XML 60 R42.htm IDEA: XBRL DOCUMENT
v3.3.1.900

Commitments And Contingencies (Narrative) (Detail) a in Millions |  | 1 Months Ended | 3 Months Ended | 12 Months Ended | 50 Months Ended |
--- | --- | --- | --- | --- | --- | ---
Mar. 14, 2016 USD ($) | Nov. 30, 2006 USD ($) item | Mar. 31, 2016 USD ($) | Dec. 31, 2015 USD ($) | Sep. 30, 2015 USD ($) | Jun. 30, 2015 USD ($) | Mar. 31, 2015 USD ($) | Dec. 31, 2014 USD ($) | Sep. 30, 2014 USD ($) | Jun. 30, 2014 USD ($) | Mar. 31, 2014 USD ($) | Dec. 31, 2013 USD ($) | Dec. 31, 2015 USD ($) a item $ / Boe | Dec. 31, 2014 USD ($) | Dec. 31, 2013 USD ($) $ / Boe | Dec. 31, 2010 km² | Dec. 31, 2012 USD ($)
Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Expected settlement of litigation |  |  |  | $ 550,000 |  |  |  |  |  |  |  |  | $ 550,000 |  |  |  |
Litigation, accrued expected recoveries |  |  |  | 0 |  |  |  |  |  |  |  |  | $ 0 |  |  |  |
Period of Charter |  |  |  |  |  |  |  |  |  |  |  |  | 2 years |  |  |  |
Percentage of share in charter payment |  |  |  |  |  |  |  |  |  |  |  |  | 28.10% |  |  |  |
Liabilities, guarantees' fair value |  |  |  | 1,000,000 |  |  |  | $ 1,000,000 |  |  |  |  | $ 1,000,000 | $ 1,000,000 |  |  |
Charter fee for production up to 20,000 BOPD | $ / Boe |  |  |  |  |  |  |  |  |  |  |  |  | 0.93 |  | 0.25 |  |
Charter fee for those bbls produced in exess of 20,000 BOPD | $ / Boe |  |  |  |  |  |  |  |  |  |  |  |  | 2.50 |  |  |  |
Company's share of charter expense |  |  |  |  |  |  |  |  |  |  |  |  | $ 10,900,000 | 11,800,000 | $ 10,400,000 |  |
Rent expense, operating leases |  |  |  |  |  |  |  |  |  |  |  |  | 4,700,000 | 4,000,000 | 4,100,000 |  |
Abandonment funding |  |  |  | 5,137,000 |  |  |  | 3,537,000 |  |  |  |  | 5,137,000 | 3,537,000 |  |  |
Allowance for accounts with partners |  |  |  |  |  |  |  | 7,600,000 |  |  |  |  |  | 7,600,000 |  |  |
Accounts with partners, net of allowance |  |  |  | 27,856,000 |  |  |  | 10,903,000 |  |  |  |  | 27,856,000 | 10,903,000 |  |  |
Recorded restricted cash |  |  |  | 15,830,000 |  |  |  | 20,830,000 |  |  |  |  | 15,830,000 | 20,830,000 |  |  |
Exploration expense |  |  |  |  |  |  |  |  |  |  |  |  | 46,453,000 | 15,358,000 | 23,928,000 |  |
Dry hole costs and impairment loss on unproved leasehold |  |  |  |  | $ 9,000,000 |  | $ 24,500,000 |  |  | $ 2,000,000 | $ 9,700,000 |  | 45,652,000 | 13,273,000 | 22,490,000 |  |
Asset retirement obligations |  |  |  | 16,166,000 |  |  |  | 14,846,000 |  |  |  | $ 11,464,000 | 16,166,000 | 14,846,000 | 11,464,000 |  | $ 10,368,000
Impairment of Oil and Gas Properties |  |  |  | 8,800,000 | $ 0 | $ 600,000 | $ 2,700,000 | $ 2,300,000 | $ 0 | $ 800,000 | $ 800,000 |  |  |  |  |  |
Inventory write-off |  |  |  | 3,400,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Gabon Taxation Department [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Tax examination settlement payment |  |  |  | 300,000 |  |  |  |  |  |  |  |  | 300,000 |  |  |  |
Sonangol P&P [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Accounts with partners, net of allowance |  |  |  | 8,100,000 |  |  |  |  |  |  |  |  | $ 8,100,000 |  |  |  |
Scenario, Forecast [Member] | Sonangol P&P [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Reversal of allowance |  |  | $ 7,600,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interst income |  |  | $ 3,200,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Gabon [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Discount |  |  |  |  |  |  |  |  |  |  |  |  | 25.00% |  |  |  |
Contractual Obligation Company Share |  |  |  |  |  |  |  |  |  |  |  |  | $ 2,300,000 | $ 3,300,000 | $ 3,000,000 |  |
Contractual Obligation accrued amount |  |  |  | 1,800,000 |  |  |  |  |  |  |  |  | 1,800,000 |  |  |  |
Offshore Gabon [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Drilling rig cost day rate |  |  |  |  |  |  |  |  |  |  |  |  | 172,000 |  |  |  |
Remaining commitment of drilling activity |  |  |  | 32,200,000 |  |  |  |  |  |  |  |  | 32,200,000 |  |  |  |
Remaining commitment of drilling activity, net |  |  |  | 9,800,000 |  |  |  |  |  |  |  |  | $ 9,800,000 |  |  |  |
Percentage of annual funding over seven years |  |  |  |  |  |  |  |  |  |  |  |  | 12.14% |  |  |  |
Funding period for initial rate |  |  |  |  |  |  |  |  |  |  |  |  | 7 years |  |  |  |
Second funding period of production license |  |  |  |  |  |  |  |  |  |  |  |  | 3 years |  |  |  |
Percentage of annual funding over last three years |  |  |  |  |  |  |  |  |  |  |  |  | 5.00% |  |  |  |
Abandonment cost related to annual funding |  |  |  |  |  |  |  |  |  |  |  |  | $ 61,100,000 |  |  |  |
Abandonment cost related to annual funding, net |  |  |  |  |  |  |  |  |  |  |  |  | $ 17,300,000 |  |  |  |
Funding period abandonment funding |  |  |  |  |  |  |  |  |  |  |  |  | 10 years |  |  |  |
