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Investments (Unrealized Gains (Losses) on Equity Securities) (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2021 | Jun. 30, 2020 | Jun. 30, 2021 | Jun. 30, 2020
Gain (Loss) on Securities [Line Items] |  |  |  |
Unrealized gains (losses) recognized in income on equity securities on securities remaining in our portfolio at June 30, 2021 | $ 7,458 | $ 5,701 | $ 16,942 | $ (11,439)
Unrealized gains (losses) recognized in income on equity securities on securities sold during period | 203 | 0 | 1,999 | 3
Total unrealized gains (losses) recognized in income on equity securities | $ 7,661 | $ 5,701 | $ 18,941 | $ (11,436)

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