Condensed Consolidated Balance Sheets Statement [Table] Statement, Scenario [Axis] Scenario, Unspecified [Domain] Statement Statement [Line Items] Assets Assets [Abstract] Current assets: Assets, Current [Abstract] Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents Cash and cash equivalents, beginning of period Cash and cash equivalents, end of period Total Inventory, Net Inventory Assets, Current Total current assets Property, plant, and equipment: Property, Plant and Equipment, Net [Abstract] Assets Total assets Liabilities and Stockholders' Equity Liabilities and Stockholders' Equity [Abstract] Current liabilities: Liabilities, Current [Abstract] Accrued Liabilities, Current Accrued liabilities Liabilities, Current Total current liabilities Common Stock, Value, Issued Common stock, $0.01 par value per share; 2,000,000,000 shares authorized, 405,867,734 and 387,531,630 issued and outstanding as of March 31, 2012 and December 31, 2011, respectively Additional Paid in Capital, Common Stock Additional paid-in capital Retained Earnings (Accumulated Deficit) Deficit accumulated during the development stage Liabilities and Equity Total liabilities and stockholders' equity Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Other property and equipment, accumulated depreciation and amortization (in dollars) Less: accumulated depreciation and amortization Common Stock, Par or Stated Value Per Share Common stock, par value (in dollars per share) Common Stock, Shares Authorized Common stock, shares authorized Common Stock, Shares, Issued Common stock, shares issued Common Stock, Shares, Outstanding Common stock, shares outstanding Condensed Consolidated Statements of Operations Oil and Gas Revenue Oil and gas revenue Operating costs and expenses: Operating Expenses [Abstract] Exploration Expense Total seismic and exploration expenses Seismic and exploration Expensed General and Administrative Expense General and administrative Operating Expenses Operating costs and expenses Total operating costs and expenses Operating costs and expense Operating Income (Loss) Operating income (loss) Other income: Nonoperating Income (Expense) [Abstract] Nonoperating Income (Expense) Total other income Other income (expense) Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest Net loss before income tax Income Tax Expense (Benefit) Income tax expense Income tax expense Earnings Per Share, Diluted Diluted income (loss) per share Diluted Earnings Per Share Pro Forma Pro forma diluted income (loss) per share Pro forma diluted income (loss) per share Condensed Consolidated Statements of Cash Flows Adjustments to reconcile net income (loss) to net cash used in operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Share-based Compensation Equity based compensation Changes in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Increase (Decrease) in Inventories Inventory Increase (Decrease) in Accrued Liabilities Accrued liabilities and other Payments to Acquire Oil and Gas Property Capital expenditures for oil and gas properties Payments to Acquire Other Property, Plant, and Equipment Capital expenditures for other property and equipment Proceeds from Sale of Oil and Gas Property and Equipment Proceeds from sale of oil and gas properties Proceeds from Issuance of Common Limited Partners Units Capital contributions prior to IPO-Class A limited partners Proceeds from Issuance Initial Public Offering Proceeds from initial public offering, net of costs Condensed Consolidated Statements of Changes in Partners' Capital and Stockholders' Equity Statement, Equity Components [Axis] Equity Component [Domain] General Partner General Partner [Member] Class A Limited Partners This element represents a party to a partnership business that has limited liability, categorized as class A limited partners. Limited Partner Class A [Member] Class B Limited Partners This element represents a party to a partnership business that has limited liability, categorized as class B limited partners. Limited Partner Class B [Member] Class C Limited Partners This element represents a party to a partnership business that has limited liability, categorized as class C limited partners. Limited Partner Class C [Member] Stockholders' Equity Stockholders' Equity Note Disclosure [Text Block] Inventory Disclosure [Text Block] Inventory Restricted Funds Oil and Gas Property, Successful Effort Method, Accumulated Depreciation, Depletion and Amortization Oil and gas properties, successful efforts method of accounting, accumulated depletion (in dollars) Oil and Gas Property, Successful Effort Method, Net Oil and gas properties, successful efforts method of accounting, net of accumulated depletion of $-0- Total oil and gas properties, net Common Stock Common Stock [Member] Additional Paid-in Capital Additional Paid-in Capital [Member] Accumulated Deficit During Development Stage Retained Earnings [Member] Stockholders' Equity, Period Increase (Decrease) Document and Entity Information Cash Flow, Supplemental Disclosures [Text Block] Supplemental Cash Flow Information Earnings Per Share [Text Block] Income (Loss) Per Share Restricted Cash and Investments, Noncurrent Long-term restricted funds Accounts Payable, Current Trade and other accounts payable Stock Issued During Period Value Closing of Over Allotment Portion of Initial Public Offering Net This element represents value of new stock issued during the period at the closing of the over allotment portion of initial public offering, net of offering costs. Common stock issued at the closing of the over-allotment portion of initial public offering, net of offering costs Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures Common stock issued for restricted stock and stock options Partners' Capital Account, Contributions Class A limited partners' contributions Partners' Capital Account, Unit-based Compensation Class B & C limited partners' equity compensation Stock Issued During Period, Value, Conversion of Units Common stock issued upon corporate reorganization Stock Issued During Period, Value, New Issues Common stock issued at initial public offering, net of offering costs Stock Issued During Period Value Private Placement This element represents value of new stock issued during the period at private placement. Common stock issued at private placement Proceeds from Issuance of Private Placement Proceeds from private placement, net of costs Increase (Decrease) in Prepaid Expense and Other Assets Prepaid expense and other assets Increase (Decrease) in Accounts Payable Trade and other accounts payable Payments for Exploratory Wells Drilling in Process This element represents the cash outflow associated with the exploratory wells drilling in process. Exploratory wells drilling in process Proceeds from Issuance of Over Allotment Portion of Initial Public Offering Net This element represents the cash inflow associated with the amount received from entity's over allotment portion of initial public offering, net of offering costs. Proceeds from over-allotment portion of initial public offering, net of costs Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Joint Interest and Other Receivables Oil and Gas Exploration and Production Industries Disclosures [Text Block] Seismic and Exploration Expenses Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Equity Based Compensation Accounts Receivable, Related Parties, Current Joint interest and other receivables Property Plant and Equipment and Intangibles Net Total property, plant, and equipment, net Tangible and intangible assets (excluding goodwill) that are held by an entity for use in the production or supply of goods and services, for rental to others, or for administrative purposes and that are expected to provide economic benefit for more than one year; net of accumulated depreciation, depletion, or amortization. Examples include land, buildings, and production equipment. Net