Taxes on Income, Reconciliation of Liability for Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of the beginning and ending amount of the liability for unrecognized tax benefits [Roll Forward]
Balance at beginning of year	$ 1,787	$ 2,019	$ 1,958
Additions based on tax positions related to the current year	254	403	187
Additions for tax positions of prior years	70	273	867
Reductions for tax positions of prior years	(668)	(908)	(441)
Settlements	0	0	(552)
Balance at end of year	1,443	1,787	2,019
Income tax penalties and interest recognized	209	120	88
Accrued liabilities for payment of interest and penalties	$ 466	$ 675	$ 554