Investment in Securities, Investment in Equity Securities (Details) - USD ($) $ in Thousands |
Dec. 31, 2021 |
Dec. 31, 2020 |
|---|---|---|
| Investments in Equity Securities and Funds [Abstract] | ||
| Cost | $ 48,833 | $ 47,726 |
| Estimated Fair Value | 32,344 | 25,845 |
| Common Stock [Member] | ||
| Investments in Equity Securities and Funds [Abstract] | ||
| Cost | 33,575 | 41,341 |
| Estimated Fair Value | 16,210 | 19,099 |
| Open-end Funds [Member] | ||
| Investments in Equity Securities and Funds [Abstract] | ||
| Cost | 5,722 | 5,757 |
| Estimated Fair Value | 5,995 | 6,128 |
| Actively Managed Semi-transparent EFTs [Member] | ||
| Investments in Equity Securities and Funds [Abstract] | ||
| Cost | 9,000 | 0 |
| Estimated Fair Value | 9,599 | 0 |
| Closed-end Funds [Member] | ||
| Investments in Equity Securities and Funds [Abstract] | ||
| Cost | 530 | 628 |
| Estimated Fair Value | 534 | 618 |
| Other [Member] | ||
| Investments in Equity Securities and Funds [Abstract] | ||
| Cost | 6 | 0 |
| Estimated Fair Value | $ 6 | $ 0 |