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Fair Value Measurements - Information about Valuation Inputs for Fixed Income Securities Classified as Level 3 (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended |  |  |
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Jun. 30, 2024 | Mar. 31, 2024 | Jun. 30, 2023 | Jun. 30, 2024 | Jun. 30, 2023 | Dec. 31, 2023 | Mar. 31, 2023 | Dec. 31, 2022
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31) |  |  |  |  |  |  |  |
Fair Value Inputs Yield Rate |  |  |  |  |  | 11.20% |  |
Asset-backed Securities [Member] |  |  |  |  |  |  |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31) |  |  |  |  |  |  |  |
Coupon rate | 5.98% |  |  | 5.98% |  | 5.97% |  |
Fair Value Inputs Maturity |  | 12 years 9 months 18 days |  | 12 years 5 months 19 days |  |  |  |
Yield | 10.00% |  |  | 10.00% |  | 12.00% |  |
Fair Value, Inputs, Level 3 [Member] |  |  |  |  |  |  |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31) |  |  |  |  |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability | $ 3,672,000 | $ 3,782,000 | $ 3,831,000 | $ 3,672,000 | $ 3,831,000 | $ 3,848,000 | $ 3,972,000 | $ 3,762,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements | (106,000) |  | (81,000) | (170,000) | (155,000) |  |  |
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held |  |  |  | 16,000 | 73,000 |  |  |
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss) | (19,000) |  | (124,000) |  |  |  |  |
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss), OCI | 15,000 |  | 64,000 | (23,000) | 152,000 |  |  |
Fair Value, Inputs, Level 3 [Member] | Investments [Member] |  |  |  |  |  |  |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31) |  |  |  |  |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability | 77,000 | $ 87,000 | 81,000 | 77,000 | 81,000 | 87,000 | 81,000 | 79,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements | (26,000) |  | 0 | (27,000) | (1,000) |  |  |
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held |  |  |  | 7,000 | 1,000 |  |  |
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss) | 7,000 |  |  |  |  |  |  |
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss), OCI | 9,000 |  |  | 9,000 | 3,000 |  |  |
Fair Value, Inputs, Level 3 [Member] | Derivative Financial Instruments, Liabilities [Member] |  |  |  |  |  |  |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31) |  |  |  |  |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability | 18,000 |  | 25,000 | 18,000 | 25,000 | 26,000 |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements |  |  |  | 0 |  |  |  |
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held |  |  |  | (8,000) |  |  |  |
Corporate Obligations [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |  |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31) |  |  |  |  |  |  |  |
Fair Value Inputs Maturity |  | 10 months 20 days |  |  |  |  |  |
Derivative Financial Instruments, Liabilities [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |  |  |  |  |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31) |  |  |  |  |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability |  |  |  |  |  |  |  | 26,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements |  |  |  |  | 0 |  |  |
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held |  |  |  |  | 0 |  |  |
Derivative Financial Instruments, Liabilities [Member] | Fair Value, Inputs, Level 3 [Member] | Derivative Financial Instruments, Liabilities [Member] |  |  |  |  |  |  |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31) |  |  |  |  |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability | 18,000 | $ 21,000 | 25,000 | 18,000 | 25,000 |  | 31,000 |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements | 0 |  | 0 |  |  |  |  |
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss) | (3,000) |  | (5,000) |  |  |  |  |
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss), OCI | 0 |  | 0 | 0 | 0 |  |  |
Variable Interest Entity, Primary Beneficiary [Member] | Fair Value, Inputs, Level 3 [Member] | Corporate Obligations [Member] |  |  |  |  |  |  |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31) |  |  |  |  |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability |  |  |  |  |  |  |  | 1,828,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements |  |  |  |  | (12,000) |  |  |
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held |  |  |  |  | 80,000 |  |  |
Variable Interest Entity, Primary Beneficiary [Member] | Fair Value, Inputs, Level 3 [Member] | Loans Receivable [Member] |  |  |  |  |  |  |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31) |  |  |  |  |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability |  |  |  |  |  |  |  | $ 1,829,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements |  |  |  |  | (141,000) |  |  |
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held |  |  |  |  | (7,000) |  |  |
Variable Interest Entity, Primary Beneficiary [Member] | Investment Contracts [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |  |  |  |  |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31) |  |  |  |  |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability | 2,010,000 |  | 1,952,000 | 2,010,000 | 1,952,000 | 2,072,000 |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements |  |  |  | (12,000) |  |  |  |
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held |  |  |  | (32,000) |  |  |  |
Variable Interest Entity, Primary Beneficiary [Member] | Investment Contracts [Member] | Fair Value, Inputs, Level 3 [Member] | Corporate Obligations [Member] |  |  |  |  |  |  |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31) |  |  |  |  |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability | 2,010,000 | 2,070,000 | 1,952,000 | 2,010,000 | 1,952,000 |  | 2,003,000 |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements | (12,000) |  | (12,000) |  |  |  |  |
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss) | (51,000) |  | (53,000) |  |  |  |  |
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss), OCI | 3,000 |  | 14,000 | (18,000) | 57,000 |  |  |
Variable Interest Entity, Primary Beneficiary [Member] | Loan Origination Commitments [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |  |  |  |  |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31) |  |  |  |  |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability | 1,567,000 |  | 1,772,000 | 1,567,000 | 1,772,000 | $ 1,663,000 |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements |  |  |  | (132,000) |  |  |  |
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held |  |  |  | 49,000 |  |  |  |
Variable Interest Entity, Primary Beneficiary [Member] | Loan Origination Commitments [Member] | Fair Value, Inputs, Level 3 [Member] | Loans Receivable [Member] |  |  |  |  |  |  |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31) |  |  |  |  |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability | 1,567,000 | $ 1,604,000 | 1,772,000 | 1,567,000 | 1,772,000 |  | $ 1,856,000 |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements | (68,000) |  | (69,000) |  |  |  |  |
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss) | 29,000 |  | (66,000) |  |  |  |  |
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss), OCI | $ 3,000 |  | $ 50,000 | $ (14,000) | $ 92,000 |  |  |

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- Definition The amount of gains or losses included in earnings attributable to unrealized gains or losses on financial instruments measured on a recurring basis using unobservable inputs that are still held at the reporting date. + References No definition available. + Details
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- Definition Amount of unrealized gain (loss) recognized in income from asset (liability) measured at fair value on recurring basis using unobservable input (level 3) and still held. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2 + Details
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