Quarterly report pursuant to Section 13 or 15(d)

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

v3.22.1
Crude Oil and Natural Gas Properties and Equipment (Narrative) (Details)
$ in Millions
 3 Months Ended 12 Months Ended
Jun. 20, 2026
Apr. 12, 2021
Feb. 25, 2021
Mar. 31, 2022
USD ($)
contract
item
Dec. 31, 2020
USD ($)
Feb. 24, 2021
Mar. 31, 2020
USD ($)
Dec. 31, 2012
Etame Marine Block [Member]                
Property, Plant and Equipment [Line Items]                
Working interest ownership, percentage     58.80%     31.10%    
Undeveloped acreage             $ 2.3  
Undeveloped leasehold value             $ 11.5  
Etame Marine Block [Member] | VAALCO Gabon S.A. [Member]                
Property, Plant and Equipment [Line Items]                
Working interest ownership, percentage       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%        
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       $ 18.6        
Production Sharing Contract, September 17, 2018 Through September 16, 2028 [Member] | Consortium [Member]                
Property, Plant and Equipment [Line Items]                
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]                
Allocated to unproved leasehold cost       $ 6.7        
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       $ 7.1        
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        
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%        
Production Sharing Contract, After September 16, 2028 [Member] | Etame Marine Block [Member]                
Property, Plant and Equipment [Line Items]                
Number of contract extension periods | contract       2        
Production license agreement term extended by government       5 years        
Sasol Gabon S.A. [Member]                
Property, Plant and Equipment [Line Items]                
Undeveloped acreage       $ 2.2        
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       13.7        
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       $ 10.0        
Potential payment         $ 3.1      
Period of development       25 years