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Investment Information - Narrative (Details) $ in Thousands | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2020 USD ($) lots | Sep. 30, 2019 USD ($) | Sep. 30, 2020 USD ($) lots | Sep. 30, 2019 USD ($) | Dec. 31, 2019 USD ($) lots
Narrative items: |  |  |  |  |
Investable assets | $ 28,420,000 |  | $ 28,420,000 |  |
Equity in net (loss) income of investment funds accounted for using the equity method | $ 126,735 | $ 17,130 | $ 57,407 | $ 96,533 |
Continuous unrealized loss, qualitative disclosures: |  |  |  |  |
Number of positions in an unrealized loss position (lots) | lots | 3,270 |  | 3,270 |  | 2,230
Total number of positions (lots) | lots | 11,090 |  | 11,090 |  | 9,590
Largest single loss | $ 900 |  | $ 900 |  | $ 900
Equity securities, at fair value | 1,502,015 |  | $ 1,502,015 |  | $ 838,925
Minimum |  |  |  |  |
Narrative items: |  |  |  |  |
Time lag for reporting |  |  | one |  |
Maximum |  |  |  |  |
Narrative items: |  |  |  |  |
Time lag for reporting |  |  | three |  |
Underwriting segments |  |  |  |  |
Narrative items: |  |  |  |  |
Investable assets | 25,720,000 |  | $ 25,720,000 |  |
Equity in net (loss) income of investment funds accounted for using the equity method | 126,735 | 17,130 | 57,407 | 96,533 |
Other |  |  |  |  |
Narrative items: |  |  |  |  |
Investable assets | 2,690,000 |  | 2,690,000 |  |
Equity in net (loss) income of investment funds accounted for using the equity method | $ 0 | $ 0 | $ 0 | $ 0 |

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