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Investments (Investments in Marketable Equity Securities) (Details 1) - USD ($) $ in Thousands | Mar. 31, 2023 | Dec. 31, 2022
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Investments [Abstract] |  |
Total Cost | $ 234,157 | $ 270,764
Gross unrealized gains | 373,842 | 363,147
Gross unrealized losses | (4,456) | (23,990)
Total Fair Value | $ 603,543 | $ 609,921

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