v3.26.3
Fair Value Measurements - Schedule of Changes in Fair Value of Securities Using Level 3 Inputs (Details) - USD ($)
$ in Thousands
 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Investments    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Fair value, beginning of year $ 941,944 $ 619,247
Total net gains (losses) for the period included in OCI (25,523) 9,198
Purchases 322,402 182,989
Sales 0 0
Issuances 0 0
Settlements (104,632) (51,152)
Transfers into Level 3 231,417 105,359
Transfers out of Level 3 (581,716) (40,098)
Fair value, ending year 783,162 826,753
Change in unrealized gains (losses) for the period included in earnings for assets held at period end (674) 468
Change in unrealized gains (losses) for the period included in OCI for assets held at period end (25,306) 8,523
Investments | Location, Statement of Income, Balance [Axis]: us-gaap:GainLossOnInvestments    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Total net gains (losses) for the period included in net income (746) 1,124
Investments | Location, Statement of Income, Balance [Axis]: us-gaap:NetInvestmentIncome    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Total net gains (losses) for the period included in net income 16 86
Obligations of states and political subdivisions    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Fair value, beginning of year 7,409 7,426
Total net gains (losses) for the period included in OCI (113) 132
Purchases 0 0
Sales 0 0
Issuances 0 0
Settlements (64) (72)
Transfers into Level 3 2,771 0
Transfers out of Level 3 (2,705) 0
Fair value, ending year 7,305 7,630
Change in unrealized gains (losses) for the period included in earnings for assets held at period end 7 144
Change in unrealized gains (losses) for the period included in OCI for assets held at period end (113) 132
Obligations of states and political subdivisions | Location, Statement of Income, Balance [Axis]: us-gaap:GainLossOnInvestments    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Total net gains (losses) for the period included in net income 7 144
Obligations of states and political subdivisions | Location, Statement of Income, Balance [Axis]: us-gaap:NetInvestmentIncome    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Total net gains (losses) for the period included in net income 0 0
Corporate securities    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Fair value, beginning of year 369,111 242,679
Total net gains (losses) for the period included in OCI (12,254) 7,164
Purchases 126,614 61,531
Sales 0 0
Issuances 0 0
Settlements (46,811) (13,704)
Transfers into Level 3 127,675 19,571
Transfers out of Level 3 (185,232) (295)
Fair value, ending year 378,398 317,267
Change in unrealized gains (losses) for the period included in earnings for assets held at period end (799) 285
Change in unrealized gains (losses) for the period included in OCI for assets held at period end (12,518) 7,169
Corporate securities | Location, Statement of Income, Balance [Axis]: us-gaap:GainLossOnInvestments    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Total net gains (losses) for the period included in net income (785) 286
Corporate securities | Location, Statement of Income, Balance [Axis]: us-gaap:NetInvestmentIncome    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Total net gains (losses) for the period included in net income 80 35
CLO and other ABS    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Fair value, beginning of year 565,089 367,994
Total net gains (losses) for the period included in OCI (9,974) 1,894
Purchases 155,324 115,903
Sales 0 0
Issuances 0 0
Settlements (56,183) (35,827)
Transfers into Level 3 100,971 85,788
Transfers out of Level 3 (358,215) (39,803)
Fair value, ending year 397,129 496,036
Change in unrealized gains (losses) for the period included in earnings for assets held at period end 118 39
Change in unrealized gains (losses) for the period included in OCI for assets held at period end (9,493) 1,214
CLO and other ABS | Location, Statement of Income, Balance [Axis]: us-gaap:GainLossOnInvestments    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Total net gains (losses) for the period included in net income 32 39
CLO and other ABS | Location, Statement of Income, Balance [Axis]: us-gaap:NetInvestmentIncome    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Total net gains (losses) for the period included in net income 85 48
Residential mortgage-backed securities (“RMBS”)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Fair value, beginning of year 0 0
Total net gains (losses) for the period included in OCI (3,187) 8
Purchases 40,464 5,555
Sales 0 0
Issuances 0 0
Settlements (1,566) (79)
Transfers into Level 3 0 0
Transfers out of Level 3 (35,564) 0
Fair value, ending year 0 5,483
Change in unrealized gains (losses) for the period included in earnings for assets held at period end 0 0
Change in unrealized gains (losses) for the period included in OCI for assets held at period end (3,187) 8
Residential mortgage-backed securities (“RMBS”) | Location, Statement of Income, Balance [Axis]: us-gaap:GainLossOnInvestments    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Total net gains (losses) for the period included in net income 0 0
Residential mortgage-backed securities (“RMBS”) | Location, Statement of Income, Balance [Axis]: us-gaap:NetInvestmentIncome    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Total net gains (losses) for the period included in net income (147) (1)
Commercial mortgage-backed securities (“CMBS”)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Fair value, beginning of year 335 340
Total net gains (losses) for the period included in OCI 5 0
Purchases 0 0
Sales 0 0
Issuances 0 0
Settlements (8) (7)
Transfers into Level 3 0 0
Transfers out of Level 3 0 0
Fair value, ending year 330 337
Change in unrealized gains (losses) for the period included in earnings for assets held at period end 0 0
Change in unrealized gains (losses) for the period included in OCI for assets held at period end 5 0
Commercial mortgage-backed securities (“CMBS”) | Location, Statement of Income, Balance [Axis]: us-gaap:GainLossOnInvestments    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Total net gains (losses) for the period included in net income 0 0
Commercial mortgage-backed securities (“CMBS”) | Location, Statement of Income, Balance [Axis]: us-gaap:NetInvestmentIncome    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Total net gains (losses) for the period included in net income $ (2) 4
Common Stock    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Fair value, beginning of year   808
Total net gains (losses) for the period included in OCI   0
Purchases   0
Sales   0
Issuances   0
Settlements   (1,463)
Transfers into Level 3   0
Transfers out of Level 3   0
Fair value, ending year   0
Change in unrealized gains (losses) for the period included in earnings for assets held at period end   0
Change in unrealized gains (losses) for the period included in OCI for assets held at period end   0
Common Stock | Location, Statement of Income, Balance [Axis]: us-gaap:GainLossOnInvestments    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Total net gains (losses) for the period included in net income   655
Common Stock | Location, Statement of Income, Balance [Axis]: us-gaap:NetInvestmentIncome    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Total net gains (losses) for the period included in net income   $ 0