Quarterly report pursuant to Section 13 or 15(d)

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

v3.20.1
Crude Oil and Natural Gas Properties and Equipment (Narrative) (Details)
$ in Thousands
 1 Months Ended 3 Months Ended
Jun. 20, 2026
Sep. 26, 2018
USD ($)
Sep. 17, 2018
USD ($)
item
Feb. 29, 2020
USD ($)
Mar. 31, 2020
USD ($)
item
Mar. 31, 2019
USD ($)
Dec. 31, 2019
USD ($)
Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]                
Reduction in VAT receivable         $ (370) $ 738    
Number of drilled wells required by agreement | item         2      
Number of appraisal wells required by agreement | item         2      
Impairment of proved crude oil and natural gas properties         $ 30,625      
Property, net         43,500   $ 68,258  
Undeveloped acreage         21,476   $ 23,771  
Etame Marine Block [Member]                
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]                
Allocated to proved leasehold cost         2,300      
Impairment of proved crude oil and natural gas properties         30,600      
Property, net         15,600      
Undeveloped leasehold value         $ 11,500      
Etame Marine Block [Member] | VAALCO Gabon S.A. [Member]                
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]                
Working interest ownership, percentage         33.575%      
Block P Offshore Equatorial Guinea [Member]                
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]                
Working interest ownership, percentage         43.00%   31.00%  
Increase (decrease) in working interest ownership percentage         12.00%      
Undeveloped acreage         $ 10,000      
Potential payment         $ 3,100      
Period of development         25 years      
Prior Production Sharing Contract, Through September 17, 2018 [Member] | Consortium [Member]                
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]                
Entitled percent for consortium after initial royalty percentage         70.00%      
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]                
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]                
Monthly royalty rate, based on production at the published price         13.00%      
Prior Production Sharing Contract, Through September 17, 2018 [Member] | Etame Marine Block [Member] | Consortium [Member]                
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]                
Working interest ownership, percentage         7.50%      
Prior Production Sharing Contract, Through September 17, 2018 [Member] | Etame Marine Block [Member] | Government Of Gabon [Member]                
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]                
Working interest ownership, percentage               7.50%
Production Sharing Contract, September 17, 2018 Through September 16, 2028 [Member]                
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]                
Deferred tax assets, basis difference in fixed assets         $ 18,600      
Deferred tax liabilities, basis difference in fixed assets         18,600      
Allocated to proved leasehold cost         22,500      
Allocated to unproved leasehold cost         13,700      
Estimated costs of technical studies         $ 400      
Production Sharing Contract, September 17, 2018 Through September 16, 2028 [Member] | Consortium [Member]                
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]                
Number of drilled wells required by agreement | item         2      
Number of appraisal wellbores required by agreement | item         2      
Number of wells drilled | item         2      
Number of wellbores drilled | item         2      
Number of technical studies required | item         2      
Estimated costs of technical studies         $ 1,300      
Entitled percent for consortium after initial royalty percentage         80.00%      
Production Sharing Contract, September 17, 2018 Through September 16, 2028 [Member] | Government Of Gabon [Member]                
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [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] | Signing Bonus [Member]                
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]                
Contractual obligation     $ 21,800          
Payment of signing bonus, allocated to proved and unproved property   $ 11,800            
Reduction in VAT receivable   8,400   $ 4,200        
Other accrued liabilities   1,700         $ 1,700  
Allocated to unproved leasehold cost         $ 6,700      
Production Sharing Contract, September 17, 2018 Through September 16, 2028 [Member] | Signing Bonus [Member] | Consortium [Member]                
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]                
Contractual obligation     $ 65,000          
Payment of signing bonus, allocated to proved and unproved property   35,000            
Reduction in VAT receivable   25,000            
Other accrued liabilities   $ 5,000            
Production Sharing Contract, September 17, 2018 Through September 16, 2028 [Member] | Tax Impact [Member]                
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]                
Allocated to unproved leasehold cost         $ 7,100      
Production Sharing Contract, September 17, 2018 Through September 16, 2028 [Member] | Etame Marine Block [Member]                
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [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]                
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [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]                
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]                
Increase (decrease) in working interest ownership percentage (0.80%)              
Production Sharing Contract, September 17, 2018 Through September 16, 2028 [Member] | Scenario, Forecast [Member] | Etame Marine Block [Member] | Government Of Gabon [Member]                
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [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]                
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]                
Entitled percent for consortium after initial royalty percentage         70.00%