Segment Operating Results - Assets by Geographic Area (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
Segment Reporting Information [Line Items]
Assets	$ 1,451,286	$ 1,662,346	$ 1,306,650
United States [Member]
Segment Reporting Information [Line Items]
Assets	1,160,457	1,376,101
Europe and Other [Member]
Segment Reporting Information [Line Items]
Assets	219,021	190,380
Latin America [Member]
Segment Reporting Information [Line Items]
Assets	$ 71,808	$ 95,865