Quarterly report pursuant to Section 13 or 15(d)

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

v3.20.2
Crude Oil and Natural Gas Properties and Equipment (Narrative) (Details)
 1 Months Ended 3 Months Ended 6 Months Ended
Jun. 20, 2026
Sep. 26, 2018
USD ($)
Sep. 17, 2018
USD ($)
item
Feb. 29, 2020
USD ($)
Jun. 30, 2020
USD ($)
Jun. 30, 2020
USD ($)
item
Jun. 30, 2019
USD ($)
Dec. 31, 2019
USD ($)
Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]                  
Reduction in VAT receivable           $ (695,000) $ 718,000    
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         $ 0 $ 30,625,000      
Property, net         41,348,000 41,348,000   $ 68,258,000  
Undeveloped acreage         21,476,000 21,476,000   $ 23,771,000  
Etame Marine Block [Member]                  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]                  
Allocated to proved leasehold cost         2,300,000 2,300,000      
Impairment of proved crude oil and natural gas properties           30,600,000      
Property, net         15,600,000 15,600,000      
Undeveloped leasehold value         $ 11,500,000 $ 11,500,000      
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% 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% 43.00%   31.00%  
Increase (decrease) in working interest ownership percentage           12.00%      
Undeveloped acreage         $ 10,000,000.0 $ 10,000,000.0      
Potential payment         $ 3,100,000 $ 3,100,000      
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% 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         $ 18,600,000 $ 18,600,000      
Deferred tax liabilities, basis difference in fixed assets         18,600,000 18,600,000      
Allocated to proved leasehold cost         22,500,000 22,500,000      
Allocated to unproved leasehold cost         13,700,000 13,700,000      
Estimated costs of technical studies           $ 400,000      
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           $ 1,300,000      
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     $ 21,800,000            
Payment of signing bonus, allocated to proved and unproved property   $ 11,800,000              
Reduction in VAT receivable   8,400,000   $ 4,200,000          
Other accrued liabilities   1,700,000           $ 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]                  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [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]                  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [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]                  
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% 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%