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Notes Payable - Schedule of Long-term Debt (Details) |  |  |  | 12 Months Ended |  |
--- | --- | --- | --- | --- | --- | ---
Feb. 13, 2024 USD ($) | Nov. 30, 2023 USD ($) | Mar. 08, 2017 USD ($) | Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($) | Nov. 18, 2022 USD ($) | Mar. 31, 2021 USD ($)
Debt Instrument [Line Items] |  |  |  |  |  |  |
Total principal amount |  |  |  | $ 575,000,000 | $ 400,000,000 |  |
Less unamortized discount and debt issuance costs |  |  |  | 1,271,000 | 1,670,000 |  |
Notes payable |  |  |  | 573,729,000 | 398,330,000 |  |
Revolving Credit Facility |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Repayments of debt |  |  | $ 320,000,000 |  |  |  |
Unsecured Notes Two | Revolving Credit Facility |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Loan maximum borrowing capacity |  | $ 250,000,000 |  |  |  | $ 200,000,000 | $ 75,000,000
Drawn down amount under credit facility |  |  |  | 200,000,000 | 25,000,000 |  |
Unamortized debt issuance cost |  |  |  | 800,000 |  |  |
Unsecured Notes Two | Revolving Credit Facility | Consolidated Insurance Subsidiary |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Drawn down amount under credit facility contributed |  |  |  | 150,000,000 |  |  |
Unsecured Notes Two | Revolving Credit Facility | Subsequent Event |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Interest rate, effective percentage | 6.84% |  |  |  |  |  |
Drawn down amount under credit facility | $ 200,000,000 |  |  |  |  |  |
Undrawn portion of credit facility | $ 50,000,000 |  |  |  |  |  |
Unsecured notes |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Notes payable |  |  |  | $ 373,729,000 | 373,330,000 |  |
Unsecured notes | Notes payable | Level 2 | Unsecured Notes One |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Interest rate, stated percentage |  |  | 4.40% | 4.40% |  |  |
Unsecured debt |  |  | $ 375,000,000 | $ 375,000,000 | 375,000,000 |  |
Debt issuance costs |  |  | $ 3,400,000 |  |  |  |
Discount percent |  |  | 99.847% |  |  |  |
Interest rate, effective percentage |  |  | 4.45% |  |  |  |
Unsecured notes | Notes payable | Level 2 | Unsecured Notes Two |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Unsecured debt |  |  |  | $ 200,000,000 | $ 25,000,000 |  |
Minimum | Unsecured Notes Two | Revolving Credit Facility |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Commitment fee on undrawn portion of facility |  | 0.125% |  | 0.175% |  |  |
Maximum | Unsecured Notes Two | Revolving Credit Facility |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt to total capital ratio |  |  |  | 0.271 |  |  |
Commitment fee on undrawn portion of facility |  | 0.225% |  |  |  |  |
Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate | Minimum | Unsecured Notes Two | Revolving Credit Facility |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt to total capital ratio |  | 0.30 |  |  |  |  |
Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate | Minimum | Unsecured notes | Notes payable | Level 2 | Unsecured Notes Two |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Basis spread on variable rate |  |  |  | 1.125% |  |  |
Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate | Maximum | Unsecured Notes Two | Revolving Credit Facility |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt to total capital ratio |  | 0.20 |  |  |  |  |
Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate | Maximum | Unsecured notes | Notes payable | Level 2 | Unsecured Notes Two |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Basis spread on variable rate |  |  |  | 1.50% |  |  |

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