Segment Information (Long-lived assets by Geographic Location) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Property and equipment, net of accumulated depreciation	$ 173,969	$ 163,860
United States
Segment Reporting Information [Line Items]
Property and equipment, net of accumulated depreciation	90,592	93,951
Europe
Segment Reporting Information [Line Items]
Property and equipment, net of accumulated depreciation	61,996	48,043
Other Geographic Locations
Segment Reporting Information [Line Items]
Property and equipment, net of accumulated depreciation	$ 21,381	$ 21,866