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Schedule I - Summary of Investments - Other Than Investments in Related Parties (Details) $ in Thousands | Dec. 31, 2024 USD ($)
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SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |
Amortized Cost or Cost | $ 9,998,002
Carrying Amount | 9,651,297
Short-term securities |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |
Amortized Cost or Cost | 509,328
Carrying Amount | 509,318
Alternative investments |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |
Amortized Cost or Cost | 440,896
Carrying Amount | 440,896
Other investments |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |
Amortized Cost or Cost | 101,065
Carrying Amount | 101,065
Held-to-maturity: | Fixed income securities |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |
Amortized Cost or Cost | 25,375
Fair Value | 24,735
Carrying Amount | 25,375
Held-to-maturity: | All other corporate securities |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |
Amortized Cost or Cost | 25,375
Fair Value | 24,735
Carrying Amount | 25,375
Available-for-sale: | Fixed income securities |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |
Amortized Cost or Cost | 8,476,078
Fair Value | 8,127,334
Carrying Amount | 8,127,334
Available-for-sale: | U.S. government and government agencies |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |
Amortized Cost or Cost | 139,906
Fair Value | 120,155
Carrying Amount | 120,155
Available-for-sale: | Foreign government |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |
Amortized Cost or Cost | 10,656
Fair Value | 9,302
Carrying Amount | 9,302
Available-for-sale: | Obligations of states and political subdivisions |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |
Amortized Cost or Cost | 483,609
Fair Value | 451,230
Carrying Amount | 451,230
Available-for-sale: | Public utilities |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |
Amortized Cost or Cost | 229,834
Fair Value | 221,386
Carrying Amount | 221,386
Available-for-sale: | All other corporate securities |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |
Amortized Cost or Cost | 2,951,212
Fair Value | 2,846,794
Carrying Amount | 2,846,794
Available-for-sale: | Collateralized loan obligation securities and other asset-backed securities |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |
Amortized Cost or Cost | 2,065,611
Fair Value | 2,033,149
Carrying Amount | 2,033,149
Available-for-sale: | Residential mortgage-backed securities |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |
Amortized Cost or Cost | 1,812,744
Fair Value | 1,692,358
Carrying Amount | 1,692,358
Available-for-sale: | Commercial mortgage-backed securities |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |
Amortized Cost or Cost | 782,506
Fair Value | 752,960
Carrying Amount | 752,960
Equity securities | Equity securities |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |
Amortized Cost or Cost | 211,486
Fair Value | 213,601
Carrying Amount | 213,601
Equity securities | Banks, trusts and insurance companies |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |
Amortized Cost or Cost | 34,781
Fair Value | 33,262
Carrying Amount | 33,262
Equity securities | Industrial, miscellaneous and all other |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |
Amortized Cost or Cost | 174,745
Fair Value | 178,505
Carrying Amount | 178,505
Equity securities | Preferred stock: |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |
Amortized Cost or Cost | 1,960
Fair Value | 1,834
Carrying Amount | 1,834
Commercial mortgage loans |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |
Amortized Cost or Cost | 233,774
Carrying Amount | $ 233,708

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