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Significant Transactions - Outrigger Re (Details) - USD ($) $ in Millions | 3 Months Ended
--- | ---
Sep. 30, 2024 | Mar. 31, 2024 | Dec. 31, 2023
Outrigger Re |  |  |
Other Significant Transactions [Line Items] |  |  |
Contributions to subsidiaries |  |  | $ 205.0
Outrigger Re |  |  |
Other Significant Transactions [Line Items] |  |  |
Ceded unearned premiums |  |  | 250.0
Rollover amount |  |  | 130.0
Short-term investments, at fair value | $ 199.9 |  | $ 265.3
Return of capital | $ 64.9 | $ 68.1 |

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- Definition The cash outflow associated with the acquisition of or advances to an entity that is related to it but not strictly controlled (for example, an unconsolidated subsidiary, affiliate, and joint venture or equity method investment) or the acquisition of an additional interest in a subsidiary (controlled entity). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 13 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-13 + Details
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- Definition The unexpired portion of premiums ceded on policies in force as of the balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 825 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477351/944-825-50-1B Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 340 -Name Accounting Standards Codification -Section 25 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479510/944-340-25-1 + Details
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