Annual report pursuant to Section 13 and 15(d)

Schedule I - Parent Company Financial Statement (Condensed Unconsolidated Balance Sheet - Additional Information) (Details)

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Schedule I - Parent Company Financial Statement (Condensed Unconsolidated Balance Sheet - Additional Information) (Details) - $ / shares
Dec. 31, 2017
Dec. 31, 2016
Condensed Balance Sheet Statements, Captions [Line Items]    
Common stock, par value $ 0.10 $ 0.10
Common stock, shares authorized 100,000,000 100,000,000
Common stock, shares issued 66,443,971 66,109,565
Common Stock, Shares, Outstanding 58,862,876 58,554,470
Treasury stock, shares 7,581,095 7,555,095
VAALCO ENERGY, INC. [Member]    
Condensed Balance Sheet Statements, Captions [Line Items]    
Common stock, par value $ 0.10 $ 0.10
Common stock, shares authorized 100,000,000 100,000,000
Common stock, shares issued 66,443,971 66,109,565
Common Stock, Shares, Outstanding 58,862,876 58,554,470
Treasury stock, shares 7,581,095 7,555,095