Investment in Securities, Investment in Equity Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Investments in Equity Securities and Funds [Abstract]
Cost	$ 57,170	$ 48,833
Estimated Fair Value	37,982	32,344
Common Stock [Member]
Investments in Equity Securities and Funds [Abstract]
Cost	33,912	33,575
Estimated Fair Value	15,261	16,210
Actively Managed Semi-transparent EFTs [Member]
Investments in Equity Securities and Funds [Abstract]
Cost	17,000	9,000
Estimated Fair Value	16,539	9,599
Open-end Funds [Member]
Investments in Equity Securities and Funds [Abstract]
Cost	5,722	5,722
Estimated Fair Value	5,664	5,995
Closed-end Funds [Member]
Investments in Equity Securities and Funds [Abstract]
Cost	530	530
Estimated Fair Value	514	534
Other [Member]
Investments in Equity Securities and Funds [Abstract]
Cost	6	6
Estimated Fair Value	$ 4	$ 6