XML 39 R27.htm IDEA: XBRL DOCUMENT
v3.5.0.2

Acquisitions And Dispositions (Narrative) (Details) a in Millions |  |  |  |  | 1 Months Ended | 9 Months Ended |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Sep. 21, 2016 USD ($) item | Jul. 28, 2016 | Mar. 14, 2016 USD ($) | Jan. 01, 2014 | Nov. 30, 2006 a item | Sep. 30, 2016 USD ($) item | Oct. 17, 2016 USD ($) | Dec. 31, 2015 USD ($) | Apr. 30, 2014 USD ($)
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |
Fair value of fields |  |  |  |  |  | $ 410,301,000 |  | $ 412,593,000 |
Fair value of fields |  |  |  |  |  | 10,000,000 |  | 10,000,000 |
Restricted cash |  |  |  |  |  | 830,000 |  | $ 15,830,000 |
Additional Term Loan Available Until Dec. 31, 2016 [Member] |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |
Notes Payable to Bank |  |  |  |  |  | $ 5,000,000 |  |  |
Hefley Field [Member] |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |
Number of wells, interest for sale | item | 2 |  |  |  |  |  |  |  |
Fair value of fields | $ 850,000 |  |  |  |  |  |  |  |
East Poplar Dome Field [Member] | Subsequent Event [Member] |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |
Fair value of fields |  |  |  |  |  |  | $ 250,000 |  |
Joint Operating With Republic Of Angola [Member] |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |
Production license agreement term |  |  |  |  |  | 4 years |  |  |
Production license agreement term extended by government |  |  |  |  |  | 3 years |  |  |
Area under acquire property exploration rights agreement term (acres) | a |  |  |  |  | 1.4 |  |  |  |
Number of exploration wells | item |  |  |  |  | 2 |  |  |  |
Number Of Additional Exploration Wells | item |  |  |  |  | 2 |  |  |  |
Joint operation agreement related to third party in working interest percentage |  |  |  |  | 40.00% |  |  |  |
Additional joint operation agreement related to third party in working interest percentage |  |  |  |  | 10.00% |  |  |  |
Drilling commitment, net |  |  |  |  |  | $ 5,000,000 |  |  |
Restricted cash |  |  |  |  |  | 15,000,000 |  |  |
Liability for the penalty |  |  |  |  |  | $ 15,000,000 |  |  |
Working interest ownership other, percentage |  |  |  | 40.00% |  |  |  |  |
Allowance for accounts with partners |  |  |  |  |  |  |  |  | $ 7,600,000
Joint Operating With Republic Of Angola [Member] | Drilling or Commencing Wells By November 30, 2017 [Member] |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |
Number of exploration wells | item |  |  |  |  |  | 4 |  |  |
Joint Operating With Republic Of Angola [Member] | Remaining Obligation [Member] |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |
Number of exploration wells | item |  |  |  |  |  | 3 |  |  |
Etame [Member] |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |
Percentage of working interest |  | 2.98% |  |  |  |  |  |  |
Percentage of participating interest |  | 3.23% |  |  |  |  |  |  |
Etame [Member] | Additional Term Loan Available Until Dec. 31, 2016 [Member] |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |
Notes Payable to Bank |  |  |  |  |  | $ 5,000,000 |  |  |
Sonangol P&P [Member] |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |
Payment from joint venture partners |  |  | $ 19,000,000 |  |  |  |  |  |
Reversal of allowance |  |  | 7,600,000 |  |  |  |  |  |
Interest income |  |  | $ 3,200,000 |  |  |  |  |  |

X
- Definition Joint operation agreement related to third party in working interest percentage. + References No definition available. + Details
Name: | egy_AcquisitionOfWorkingInterestInBlock
Namespace Prefix: | egy_
Data Type: | num:percentItemType
Balance Type: | na
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 Business Acquisition Percentage Of Participating Interest + References No definition available. + Details
Name: | egy_BusinessAcquisitionPercentageOfParticipatingInterest
Namespace Prefix: | egy_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Business Acquisition Percentage Of Working Interest + References No definition available. + Details
Name: | egy_BusinessAcquisitionPercentageOfWorkingInterest
Namespace Prefix: | egy_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

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 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 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 exploration wells on project. + References No definition available. + Details
Name: | egy_NumberOfExplorationWellsOnProject
Namespace Prefix: | egy_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number Of Wells, Interest For Sale + References No definition available. + Details
Name: | egy_NumberOfWellsInterestForSale
Namespace Prefix: | egy_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Payment From Joint Venture Partners + References No definition available. + Details
Name: | egy_PaymentFromJointVenturePartners
Namespace Prefix: | egy_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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 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 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 Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_BusinessAcquisitionLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
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 Reflects the estimated amount of loss from the specified contingency as of the balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14435-108349 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 9 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14557-108349 + Details
Name: | us-gaap_LossContingencyEstimateOfPossibleLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Including the current and noncurrent portions, the carrying value as of the balance sheet date of notes payable to banks, excluding mortgage notes, initially due beyond one year or beyond the operating cycle if longer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 20, 22 -Article 5 + Details
Name: | us-gaap_NotesPayableToBank
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Oil and Gas properties with proved reserves under the successful effort method. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 360 -Glossary Proved Properties -URI http://asc.fasb.org/extlink&oid=6522428 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 360 -Section 25 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=56951519&loc=d3e64746-109465 + Details
Name: | us-gaap_ProvedOilAndGasPropertySuccessfulEffortMethod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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
- Definition Oil and Gas properties with unproved reserves under the successful effort method. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 14 -URI http://asc.fasb.org/extlink&oid=51678428&loc=d3e61926-109447 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -Glossary Unproved Properties -URI http://asc.fasb.org/extlink&oid=6527831 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 360 -Section 25 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=56951519&loc=d3e64746-109465 + Details
Name: | us-gaap_UnprovedOilAndGasPropertySuccessfulEffortMethod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_DebtInstrumentAxis=egy_AdditionalTermLoanAvailableUntil123116Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=egy_HefleyFieldMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=egy_EastPoplarDomeFieldMember
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: |

X
- Details
Name: | us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=egy_JointOperatingWithRepublicOfAngolaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementScenarioAxis=egy_DrillingOrCommencingWellsByNovember302017Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=egy_EtameMember
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: |