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Financial Guarantee Insurance Contracts - Summary of Loss Reserve Roll-Forward, Net of Subrogation Recoverable and Reinsurance (Detail) - USD ($) $ in Thousands | 12 Months Ended |
--- | --- | ---
Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
Loss And Loss Adjustment Expense Reserves [Line Items] |  |  |  |
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims | $ 72,626 | $ 36,712 | $ 9,072 |
Policyholder Benefits and Claims Incurred, Ceded | 191,151 | 113,622 | 52,960 |
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward] |  |  |  |
Beginning balance of net loss and loss expense reserves | 40,788 | 9,752 | 474 |
Current year: |  |  |  |
Claim and loss expense payments, net of subrogation and reinsurance | (16,202) | (3,798) | 206 |
Prior years: |  |  |  |
Claim and loss expense (payments) recoveries, net of subrogation and reinsurance | (18,231) | (1,878) | 0 |
Liability for Unpaid Claims and Claims Adjustment Expense, Net | 78,981 | 40,788 | 9,752 | $ 474
Liabillity for Claim and Claim Adjustment Expense, with Impact of VIE Consolidation | 349,062 | 197,089 | 89,907 | 32,169
Current Year Claims and Claims Adjustment Expense | 67,937 | 36,569 | 9,049 |
Prior Year Claims and Claims Adjustment Expense | 4,689 | 143 | 23 |
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid | 34,433 | 5,676 | (206) |
Ceded Loss And Loss Expenses Paid Not Yet Recovered |  | 8,765 | 1,397 |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments | 270,081 | 156,301 | $ 80,155 | $ 31,695
Liability for Claims and Claims Adjustment Expense | 349,062 | $ 197,089 |  |
Segment Reporting, Reconciling Item, Corporate Nonsegment | Other Insurance Contracts |  |  |  |
Prior years: |  |  |  |
Liability for Claims and Claims Adjustment Expense | $ 35,146 |  |  |

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- Definition The amount needed to reflect the estimated ultimate cost of settling claims relating to insured events that have occurred on or before the balance sheet date, whether or not reported to the insurer at that date. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 55 -Paragraph 7 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480046/944-40-55-7 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 55 -Paragraph 9E -Publisher FASB -URI https://asc.fasb.org/1943274/2147480046/944-40-55-9E Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (cc) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-3 Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 944 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(13)(a)(1)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1 + Details
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- Definition Liability as of the balance sheet date for amounts representing estimated cost of settling unpaid claims under the terms of the underlying insurance policies, less estimated reinsurance recoveries on such claims. This includes an estimate for claims which have been incurred but not reported. Claim adjustment expenses represent the costs estimated to be incurred in the settlement of unpaid claims. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 944 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(13)(a)(1)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (cc) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-3 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-3 + Details
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