Quarterly report pursuant to Section 13 or 15(d)

Crude Oil and Natural Gas Properties and Equipment (Narrative) (Details)

v3.21.2
Crude Oil and Natural Gas Properties and Equipment (Narrative) (Details)
1 Months Ended 3 Months Ended 6 Months Ended 12 Months Ended
Jun. 20, 2026
Apr. 12, 2021
Feb. 25, 2021
Sep. 26, 2018
USD ($)
Sep. 17, 2018
USD ($)
item
Sep. 30, 2020
USD ($)
Jun. 30, 2021
USD ($)
Jun. 30, 2020
USD ($)
Mar. 31, 2020
USD ($)
Jun. 30, 2021
USD ($)
item
Jun. 30, 2020
USD ($)
Dec. 31, 2020
USD ($)
Feb. 24, 2021
Dec. 31, 2012
Property, Plant and Equipment [Line Items]                            
Reduction in VAT receivable                   $ (500,000) $ (695,000)      
Impairment of proved crude oil and natural gas properties             $ 0 $ 0   0 $ 30,625,000      
Property, net             $ 74,202,000     $ 74,202,000   $ 37,036,000    
Etame Marine Block [Member]                            
Property, Plant and Equipment [Line Items]                            
Working interest ownership, percentage     58.80%                   31.10%  
Impairment of proved crude oil and natural gas properties                 $ 30,600,000          
Property, net                 15,600,000          
Undeveloped acreage                 2,300,000          
Undeveloped leasehold value                 $ 11,500,000          
Etame Marine Block [Member] | VAALCO Gabon S.A. [Member]                            
Property, Plant and Equipment [Line Items]                            
Working interest ownership, percentage             63.575%     63.575%        
Prior Production Sharing Contract, Through September 17, 2018 [Member] | Etame Marine Block [Member] | Consortium [Member]                            
Property, Plant and Equipment [Line Items]                            
Working interest ownership, percentage             7.50%     7.50%        
Production Sharing Contract, September 17, 2018 Through September 16, 2028 [Member]                            
Property, Plant and Equipment [Line Items]                            
Deferred tax assets, basis difference in fixed assets             $ 18,600,000     $ 18,600,000        
Estimated costs of technical studies           $ 500,000                
Production Sharing Contract, September 17, 2018 Through September 16, 2028 [Member] | Consortium [Member]                            
Property, Plant and Equipment [Line Items]                            
Number of wells drilled | item                   2        
Number of wellbores drilled | item                   2        
Number of technical studies required | item                   2        
Estimated costs of technical studies           $ 1,500,000                
Entitled percent for consortium after initial royalty percentage                   80.00%        
Production Sharing Contract, September 17, 2018 Through September 16, 2028 [Member] | Signing Bonus [Member]                            
Property, Plant and Equipment [Line Items]                            
Contractual obligation         $ 21,800,000                  
Payment of signing bonus, allocated to proved and unproved property       $ 11,800,000                    
Reduction in VAT receivable       8,400,000                    
Other accrued liabilities       1,700,000                    
Allocated to unproved leasehold cost             6,700,000     $ 6,700,000        
Production Sharing Contract, September 17, 2018 Through September 16, 2028 [Member] | Signing Bonus [Member] | Consortium [Member]                            
Property, Plant and Equipment [Line Items]                            
Contractual obligation         $ 65,000,000.0                  
Payment of signing bonus, allocated to proved and unproved property       35,000,000.0                    
Reduction in VAT receivable       25,000,000.0                    
Other accrued liabilities       $ 5,000,000.0                    
Production Sharing Contract, September 17, 2018 Through September 16, 2028 [Member] | Tax Impact [Member]                            
Property, Plant and Equipment [Line Items]                            
Allocated to unproved leasehold cost             $ 7,100,000     $ 7,100,000        
Production Sharing Contract, September 17, 2018 Through September 16, 2028 [Member] | Etame Marine Block [Member]                            
Property, Plant and Equipment [Line Items]                            
Number of exploitation areas | item         3                  
Period of agreement for exploitation areas         10 years         10 years        
Number of contract extension periods | item         2                  
Production license agreement term extended by government         5 years                  
Production Sharing Contract, September 17, 2018 Through September 16, 2028 [Member] | Etame Marine Block [Member] | Government Of Gabon [Member]                            
Property, Plant and Equipment [Line Items]                            
Working interest ownership, percentage             7.50%     7.50%        
Production Sharing Contract, September 17, 2018 Through September 16, 2028 [Member] | Scenario, Forecast [Member] | Etame Marine Block [Member]                            
Property, Plant and Equipment [Line Items]                            
Increase (decrease) in working interest ownership percentage (1.60%)                          
Production Sharing Contract, September 17, 2018 Through September 16, 2028 [Member] | Scenario, Forecast [Member] | Etame Marine Block [Member] | Government Of Gabon [Member]                            
Property, Plant and Equipment [Line Items]                            
Working interest ownership, percentage 10.00%                          
Increase (decrease) in working interest ownership percentage 2.50%                          
Production Sharing Contract, After September 16, 2028 [Member] | Consortium [Member]                            
Property, Plant and Equipment [Line Items]                            
Entitled percent for consortium after initial royalty percentage                   70.00%        
Sasol Gabon S.A. [Member]                            
Property, Plant and Equipment [Line Items]                            
Undeveloped acreage             $ 2,200,000     $ 2,200,000        
Sasol Gabon S.A. [Member] | Etame Marine Block [Member]                            
Property, Plant and Equipment [Line Items]                            
Increase (decrease) in working interest ownership percentage     27.80%                      
Undeveloped leasehold value             13,700,000     13,700,000        
Block P Offshore Equatorial Guinea [Member]                            
Property, Plant and Equipment [Line Items]                            
Working interest ownership, percentage                       43.00%   31.00%
Increase (decrease) in working interest ownership percentage   45.90%                   12.00%    
Undeveloped acreage             $ 10,000,000.0     $ 10,000,000.0        
Potential payment                       $ 3,100,000    
Period of development                   25 years