Quarterly report pursuant to Section 13 or 15(d)

Segment Information (Long-lived Assets From Continuing Operations) (Details)

v3.10.0.1
Segment Information (Long-lived Assets From Continuing Operations) (Details) - USD ($)
$ in Thousands
Jun. 30, 2018
Dec. 31, 2017
Segment Reporting Information [Line Items]    
Total assets $ 100,276 $ 79,633
Continuing Operations [Member]    
Segment Reporting Information [Line Items]    
Long lived assets 21,127 23,221
Total assets 97,104 76,797
Operating Segments [Member] | Continuing Operations [Member] | Gabon Segment [Member]    
Segment Reporting Information [Line Items]    
Long lived assets 10,659 12,638
Total assets 64,846 63,122
Operating Segments [Member] | Continuing Operations [Member] | Equatorial Guinea Segment [Member]    
Segment Reporting Information [Line Items]    
Long lived assets 10,000 10,000
Total assets 10,089 10,095
Corporate And Other [Member] | Continuing Operations [Member]    
Segment Reporting Information [Line Items]    
Long lived assets 468 583
Total assets $ 22,169 $ 3,580