XML 80 R64.htm IDEA: XBRL DOCUMENT
v2.4.0.8

Supplemental Information on Oil and Gas Producing Activities - Additional Information (Detail) (USD $) | 12 Months Ended
--- | ---
Dec. 31, 2013 | Dec. 31, 2012 | Dec. 31, 2011
Costs Incurred Oil And Gas Property Acquisition Exploration And Development Activities [Line Items] |  |  |
Exploration expense | $ 23,900,000 | $ 37,300,000 | $ 100,000
Percentage of working interest acquired | 31.00% |  |
Acquisition of Working Interest, cost | 10,000,000 |  |
Asset retirement cost | 5,200,000 | 4,700,000 | 10,400,000
Future development costs | 52,800,000 |  |
Development cost to company | 14,800,000 |  |
Minimum |  |  |
Costs Incurred Oil And Gas Property Acquisition Exploration And Development Activities [Line Items] |  |  |
Net share that the consortium receives from production, Minimum | 67.70% |  |
Maximum |  |  |
Costs Incurred Oil And Gas Property Acquisition Exploration And Development Activities [Line Items] |  |  |
Net share that the consortium receives from production, Maximum | 82.50% |  |
United States |  |  |
Costs Incurred Oil And Gas Property Acquisition Exploration And Development Activities [Line Items] |  |  |
Unsuccessful exploration wells | 2 |  |
Future development costs | 113,000 | 9,689,000 | 14,936,000
United States | Oil |  |  |
Costs Incurred Oil And Gas Property Acquisition Exploration And Development Activities [Line Items] |  |  |
Contractual price | 87.61 |  |
United States | Gas |  |  |
Costs Incurred Oil And Gas Property Acquisition Exploration And Development Activities [Line Items] |  |  |
Contractual price | 4.51 |  |
Foreign Tax Authority |  |  |
Costs Incurred Oil And Gas Property Acquisition Exploration And Development Activities [Line Items] |  |  |
Unsuccessful exploration wells | 3 |  |
Future development costs | 54,420,000 | 4,022,000 | 8,011,000
Contractual price | 107.69 |  |
Fixed royalty rate | 13.00% |  |
Consortium |  |  |
Costs Incurred Oil And Gas Property Acquisition Exploration And Development Activities [Line Items] |  |  |
Percentage of production | 70.00% |  |
Net cost account | 30,100,000 |  |
Production Rate Maximum | 25,000 |  |
Production rate, Minimum | 5,000 |  |
Cost Recovered | 929,400 | 367,000 | 304,000
Theoretical Cost | 1,079,300 | 1,197,000 | 1,303,000
Consortium | Minimum |  |  |
Costs Incurred Oil And Gas Property Acquisition Exploration And Development Activities [Line Items] |  |  |
Percentage of contract area, Minimum | 50.00% |  |
Consortium | Maximum |  |  |
Costs Incurred Oil And Gas Property Acquisition Exploration And Development Activities [Line Items] |  |  |
Percentage of contract area, Maximum | 60.00% |  |
Etame |  |  |
Costs Incurred Oil And Gas Property Acquisition Exploration And Development Activities [Line Items] |  |  |
Period of development | 20 years |  |
Expiration of development | expire in 2021 |  |
Exploration area expiration year | expires in July 2014 |  |
Avouma |  |  |
Costs Incurred Oil And Gas Property Acquisition Exploration And Development Activities [Line Items] |  |  |
Period of development | 20 years |  |
Expiration of development | expire in 2025 |  |
Ebouri |  |  |
Costs Incurred Oil And Gas Property Acquisition Exploration And Development Activities [Line Items] |  |  |
Period of development | 20 years |  |
Expiration of development | expire in 2026 |  |
Mutamba Iroru |  |  |
Costs Incurred Oil And Gas Property Acquisition Exploration And Development Activities [Line Items] |  |  |
Percentage of production | 70.00% |  |
Net cost account | 36,400,000 |  |
Production Rate Maximum | 20,000 |  |
Production rate, Minimum | 7,500 |  |
Proved reserves | 0 |  |
Mutamba Iroru | Minimum |  |  |
Costs Incurred Oil And Gas Property Acquisition Exploration And Development Activities [Line Items] |  |  |
Percentage of contract area, Minimum | 50.00% |  |
Net share that the consortium receives from production, Minimum | 72.00% |  |
Mutamba Iroru | Maximum |  |  |
Costs Incurred Oil And Gas Property Acquisition Exploration And Development Activities [Line Items] |  |  |
Percentage of contract area, Maximum | 63.00% |  |
Net share that the consortium receives from production, Maximum | 85.00% |  |
Block 5 Production |  |  |
Costs Incurred Oil And Gas Property Acquisition Exploration And Development Activities [Line Items] |  |  |
Percentage of production | 50.00% |  |
Period of development | 20 years |  |
Proved reserves | 0 |  |
Royalty Payments | 0 |  |
Block 5 Production | Minimum |  |  |
Costs Incurred Oil And Gas Property Acquisition Exploration And Development Activities [Line Items] |  |  |
Percentage of contract area, Minimum | 30.00% |  |
Block 5 Production | Maximum |  |  |
Costs Incurred Oil And Gas Property Acquisition Exploration And Development Activities [Line Items] |  |  |
Percentage of contract area, Maximum | 90.00% |  |
Block P Production |  |  |
Costs Incurred Oil And Gas Property Acquisition Exploration And Development Activities [Line Items] |  |  |
Percentage of production | 70.00% |  |
Period of development | 25 years |  |
Proved reserves | $ 0 |  |
Income tax on net profits | 25.00% |  |
Block P Production | Minimum |  |  |
Costs Incurred Oil And Gas Property Acquisition Exploration And Development Activities [Line Items] |  |  |
Fixed royalty rate | 10.00% |  |
Percentage of contract area, Minimum | 10.00% |  |
Block P Production | Maximum |  |  |
Costs Incurred Oil And Gas Property Acquisition Exploration And Development Activities [Line Items] |  |  |
Fixed royalty rate | 16.00% |  |
Percentage of contract area, Maximum | 60.00% |  |

