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Segment Reporting Disclosures (Summary of Top Five Independent Brokers Concentration) (Details) - Top Five Independent Brokers | 12 Months Ended
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Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
Insurance [Member] |  |  |
Summary of Top Five Independent Brokers Concentration [Line Items] |  |  |
Percentage of gross premiums written | 33.00% | 34.00% | 32.00%
Reinsurance [Member] |  |  |
Summary of Top Five Independent Brokers Concentration [Line Items] |  |  |
Percentage of gross premiums written | 95.00% | 99.00% | 90.00%
Underwriting Operations [Member] |  |  |
Summary of Top Five Independent Brokers Concentration [Line Items] |  |  |
Percentage of gross premiums written | 37.00% | 40.00% | 38.00%

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