Taxes on Income, Reconciliation of Liability for Unrecognized Tax Benefits (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of the beginning and ending amount of the liability for unrecognized tax benefits [Roll Forward]
Balance at beginning of year	$ 883,000	$ 1,443,000	$ 1,787,000
Additions based on tax positions related to the current year	262,000	51,000	254,000
Additions for tax positions of prior years	114,000	58,000	70,000
Reductions for tax positions of prior years	(266,000)	(669,000)	(668,000)
Settlements	(210,000)	0	0
Balance at end of year	783,000	883,000	1,443,000
Income tax penalties and interest recognized	(90,000)	(71,000)	$ (209,000)
Accrued liabilities for payment of interest and penalties	$ 172,000	$ 289,000