Quarterly report pursuant to Section 13 or 15(d)

Commitments and Contingencies (Narrative) (Detail)

v3.3.0.814
Commitments and Contingencies (Narrative) (Detail)
$ in Thousands, a in Millions
 1 Months Ended 3 Months Ended 6 Months Ended 9 Months Ended 12 Months Ended
Nov. 30, 2014
item
Oct. 31, 2014
USD ($)
km²
item
Dec. 31, 2010
item
Nov. 30, 2006
a
item
Sep. 30, 2015
USD ($)
Mar. 31, 2015
USD ($)
Sep. 30, 2014
USD ($)
Jun. 30, 2015
USD ($)
Sep. 30, 2015
USD ($)
item
Sep. 30, 2014
USD ($)
Dec. 31, 2014
USD ($)
item
Dec. 31, 2013
USD ($)
Oct. 01, 2014
USD ($)
Apr. 30, 2014
USD ($)
Commitments And Contingencies [Line Items]                            
Number of drilling rigs contracts | item                     2      
Drilling rig daily rate, gross basis, year one               $ 168            
Drilling rig daily rate, gross basis, year two               $ 172            
Remaining commitment of drilling activity                         $ 25,800  
DGH audit settlement         $ 300                  
Allowance for accounts with partners         7,600       $ 7,600   $ 7,600      
Accounts with partners, net of allowance         17,930       17,930   10,903      
Recorded restricted cash         15,830       15,830   20,830      
Exploration expense         9,007   $ 598   37,579 $ 15,213        
Dry hole costs and impairment loss on unproved leasehold                 36,848 13,273        
Asset retirement obligations         16,198   $ 13,659   16,198 $ 13,659 $ 14,846 $ 11,463    
Sonangol P&P [Member]                            
Commitments And Contingencies [Line Items]                            
Accounts with partners, net of allowance         7,300       $ 7,300          
Subsequent Exploration Phase [Member]                            
Commitments And Contingencies [Line Items]                            
Number of exploration wells | item                 4          
Offshore Gabon [Member]                            
Commitments And Contingencies [Line Items]                            
Annual funding related to production license, term                 10 years          
Percentage of annual funding over seven years                 12.14%          
Funding period for initial rate                 7 years          
Second funding period of production license                 3 years          
Percentage of annual funding over last three years                 5.00%          
Cash funding arrangement for abandonment of the offshore wells, platforms and facilities   $ 8,400       $ 4,200                
Cash funding arrangement for abandonment of the offshore wells, platforms and facilities net   $ 2,300       $ 1,200                
Abandonment cost related to annual funding                 $ 10,100          
Number of additional exploration wells due to exploration period extension | item                 2          
Production license agreement term extended by government                 5 years          
Offshore Gabon [Member] | Third-Party Study, Estimated Increase Cost [Member]                            
Commitments And Contingencies [Line Items]                            
Annual abandonment requirements cost increase                 $ 600          
Annual abandonment funding cost                 2,500          
Offshore Gabon [Member] | Third-Party Study, Estimated Increase Cost [Member] | Maximum [Member]                            
Commitments And Contingencies [Line Items]                            
Abandonment cost related to annual funding                 28,000          
Offshore Gabon [Member] | Third-Party Study, Estimated Increase Cost [Member] | Minimum [Member]                            
Commitments And Contingencies [Line Items]                            
Abandonment cost related to annual funding                 $ 14,000          
Angola [Member]                            
Commitments And Contingencies [Line Items]                            
Area under acquire property exploration rights agreement term | a       1.4                    
Joint operation agreement related to third party in working interest percentage       40.00%                    
Additional joint operation agreement related to third party in working interest percentage       10.00%                    
Production license agreement term       4 years                    
Number of exploration wells | item   2   2                    
Extended drilling period   3 years             1 year          
Allowance for accounts with partners                       $ 7,600    
Percentage of working interest for amounts owned                       40.00%    
Percent of carried interest                       10.00%    
Proceeds from Customers                 $ 22,200          
Number of additional exploration wells due to exploration period extension | item 2   2                      
Production license agreement term extended by government       3 years                    
Total assessment of the exploration         10,000       10,000          
Assessment net to VAALCO         5,000       5,000          
Recorded restricted cash         $ 15,000       $ 15,000          
Angola [Member] | Sonangol P&P [Member]                            
Commitments And Contingencies [Line Items]                            
Accounts with partners, net of allowance                           $ 7,600
Angola [Member] | Seismic Obligation [Member]                            
Commitments And Contingencies [Line Items]                            
Length of acquired property | km²   600