Segment and Geographic Data (Property and Equipment, Net) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	$ 61,270	$ 59,419
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	12,009	10,933
United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	4,011	3,960
Other Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	1,498	1,430
Israel
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	22,903	22,682
Asia
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	19,118	19,090
Canada and Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	$ 1,731	$ 1,324