X
- Definition Amount in cost account for company. + References No definition available. + Details
Name: | egy_AmountInCostAccountForCompany
Namespace Prefix: | egy_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Contractual price per unit. + References No definition available. + Details
Name: | egy_ContractualPricePerUnit
Namespace Prefix: | egy_
Data Type: | us-types:perUnitItemType
Balance Type: | na
Period Type: | duration

X
- Definition Cost recovered quantity. + References No definition available. + Details
Name: | egy_CostRecoveredQuantity
Namespace Prefix: | egy_
Data Type: | num:volumeItemType
Balance Type: | na
Period Type: | duration

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

X
- Definition Expiration year. + References No definition available. + Details
Name: | egy_ExpirationYear
Namespace Prefix: | egy_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Exploration area expiration year. + References No definition available. + Details
Name: | egy_ExplorationAreaExpirationYear
Namespace Prefix: | egy_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Net share consortium receives from production percentage maximum. + References No definition available. + Details
Name: | egy_NetShareConsortiumReceivesFromProductionPercentageMaximum
Namespace Prefix: | egy_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Net share consortium receives from production percentage minimum. + References No definition available. + Details
Name: | egy_NetShareConsortiumReceivesFromProductionPercentageMinimum
Namespace Prefix: | egy_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of contract area maximum. + References No definition available. + Details
Name: | egy_PercentageOfContractAreaMaximum
Namespace Prefix: | egy_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of contract area minimum. + References No definition available. + Details
Name: | egy_PercentageOfContractAreaMinimum
Namespace Prefix: | egy_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of production remaining after deducting royalty. + References No definition available. + Details
Name: | egy_PercentageOfProductionRemainingAfterDeductingRoyalty
Namespace Prefix: | egy_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of working interest acquired. + References No definition available. + Details
Name: | egy_PercentageOfWorkingInterestAcquired
Namespace Prefix: | egy_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Period of development area. + References No definition available. + Details
Name: | egy_PeriodOfDevelopmentArea
Namespace Prefix: | egy_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Production rate maximum. + References No definition available. + Details
Name: | egy_ProductionRateMaximum
Namespace Prefix: | egy_
Data Type: | num:volumeItemType
Balance Type: | na
Period Type: | duration

X
- Definition Production rate minimum. + References No definition available. + Details
Name: | egy_ProductionRateMinimum
Namespace Prefix: | egy_
Data Type: | num:volumeItemType
Balance Type: | na
Period Type: | duration

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

X
- Definition Rate of fixed royalty payable under production sharing contract. + References No definition available. + Details
Name: | egy_RateOfFixedRoyaltyPayableUnderProductionSharingContract
Namespace Prefix: | egy_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Rate of income tax on net profits. + References No definition available. + Details
Name: | egy_RateOfIncomeTaxOnNetProfits
Namespace Prefix: | egy_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Theoretical cost quantity. + References No definition available. + Details
Name: | egy_TheoreticalCostQuantity
Namespace Prefix: | egy_
Data Type: | num:volumeItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of asset retirement obligations (ARO) costs incurred (whether capitalized or charged to expense) during the period. + 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)(1) -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849 + Details
Name: | us-gaap_CostsIncurredAssetRetirementObligationIncurred
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Development costs incurred, including capitalized costs and costs charged to expense, in oil and gas activities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 18 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e62014-109447 + Details
Name: | us-gaap_CostsIncurredDevelopmentCosts
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_CostsIncurredOilAndGasPropertyAcquisitionExplorationAndDevelopmentActivitiesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of nonproductive development wells (dry wells) drilled in the geographic area. A dry well (hole) is a well found to be incapable of producing either oil or gas in sufficient quantities to justify completion as an oil or gas well. The number of wells drilled refers to the number of wells (holes) completed at any time during the fiscal years, regardless when drilling was initiated. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Industry Guide -Number 2 -Paragraph 6 -Subparagraph A + Details
Name: | us-gaap_DevelopmentWellsDrilledNetNonproductive
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Dry hole costs from oil and gas producing activities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 360 -Section 25 -Paragraph 9 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6474861&loc=d3e64954-109465 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 23 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e62136-109447 + Details
Name: | us-gaap_ResultsOfOperationsDryHoleCosts
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of expense related to royalty payments under a contractual arrangement such as payment for mineral and drilling rights and use of technology or intellectual property. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.3) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 + Details
Name: | us-gaap_RoyaltyExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Significant costs that have been incurred, including capitalized costs and costs charged to expense, to acquire mineral interests that have proved reserves. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 19 -URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e62038-109447 + Details
Name: | us-gaap_SignificantCostsIncurredToAcquireMineralInterestOfProvedReserves
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration