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Investments (Net Realized Gains (Losses) on Disposals) (Details) - USD ($) $ in Thousands | 3 Months Ended
--- | ---
Mar. 31, 2019 | Mar. 31, 2018
Schedule of Realized Gains (Losses) on Disposals Excluding OTTI [Line Items] |  |
HTM fixed income securities Gains | $ 0 | $ 2
HTM fixed income securities Losses | 0 | 0
Equity securities Gains | 2,280 | 8,399
Equity securities Losses | 0 | (330)
Short-term investments Gains | 14 | 1
Short-term investments Losses | 0 | (4)
Other investments Gains | 7 | 0
Other investments Losses | 0 | 0
Net realized investment gains on disposals | 3,444 | 4,731
Proceeds from sale of fixed income securities, AFS | 218,411 | 675,396
Proceeds from sale of equity securities | 3,721 | 40,740
Fixed Maturities [Member] |  |
Schedule of Realized Gains (Losses) on Disposals Excluding OTTI [Line Items] |  |
AFS securities Gains | 1,844 | 2,623
AFS securities Losses | (701) | (5,960)
Equity Securities [Member] |  |
Schedule of Realized Gains (Losses) on Disposals Excluding OTTI [Line Items] |  |
Net realized investment gains on disposals | $ 2,280 | $ 8,069

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