Investments In Securities and Fair Value (Schedule of Equity Securities) (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities, Cost	$ 19,424	$ 25,278
Equity securities, estimated fair value	31,831	51,691
Common stocks
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities, Cost	19,424	25,278
Equity securities, estimated fair value	$ 31,831	$ 51,691