Quarterly report pursuant to Section 13 or 15(d)

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

v3.21.1
Crude Oil and Natural Gas Properties and Equipment (Narrative) (Details)
3 Months Ended
Jun. 20, 2026
Apr. 12, 2021
Feb. 25, 2021
Sep. 26, 2018
USD ($)
Sep. 17, 2018
USD ($)
item
Mar. 31, 2021
USD ($)
item
Mar. 31, 2020
USD ($)
Feb. 24, 2021
Dec. 31, 2020
USD ($)
Dec. 31, 2012
Property, Plant and Equipment [Line Items]                    
Reduction in VAT receivable           $ (149,000) $ (370,000)      
Impairment of proved crude oil and natural gas properties           0 30,625,000      
Property, net           $ 78,192,000     $ 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%        
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           12.00%        
Undeveloped acreage           $ 10,000,000.0        
Potential payment           $ 3,100,000        
Period of development           25 years        
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%        
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        
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        
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        
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%        
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        
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        
Subsequent Event [Member] | Block P Offshore Equatorial Guinea [Member]                    
Property, Plant and Equipment [Line Items]                    
Increase (decrease) in working interest ownership percentage   45.90%