Operating Segments (Schedule of Operating Segment Assets) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Total assets	$ 238,571	$ 228,046
Continuing Operations [Member]
Segment Reporting Information [Line Items]
Total assets	238,571	228,043
Continuing Operations [Member] | Venezuela [Member]
Segment Reporting Information [Line Items]
Total assets	164,864	165,214
Continuing Operations [Member] | Gabon [Member]
Segment Reporting Information [Line Items]
Total assets	55,307	60,051
Continuing Operations [Member] | Indonesia [Member]
Segment Reporting Information [Line Items]
Total assets	19	176
Continuing Operations [Member] | United States and Other [Member]
Segment Reporting Information [Line Items]
Total assets	$ 18,381	2,602
Discontinued Operations [Member]
Segment Reporting Information [Line Items]
Total assets		$ 3