properties and equipment Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Equity based compensation Increase (Decrease) in Due from Other Related Parties, Current Joint interest and other receivables Dry hole expense and impairment Dry hole expense and impairment of unproved properties Dry Hole Expense and Impairment This element represents dry hole costs from oil and gas producing activities and the impairment of leasehold properties. Cash and Cash Equivalents Disclosure [Text Block] Cash and Cash Equivalents Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Investments Long-term Debt [Text Block] Other Long-Term Obligations Long-term investments Long-term Investments Restricted Cash and Investments, Current Short-term restricted funds Short-term investments Short-term Investments Net carrying value of investments invested through the funds Long-term contractual obligations Other Liabilities, Noncurrent Long-term Contractual Obligations: Social obligation payments Weighted Average Number of Shares Outstanding, Basic Basic weighted average common shares outstanding Weighted Average Number of Shares Outstanding, Diluted Diluted weighted average common shares outstanding Proceeds from Sale and Maturity of Held-to-maturity Securities Proceeds from maturity of investment securities Payments to Acquire Held-to-maturity Securities Purchase of investment securities Other assets Other Assets, Noncurrent Amortization of premium (accretion of discount) on investment securities Accretion (Amortization) of Discounts and Premiums, Investments Other Noncash Income (Expense) Other Prepaid Expense and Other Assets, Current Prepaid expenses and other current assets Stock Issued During Period, Value, Other Common stock issued at public offering, net of costs Proceeds from Issuance of Common Stock Proceeds from public offerings, net of costs Net proceeds from registered underwritten public offering Organization and Operations Summary of Significant Accounting Policies Cash and Cash Equivalents Investments Joint Interest and Other Receivables Joint Interest and Other Receivables Inventory Property, Plant, and Equipment Prepaid Expenses and Other Current Assets Contractual Obligations Stockholders' Equity Seismic and Exploration Expenses Equity Based Compensation Contingencies Income (Loss) Per Share Income (Loss) Per Share Supplemental Cash Flow Information Subsequent Events Pro forma basic income (loss) per share Basic Earnings Per Share, Pro Forma Entity Registrant Name Entity Central Index Key Document Type Document Period End Date Amendment Flag Amendment Description Current Fiscal Year End Date Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Current Reporting Status Entity Filer Category Entity Public Float Entity Common Stock, Shares Outstanding Document Fiscal Year Focus Document Fiscal Period Focus Interest income Interest Income (Expense), Nonoperating, Net Interest income Summary of Significant Accounting Policies Basis of Presentation and Significant Accounting Policies [Text Block] Restricted Funds Restricted Assets Disclosure [Text Block] Subsequent Events [Text Block] Subsequent Events Basic and diluted income (loss) per share (in dollars per share) Earnings Per Share, Basic and Diluted Earnings Per Share, Basic Basic income (loss) per share Net Income (Loss) Available to Common Stockholders, Basic Net income (loss) Net income (loss) Net income (loss) as reported Property, Plant and Equipment [Table Text Block] Property, Plant and Equipment Schedule of Property, Plant, and Equipment Selected Quarterly Financial Data-Unaudited Quarterly Financial Information [Text Block] Selected Quarterly Financial Data-Unaudited Income Taxes Income Taxes Income Tax Disclosure [Text Block] Employee Benefit Plan Employee Benefit Plan Pension and Other Postretirement Benefits Disclosure [Text Block] Segment Information Segment Information Segment Reporting Disclosure [Text Block] Supplemental Information on Oil and Gas Exploration and Production Activities Disclosure [Text Block] Supplemental Information on Oil and Gas Exploration and Production Activities (Unaudited) Represents the disclosure for oil and gas exploration and producing industries. Other Assets Other Assets Disclosure [Text Block] Other Assets Stockholders' Equity: Stockholders' Equity Attributable to Parent [Abstract] Total stockholders' equity Balance (Inception) Balance Stockholders' Equity Attributable to Parent Cash flows provided from operating activities Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract] Net cash provided by (used in) 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] Net cash provided by (used in) investing activities Net Cash Provided by (Used in) Investing Activities, Continuing Operations Cash flows from financing activities Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract] Net cash provided by (used in) financing activities Net Cash Provided by (Used in) Financing Activities, Continuing Operations Net increase (decrease) in cash and cash equivalents Net Cash Provided by (Used in) Continuing Operations Fair Value Measurements Fair Value Measurements Fair Value Disclosures [Text Block] Contractual Obligations and Commitments Commitments Disclosure [Text Block] Prepaid Expenses and Other Current Assets Disclosure [Text Block] Prepaid Expenses and Other Current Assets The entire disclosure for prepaid expenses and other current assets of the reporting entity. Schedule of Cash and Cash Equivalents [Table Text Block] Cash and Cash Equivalents Cash Cash at banks Money Market Funds, at Carrying Value Money market funds Held-to-maturity Securities at Carrying Value Held-to-maturity securities This item represents investments in debt securities which are categorized as held-to-maturity and that have scheduled maturities within 90 days of the balance sheet date. The held-to-maturity category is for those securities for which the entity has a positive intent and ability to hold until maturity. Maximum Term of Original Maturity to Classify Held-to-maturity Securities as Cash and Cash Equivalents Maximum term of original maturity to classify held-to-maturity securities as cash and cash equivalents (in months) Represents the maximum original term of maturity for Held-to-maturity securities to be classified as cash or cash equivalent. Held-to-maturity Securities [Table Text Block] Schedule of fair value of held-to-maturity securities stated at amortized cost Investments Classified by Contractual Maturity Date [Table Text Block] Schedule of contractual maturities of held-to-maturity securities Schedule of Held-to-maturity Securities [Table] Debt Security [Axis] Major Types of Debt Securities [Domain] US Treasury Securities [Member] U.S. Treasury securities U.S. Treasury bills Corporate Debt Securities [Member] Corporate securities Corporate bonds Commercial Paper [Member] Commercial paper US Government Agencies Debt Securities [Member] U.S. government agency securities US States and Political Subdivisions Debt Securities [Member] Municipal bonds Certificates of Deposit [Member] Certificates of deposit Held-to-maturity Securities by Balance Sheet Location [Axis] Pertinent information related to held- to-maturity securities by line item in the statement of financial position. Held-to-maturity Securities by Balance Sheet Location [Domain] Line item in the statement of financial position in which the fair value amounts of the held-to-maturity securities are included. Cash and Cash Equivalents [Member] Cash and cash equivalents Short-term Investments [Member] Short-term investments Long-term Restricted Funds [Member] Long-term restricted funds Represents the long-term cash and cash equivalent items which are restricted to withdrawal or usage. Long-term Investments [Member] Long-term investments Investments which the entity has the ability and intent to hold for more than an year from the date of the balance sheet. Schedule of Held-to-maturity Securities [Line Items] Investments Held-to-maturity Securities, Fair Value Fair market value Fair Value Held-to-maturity Securities, Debt Maturities, within One Year, Net Carrying Amount Within 1 year Held-to-maturity Securities Debt Maturities after One Year, Net Carrying Amount After 1 year This item represents debt securities, at cost, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments, as defined), and fair value hedge accounting adjustments, if any, which are expected to mature after one year from the balance sheet date and which are categorized as held-to-maturity. Held-to-maturity Securities, Debt Maturities, Fair Value [Abstract] Held-to-maturity securities, Estimated fair value Held-to-maturity Securities, Debt Maturities, within One Year, Fair Value Within 1 year Held-to-maturity Securities, Debt Maturities after One Year, Fair Value After 1 year This item represents the fair value of debt securities which are expected to mature after one year from the balance sheet date and which are categorized as held-to-maturity. Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Schedule of payments due for the estimated contractual obligations Operating Leases, Future Minimum Payments Due [Abstract] Estimated contractual obligations Operating Leases, Future Minimum Payments Due, Current 2012 2013 Operating Leases, Future Minimum Payments, Due in Two Years Operating Leases, Future Minimum Payments, Due in Three Years 2014 Operating Leases, Future Minimum Payments, Due in Four Years 2015 Operating Leases, Future Minimum Payments, Due in Five Years 2016 Operating Leases, Future Minimum Payments, Due Thereafter Thereafter Schedule of Segment Reporting Information, by Segment [Table Text Block] Schedule of segment information by geographic operating segment Number of Geographic Operating Segments Number of geographic operating segments Represents the number of geographic operating segments of the entity. Schedule of Segment Reporting Information, by Segment [Table] Statement, Geographical [Axis] Segment, Geographical [Domain] U.S. Gulf of Mexico [Member] U.S. Gulf of Mexico Represents the U.S. Gulf of Mexico geographic segment. Segment Reporting Information [Line Items] Segment Information Schedule of Quarterly Financial Information [Table Text Block] Schedule of Selected Quarterly Financial Data Unaudited Selected Quarterly Financial Information [Abstract] Selected Quarterly Financial Data Unaudited Capitalized Costs Relating to Oil and Gas Producing Activities Disclosure [Table Text Block] Schedule of Capitalized Costs Related to Oil and Gas Activities Cost Incurred in Oil and Gas Property Acquisition, Exploration, and Development Activities Disclosure [Table Text Block] Schedule of Costs Incurred in Oil and Gas Activities Schedule of Gas and Oil Acreage [Table Text Block] Schedule of total acreage of the Company's existing oil and gas properties Capitalized Costs Relating to Oil and Gas Producing Activities, by Geographic Area [Table] West Africa [Member] West Africa Represents the West Africa geographic segment. Capitalized Costs Relating to Oil and Gas Producing Activities, by Geographic Area [Line Items] Capitalized Costs Related to Oil and Gas Activities Capitalized Costs, Unproved Properties Unproved properties Capitalized Costs, Proved Properties Proved properties Capitalized Costs, Oil and Gas Producing Activities, Gross Capitalized costs, gross Costs capitalized to oil and gas properties Capitalized Costs, Accumulated Depreciation, Depletion, Amortization and Valuation Allowance Relating to Oil and Gas Producing Activities Accumulated depreciation, depletion and amortization Capitalized Costs, Oil and Gas Producing Activities, Net Net capitalized costs Costs Incurred in Oil and Gas Property Acquisition, Exploration, and Development Activities [Table] Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items] Costs Incurred in Oil and Gas Activities Costs Incurred, Acquisition of Oil and Gas Properties [Abstract] Property acquisition Costs Incurred, Acquisition of Unproved Oil and Gas Properties Unproved Costs Incurred, Acquisition of Oil and Gas Properties with Proved Reserves Proved Costs Incurred, Exploration Costs Exploration Costs Incurred, Development Costs Development Gas and Oil Acreage [Table] Gas and Oil Acreage [Line Items] Total acreage of the Company's existing oil and gas properties: Gas and Oil Acreage, Developed, Gross Developed, gross (in acres) Gas and Oil Acreage, Developed, Net Developed, net (in acres) Gas and Oil Acreage, Undeveloped, Gross Undeveloped, gross (in acres) Gas and Oil Acreage, Undeveloped, Net Undeveloped, net (in acres) Payments to Acquire Property, Plant, and Equipment Capital expenditures Held-to-maturity Securities, Debt Maturities, Fair Value Total Proceeds from Sale and Exchange of Leasehold Interests Proceeds from sale and exchange of leasehold interests transactions Represents proceeds from sale and exchange of leasehold interests transactions which are netted from capitalized costs related to oil and gas activities. Stock Issued During Period, Shares, Private Placement Common stock issued in a private placement Represents number of new shares issued during the period in a private placement. Stock Issued During Period, New Shares, Offering Price Per Share Represents the per share issuance price of shares issued in public offerings and related overallotment options. Public offering price of sale of additional shares of common stock (in dollars per share) Stock Issued During Period, Shares, Conversion of Units Number of shares issued in exchange for Partnership interests Stock Issued During Period, Shares, New Issues Sale of additional shares of common stock at the closing of the over-allotment portion of initial public offering Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Schedule of joint interest and other receivables Oil and Gas Joint Interest Billing Receivables by Related Party [Table] Schedule of net carrying value as of the Balance Sheet date of accounts receivable attributable to joint interest partners in oil and gas properties categorized by related party relationship. Related Party Transactions, by Related Party [Axis] Related Party [Domain] Oil and Gas Joint Interest Billing Receivables [Line Items] Joint Interests Receivables Partners in West Africa [Member] Partners in West Africa Represents the joint interest partners in West Africa. Partners in US Gulf of Mexico [Member] Partners in the U.S. Gulf of Mexico Represents the joint interest partners in U.S. Gulf of Mexico. Oil and Gas Joint Interest Billing Receivables, Current Receivable attributable to joint interest partners Accrued Investment Income Receivable Other receivables Vendor's receivable Vendors Receivable, Current Represents the carrying amount of receivables, due within one year of the balance sheet date (or one operating cycle, if longer) from vendors. Other Receivables, Net, Current Other Other Liabilities Social obligation Other Liabilities Noncurrent Payment Period Payment period of a portion of long-term social obligation (in years) Represents the period of time over which the non-current liabilities are to be paid. Recovery of Seismic Costs Seismic cost recovery Represents the number of months following the date of hire after which employees become eligible to participate in the Plan. Carrying Costs, Property and Exploration Rights Leasehold delay rentals Exploration and Production Costs Seismic costs Force Majeure Expense Force Majeure expense Represents the expenditures associated with suspension of drilling activities as a result of the explosion and sinking activities. Oil and Gas Production Expense Drilling rig expense Defined Contribution Plan Minimum Period to be Eligible for Participation Employees Minimum period following date of hire after which employees become eligible to participate in the Plan (in months) Represents the number of months following the