Quarterly report pursuant to Section 13 or 15(d)

Segment Information (Segment Activity) (Details)

v3.7.0.1
Segment Information (Segment Activity) (Details) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Dec. 31, 2016
Segment Reporting Information [Line Items]      
Revenues-oil and natural gas sales $ 21,266 $ 10,976  
Depreciation, depletion and amortization 1,869 2,238  
Bad debt expense and other 98 343  
Operating income (loss) 8,148 (13,515)  
Interest income (expense), net (403) (488)  
Income tax expense 3,194 1,685  
Additions to properties and equipment 262    
Total assets 79,997   $ 81,032
Continuing Operations [Member]      
Segment Reporting Information [Line Items]      
Total assets 77,582   78,893
Operating Segments [Member] | Gabon [Member]      
Segment Reporting Information [Line Items]      
Revenues-oil and natural gas sales 21,246 10,908  
Depreciation, depletion and amortization 1,809 2,143  
Bad debt expense and other 98 343  
Operating income (loss) 10,960 (11,956)  
Interest income (expense), net (403) (488)  
Income tax expense 3,194 1,685  
Additions to properties and equipment 262    
Operating Segments [Member] | Gabon [Member] | Continuing Operations [Member]      
Segment Reporting Information [Line Items]      
Total assets 64,108   64,478
Operating Segments [Member] | Equatorial Guinea [Member]      
Segment Reporting Information [Line Items]      
Operating income (loss) (38) (48)  
Operating Segments [Member] | Equatorial Guinea [Member] | Continuing Operations [Member]      
Segment Reporting Information [Line Items]      
Total assets 10,119   10,122
Operating Segments [Member] | U.S. [Member]      
Segment Reporting Information [Line Items]      
Revenues-oil and natural gas sales 20 68  
Depreciation, depletion and amortization 1 21  
Operating income (loss) 7 (3)  
Operating Segments [Member] | U.S. [Member] | Continuing Operations [Member]      
Segment Reporting Information [Line Items]      
Total assets 173   382
Corporate And Other [Member]      
Segment Reporting Information [Line Items]      
Depreciation, depletion and amortization 59 74  
Operating income (loss) (2,781) $ (1,508)  
Corporate And Other [Member] | Continuing Operations [Member]      
Segment Reporting Information [Line Items]      
Total assets $ 3,182   $ 3,911