Taxes on Income - Net Deferred Taxes (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred income tax assets:
Foreign tax credit carryforwards	$ 507	$ 466
Net operating loss carryforwards	22,909	23,216
Accrued expenses	12,987	12,107
Other	8,652	4,707
Total gross deferred income tax assets	45,055	40,496
Less valuation allowance	(28,451)	(29,782)
Net deferred income tax assets	16,604	10,714
Deferred income tax liabilities:
Property, plant and equipment	(6,038)	(9,482)
Intangible assets	(10,609)	(2,201)
Other	(6,757)	(6,576)
Total deferred income tax liabilities	(23,404)	(18,259)
Net deferred income tax liabilities	$ (6,800)	$ (7,545)