date of hire after which employees become eligible to participate in the defined contribution plan. Defined Contribution Plan Employer Matching Contribution Percent Employee contribution match in plan (as a percent) Represents the percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution Plan. Defined Contribution Plan, Cost Recognized Expenses recorded in benefit contributions to the Plan Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule showing calculation of basic and diluted income (loss) per share and pro forma basic and diluted income (loss) per share Pro Forma Income Tax Expense (Benefit) Pro forma income tax expense Represents the pro forma income tax expense (benefit) for a period as if the corporate reorganization had been completed at the beginning of the period. Pro Forma Management Fees Pro forma management fees Represents the pro forma management fees for a period as if the corporate reorganization had been completed at the beginning of the period. Weighted Average Number of Shares Outstanding, Basic and Diluted Weighted average common shares outstanding Weighted Average Basic Shares Outstanding, Pro Forma Weighted average common shares outstanding used in pro forma basic net income (loss) per common share Pro Forma Weighted Average Shares Outstanding, Diluted Weighted average common shares outstanding used in pro forma diluted net income (loss) per common share Use of Estimates, Policy [Policy Text Block] Use of Estimates Revenue Recognition, Policy [Policy Text Block] Revenue Recognition Cash and Cash Equivalents, Policy [Policy Text Block] Cash and Cash Equivalents Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] Restricted Cash Investment, Policy [Policy Text Block] Investments Property, Plant and Equipment, Policy [Policy Text Block] Property, Plant, and Equipment Asset Retirement Obligations, Policy [Policy Text Block] Asset Retirement Obligations Inventory, Policy [Policy Text Block] Inventory Income Tax, Policy [Policy Text Block] Income Taxes Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block] Equity-Based Compensation Maximum Term of Original Maturity to Classify Instrument as Cash and Cash Equivalents Maximum term of original maturity to classify instrument as cash and cash equivalents (in months) Represents the maximum original term of maturity for an instrument to be classified as cash or cash equivalent. Cash and Cash Equivalent [Abstract] Cash and cash equivalents Maximum Term of Maturity to Classify Investment as Cash Equivalents Maximum term of maturity to classify highly liquid interest earning investments as cash equivalent (in months) Represents the maximum term of maturity to classify highly liquid interest earning investments as cash equivalent. Minimum Term of Maturity to Classify Investment as Short-term Investment Minimum term of maturity to classify an investment as short-term investment (in months) Represents the minimum term of maturity to classify an investment as short-term investment. Investment Threshold Period of Maturity for Classification Maximum term of maturity to classify an investment as short-term investment (in years) Represents the threshold of original maturity used to distinguish short and long-term investments. Investments [Abstract] Investments Maximum Settlement Period of Receivables Settlement period of receivables, maximum (in days) Represents the maximum settlement period within which joint interest and other receivables are usually settled from invoice date. Schedule of Restricted Cash and Cash Equivalents [Table Text Block] Schedule of restricted funds Schedule of Restricted Cash and Cash Equivalents [Table] Restricted Cash and Cash Equivalents, Cash and Cash Equivalents [Axis] Restricted Cash and Cash Equivalents, Cash and Cash Equivalents [Domain] Ocean Confidence Escrow Account [Member] Ocean Confidence escrow account Represents the escrow account established to provide guarantee of performance to Z North Sea Ltd., a subsidiary of Diamond Offshore Drilling, Inc. for the Ocean Confidence drilling rig contract. Collateral on Letters of Credit [Member] Collateral on Letters of Credit for Angola Represents collateral account established as collateral for letters of credit issued in support of the Company's contractually agreed work program obligations on Blocks 21 and 9 offshore Angola. Ensco 8503 Escrow Account [Member] Ensco 8503 escrow account Represents the escrow account established to provide guarantee of performance to Ensco Offshore Company for the Ensco 8503 drilling rig contract. Other Vendor Restricted Deposits [Member] Other vendor restricted funds Represents the other vendor restricted deposits. US Treasury and Government [Member] U.S. Treasury bills and government guaranteed corporate bonds Number of Wells for Which Work Program Obligations have Been Fulfilled Number of wells for which work program obligations have been fulfilled Represents the number of wells for which work program obligations have been fulfilled. Expected Reduction in Collateral within Next Twelve Months Expected reduction in collateral within the next twelve months Represents the expected reduction in collateral established for letters of credit issued in support of the Company's contractually agreed work program obligations. Restricted Cash and Cash Equivalents Items [Line Items] Restricted Funds Cash Collateral for Borrowed Securities Collateral held Increase (Decrease) in Cash Collateral for Borrowed Securities Reduction in collateral Period within Which Collateral is Estimated to be Reduced Period within which collateral is expected to be reduced (in months) Represents the period within which collateral established for letters of credit issued in support of the Company's contractually agreed work program obligations is expected to be reduced. Investment Maturity Period Maturity period of investments (in months or years) Represents the maturity period of investments. It may be expressed in days, months and years. Schedule of Aging of Capitalized Exploratory Well Costs [Table Text Block] Schedule of cumulative costs of capitalized exploratory well costs Capitalized Exploratory Well Costs, Roll Forward [Table Text Block] Schedule of net changes in capitalized exploratory well costs Computer Equipment and Software [Member] Computer equipment and software Represents the computer equipment and software that are used in the creation, maintenance and utilization of information systems. Office Equipment and Furniture [Member] Office equipment and furniture Represents the office equipment and furniture not directly used in the production process for inventories or facilities. Unproved Leasehold Properties [Member] Unproved leasehold properties Represents the unproved leasehold properties. Unproved Oil and Gas Property Successful Effort Method Group of Properties Upper Limit of Individual Properties Upper limit of unproved leasehold costs on individual properties included in group amortization Represents the upper limit of the carrying value of unproved leasehold costs on individual properties that are included in a group for amortization purposes. Unproved Oil and Gas Property Successful Effort Method Group of Properties with Individual Costs of Less than 1 Million Carrying amount of properties that were included in group amortization Represents the carrying amount of unproved leasehold costs on individual properties less than $1 million that are grouped for amortization purposes. Schedule of Property, Plant and Equipment [Table] Property, Plant and Equipment by Type [Axis] Property, Plant and Equipment, Type [Domain] Oil and Gas Properties [Member] Unproved oil and gas properties, net Uncompleted Wells Equipment and Facilities [Member] Exploratory wells in process Vehicles [Member] Vehicles Leasehold Improvements [Member] Leasehold improvements Property, Plant and Equipment [Line Items] Property, Plant, and Equipment Property, Plant and