Segment and Geographic Information - Net Revenues by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Summary of net revenues by geographic area
Net revenues	$ 35,369	$ 78,622	$ 36,152	$ 22,665	$ 77,466	$ 66,674	$ 36,795	$ 40,578	$ 172,808	$ 221,513	$ 509,558
Europe [Member]
Summary of net revenues by geographic area
Net revenues									41,674	72,577	100,188
Africa [Member]
Summary of net revenues by geographic area
Net revenues									41,417	13,182	75,507
North America [Member]
Summary of net revenues by geographic area
Net revenues									38,005	74,634	130,224
Latin America [Member]
Summary of net revenues by geographic area
Net revenues									24,090	16,406	111,078
Asia Pacific [Member]
Summary of net revenues by geographic area
Net revenues									16,226	19,135	49,881
Middle East [Member]
Summary of net revenues by geographic area
Net revenues									9,467	14,571	39,142
Commonwealth of Independent States [Member]
Summary of net revenues by geographic area
Net revenues									$ 1,929	$ 11,008	$ 3,538