Fair Value - Fair Value Measurements on a Recurring Basis by Asset Class and Level of Input (Details) - USD ($) $ in Thousands | Sep. 30, 2021 | Dec. 31, 2020 |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | $ 937,504 | $ 928,236 |
Corporate debt securities | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 567,966 | 566,425 |
Collateralized debt obligations | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 114,004 | 110,447 |
Commercial mortgage-backed securities | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 96,827 | 120,201 |
Residential mortgage-backed securities | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 127,231 | 112,179 |
Other debt securities | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 25,727 | 18,984 |
U.S. Treasury | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 5,749 | |
Fair Value, Measurements, Recurring Basis | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Total | 1,023,784 | 1,022,326 |
Fair Value, Measurements, Recurring Basis | Available-for-sale securities | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 937,504 | 928,236 |
Fair Value, Measurements, Recurring Basis | Corporate debt securities | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 567,966 | 566,425 |
Fair Value, Measurements, Recurring Basis | Collateralized debt obligations | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 114,004 | 110,447 |
Fair Value, Measurements, Recurring Basis | Commercial mortgage-backed securities | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 96,827 | 120,201 |
Fair Value, Measurements, Recurring Basis | Residential mortgage-backed securities | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 127,231 | 112,179 |
Fair Value, Measurements, Recurring Basis | Other debt securities | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 25,727 | 18,984 |
Fair Value, Measurements, Recurring Basis | U.S. Treasury | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 5,749 | |
Fair Value, Measurements, Recurring Basis | Equity securities | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Equity securities | 86,280 | 94,090 |
Fair Value, Measurements, Recurring Basis | Nonredeemable preferred stock | Financial services sector | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Equity securities | 70,432 | 76,575 |
Fair Value, Measurements, Recurring Basis | Nonredeemable preferred stock | Utilities sector | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Equity securities | 7,046 | 8,742 |
Fair Value, Measurements, Recurring Basis | Nonredeemable preferred stock | Consumer sector | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Equity securities | 2,218 | 3,068 |
Fair Value, Measurements, Recurring Basis | Nonredeemable preferred stock | Communications sector | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Equity securities | 1,013 | 2,699 |
Fair Value, Measurements, Recurring Basis | Nonredeemable preferred stock | Industrial sector | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Equity securities | 255 | 800 |
Fair Value, Measurements, Recurring Basis | Nonredeemable preferred and common stock | Energy sector | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Equity securities | 5,316 | 2,206 |
Fair Value, Measurements, Recurring Basis | Level 1 | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Total | 6,880 | 34,970 |
Fair Value, Measurements, Recurring Basis | Level 1 | Available-for-sale securities | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 555 | 1,281 |
Fair Value, Measurements, Recurring Basis | Level 1 | Corporate debt securities | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 555 | 1,281 |
Fair Value, Measurements, Recurring Basis | Level 1 | Collateralized debt obligations | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 0 | 0 |
Fair Value, Measurements, Recurring Basis | Level 1 | Commercial mortgage-backed securities | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 0 | 0 |
Fair Value, Measurements, Recurring Basis | Level 1 | Residential mortgage-backed securities | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 0 | 0 |
Fair Value, Measurements, Recurring Basis | Level 1 | Other debt securities | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 0 | 0 |
Fair Value, Measurements, Recurring Basis | Level 1 | U.S. Treasury | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 0 | |
Fair Value, Measurements, Recurring Basis | Level 1 | Equity securities | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Equity securities | 6,325 | 33,689 |
Fair Value, Measurements, Recurring Basis | Level 1 | Nonredeemable preferred stock | Financial services sector | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Equity securities | 4,850 | 24,981 |
Fair Value, Measurements, Recurring Basis | Level 1 | Nonredeemable preferred stock | Utilities sector | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Equity securities | 1,210 | 3,957 |
Fair Value, Measurements, Recurring Basis | Level 1 | Nonredeemable preferred stock | Consumer sector | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Equity securities | 0 | 576 |
Fair Value, Measurements, Recurring Basis | Level 1 | Nonredeemable preferred stock | Communications sector | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Equity securities | 0 | 2,699 |
