Taxes on Income - Components of Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current:
Federal	$ (4,765)	$ 3,764	$ (636)
Foreign	6,025	7,512	3,585
State	(651)	3,351	175
Subtotal	609	14,627	3,124
Deferred:
Federal	947	(8,706)	2,158
Foreign	(1,531)	(1,099)	475
State	(157)	183	352
Subtotal	(741)	(9,622)	2,985
Total tax provision	$ (132)	$ 5,005	$ 6,109