Annual report pursuant to Section 13 and 15(d)

Long Term Debt - Additional Information (Detail)

v2.4.1.9
Long Term Debt - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Jan. 31, 2014
Line Of Credit Facility [Line Items]    
Maximum borrowing capacity under loan agreement   $ 65.0us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Borrowings under credit facility 15.0us-gaap_LineOfCredit  
Debt maturity period 2019-12  
Average interest rate on bank debt 4.32%us-gaap_LineOfCreditFacilityInterestRateDuringPeriod  
Net assets pledged for secured debt facility 58.7us-gaap_PledgedAssetsNotSeparatelyReportedOnStatementOfFinancialPosition  
Debt instrument decrease period description Every six months beginning June 30, 2016 through December 2019.  
Credit facility borrowing base 25.0us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity  
Maximum    
Line Of Credit Facility [Line Items]    
Ratio Of Indebtedness To Net Capital 1.5us-gaap_RatioOfIndebtednessToNetCapital1
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
 
Fair Value Inputs Earnings Before Interest Taxes Depreciation And Amortization Multiple 3.0us-gaap_FairValueInputsEarningsBeforeInterestTaxesDepreciationAndAmortizationMultiple
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
 
Senior Tranche    
Line Of Credit Facility [Line Items]    
Maximum borrowing capacity under loan agreement   50.0us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
Decrease in debt instrument 6.25us-gaap_DebtInstrumentIncreaseDecreaseForPeriodNet
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
 
Debt instrument, commitment fee 1.50%egy_DebtInstrumentCommitmentFee
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
 
Senior Tranche | London Interbank Offered Rate (LIBOR)    
Line Of Credit Facility [Line Items]    
Debt instrument interest rate 3.75%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
/ us-gaap_VariableRateAxis
= us-gaap_LondonInterbankOfferedRateLIBORMember
 
Subordinated Tranche    
Line Of Credit Facility [Line Items]    
Maximum borrowing capacity under loan agreement   15.0us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SubordinatedDebtMember
Decrease in debt instrument $ 1.88us-gaap_DebtInstrumentIncreaseDecreaseForPeriodNet
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SubordinatedDebtMember
 
Debt instrument, commitment fee 2.30%egy_DebtInstrumentCommitmentFee
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SubordinatedDebtMember
 
Subordinated Tranche | London Interbank Offered Rate (LIBOR)    
Line Of Credit Facility [Line Items]    
Debt instrument interest rate 5.75%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SubordinatedDebtMember
/ us-gaap_VariableRateAxis
= us-gaap_LondonInterbankOfferedRateLIBORMember