Segment and Geographic Data (Property and Equipment, Net) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	$ 75,016	$ 61,270
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	11,036	12,009
United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	4,153	4,011
Other Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	1,813	1,498
Israel
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	38,339	22,903
Asia
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	17,953	19,118
Canada and Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	$ 1,722	$ 1,731