policies [Text Block] Composition of assets included in assets held for sale: Disposal Group, Including Discontinued Operation, Assets [Abstract] Current assets Disposal Group, Including Discontinued Operation, Assets, Current Goodwill Disposal Group, Including Discontinued Operation, Goodwill, Noncurrent Total assets Composition of liabilities included in liabilities held for sale: Disposal Group, Including Discontinued Operation, Liabilities [Abstract] Other liabilities Disposal Group, Including Discontinued Operation, Other Liabilities Total liabilities Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Derivative gains (losses), net Derivative Gains Losses [Member] Derivative gains (losses) [Member] Accounts receivable balance representing amounts due or billable Accounts Receivable, Net Schedule of assets and liabilities measured at fair value on a recurring basis Fair Value, Assets Measured on Recurring Basis [Table Text Block] Schedule of carrying values and financial instruments not carried at fair value Fair Value, by Balance Sheet Grouping [Table Text Block] Cash and cash equivalents and investments Cash, Cash Equivalents and Investments [Table Text Block] Revenue, Initial Application Period Cumulative Effect Transition [Table] Revenue, Initial Application Period Cumulative Effect Transition [Table] Initial Application Period Cumulative Effect Transition [Axis] Initial Application Period Cumulative Effect Transition [Axis] Initial Application Period Cumulative Effect Transition [Domain] Initial Application Period Cumulative Effect Transition [Domain] ASC 605 (Without Adoption of ASC 606) Calculated under Revenue Guidance in Effect before Topic 606 [Member] Effect of Change Higher (Lower) Difference between Revenue Guidance in Effect before and after Topic 606 [Member] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] Accounting Standards Update 2014-09 [Member] Accounting Standards Update 2014-09 [Member] Revenue, Initial Application Period Cumulative Effect Transition [Line Items] Revenue, Initial Application Period Cumulative Effect Transition [Line Items] Operating lease term Lessee, Operating Lease, Term of Contract Annual base rent Future Rent Expense Future Rent Expense [Line Items] Capitalized construction costs Capital Leases, Balance Sheet, Assets by Major Class, Net