Annual report pursuant to Section 13 and 15(d)

Segment Information (Segment Activity) (Details)

v3.22.0.1
Segment Information (Segment Activity) (Details) - USD ($)
 12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Segment Reporting Information [Line Items]      
Revenues-crude oil and natural gas sales $ 199,075,000 $ 67,176,000 $ 84,521,000
Depreciation, depletion and amortization 21,060,000 9,382,000 7,083,000
Gain on revision of asset retirement obligations     (379,000)
Impairment of proved crude oil and natural gas properties 0 30,625,000  
Bad debt (recovery) expense and other 875,000 1,165,000 (341,000)
Other operating expense, net (440,000) (1,669,000) (4,421,000)
Operating income (loss) 79,100,000 (27,263,000) 21,193,000
Derivative instruments gain (loss), net (22,826,000) 6,577,000 (446,000)
Interest income (expense), net   155,000 733,000
Other, net 3,494,000 129,000 (438,000)
Income tax expense (benefit) (22,156,000) 27,681,000 23,890,000
Additions to crude oil and natural gas properties and equipment - accrual 79,221,000 10,494,000 22,173,000
Operating Segments [Member] | Gabon Segment [Member]      
Segment Reporting Information [Line Items]      
Revenues-crude oil and natural gas sales 199,075,000 67,176,000 84,521,000
Depreciation, depletion and amortization 20,972,000 9,028,000 6,825,000
Gain on revision of asset retirement obligations     (379,000)
Impairment of proved crude oil and natural gas properties   30,625,000  
Bad debt (recovery) expense and other 875,000 1,165,000 (341,000)
Other operating expense, net (440,000) (1,669,000) (4,456,000)
Operating income (loss) 93,191,000 (17,261,000) 35,049,000
Interest income (expense), net     5,000
Other, net 6,925,000 194,000 (230,000)
Income tax expense (benefit) 12,392,000 16,204,000 20,311,000
Additions to crude oil and natural gas properties and equipment - accrual 79,169,000 10,503,000 22,116,000
Operating Segments [Member] | Equatorial Guinea Segment [Member]      
Segment Reporting Information [Line Items]      
Operating income (loss) (853,000) (431,000) (438,000)
Other, net (3,000) 3,000 (3,000)
Income tax expense (benefit) 1,000 1,000 12,000
Corporate and Other [Member]      
Segment Reporting Information [Line Items]      
Depreciation, depletion and amortization 88,000 354,000 258,000
Other operating expense, net     35,000
Operating income (loss) (13,238,000) (9,571,000) (13,418,000)
Derivative instruments gain (loss), net (22,826,000) 6,577,000 (446,000)
Interest income (expense), net   155,000 728,000
Other, net (3,428,000) (68,000) (205,000)
Income tax expense (benefit) (34,549,000) 11,476,000 3,567,000
Additions to crude oil and natural gas properties and equipment - accrual $ 52,000 $ (9,000) $ 57,000