Abandonment funding, gross |  |  |  | 18,300,000 |  |  |  |  |  |  |  |  | $ 18,300,000 |  |  |  |
Abandonment funding |  |  |  | 5,100,000 |  |  |  |  |  |  |  |  | $ 5,100,000 |  |  |  |
Number of contract extension periods | item |  |  |  |  |  |  |  |  |  |  |  |  | 2 |  |  |  |
Production license agreement term extended by government |  |  |  |  |  |  |  |  |  |  |  |  | 5 years |  |  |  |
Angola [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Cost related to drilling |  | $ 29,500,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Drilling cost to company |  | $ 14,800,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Area under acquire property exploration rights agreement term (acres) | a |  |  |  |  |  |  |  |  |  |  |  |  | 1.4 |  |  |  |
Additional joint operation agreement related to third party in working interest percentage |  |  |  |  |  |  |  |  |  |  |  |  | 10.00% |  |  |  |
Production license agreement term |  |  |  |  |  |  |  |  |  |  |  |  | 4 years |  |  |  |
Extended drilling period |  |  |  |  |  |  |  |  |  |  |  |  | 1 year |  |  |  |
Number of additional exploration wells due to exploration period extension | item |  |  |  |  |  |  |  |  |  |  |  |  | 2 |  |  |  |
Production license agreement term extended by government |  |  |  |  |  |  |  |  |  |  |  |  | 3 years |  |  |  |
Recorded restricted cash |  |  |  | 15,000,000 |  |  |  |  |  |  |  |  | $ 15,000,000 |  |  |  |
Working interest ownership, percentage |  | 40.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Impairment of Oil and Gas Properties |  |  |  |  |  |  |  |  |  |  |  |  | 8,200,000 |  |  |  |
Inventory write-off |  |  |  |  |  |  |  |  |  |  |  |  | 1,900,000 |  |  |  |
Number of wells drilling commitment | item |  | 2 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Working interest ownership other, percentage |  |  |  |  |  |  |  |  |  |  |  | 40.00% |  |  |  |  |
Drilling commitment, gross |  |  |  | 10,000,000 |  |  |  |  |  |  |  |  | 10,000,000 |  |  |  |
Drilling commitment, net |  |  |  | $ 5,000,000 |  |  |  |  |  |  |  |  | $ 5,000,000 |  |  |  |
Angola [Member] | Seismic Obligation [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Length of acquired property | km² |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1,000 |
Subsequent Event [Member] | Sonangol P&P [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest receivable | $ 3,200,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Accounts with partners, net of allowance | 7,600,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Joint interest owner payments | $ 19,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |

X
- Definition Abandonment cost related to annual funding. + References No definition available. + Details
Name: | egy_AbandonmentCostRelatedToAnnualFunding
Namespace Prefix: | egy_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Abandonment Cost Related To Annual Funding, Net + References No definition available. + Details
Name: | egy_AbandonmentCostRelatedToAnnualFundingNet
Namespace Prefix: | egy_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Abandonment funding. + References No definition available. + Details
Name: | egy_AbandonmentFunding
Namespace Prefix: | egy_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Abandonment Funding, Gross + References No definition available. + Details
Name: | egy_AbandonmentFundingGross
Namespace Prefix: | egy_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Accrued contractual obligation. + References No definition available. + Details
Name: | egy_AccruedContractualObligation
Namespace Prefix: | egy_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Additional joint operation agreement related to third party in working interest percentage. + References No definition available. + Details
Name: | egy_AdditionalJointOperationAgreementRelatedToThirdPartyInWorkingInterestPercentage
Namespace Prefix: | egy_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Area under acquire property exploration rights agreement term. + References No definition available. + Details
Name: | egy_AreaUnderPropertyExplorationRights
Namespace Prefix: | egy_
Data Type: | num:areaItemType
Balance Type: | na
Period Type: | duration

X
- Definition Charter expenses. + References No definition available. + Details
Name: | egy_CharterExpenses
Namespace Prefix: | egy_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Charter Fee Per Barrel For Production Level One + References No definition available. + Details
Name: | egy_CharterFeePerBarrelForProductionLevelOne
Namespace Prefix: | egy_
Data Type: | us-types:perUnitItemType
Balance Type: | na
Period Type: | duration

X
- Definition Charter Fee Per Barrel For Production Level Two + References No definition available. + Details
