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Investments - Schedule of Net Realized and Unrealized Investment Gains and (Losses) (Details) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022
Gain (Loss) on Securities [Line Items] |  |  |
Gross gains on sales | $ 12,839 | $ 5,896 | $ 28,419
Gross losses on sales | (6,563) | (30,760) | (60,055)
Net realized gains (losses) on disposals | 6,276 | (24,864) | (31,636)
Net unrealized gains (losses) on equity securities | (1,964) | 9,510 | (32,127)
Losses on securities for which we have the intent to sell | (1,248) | (921) | (11,823)
Other realized gains (losses) | (602) | 0 | 0
Net realized and unrealized investment gains (losses) | (2,949) | (3,552) | (114,808)
AFS securities |  |  |
Gain (Loss) on Securities [Line Items] |  |  |
Net credit loss benefit (expense) | (5,628) | 12,898 | (39,169)
Held-to-Maturity ("HTM") securities |  |  |
Gain (Loss) on Securities [Line Items] |  |  |
Net credit loss benefit (expense) | 0 | 0 | 63
CMLs |  |  |
Gain (Loss) on Securities [Line Items] |  |  |
Net credit loss benefit (expense) | $ 217 | $ (175) | $ (116)

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