Segment Information (Long-lived assets by Geographic Location) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Property and equipment, net of accumulated depreciation	$ 171,092	$ 163,860
United States
Segment Reporting Information [Line Items]
Property and equipment, net of accumulated depreciation	89,664	93,951
Europe
Segment Reporting Information [Line Items]
Property and equipment, net of accumulated depreciation	60,415	48,043
Other Geographic Locations
Segment Reporting Information [Line Items]
Property and equipment, net of accumulated depreciation	$ 21,013	$ 21,866