Name: | egy_CharterFeePerBarrelForProductionLevelTwo
Namespace Prefix: | egy_
Data Type: | us-types:perUnitItemType
Balance Type: | na
Period Type: | duration

X
- Definition Commitments And Contingencies Line Items + References No definition available. + Details
Name: | egy_CommitmentsAndContingenciesLineItems
Namespace Prefix: | egy_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Cost related to drilling. + References No definition available. + Details
Name: | egy_CostRelatedToDrilling
Namespace Prefix: | egy_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Discount on market price. + References No definition available. + Details
Name: | egy_DiscountOnMarketPrice
Namespace Prefix: | egy_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Drilling Commitment, Gross + References No definition available. + Details
Name: | egy_DrillingCommitmentGross
Namespace Prefix: | egy_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Drilling Commitment, Net + References No definition available. + Details
Name: | egy_DrillingCommitmentNet
Namespace Prefix: | egy_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Drilling cost to company. + References No definition available. + Details
Name: | egy_DrillingCostToCompany
Namespace Prefix: | egy_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Drilling Rig Daily Rate. + References No definition available. + Details
Name: | egy_DrillingRigDailyRate
Namespace Prefix: | egy_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Production license agreement term. + References No definition available. + Details
Name: | egy_ExplorationRightsAgreementTerm
Namespace Prefix: | egy_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Extended drilling period. + References No definition available. + Details
Name: | egy_ExtendedDrillingPeriod
Namespace Prefix: | egy_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Funding Period Abandonment Funding + References No definition available. + Details
Name: | egy_FundingPeriodAbandonmentFunding
Namespace Prefix: | egy_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Funding Period For Initial Rate + References No definition available. + Details
Name: | egy_FundingPeriodForInitialRate
Namespace Prefix: | egy_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Guarantee Obligations Current Fair Value + References No definition available. + Details
Name: | egy_GuaranteeObligationsCurrentFairValue
Namespace Prefix: | egy_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Joint Interest Owner Payments + References No definition available. + Details
Name: | egy_JointInterestOwnerPayments
Namespace Prefix: | egy_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Litigation, Accrued Expected Recoveries + References No definition available. + Details
Name: | egy_LitigationAccruedExpectedRecoveries
Namespace Prefix: | egy_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Number of additional exploration wells. + References No definition available. + Details
Name: | egy_NumberOfAdditionalExplorationWells
Namespace Prefix: | egy_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number Of Contract Extension Periods + References No definition available. + Details
Name: | egy_NumberOfContractExtensionPeriods
Namespace Prefix: | egy_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number Of Wells Drilling Commitment + References No definition available. + Details
Name: | egy_NumberOfWellsDrillingCommitment
Namespace Prefix: | egy_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Payments of contractual obligation. + References No definition available. + Details
Name: | egy_PaymentsOfContractualObligation
Namespace Prefix: | egy_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Percentage of annual funding over last three years. + References No definition available. + Details
Name: | egy_PercentageOfAnnualFundingOverLastThreeYears
Namespace Prefix: | egy_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of annual funding over seven years. + References No definition available. + Details
Name: | egy_PercentageOfAnnualFundingOverSevenYears
Namespace Prefix: | egy_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage Of Share In Charter Payment + References No definition available. + Details
Name: | egy_PercentageOfShareInCharterPayment
Namespace Prefix: | egy_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Period Of Charter + References No definition available. + Details
Name: | egy_PeriodOfCharter
Namespace Prefix: | egy_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Production license agreement term extended by government. + References No definition available. + Details
Name: | egy_ProductionLicenseAgreementTermExtendedByGovernment
