v3.26.1
LOSS AND LOSS ADJUSTMENT EXPENSE RESERVES - Narrative (Details)
$ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2026
USD ($)
Jun. 30, 2025
USD ($)
Jun. 30, 2026
USD ($)
event
Jun. 30, 2025
USD ($)
Liability for Claims and Claims Adjustment Expense        
Loss from catastrophes $ 26,511 $ 0 $ 31,511 $ 27,016
Prior years 716 3,047 (1,773) 7,265
Operating Segments        
Liability for Claims and Claims Adjustment Expense        
Prior years     (3,536) 5,919
Operating Segments | Open Market        
Liability for Claims and Claims Adjustment Expense        
Loss from catastrophes 26,511 0 31,511 27,016
Prior years (2,845) (941) (5,692) 3,955
Operating Segments | Innovations        
Liability for Claims and Claims Adjustment Expense        
Loss from catastrophes 0 0 0 0
Prior years $ 1,798 $ 2,531 2,156 1,964
Operating Segments | Reinsurance Contract [Axis]: Adverse Reserve Development | Open Market        
Liability for Claims and Claims Adjustment Expense        
Prior years     $ 6,800 32,000
Number of specialty business relating to large loss events | event     2  
Operating Segments | Reinsurance Contract [Axis]: Adverse Reserve Development | Innovations        
Liability for Claims and Claims Adjustment Expense        
Prior years     $ 5,200 2,300
Operating Segments | Reinsurance Contract [Axis]: Favorable Reserve Development | Open Market        
Liability for Claims and Claims Adjustment Expense        
Prior years     (12,400) (28,000)
Operating Segments | Reinsurance Contract [Axis]: Favorable Reserve Development | Innovations        
Liability for Claims and Claims Adjustment Expense        
Prior years     $ (3,000) $ (400)