Taxes on Income - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	$ 2,465	$ 2,410	$ 2,672
Additions for tax positions of prior years related to acquisitions	0	148	0
Additions for tax positions of prior years	12	10	10
Lapse in statute of limitations	(274)	(83)	(218)
Foreign currency translation, increase	26
Foreign currency translation, decrease		(20)	(54)
Ending balance	$ 2,229	$ 2,465	$ 2,410