Namespace Prefix: | egy_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Purchase Commitment Remaining Minimum Amount Committed, Net + References No definition available. + Details
Name: | egy_PurchaseCommitmentRemainingMinimumAmountCommittedNet
Namespace Prefix: | egy_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Reprocess area. + References No definition available. + Details
Name: | egy_ReprocessArea
Namespace Prefix: | egy_
Data Type: | num:areaItemType
Balance Type: | na
Period Type: | duration

X
- Definition Second Funding Period Of Production License + References No definition available. + Details
Name: | egy_SecondFundingPeriodOfProductionLicense
Namespace Prefix: | egy_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tax Examination Settlement Payment + References No definition available. + Details
Name: | egy_TaxExaminationSettlementPayment
Namespace Prefix: | egy_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Working Interest Ownership Other, Percentagec + References No definition available. + Details
Name: | egy_WorkingInterestOwnershipOtherPercentage
Namespace Prefix: | egy_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Working Interest Ownership, Percentage + References No definition available. + Details
Name: | egy_WorkingInterestOwnershipPercentage
Namespace Prefix: | egy_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition A valuation allowance for trade and other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that are expected to be uncollectible. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.4) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=49124121&loc=d3e5074-111524 + Details
Name: | us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of recoveries of receivables doubtful of collection that were previously charged off. + References No definition available. + Details
Name: | us-gaap_AllowanceForDoubtfulAccountsReceivableRecoveries
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Noncurrent portion of the carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849 + Details
Name: | us-gaap_AssetRetirementObligationsNoncurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The adjustment to expense previously capitalized costs of drilling exploratory wells when proved reserves are not found or when the entity obtains information that raises substantial doubt about the economic or operational viability of the project. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 360 -Section 40 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6475089&loc=d3e66625-109467 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 360 -Section 35 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=28370743&loc=d3e66150-109466 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 360 -Section 40 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6475089&loc=d3e66584-109467 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 360 -Section 40 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6475089&loc=d3e66610-109467 + Details
Name: | us-gaap_ExplorationAbandonmentAndImpairmentExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Exploration expenses (including prospecting) related to oil and gas producing entities and would be included in operating expenses of that entity. Costs incurred in identifying areas that may warrant examination and in examining specific areas that are considered to have prospects of containing oil and gas reserves, including costs of drilling exploratory wells and exploratory-type stratigraphic test wells. Exploration costs may be incurred both before acquiring the related property (sometimes referred to in part as prospecting costs) and after acquiring the property. Principal types of exploration costs, which include depreciation and applicable operating costs of support equipment and facilities and other costs of exploration activities, are: (i) Costs of topographical, geographical and geophysical studies, rights of access to properties to conduct those studies, and salaries and other expenses of geologists, geophysical crews, and others conducting those studies. Collectively, these are sometimes referred to as geological and geophysical or "G&G" costs. (ii) Costs of carrying and retaining undeveloped properties, such as delay rentals, ad valorem taxes on properties, legal costs for title defense, and the maintenance of land and lease records. (iii) Dry hole contributions and bottom hole contributions. (iv) Costs of drilling and equipping exploratory wells. (v) Costs of drilling exploratory-type stratigraphic test wells. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 360 -Section 25 -Paragraph 9 -URI http://asc.fasb.org/extlink&oid=56951519&loc=d3e64954-109465 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-10.(a)(15)) -URI http://asc.fasb.org/extlink&oid=50486907&loc=d3e511914-122862 + Details
