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Other Investments - Investments without Readily Determinable Fair Value (Details) - USD ($) | 3 Months Ended |  |  |
--- | --- | --- | --- | ---
Mar. 31, 2022 | Dec. 31, 2021 | Mar. 31, 2021 | Dec. 31, 2020
Investments, All Other Investments [Abstract] |  |  |  |
Cost | $ 8,500,000 | $ 8,500,000 |  |
Cumulative unrealized gains | 41,900,000 | 41,900,000 |  |
Carrying amount | 50,400,000 | $ 50,400,000 | $ 13,800,000 | $ 13,800,000
Upward adjustments | $ 0 |  |  |

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