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Fair Value Measurements - Changes in Fair Value of Securities Using Level 3 Inputs (Details) - USD ($) $ in Thousands | 3 Months Ended
--- | ---
Mar. 31, 2024 | Mar. 31, 2023
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Fair value, beginning balance | $ 551,689 |
Fair value, ending balance | 556,762 |
Obligations of states and political subdivisions |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Fair value, beginning balance | 7,834 | $ 6,661
Purchases | 0 | 0
Sales | 0 | 0
Issuances | 0 | 0
Settlements | 0 | 0
Transfers into Level 3 | 0 | 0
Transfers out of Level 3 | 0 | 0
Fair value, ending balance | 7,747 | 6,874
Change in unrealized gains (losses) for the period included in earnings for assets held at period end | (1) | 61
Change in unrealized gains (losses) for the period included in OCI for assets held at period end | (86) | 152
Obligations of states and political subdivisions | Other Comprehensive Income (Loss) |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Total net gains (losses) for the period included in OCI | (86) | 152
Corporate securities |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Fair value, beginning balance | 297,332 | 187,980
Purchases | 1,152 | 24,799
Sales | 0 | 0
Issuances | 0 | 0
Settlements | (2,870) | (4,044)
Transfers into Level 3 | 20,065 | 361
Transfers out of Level 3 | (28,227) | 0
Fair value, ending balance | 287,496 | 211,585
Change in unrealized gains (losses) for the period included in earnings for assets held at period end | 140 | 72
Change in unrealized gains (losses) for the period included in OCI for assets held at period end | (376) | 2,405
Corporate securities | Other Comprehensive Income (Loss) |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Total net gains (losses) for the period included in OCI | (376) | 2,405
CLO and other ABS |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Fair value, beginning balance | 245,313 | 153,342
Purchases | 14,658 | 13,403
Sales | 0 | 0
Issuances | 0 | 0
Settlements | (1,173) | (1,192)
Transfers into Level 3 | 19,537 | 14,148
Transfers out of Level 3 | (18,693) | (534)
Fair value, ending balance | 260,097 | 179,758
Change in unrealized gains (losses) for the period included in earnings for assets held at period end | 57 | (73)
Change in unrealized gains (losses) for the period included in OCI for assets held at period end | 399 | 696
CLO and other ABS | Other Comprehensive Income (Loss) |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Total net gains (losses) for the period included in OCI | 399 | 696
CMBS |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Fair value, beginning balance | 356 | 375
Purchases | 0 | 0
Sales | 0 | 0
Issuances | 0 | 0
Settlements | (3) | (3)
Transfers into Level 3 | 0 | 2,848
Transfers out of Level 3 | 0 | 0
Fair value, ending balance | 355 | 3,236
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 | 17
CMBS | Other Comprehensive Income (Loss) |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Total net gains (losses) for the period included in OCI | 3 | 17
Common stock: |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Fair value, beginning balance | 854 | 897
Purchases | 0 | 0
Sales | 0 | 0
Issuances | 0 | 0
Settlements | 0 | 0
Transfers into Level 3 | 0 | 0
Transfers out of Level 3 | 0 | 0
Fair value, ending balance | 1,067 | 628
Change in unrealized gains (losses) for the period included in earnings for assets held at period end | 213 | (269)
Change in unrealized gains (losses) for the period included in OCI for assets held at period end | 0 | 0
Common stock: | Other Comprehensive Income (Loss) |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Total net gains (losses) for the period included in OCI | 0 | 0
Investments |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Fair value, beginning balance | 551,689 | 349,255
Purchases | 15,810 | 38,202
Sales | 0 | 0
Issuances | 0 | 0
Settlements | (4,046) | (5,239)
Transfers into Level 3 | 39,602 | 17,357
Transfers out of Level 3 | (46,920) | (534)
Fair value, ending balance | 556,762 | 402,081
Change in unrealized gains (losses) for the period included in earnings for assets held at period end | 409 | (209)
Change in unrealized gains (losses) for the period included in OCI for assets held at period end | (60) | 3,270
Investments | Other Comprehensive Income (Loss) |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Total net gains (losses) for the period included in OCI | (60) | 3,270
Gain (Loss) on Investments | Obligations of states and political subdivisions |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Total net gains (losses) for the period included in net income | (1) | 61
Gain (Loss) on Investments | Corporate securities |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Total net gains (losses) for the period included in net income | 140 | 72
Gain (Loss) on Investments | CLO and other ABS |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Total net gains (losses) for the period included in net income | 57 | (73)
Gain (Loss) on Investments | CMBS |  |
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
Gain (Loss) on Investments | Common stock: |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Total net gains (losses) for the period included in net income | 213 | (269)
Gain (Loss) on Investments | Investments |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Total net gains (losses) for the period included in net income | 409 | (209)
Net Investment Income Earned | Obligations of states and political subdivisions |  |
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
Net Investment Income Earned | Corporate securities |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Total net gains (losses) for the period included in net income | 280 | 12
Net Investment Income Earned | CLO and other ABS |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Total net gains (losses) for the period included in net income | (1) | (32)
Net Investment Income Earned | CMBS |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Total net gains (losses) for the period included in net income | (1) | (1)
Net Investment Income Earned | Common stock: |  |
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
Net Investment Income Earned | Investments |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Total net gains (losses) for the period included in net income | $ 278 | $ (21)

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- Definition Amount of gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2 + Details
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