Marketable Investments (Details 3) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Net Investment Income [Line Items]
Unrealized net gain (loss) on equity securities reflected in the Consolidated Statements of Income	$ 1,839	$ (591)
Proceeds received on tender of equity securities	1,875	53
Realized loss on tender/sale of equity securities reflected in the Consolidated Statements of Income	(140)	53
Equity Securities, Investment Summary [Member]
Net Investment Income [Line Items]
Unrealized net gain (loss) on equity securities reflected in the Consolidated Statements of Income	1,839	(591)
Proceeds received on tender of equity securities	1,875
Realized loss on tender/sale of equity securities reflected in the Consolidated Statements of Income	$ (140)