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Investment Information - Net investment income (Details) - USD ($) $ in Thousands | 3 Months Ended
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Mar. 31, 2022 | Mar. 31, 2021
Net investment income: |  |  |
Gross investment income |  | $ 102,942 | $ 125,966
Investment expenses |  | (22,506) | (27,110)
Net investment income |  | 80,436 | 98,856
Fixed maturities |  |  |
Net investment income: |  |  |
Gross investment income |  | 82,053 | 90,626
Term loans |  |  |
Net investment income: |  |  |
Gross investment income |  | 1,617 | 14,728
Equity securities |  |  |
Net investment income: |  |  |
Gross investment income |  | 6,238 | 5,650
Short-term investments |  |  |
Net investment income: |  |  |
Gross investment income |  | 2,575 | 607
Other |  |  |
Net investment income: |  |  |
Gross investment income | [1] | $ 10,459 | $ 14,355
[1] | Includes income distributions from investment funds and other items.

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