v3.25.4
RELATED PARTY TRANSACTIONS AND MAJOR CUSTOMERS - Narratives (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Related Party Transaction [Line Items]      
Equity method investment, dividends and distributions $ 53.2 $ 109.8 $ 41.4
Three Brokers | Gross premiums written | Customer Concentration Risk      
Related Party Transaction [Line Items]      
Concentration risk , percentage 81.30% 82.10% 84.30%
Aon plc | Gross premiums written | Customer Concentration Risk      
Related Party Transaction [Line Items]      
Concentration risk , percentage 34.50% 32.00%  
Marsh & McLennan Companies, Inc. | Gross premiums written | Customer Concentration Risk      
Related Party Transaction [Line Items]      
Concentration risk , percentage 33.80% 36.50%  
Arthur J Gallagher | Gross premiums written | Customer Concentration Risk      
Related Party Transaction [Line Items]      
Concentration risk , percentage 13.00% 13.60%  
Tower Hill Companies | Related Party      
Related Party Transaction [Line Items]      
Equity method investment, dividends and distributions $ 32.6 $ 34.4 $ 22.6
Top Layer Reinsurance Ltd. | Related Party      
Related Party Transaction [Line Items]      
Equity method investment, dividends and distributions 14.0 16.8 7.8
Top Layer Reinsurance Ltd. | Related Party | Management Fee      
Related Party Transaction [Line Items]      
Revenue recorded $ 2.5 $ 3.0 $ 3.4