XML 107 R88.htm IDEA: XBRL DOCUMENT
v3.25.4

Insurance Contracts (Details) $ in Thousands | Dec. 31, 2025 USD ($) | Dec. 31, 2024 USD ($) | Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($) | Dec. 31, 2021 USD ($)
--- | --- | --- | --- | --- | ---
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | $ 84,268 | $ 78,981 |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments | 375,722 | 270,081 | $ 156,301 | $ 80,155 |
Liability for Claims and Claims Adjustment Expense | 459,990 | 349,062 |  |  |
Commercial Auto | Operating Segments |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments | 136,132 | 129,752 |  |  |
Liability for Claims and Claims Adjustment Expense | 159,194 | 158,472 |  |  |
Unallocated Loss Adjustment Expense Reserve | Segment Reporting, Reconciling Item, Excluding Corporate Nonsegment |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments | 9,317 | 5,660 |  |  |
Liability for Claims and Claims Adjustment Expense | 14,869 | 12,238 |  |  |
Other Insurance Contracts | Segment Reporting, Reconciling Item, Excluding Corporate Nonsegment |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments | 24,544 | 36,231 |  |  |
Liability for Claims and Claims Adjustment Expense | 24,834 | 36,551 |  |  |
Excess and General Liability | Operating Segments |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments | 99,713 | 43,677 |  |  |
Liability for Claims and Claims Adjustment Expense | 116,610 | 50,248 |  |  |
Workers' Compensation Insurance | Operating Segments |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments | 0 | 0 |  |  |
Liability for Claims and Claims Adjustment Expense | 17,798 | 14,465 |  |  |
Non-standard Personal Auto | Operating Segments |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments | 191 | 504 |  |  |
Liability for Claims and Claims Adjustment Expense | 3,826 | 12,689 |  |  |
General Liability | Operating Segments |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments | 51,024 | 26,925 |  |  |
Liability for Claims and Claims Adjustment Expense | 63,596 | 35,211 |  |  |
Professional Liability Insurance | Operating Segments |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments | 37,996 | 15,891 |  |  |
Liability for Claims and Claims Adjustment Expense | 40,846 | 17,698 |  |  |
Multi Peril / Business Owners (BOP) | Operating Segments |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments | 4,666 | 230 |  |  |
Liability for Claims and Claims Adjustment Expense | 6,185 | 273 |  |  |
Surety Product Line | Operating Segments |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments | 12,140 | 11,211 |  |  |
Liability for Claims and Claims Adjustment Expense | 12,233 | 11,217 |  |  |
Specialty Property & Casualty Program |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments | 375,722 | 270,081 |  |  |
Specialty Property & Casualty Program | Operating Segments |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Liability for Claims and Claims Adjustment Expense | 459,991 | 349,062 |  |  |
Specialty Property & Casualty Program | Commercial Auto |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | 23,062 |  |  |  |
Short-Duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 56,024 |  |  |  |
Short-Duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 32,962 |  |  |  |
Short Duration Insurance Contract Liability For Unpaid Clams and Allocated Claim Adjustment Expense Subtotal For Separately Presented | $ 23,062 | 0 |  |  |
Short-Duration Insurance Contracts, Historical Claims Duration, Year One | 11.40% |  |  |  |
Short-Duration Insurance Contracts, Historical Claims Duration, Year Two | 19.60% |  |  |  |
Short-Duration Insurance Contracts, Historical Claims Duration, Year Three | 19.00% |  |  |  |
Short-Duration Insurance Contracts, Historical Claims Duration, Year Four | 30.80% |  |  |  |
Short-Duration Insurance Contracts, Historical Claims Duration, Year Five | 27.40% |  |  |  |
Specialty Property & Casualty Program | Commercial Auto | Short-Duration Insurance Contract, Accident Year 2021 |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 1,212 | 962 | 978 | 468 | $ 432
Short-Duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 1,013 | 681 | 150 | 45 | 7
Short-Duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 88 |  |  |  |
Short-Duration Insurance Contract, Cumulative Number of Reported Claims | 82 |  |  |  |
Specialty Property & Casualty Program | Commercial Auto | Short-Duration Insurance Contract, Accident Year 2022 |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 9,832 | 9,099 | 7,866 | 8,225 |
Short-Duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 6,450 | 4,701 | 2,325 | 555 |
Short-Duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 1,292 |  |  |  |
Short-Duration Insurance Contract, Cumulative Number of Reported Claims | 1,162 |  |  |  |
Specialty Property & Casualty Program | Commercial Auto | Short-Duration Insurance Contract, Accident Year 2023 |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 25,345 | 23,309 | 19,459 |  |
Short-Duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 17,056 | 10,984 | 3,914 |  |
Short-Duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 4,279 |  |  |  |
Short-Duration Insurance Contract, Cumulative Number of Reported Claims | 3,282 |  |  |  |
Specialty Property & Casualty Program | Commercial Auto | Short-Duration Insurance Contract, Accident Year 2024 |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 14,851 | 15,217 |  |  |
Short-Duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 7,885 | 3,554 |  |  |
Short-Duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 4,027 |  |  |  |
Short-Duration Insurance Contract, Cumulative Number of Reported Claims | 3,243 |  |  |  |
Specialty Property & Casualty Program | Commercial Auto | Short-Duration Insurance Contract, Accident Year 2025 |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 4,783 |  |  |  |
Short-Duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 557 |  |  |  |
Short-Duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 2,972 |  |  |  |
Short-Duration Insurance Contract, Cumulative Number of Reported Claims | 1,564 |  |  |  |
Specialty Property & Casualty Program | Commercial Auto | Operating Segments |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | $ 23,062 | 28,720 |  |  |
