Quarterly report pursuant to Section 13 or 15(d)

Organization and Accounting Policies (Narrative) (Details)

v3.20.1
Organization and Accounting Policies (Narrative) (Details)
$ in Thousands
 3 Months Ended
Mar. 31, 2020
USD ($)
/ $
Mar. 31, 2019
USD ($)
Jun. 20, 2026
Dec. 31, 2019
/ $
Dec. 31, 2018
Organization And Accounting Policies [Line Items]          
Receivable balance, gross, noncurrent $ 3,500        
Exchange rate | / $ 593.1     585.7  
Bad debt recovery (expense) $ (810) $ 29      
Transfers between levels 0 0      
Consortium [Member]          
Organization And Accounting Policies [Line Items]          
Receivable balance, gross, noncurrent 10,400        
Government Of Gabon [Member]          
Organization And Accounting Policies [Line Items]          
Bad debt recovery (expense) $ (800) $ 32      
Prior Production Sharing Contract, Through September 17, 2018 [Member] | Consortium [Member]          
Organization And Accounting Policies [Line Items]          
Monthly royalty rate, based on production at the published price 13.00%        
Prior Production Sharing Contract, Through September 17, 2018 [Member] | Government Of Gabon [Member]          
Organization And Accounting Policies [Line Items]          
Monthly royalty rate, based on production at the published price 13.00%        
Production Sharing Contract, September 17, 2018 Through September 16, 2028 [Member] | Government Of Gabon [Member]          
Organization And Accounting Policies [Line Items]          
Monthly royalty rate, based on production at the published price 13.00%        
Etame Marine Block [Member] | Prior Production Sharing Contract, Through September 17, 2018 [Member] | Consortium [Member]          
Organization And Accounting Policies [Line Items]          
Working interest ownership, percentage 7.50%        
Etame Marine Block [Member] | Prior Production Sharing Contract, Through September 17, 2018 [Member] | Government Of Gabon [Member]          
Organization And Accounting Policies [Line Items]          
Working interest ownership, percentage         7.50%
Etame Marine Block [Member] | Production Sharing Contract, September 17, 2018 Through September 16, 2028 [Member] | Government Of Gabon [Member]          
Organization And Accounting Policies [Line Items]          
Working interest ownership, percentage 7.50%        
Etame Marine Block [Member] | Scenario, Forecast [Member] | Production Sharing Contract, September 17, 2018 Through September 16, 2028 [Member] | Government Of Gabon [Member]          
Organization And Accounting Policies [Line Items]          
Working interest ownership, percentage     10.00%