Name: | us-gaap_ExplorationExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The expense recorded to reduce the value of oil and gas assets consisting of proved properties and unproved properties as the estimate of future successful production from these properties is reduced. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=51719941&loc=d3e2921-110230 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 360 -Section 35 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=28370743&loc=d3e66150-109466 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585 + Details
Name: | us-gaap_ImpairmentOfOilAndGasProperties
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of interest income earned from interest bearing assets not separately disclosed. + References No definition available. + Details
Name: | us-gaap_InterestIncomeOther
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Carrying amount as of the balance sheet date of interest earned but not received. Also called accrued interest or accrued interest receivable. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.8) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_InterestReceivable
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Charge to cost of goods sold that represents the reduction of the carrying amount of inventory, generally attributable to obsolescence or market conditions. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 330 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=28360613&loc=d3e4542-108314 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.2) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 + Details
Name: | us-gaap_InventoryWriteDown
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of lease operating expense related to property used in oil and gas production. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41499-112717 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 10 -Paragraph a -Subparagraph 17 -Article 4 + Details
Name: | us-gaap_LeaseOperatingExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Aggregate carrying amount of the estimated litigation liability for known or estimated probable loss from litigation, which may include attorneys' fees and other litigation costs. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14326-108349 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.25) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_LitigationReserve
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Current portion of accounts receivable attributable to joint interest partners in oil and gas properties. These are billings to the non-operators associated with the operation of wells and are based on those owners' working interests in the wells. For classified balance sheets, represents the current amount receivable, that is amounts expected to be collected within one year or the normal operating cycle, if longer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 323 -Section 25 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6474814&loc=d3e64006-109457 + Details
Name: | us-gaap_OilAndGasJointInterestBillingReceivablesCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Minimum amount to be expended to satisfy the terms of arrangements in which the entity has agreed to expend funds to procure goods or services, excluding long-term purchase commitments or unconditional purchase obligations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.(a)(19)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.25) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.17) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 19 -Article 7 + Details
Name: | us-gaap_PurchaseCommitmentRemainingMinimumAmountCommitted
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Cash and equivalents whose use in whole or in part is restricted for the long-term, generally by contractual agreements or regulatory requirements. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.1) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_RestrictedCashAndCashEquivalentsNoncurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_IncomeTaxAuthorityNameAxis=egy_GabonTaxationDepartmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PartnerTypeOfPartnersCapitalAccountAxis=egy_SonangolPPMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementScenarioAxis=us-gaap_ScenarioForecastMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementGeographicalAxis=country_GA
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementGeographicalAxis=egy_OffshoreGabonMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementGeographicalAxis=country_AO
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_OilAndGasDeliveryCommitmentsAndContractsAxis=egy_SeismicObligationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |