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Investments (Net Realized and Unrealized Investment Gains and (Losses)) (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] |  |  |  |
Gross gains on sales | $ 2,079 | $ 6,478 | $ 5,755 | $ 12,151
Gross losses on sales | (1,811) | (3,863) | (6,282) | (5,436)
Net realized investment gains (losses) on disposals | 268 | 2,615 | (527) | 6,715
Net unrealized gains (losses) on equity securities | 7,661 | 5,701 | 18,941 | (11,436)
Losses on securities for which we have the intent to sell | (91) | (613) | (453) | (16,215)
Net realized and unrealized investment gains (losses) | 10,057 | 12,649 | 15,176 | (32,017)
Available-for-sale Securities [Member] |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |
Net credit loss benefit (expense) on fixed maturities | 2,272 | 4,923 | (2,725) | (10,864)
Held-to-maturity Securities [Member] |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |
Net credit loss benefit (expense) on fixed maturities | (53) | 1 | (60) | 1
Commercial Mortgage Loans [Member] |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |
Net credit loss benefit (expense) on fixed maturities | $ 0 | $ 22 | $ 0 | $ (218)

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