Equipment, Estimated Useful Lives Estimated Useful Life (in years) Amortization Amortization expense Shenandoah #1 Exploratory Well Represents the Shenandoah #1 Exploratory Well. Shenandoah 1 Exploratory Well [Member] Heidelberg #1 Exploratory Well Represents the Heidelberg #1 Exploratory Well. Heidelberg 1 Exploratory Well [Member] Heidelberg #2 Appraisal Well Represents the Heidelberg #2 Appraisal Well. Heidelberg 2 Appraisal Well [Member] Ligurian #1 Exploratory Well Represents the Ligurian #1 Exploratory Well. Ligurian 1 Exploratory Well [Member] Criollo #1 Exploratory Well Represents the Criollo #1 Exploratory Well. Criollo 1 Exploratory Well [Member] Firefox #1 Exploratory Well Represents the Firefox #1 Exploratory Well. Firefox 1 Exploratory Well [Member] Bicuar #1 Exploratory Well costs Represents the Bicuar #1 Exploratory Well. Bicuar 1 Exploratory Well Costs [Member] Cameia #1 Exploratory Well costs Represents the Cameia #1 Exploratory Well. Cameia 1 Exploratory Well Costs [Member] Capitalized Exploratory Well Costs that Have Been Capitalized for Period Greater than One Year Exploratory Well costs capitalized for a period greater than one year after completion of drilling Increase (Decrease) in Capitalized Exploratory Well Costs that are Pending Determination of Proved Reserves [Roll Forward] Net changes in capitalized exploratory well costs (excluding any related leasehold costs) Capitalized Exploratory Well Costs Beginning of period End of period Cumulative costs Capitalized Exploratory Well Cost, Additions Pending Determination of Proved Reserves Addition to capitalized exploratory well cost pending determination of proved reserves Reclassification to Well, Facilities, and Equipment Based on Determination of Proved Reserves Reclassifications to wells, facilities, and equipment based on determination of proved reserves Capitalized Exploratory Well Cost, Charged to Expense Amounts charged to expense Capitalized Exploratory Well Costs [Abstract] Cumulative costs of capitalized exploratory well costs (excluding any related leasehold costs) Deferred Tax Assets Liabilities, Net by Balance Sheet Classification [Table Text Block] Schedule of net deferred assets by balance sheet classification Tabular disclosure of deferred tax assets and liabilities by balance sheet classification. Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Schedule of Company's deferred tax assets and liabilities Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Schedule of effective income tax reconciliation Schedule of Income (Loss) Pre or Post Corporate Reorganization [Table Text Block] Schedule of net income pre or post of corporate reorganization Tabular disclosure of net income (loss) applicable to period before or after corporate reorganization. Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Schedule of components of the income tax provision (benefit) Deferred Tax Assets, Net Net deferred tax asset Total deferred assets, net Deferred Tax Assets, Valuation Allowance Valuation allowance Net deferred tax assets from corporate reorganization Represents the net deferred tax assets that resulted at the time of the corporate reorganization. Deferred Tax Assets Resulting from Corporate Reorganization Deferred Tax Assets Resulting from Corporate Reorganization Valuation Allowance Valuation allowances on net deferred tax assets from corporate reorganization Represents the valuation allowances on net deferred tax assets that resulted at the time of the corporate reorganization. Components of Income Tax Expense (Benefit), Continuing Operations [Abstract] Components of the income tax provision (benefit) Current Income Tax Expense (Benefit) Current taxes Deferred Income Tax Expense (Benefit) Deferred taxes Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest [Abstract] Components of income (loss) Less: net income (loss) applicable to period before corporate reorganization Net Income (Loss) Available to Common Stockholders, Pre Corporate Reorganization Net income after adjustments for dividends on preferred stock (declared during the period) and/or cumulative preferred stock (accumulated during the period) allocated to pre-corporate reorganization period. Net Income (Loss) Available to Common Stockholders Post Corporate Reorganization Net income (loss) applicable to period after corporate reorganization Net income after adjustments for dividends on preferred stock (declared during the period) and/or cumulative preferred stock (accumulated during the period) allocated to post corporate reorganization period. Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract] Reconciliation of income taxes computed at the U.S. federal statutory tax rate to the Company's income tax expense (benefit) Income Tax Reconciliation, Income Tax Expense (Benefit), at Federal Statutory Income Tax Rate Income tax expense (benefit) at the federal statutory rate Income Tax Reconciliation, State and Local Income Taxes State income taxes, net of federal income tax benefit Income Tax Reconciliation, Other Adjustments Other Income Tax Reconciliation, Change in Deferred Tax Assets Valuation Allowance Valuation allowance Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract] Reconciliation of income taxes computed at the U.S. federal statutory tax rate to the Company's income tax expense (benefit) Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate Income tax expense (benefit) at the federal statutory rate (as a percent) Effective Income Tax Rate Reconciliation, State and Local Income Taxes State income taxes, net of federal income tax benefit (as a percent) Effective Income Tax Rate Reconciliation, Other Adjustments Other (as a percent) Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance Valuation allowance (as a percent) Effective Income Tax Rate, Continuing Operations Income tax expense (benefit) at the effective rate (as a percent) Components of Deferred Tax Assets and Liabilities [Abstract] Components of the Company's deferred tax assets and liabilities Components of Deferred Tax Liabilities [Abstract] Deferred tax liabilities: Deferred Tax Liabilities, Property, Plant and Equipment Oil and gas properties Deferred Tax Liabilities, Other Other Deferred Tax Liabilities Total deferred liabilities Components of Deferred Tax Assets [Abstract] Deferred tax assets: Seismic and exploration costs Deferred Tax Assets Seismic and Exploration Costs The tax effect as of the balance sheet date of the amount of the estimated future tax deductions attributable to seismic and exploration costs which can only be realized if sufficient taxable income is generated in future periods to enable the deduction to be taken. Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost Stock-based compensation Tax credits and NOL carry forwards Deferred Tax Assets Tax Credits and Net Operating Loss Carryforwards The sum of the tax effects as of the balance sheet date of the amount of excesses of tax deductions over gross income in a year which cannot be used on the tax returns in the current year but can be carried forward to reduce taxable income or income taxes payable in a future year, for which there must be sufficient tax-basis income to utilize a portion or all of the tax credits and NOL carryforward amount to realize the deferred tax asset. Deferred Tax Assets, Other Other Deferred Tax Assets (Liabilities), Net Net deferred assets Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration NOL carryforward begins to expire in 2024 Net deferred tax asset Represents the net amount of deferred tax assets and liabilities as of the balance sheet date before deducting valuation allowance there from. Deferred Tax Assets (Liabilities), Net, before Valuation Allowance Income Tax Reconciliation, Nondeductible Expense, Restructuring Charges Deferred income taxes established at date of corporate reorganization Effective Income Tax Rate Reconciliation, Nondeductible Expense, Restructuring