Quarterly report pursuant to Section 13 or 15(d)

Organization and Accounting Policies (Narrative) (Details)

v3.20.2
Organization and Accounting Policies (Narrative) (Details)
 3 Months Ended 9 Months Ended
Sep. 30, 2020
USD ($)
/ $
Mar. 31, 2020
USD ($)
Sep. 30, 2019
USD ($)
Sep. 30, 2020
USD ($)
/ $
Sep. 30, 2019
USD ($)
Jun. 20, 2026
Dec. 31, 2019
/ $
Dec. 31, 2018
Organization And Accounting Policies [Line Items]                
Impairment of proved crude oil and natural gas properties $ 0     $ 30,625,000        
Receivable balance, gross, noncurrent $ 4,100,000     $ 4,100,000        
Exchange rate | / $ 560.3     560.3     585.7  
Bad debt expense and other $ 151,000   $ 54,000 $ 1,140,000 $ 30,000      
Transfers between levels 0   $ 0 $ 0 $ 0      
Office and Miscellaneous Equipment [Member]                
Organization And Accounting Policies [Line Items]                
Estimated useful life of assets       5 years        
Leasehold Improvements [Member] | Minimum [Member]                
Organization And Accounting Policies [Line Items]                
Estimated useful life of assets       5 years        
Leasehold Improvements [Member] | Maximum [Member]                
Organization And Accounting Policies [Line Items]                
Estimated useful life of assets       7 years        
Consortium [Member]                
Organization And Accounting Policies [Line Items]                
Receivable balance, gross, noncurrent $ 12,200,000     $ 12,200,000        
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]                
Organization And Accounting Policies [Line Items]                
Impairment of proved crude oil and natural gas properties   $ 30,600,000            
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%     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%     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%