Fair Value, Measurements, Recurring Basis | Level 1 | Nonredeemable preferred stock | Industrial sector | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Equity securities | 255 | 800 |
Fair Value, Measurements, Recurring Basis | Level 1 | Nonredeemable preferred and common stock | Energy sector | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Equity securities | 10 | 676 |
Fair Value, Measurements, Recurring Basis | Level 2 | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Total | 994,165 | 961,132 |
Fair Value, Measurements, Recurring Basis | Level 2 | Available-for-sale securities | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 916,316 | 900,731 |
Fair Value, Measurements, Recurring Basis | Level 2 | Corporate debt securities | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 561,214 | 559,319 |
Fair Value, Measurements, Recurring Basis | Level 2 | Collateralized debt obligations | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 114,004 | 110,447 |
Fair Value, Measurements, Recurring Basis | Level 2 | Commercial mortgage-backed securities | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 87,133 | 100,739 |
Fair Value, Measurements, Recurring Basis | Level 2 | Residential mortgage-backed securities | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 122,943 | 111,242 |
Fair Value, Measurements, Recurring Basis | Level 2 | Other debt securities | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 25,273 | 18,984 |
Fair Value, Measurements, Recurring Basis | Level 2 | U.S. Treasury | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 5,749 | |
Fair Value, Measurements, Recurring Basis | Level 2 | Equity securities | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Equity securities | 77,849 | 60,401 |
Fair Value, Measurements, Recurring Basis | Level 2 | Nonredeemable preferred stock | Financial services sector | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Equity securities | 63,476 | 51,594 |
Fair Value, Measurements, Recurring Basis | Level 2 | Nonredeemable preferred stock | Utilities sector | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Equity securities | 5,836 | 4,785 |
Fair Value, Measurements, Recurring Basis | Level 2 | Nonredeemable preferred stock | Consumer sector | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Equity securities | 2,218 | 2,492 |
Fair Value, Measurements, Recurring Basis | Level 2 | Nonredeemable preferred stock | Communications sector | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Equity securities | 1,013 | 0 |
Fair Value, Measurements, Recurring Basis | Level 2 | Nonredeemable preferred stock | Industrial sector | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Equity securities | 0 | 0 |
Fair Value, Measurements, Recurring Basis | Level 2 | Nonredeemable preferred and common stock | Energy sector | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Equity securities | 5,306 | 1,530 |
Fair Value, Measurements, Recurring Basis | Level 3 | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Total | 22,739 | 26,224 |
Fair Value, Measurements, Recurring Basis | Level 3 | Available-for-sale securities | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 20,633 | 26,224 |
Fair Value, Measurements, Recurring Basis | Level 3 | Corporate debt securities | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 6,197 | 5,825 |
Fair Value, Measurements, Recurring Basis | Level 3 | Collateralized debt obligations | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 0 | 0 |
Fair Value, Measurements, Recurring Basis | Level 3 | Commercial mortgage-backed securities | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 9,694 | 19,462 |
Fair Value, Measurements, Recurring Basis | Level 3 | Residential mortgage-backed securities | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 4,288 | 937 |
Fair Value, Measurements, Recurring Basis | Level 3 | Other debt securities | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 454 | 0 |
Fair Value, Measurements, Recurring Basis | Level 3 | U.S. Treasury | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Available-for-sale securities | 0 | |
Fair Value, Measurements, Recurring Basis | Level 3 | Equity securities | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Equity securities | 2,106 | 0 |
Fair Value, Measurements, Recurring Basis | Level 3 | Nonredeemable preferred stock | Financial services sector | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Equity securities | 2,106 | 0 |
Fair Value, Measurements, Recurring Basis | Level 3 | Nonredeemable preferred stock | Utilities sector | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Equity securities | 0 | 0 |
Fair Value, Measurements, Recurring Basis | Level 3 | Nonredeemable preferred stock | Consumer sector | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Equity securities | 0 | 0 |
Fair Value, Measurements, Recurring Basis | Level 3 | Nonredeemable preferred stock | Communications sector | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Equity securities | 0 | 0 |
Fair Value, Measurements, Recurring Basis | Level 3 | Nonredeemable preferred stock | Industrial sector | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Equity securities | 0 | 0 |
Fair Value, Measurements, Recurring Basis | Level 3 | Nonredeemable preferred and common stock | Energy sector | | |
Fair value measurements on a recurring basis by asset class and level of input | | |
Equity securities | $ 0 | $ 0 |