v3.26.1
Investments - Narrative (Details)
$ in Thousands
3 Months Ended 6 Months Ended
May 01, 2026
USD ($)
Jan. 01, 2025
USD ($)
Jan. 01, 2023
USD ($)
Apr. 01, 2018
Jun. 30, 2026
USD ($)
issuer
Jun. 30, 2025
USD ($)
Jun. 30, 2026
USD ($)
issuer
Jun. 30, 2025
USD ($)
Dec. 31, 2025
USD ($)
Apr. 01, 2025
USD ($)
Net Investment Income [Line Items]                    
Proceeds from sale of debt securities, available-for-sale         $ 18,600 $ 220,900 $ 161,858 $ 290,208    
Debt securities, available-for-sale, realized gain         100 3,500 1,400 6,400    
Debt securities, available-for-sale, realized loss         $ 200 0 $ 400 0    
Held securities (issuer) | issuer         36   36      
Total fair value         $ 230,824   $ 230,824   $ 62,716  
Gross unrealized losses         1,975   1,975   207  
Annual fixed fee (as a percent)       2.00%            
Quarterly fixed fee (as a percent)       0.50%            
Management fee (reversal)         1,058 (1,286) 2,038 115    
Incentive allocation, percentage       20.00%            
Incentive allocation         3,700 0 5,400 0    
Initial investment in limited partnership interests $ 10,000                  
Loans to affiliates         106,500   106,500   106,500  
Assets held by insurance regulators         100   100   100  
ZP Utility Insurance Fund, L.P                    
Net Investment Income [Line Items]                    
Management fee (reversal)         1,000 $ (1,300) 1,900 0    
Related Party                    
Net Investment Income [Line Items]                    
Management fee (reversal)               $ (2,600)    
Initial investment in limited partnership interests   $ 10,000                
Loans to affiliates                   $ 94,000
Fixed interest rate                   5.50%
Technology Transactions | Related Party                    
Net Investment Income [Line Items]                    
Loans to affiliates     $ 13,500   $ 12,500   $ 12,500   $ 12,500  
Promissory note, interest rate     7.42%