Charges Deferred income taxes established at date of corporate reorganization (as a percent) Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block] Schedule of restricted stock awarded to employees Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Schedule of assumptions used to determine the fair value of each stock option granted using the Black-Scholes-Merton option-pricing model Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block] Schedule of stock options activity Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block] Schedule of recognized equity-based compensation costs Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Long-term Incentive Plan [Member] Incentive Plan Represents Long Term Incentive Plan of the entity under which the entity may issue stock options, stock appreciation rights, restricted stock, restricted stock units, performance awards and other stock-based awards to employees. Non-Employee Directors Compensation Plan [Member] NED Plan Represents the Non-Employee Directors Compensation Plan under which the Company may issue options, restricted stock units, other stock based award or retainer to non-employee directors. Restricted Shares [Member] Restricted Stock Represents details of restricted shares awarded by the entity. Retainer Award [Member] Retainer awards Represents the retainer award for employees who elected to be compensated by stock in lieu of cash payments. Former Employee [Member] Former employee A former employee of the entity. Non-Employee Director [Member] Non-employee directors A non-employee director of the entity. Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Equity based Compensation Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Shares available for grant under the plan Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward] Restricted stock activity Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Non-vested shares at beginning of year Non-vested shares at end of year Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments, Other than Options, Grants Pre-Reorganization Granted pre-reorganization (in shares) The number of grants made during the period, pre-reorganization, on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments, Other than Options, Grants Post-Reorganization Granted post-reorganization (in shares) The number of grants made during the period, post-reorganization, on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments, Other than Options, Forfeited and Expired in Period Forfeited or expired (in shares) The number of equity-based payment instruments, excluding stock (or unit) options that were forfeited and expired during the reporting period. Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract] Weighted Average Grant Date Fair Value Per Share Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Non-vested shares at beginning of year (in dollars per share) Non-vested shares at end of year (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments, Other than Options, Grants Post-Reorganization, Weighted Average Grant Date Fair Value Granted post-reorganization (in dollars per share) The weighted average fair value at grant date for nonvested equity-based awards that were issued pre-reorganization on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments, Other than Options, Grants Pre-Reorganization, Weighted Average Grant Date Fair Value Granted pre-reorganization (in dollars per share) The weighted average fair value at grant date for nonvested equity-based awards that were issued post-reorganization on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Vested (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments, other than Options, Forfeited or Expired in Period, Weighted Average Grant Date Fair Value Forfeited or expired (in dollars per share) The weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were expired or forfeited during the reporting period. Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Outstanding, Weighted Average Remaining Contractual Term Weighted-average period remaining (in years) Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized Unrecognized compensation Unrecognized compensation cost Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Non-vested restricted shares forfeited pursuant to the terms of the separation agreement Allocated Share-based Compensation Expense Stock compensation expense Equity-based compensation costs Share-based Compensation Arrangement by Share-based Payment Award, Reduction in Expense Reduction to the stock compensation expense for the forfeited shares Represents the reduction to the stock compensation expense for the forfeited shares recognized during the period. Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Awards granted (in shares) Granted during the period (in shares) Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Weighted average fair value of shares at grant date (in dollars per share) Closing price of the entity's common stock at the date of grant (in dollars per share) Granted (in dollars per share) Employee Stock Option [Member] Non-Qualified Stock Options Stock options Schedule of Share-based Compensation Arrangement by Share-based Payment Award, Award Type and Plan Name [Axis] Share-based Compensation Arrangements by Share-based Payment Award, Award Type and Plan Name [Domain] Deferred Compensation Arrangement with Individual, Share-based Payments, by Title of Individual [Axis] Title of Individual with Relationship to Entity [Domain] Share-based Compensation Arrangement by Share-based Payment Award, Award Contractual Term Contractual term for options granted in December 2010 / February 2012 (in years) Represents the contractual term of equity-based award which may be presented in a variety of ways (for example, year, month and year, day, month and year, quarter of a year). Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Vesting period (in years) Vesting period (in years) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract] Assumptions used to determine the fair value of each stock option granted using the Black-Scholes-Merton option-pricing model Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term Expected Term in Years Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate Expected Volatility (as a percent) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Expected Dividends (as a percent) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Risk-Free Interest Rate (as a percent) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Number of Stock Options Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Outstanding at the beginning of the period (in shares) Outstanding at the end of the period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Exercised (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period Forfeited or expired (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number Vested or expected to vest at the end of the period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Exercisable at the end of the period (in shares) Exercisable at the end of the period Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract] Weighted Average Exercise Price Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Outstanding at the beginning of the period (in dollars per share) Outstanding at the end of the period (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Granted (in dollars per share) Weighted-average grant-date fair value of awards granted (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Exercised (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price Forfeited or expired (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price Vested or expected to vest at the end of the period (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Exercisable at the end of the period (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Weighted Average Remaining Contractual Term [Abstract] Weighted-Average Remaining Contractual Term (in years) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Outstanding at the beginning of the period (in years) Outstanding at the end of the period (in years) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term Vested or expected to vest at the end of the period (in years) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Exercisable at the end of the period (in years) Share-based Compensation Arrangement by Share-based Payment Award, Options, Aggregate Intrinsic Value [Abstract] Aggregate Intrinsic Value Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Outstanding at the beginning of the period Outstanding at the end of the period Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Aggregate Intrinsic Value Vested or expected to vest at the end of the period Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition Period for recognition of unrecognized compensation cost (in years) Restricted Stock Units (RSUs) [Member] Restricted stock units (performance-based) Restricted stock units Range [Axis] Range [Domain] Minimum [Member] Minimum Maximum [Member] Maximum Employee [Member] Employees An employee of the entity. Executive Officer [Member] Executive officers Deferred Compensation Arrangement with Individual, Share-based Payments, by Type of Deferred Compensation [Axis] Type of Deferred Compensation [Domain] Deferred Compensation, Share-based Payments [Member] Deferred stock compensation Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Shares authorized under the plan Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Percentage Vesting percentage Represents the vesting percentage of awards awarded on scheduled vesting dates contingent upon the recipient's continued service at each vesting date and based on the achievement of targets specified in the agreement. Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Percentage Multiplier Multiplier to determine awards vested (as a percent) Represents the multiplier to determine the awards vested, which is calculated by the number of successful wells drilled during the respective years multiplied by the vesting percentage. Share-based Compensation Arrangement by Share-based Payment Award Minimum Required Percentage of Successful Drilled Wells, over Total Spud Wells for Payout Minimum required percentage of successful wells drilled over total wells spud for payout Represents the minimum required percentage of successful wells drilled over total wells spud, which is required to be maintained for any payout. Deferred Compensation Arrangement with Individual, Shares Authorized for Issuance Shares available under the plan to be distributed to these executives Schedule of Share-based Compensation Arrangement by Title of Individual [Axis] Reflects the pertinent provisions pertaining to equity-based compensation arrangement, by individual. Schedule of Share-based Compensation Arrangement by Title of Individual with Relationship to Entity [Domain] Title of the individual (or the nature of the entity's relationship with the individual) who is party to the equity-based compensation arrangement. Investment [Axis] Investment [Domain] Contractual Obligations and Commitments. Office and delay rental expense Operating Leases, Rent Expense, Net Accumulated valuationtion allowance Impairment of Oil and Gas Properties Costs Incurred in Oil and Gas Property, Acquisition Exploration and Development Activities The total of costs incurred for oil and gas property acquisition, exploration and development activities. Total Costs Incurred Supplemental Information on Oil and Gas Exploration and Production Activities (Unaudited) Held-to-maturity Securities, Debt Maturities, Net Carrying Amount [Abstract] Held-to-maturities, Amortized Cost Total Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment Amortized Cost Schedule of held-to-maturity securities included in the company's balance sheets Held-to-maturity Securities by Balance Sheet Location [Table Text Block] Tabular disclosure of the balance sheet location of held to maturity securities. Basis of Accounting [Policy Text Block] Disclosure of the basis of accounting, or basis of presentation, used to prepare the financial statements (for example, US Generally Accepted Accounting Principles). Basis of Presentation Joint Interest and Other Receivables Receivables, Policy [Policy Text Block] Oil and Gas Property, Successful Effort Method, and Property Plant and Equipment Gross Represents the total of oil and gas properties carried under the successful effort method and long-lived physical assets used in the normal conduct of business. Property, plant, and equipment, gross Oil and Gas Property, Successful Effort Method and Property, Plant and Equipment, Net Represents the total of oil and gas properties carried under the successful effort method and long-lived physical assets used in the normal conduct of business, net of accumulated depreciation, depletion and amortization. Property, plant, and equipment, net Total property, plant, and equipment, net Exploratory Wells Drilled [Table] Projects with Exploratory Well Costs Capitalized by Project [Axis] Information, by project, about projects on which exploratory well costs have been capitalized. Project with Exploratory Well Costs Capitalized Name [Domain] A group of projects on which exploratory well costs have been capitalized. Capitalized Exploratory Well Cost Additions Pre-spud Costs Additions to capitalized exploratory well costs for pre-spud costs not specified elsewhere in the taxonomy. Addition to capitalized exploratory well cost, other pre-spud costs Capitalized Exploratory Well Cost Additions Containment Pre-spud Costs Additions to capitalized exploratory well costs for containment pre-spud costs not specified elsewhere in the taxonomy. Addition to capitalized exploratory well cost, Helix subsea containment pre-spud costs Capitalized Exploratory Well Costs Exploratory Wells Drilled [Line Items] Capitalized Exploratory Well Cost Containment Pre-spud Costs Capitalized exploratory well costs for containment pre-spud costs not specified elsewhere in the taxonomy. Helix subsea containment pre-spud costs Accumulated cost associated with the Ensco 8503 drilling rig included in other assets Other Assets, Miscellaneous, Noncurrent Pro Forma Net Income (Loss) Represents the pro forma net Income or Loss for the period as if the corporate reorganization had been completed at the beginning of a period. Pro forma net income (loss) Property, Plant, and Equipment Property, Plant and Equipment and Suspended Wel Costs Disclosure [Text Block] The entire disclosure for long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale. Also includes disclosure of information related to capitalized exploratory well costs. Organization and Operations Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Other property and equipment, net of accumulated depreciation and amortization of $3,756 and $3,555, as of March 31, 2012 and December 31, 2011, respectively Property, Plant and Equipment, Net Total other property and equipment Contingencies Legal Matters and Contingencies [Text Block] Depreciation, Amortization and Depletion Represents the depreciation, depletion and amortization of tangible assets, depleting assets and intangible assets recognized in the current period. For oil and gas properties accounted for under the successful efforts method, this amount does not include amortization related to unproved reserves. Depreciation and amortization Depreciation and amortization expense Other Liabilities, Current Short-term contractual obligations Short-term Contractual Obligations: Social obligation payments Payments for Repurchase of Common Stock Payments for common stock withheld for taxes on equity based compensation Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Non-Cash Disclosures Capital Expenditures Incurred but Not yet Paid