Segment Information (Long-Lived Assets by Geographic Region) (Details) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Total long-lived assets		$ 132,273	$ 129,955
United States [Member]
Segment Reporting Information [Line Items]
Total long-lived assets		98,279	95,716
Israel [Member]
Segment Reporting Information [Line Items]
Total long-lived assets		13,263	13,079
Australia [Member]
Segment Reporting Information [Line Items]
Total long-lived assets		9,276	9,504
Netherlands [Member]
Segment Reporting Information [Line Items]
Total long-lived assets		8,252	8,363
Other [Member]
Segment Reporting Information [Line Items]
Total long-lived assets	[1]	$ 3,203	$ 3,293

[1] United Kingdom, Germany, Japan, France and Italy