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Investments (Components of Net Realized and Unrealized Gains (Losses)) (Details) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Gain (Loss) on Securities [Line Items] |  |  |
Unrealized Gain (Loss) on Investments recognized in income on equity securities remaining in our portfolio at end of period | $ 16,473 | $ 7,936 | $ 1,219
Unrealized gains (losses) recognized in income on equity securities that were sold in the respective period | 1,408 | 3 | (9,868)
Total unrealized (losses) recognized in income on equity securities | 17,881 | 7,939 | (8,649)
Sale of fixed income securities, available-for-sale | 502,911 | 487,087 | $ 594,743
Losses on securities for which we have the intent to sell | $ 519 | $ 16,266 |

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