Segment Reporting and Major Customers - Property and Equipment, net (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Property and equipment, net, by geographic areas
Property and equipment, net of accumulated depreciation and amortization	$ 282,490	$ 282,345
United States
Property and equipment, net, by geographic areas
Property and equipment, net of accumulated depreciation and amortization	231,264	236,913
Europe
Property and equipment, net, by geographic areas
Property and equipment, net of accumulated depreciation and amortization	43,935	38,866
Other
Property and equipment, net, by geographic areas
Property and equipment, net of accumulated depreciation and amortization	$ 7,291	$ 6,566