Annual report pursuant to Section 13 and 15(d)

Summary Of Significant Accounting Policies (Narrative I) (Details)

v3.6.0.2
Summary Of Significant Accounting Policies (Narrative I) (Details)
$ in Thousands, XAF in Billions
 12 Months Ended
Dec. 31, 2016
USD ($)
item
Dec. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
Dec. 31, 2015
XAF
Dec. 31, 2015
USD ($)
Error Corrections and Prior Period Adjustments Restatement [Line Items]          
Allowance For Doubtful Accounts Receivable $ 5,211   $ 2,400   $ 4,221
Recorded allowance 1,222 $ 2,699 2,400    
Receivable balance, net $ 6,751       5,353
Value Added Tax Reimbursement Monthly Payment   200      
Number Of Value Added Tax Reimbursement Payments | item 36        
Other operating income (loss), net $ (266) (1,092)      
Gas imbalance receivable 0       $ 0
Gains (Loss) on foreign currency transactions 500 1,500 (700)    
Angola [Member] | Overstated [Member]          
Error Corrections and Prior Period Adjustments Restatement [Line Items]          
Allowance For Doubtful Accounts Receivable 7,600        
Gabon [Member]          
Error Corrections and Prior Period Adjustments Restatement [Line Items]          
Recorded allowance 700 2,700 $ 2,400    
Receivable balance, gross | XAF       XAF 16.3  
Receivable balance, net | XAF       XAF 4.9  
Gabon And Angola [Member]          
Error Corrections and Prior Period Adjustments Restatement [Line Items]          
Other operating income (loss), net $ (300) $ (1,500)      
Office Equipment          
Error Corrections and Prior Period Adjustments Restatement [Line Items]          
Estimated useful life 5 years        
Leasehold Improvements | Minimum [Member]          
Error Corrections and Prior Period Adjustments Restatement [Line Items]          
Estimated useful life 5 years        
Leasehold Improvements | Maximum [Member]          
Error Corrections and Prior Period Adjustments Restatement [Line Items]          
Estimated useful life 7 years