Capital expenditures in liabilities Debt Disclosure [Text Block] Contractual Obligations Reclassifications Comparability of Prior Year Financial Data, Policy [Policy Text Block] Reclassification from Restricted Cash and Investments Noncurrent to Restricted Cash and Investments Current Amount reclassified from long-term restricted cash to short-term restricted cash Represents the amount of noncurrent restricted cash and investment reclassified to current. Number of Wells Expected to be Drilled Number of wells expected to be drilled Represents the number of wells that are expected to be drilled within specified period. Period within which Wells Expected to be Drilled Period within which wells are expected to be drilled (in months) Represents the period during which the wells are expected to be drilled. Schedule of Other Liabilities by Location [Table Text Block] Summary of components of short-term and long-term contractual obligations Tabular disclosure of other liabilities not separately disclosed on the balance sheet. Schedule of Other Liabilities by Location [Table] Table disclosing other liabilities not separately disclosed on the balance sheet by working location. Working Location [Axis] Information pertaining to different working locations of the entity. Working Location [Domain] A domain representing all locations pertaining to which information is provided. Block 9 Offshore Angola [Member] Block 9, offshore Angola Represents the information pertaining to Block 9, offshore Angola. Block 21 Offshore Angola [Member] Block 21, offshore Angola Represents the information pertaining to Block 21, offshore Angola. Block 20 Offshore Angola [Member] Block 20, offshore Angola Represents the information pertaining to Block 20, offshore Angola. Block 20 offshore Angola Heidelberg 2 Replacement Appraisal Well [Member] Heidelberg #2 Replacement Appraisal Well Represents the Heidelberg #2 Replacement Appraisal Well. Ligurian 2 Exploratory Well [Member] Ligurian #2 Exploratory Well Represents the Ligurian #2 Exploratory Well. Blocks 9 and 21 Offshore Angola and Gabon [Member] Blocks 9 and 21 offshore Angola and Gabon Represents the information pertaining to Blocks 9 and 21, offshore Angola and Gabon. Other Liabilities by Location [Line Items] Contractual obligations Percentage of Working Interest Acquired Percentage of working interest acquired Represents the percentage of working interests acquired by the entity. Working Interest Acquisition, Aggregate Consideration Consideration for the acquisition Represents the aggregate amount of consideration paid for working interests acquired. Working Interest Acquisition, Consideration Payable over Specified Period Consideration payable over five years on acquisition Represents the amount of consideration payable for working interests acquired over a specified period. Working Interest Acquisition, Consideration Payable Period Period over which consideration is payable (in years) Represents the period over which the consideration is payable for working interests acquired. Unproved Property Acquisition Costs Unproved property acquisition costs Represents the amount of acquisition costs related to unproved property. Unproved Property Acquisition Costs, Net of Valuation Allowance Unproved property acquisition costs, net of valuation allowance, relating to properties offshore Represents the amount of unproved property acquisition costs, net of valuation allowance, relating to properties offshore. Money market funds Money Market Funds [Member] Common stock purchased and held in treasury for restricted stock vested Treasury Stock, Shares, Acquired Restricted stock vesting price (in dollars per share) Treasury Stock Acquired, Average Cost Per Share Operating Costs and Expenses [Policy Text Block] Operating Costs and Expenses Disclosure of accounting policy for identification of operating costs and expenses. Generally recurring costs associated with normal operations except for the portion of these expenses which can be clearly related to production and included in cost of sales or services. Includes selling, general and administrative expense. Treasury Stock, Value Treasury stock (13,764 shares as of December 31, 2011) Treasury Stock [Member] Treasury Stock Number of Exploratory Wells Drilled as Operator Number of exploratory wells drilled by the Company as operator in the U.S. Gulf of Mexico Represents the number of exploratory wells drilled by the company as operator. Number of Exploratory Wells Participated as Non Operator Number of exploratory wells in which the Company participated as non-operator in the U.S. Gulf of Mexico Represents the number of exploratory wells in which the company participated as non-operator. Number of Appraisal Wells Participated as Non Operator Number of appraisal wells in which the Company participated as non-operator in the U.S. Gulf of Mexico Represents the number of appraisal wells in which the company participated as non-operator. Long-term Investments Maximum, Original Maturity Period Maximum original maturity period of long-term investments (in months) Represents the maximum original maturity period of long-term investments. Current Income Tax Expense (Benefit) [Abstract] Current taxes: U.S. federal Current Federal Tax Expense (Benefit) Foreign Current Foreign Tax Expense (Benefit) Deferred Income Tax Expense (Benefit) [Abstract] Deferred taxes: U.S. federal Deferred Federal Income Tax Expense (Benefit) Foreign Deferred Foreign Income Tax Expense (Benefit) Net Income (Loss) Available to Common Stockholders, Basic Domestic Net income (loss) as reported Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period) that is attributable to domestic operations. Net Income (Loss) Available to Common Stockholders Pre-corporate Reorganization Domestic Less: net income (loss) applicable to period before corporate reorganization Net income after adjustments for dividends on preferred stock (declared during the period) and/or cumulative preferred stock (accumulated during the period) allocated to pre-corporate reorganization period that is attributable to domestic operations. Net Income (Loss) Available to Common Stockholders, Basic Foreign [Abstract] Foreign: Net Income (Loss) Available to Common Stockholders, Basic Foreign Net income (loss) as reported Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period) that is attributable to foreign operations. Net Income (Loss) Available to Common Stockholders Pre-corporate Reorganization Foreign Less: net income (loss) applicable to period before corporate reorganization Net income after adjustments for dividends on preferred stock (declared during the period) and/or cumulative preferred stock (accumulated during the period) allocated to pre-corporate reorganization period that is attributable to foreign operations. Net Income (Loss) Available to Common Stockholders, Basic Domestic [Abstract] U.S.: NOL carryforwards for foreign income tax purposes begin to expire in 2012 Represents the foreign operating loss carryforwards, before tax effects, available to reduce future taxable income under enacted tax laws. Operating Loss Carryforwards, Foreign Costs Incurred Exploration Costs [Abstract] Exploration Exploration Costs Capitalized Capitalized Represents the exploration costs incurred in oil and gas activities that were capitalized during the period. Contractual Obligation [Axis] Information of contractual arrangements directly or indirectly entered into by the reporting entity. Contractual Obligation [Domain] Represents the contractual arrangements directly or indirectly entered into by the reporting entity. Drilling Rig and Related Contracts [Member] Drilling Rig and Related Contracts Represents the drilling rig and related contracts entered into by the entity. Operating Leases [Member] Operating Leases Represents the operating leases. Lease Rentals [Member] Lease Rentals Represents the lease rentals related to assets.