Quarterly report pursuant to Section 13 or 15(d)

Segment Information (Segment Activity) (Details)

v3.8.0.1
Segment Information (Segment Activity) (Details) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2017
Sep. 30, 2016
Jun. 30, 2016
Mar. 31, 2016
Sep. 30, 2017
Sep. 30, 2016
Dec. 31, 2016
Segment Reporting Information [Line Items]              
Revenues-oil and natural gas sales $ 18,178 $ 14,635     $ 59,869 $ 44,458  
Depreciation, depletion and amortization 1,700 1,607     5,539 5,787  
Impairment of proved properties   88 $ 0 $ 0   88  
Bad debt provision (49) 63     232 577  
Other operating expense   324       9,959  
Operating income (loss) 3,721 3,690     17,456 (5,210)  
Interest income (expense), net (327) (327)     (1,108) (2,285)  
Income tax expense 2,749 2,198     9,039 6,884  
Additions to properties and equipment - accrual 297 681     1,111 (1,672)  
Total assets 76,535       76,535   $ 81,032
Continuing Operations [Member]              
Segment Reporting Information [Line Items]              
Total assets 73,762       73,762   78,893
Operating Segments [Member] | Gabon Segment [Member]              
Segment Reporting Information [Line Items]              
Revenues-oil and natural gas sales 18,162 14,540     59,823 44,212  
Depreciation, depletion and amortization 1,633 1,508     5,344 5,484  
Bad debt provision (49) 63     232 577  
Other operating expense   324       9,959  
Operating income (loss) 6,067 5,013     25,117 1,481  
Interest income (expense), net (327) (329)     (1,108) (2,285)  
Income tax expense 2,749 2,305     9,039 6,884  
Additions to properties and equipment - accrual 237 674     1,051 (1,819)  
Operating Segments [Member] | Equatorial Guinea Segment [Member]              
Segment Reporting Information [Line Items]              
Operating income (loss) (44) (184)     (97) (319)  
Operating Segments [Member] | U. S. Segment [Member]              
Segment Reporting Information [Line Items]              
Revenues-oil and natural gas sales 16 95     46 246  
Depreciation, depletion and amortization   38     1 121  
Impairment of proved properties   88       88  
Operating income (loss) 10 (61)     356 (64)  
Additions to properties and equipment - accrual           140  
Operating Segments [Member] | Continuing Operations [Member] | Gabon Segment [Member]              
Segment Reporting Information [Line Items]              
Total assets 61,694       61,694   64,478
Operating Segments [Member] | Continuing Operations [Member] | Equatorial Guinea Segment [Member]              
Segment Reporting Information [Line Items]              
Total assets 10,093       10,093   10,122
Operating Segments [Member] | Continuing Operations [Member] | U. S. Segment [Member]              
Segment Reporting Information [Line Items]              
Total assets 83       83   382
Corporate And Other [Member]              
Segment Reporting Information [Line Items]              
Depreciation, depletion and amortization 67 61     194 182  
Operating income (loss) (2,312) (1,078)     (7,920) (6,308)  
Interest income (expense), net   2          
Income tax expense   (107)          
Additions to properties and equipment - accrual 60 $ 7     60 $ 7  
Corporate And Other [Member] | Continuing Operations [Member]              
Segment Reporting Information [Line Items]              
Total assets $ 1,892       $ 1,892   $ 3,911