v3.26.1
Investments - Summary of Fair Value, Including Financial Guarantee, and Weighted-Average Underlying Rating, Excluding Financial Guarantee, of Insured Securities (Phantom) (Details) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Investment [Line Items]    
Investment expense $ (100) $ 2
Investment income 2,355 2,815
Fixed Income Investments [Member]    
Investment [Line Items]    
Gross Investment Income, Operating 1,211 1,400
Short-Term [Member]    
Investment [Line Items]    
Gross Investment Income, Operating 1,244 1,457
Other Investments [Member]    
Investment [Line Items]    
Gross Investment Income, Operating $ 0 $ (79)