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Investment Information - Narrative (Details) $ in Thousands | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2021 USD ($) lots | Sep. 30, 2020 USD ($) | Sep. 30, 2021 USD ($) lots | Sep. 30, 2020 USD ($) | Dec. 31, 2020 USD ($) lots
Narrative items: |  |  |  |  |
Equity in net (loss) income of investment funds accounted for using the equity method | $ 105,398 | $ 126,735 | $ 299,270 | $ 57,407 |
Equity securities, at fair value | $ 1,790,640 |  | $ 1,790,640 |  | $ 1,444,830
Continuous unrealized loss, qualitative disclosures: |  |  |  |  |
Number of positions in an unrealized loss position (lots) | lots | 3,910 |  | 3,910 |  | 2,320
Total number of positions (lots) | lots | 10,020 |  | 10,020 |  | 11,180
Largest single loss | $ 2,500 |  | $ 2,500 |  | $ 900
Minimum |  |  |  |  |
Narrative items: |  |  |  |  |
Time lag for reporting |  |  | 1 month |  |
Maximum |  |  |  |  |
Narrative items: |  |  |  |  |
Time lag for reporting |  |  | 3 months |  |

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