Annual report pursuant to Section 13 and 15(d)

Summary Of Significant Accounting Policies (Narrative) (Details)

v3.10.0.1
Summary Of Significant Accounting Policies (Narrative) (Details)
$ in Thousands, in Billions
 3 Months Ended 12 Months Ended
Sep. 17, 2018
XAF ( )
Sep. 17, 2018
USD ($)
Sep. 30, 2018
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Dec. 31, 2018
XAF ( )
$ / bbl
/ $
Dec. 31, 2018
USD ($)
$ / bbl
/ $
Organization And Accounting Policies [Line Items]                
Capitalized oil and gas property     $ 442,203   $ 409,367     $ 443,329
Deferred tax assets     50,195   1,260     $ 40,077
Exchange rate | / $             573.000 573.000
Other operating income (expense), net       $ 365 (84) $ (266)    
Inventory write-off       400        
Asset retirement obligation, revision of estimate       (6,527) 703 (1)    
Receivable balance, net         3,556     $ 11,907
Value added tax and other receivables, net     2,306   6,925     2,226
Gains on foreign currency transactions       100 500 30    
Interest expense capitalized       $ 0 0 0    
Monthly royalty rate, based on production at the published price       13.00%        
Working interest of carried partner, percentage       7.50%        
Future working interest of carried partner percentage       10.00%        
Deferred tax assets, gross         154,465     131,012
Valuation allowance         153,205 211,800   $ 90,935
Change in valuation allowance       $ (16,500) 57,600      
Derivative cap price | $ / bbl             74.00 74.00
Derivative floor price | $ / bbl             74.00 74.00
Cash paid to settle derivatives       700        
Cash received to settle derivatives         200      
Restatement Adjustment [Member]                
Organization And Accounting Policies [Line Items]                
Capitalized oil and gas property     18,612          
Deferred tax assets     (18,612)          
Accrued liabilities         (2,600)      
Deferred Tax Liability, Understated [Member]                
Organization And Accounting Policies [Line Items]                
Amount misstated     $ 18,600          
Gabon                
Organization And Accounting Policies [Line Items]                
Other operating income (expense), net       400 (300) (300)    
Receivable balance, gross |             6.9  
Receivable balance, net |             2.3  
Reduction of VAT receivable | 14.1              
Reduction of VAT receivable, net 4.7 $ 4,200            
Recoveries (allowances) of VAT receivable       $ 100 $ (400) $ (700)    
Office Equipment                
Organization And Accounting Policies [Line Items]                
Estimated useful life       5 years        
Leasehold Improvements | Minimum                
Organization And Accounting Policies [Line Items]                
Estimated useful life       5 years        
Leasehold Improvements | Maximum                
Organization And Accounting Policies [Line Items]                
Estimated useful life       7 years