Taxes on Income - Valuation Allowance Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance, at beginning of year	$ 29,782	$ 15,428	$ 18,897
Additions	1,879	19,260	3,095
Reversals	(2,102)	(183)	(4,984)
Remeasurement of U.S. deferred tax balances	0	(5,141)	0
Other adjustments	(1,108)	418	(1,580)
Balance, at end of year	$ 28,451	$ 29,782	$ 15,428