Specialty Property & Casualty Program | Unallocated Loss Adjustment Expense Reserve | Segment Reporting, Reconciling Item, Excluding Corporate Nonsegment |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | 5,552 | 6,578 |  |  |
Specialty Property & Casualty Program | Other Insurance Contracts | Segment Reporting, Reconciling Item, Excluding Corporate Nonsegment |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | 289 | 320 |  |  |
Specialty Property & Casualty Program | Excess and General Liability | Operating Segments |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | 16,897 | 6,571 |  |  |
Specialty Property & Casualty Program | Workers' Compensation Insurance |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | 17,798 |  |  |  |
Short-Duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 39,260 |  |  |  |
Short-Duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 21,463 |  |  |  |
Short Duration Insurance Contract Liability For Unpaid Clams and Allocated Claim Adjustment Expense Subtotal For Separately Presented | $ 17,798 | 0 |  |  |
Short-Duration Insurance Contracts, Historical Claims Duration, Year One | 21.80% |  |  |  |
Short-Duration Insurance Contracts, Historical Claims Duration, Year Two | 42.90% |  |  |  |
Short-Duration Insurance Contracts, Historical Claims Duration, Year Three | 31.10% |  |  |  |
Short-Duration Insurance Contracts, Historical Claims Duration, Year Four | 0.00% |  |  |  |
Short-Duration Insurance Contracts, Historical Claims Duration, Year Five | 0.00% |  |  |  |
Specialty Property & Casualty Program | Workers' Compensation Insurance | Short-Duration Insurance Contract, Accident Year 2021 |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 0 | 0 | 0 | 0 | 0
Short-Duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 0 | 0 | 0 | 0 | 0
Short-Duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 0 |  |  |  |
Short-Duration Insurance Contract, Cumulative Number of Reported Claims | 0 |  |  |  |
Specialty Property & Casualty Program | Workers' Compensation Insurance | Short-Duration Insurance Contract, Accident Year 2022 |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 0 | 0 | 0 | 0 |
Short-Duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 0 | 0 | 0 | 0 |
Short-Duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 0 |  |  |  |
Short-Duration Insurance Contract, Cumulative Number of Reported Claims | 0 |  |  |  |
Specialty Property & Casualty Program | Workers' Compensation Insurance | Short-Duration Insurance Contract, Accident Year 2023 |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 7,362 | 6,056 | 6,053 |  |
Short-Duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 6,230 | 3,938 | 807 |  |
Short-Duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 2,675 |  |  |  |
Short-Duration Insurance Contract, Cumulative Number of Reported Claims | 2,384 |  |  |  |
Specialty Property & Casualty Program | Workers' Compensation Insurance | Short-Duration Insurance Contract, Accident Year 2024 |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 15,146 | 16,486 |  |  |
Short-Duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 10,692 | 4,139 |  |  |
Short-Duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 5,150 |  |  |  |
Short-Duration Insurance Contract, Cumulative Number of Reported Claims | 4,889 |  |  |  |
Specialty Property & Casualty Program | Workers' Compensation Insurance | Short-Duration Insurance Contract, Accident Year 2025 |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 16,752 |  |  |  |
Short-Duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 4,541 |  |  |  |
Short-Duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 404 |  |  |  |
Short-Duration Insurance Contract, Cumulative Number of Reported Claims | 4,252 |  |  |  |
Specialty Property & Casualty Program | Workers' Compensation Insurance | Operating Segments |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | $ 17,798 | 14,465 |  |  |
Specialty Property & Casualty Program | Non-standard Personal Auto | Operating Segments |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | 3,635 | 12,185 |  |  |
Specialty Property & Casualty Program | Insurance, Other |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | 8,388 |  |  |  |
Short-Duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 33,829 |  |  |  |
Short-Duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 25,441 |  |  |  |
Short Duration Insurance Contract Liability For Unpaid Clams and Allocated Claim Adjustment Expense Subtotal For Separately Presented | $ 8,388 | 0 |  |  |
Short-Duration Insurance Contracts, Historical Claims Duration, Year One | 18.20% |  |  |  |
Short-Duration Insurance Contracts, Historical Claims Duration, Year Two | 31.10% |  |  |  |
Short-Duration Insurance Contracts, Historical Claims Duration, Year Three | 10.10% |  |  |  |
Short-Duration Insurance Contracts, Historical Claims Duration, Year Four | 0.00% |  |  |  |
Short-Duration Insurance Contracts, Historical Claims Duration, Year Five | 0.00% |  |  |  |
Specialty Property & Casualty Program | Insurance, Other | Short-Duration Insurance Contract, Accident Year 2021 |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 0 | 0 | 0 | 0 | 0
Short-Duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 0 | 0 | 0 | 0 | 0
Short-Duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 0 |  |  |  |
Short-Duration Insurance Contract, Cumulative Number of Reported Claims | 0 |  |  |  |
Specialty Property & Casualty Program | Insurance, Other | Short-Duration Insurance Contract, Accident Year 2022 |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 1 | 3 | 1 | 1 |
Short-Duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 0 | 0 | 0 | 0 |
Short-Duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 1 |  |  |  |
Short-Duration Insurance Contract, Cumulative Number of Reported Claims | 788 |  |  |  |
Specialty Property & Casualty Program | Insurance, Other | Short-Duration Insurance Contract, Accident Year 2023 |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 5,884 | 5,907 | 6,142 |  |
Short-Duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 5,522 | 4,342 | 966 |  |
Short-Duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 2,441 |  |  |  |
Short-Duration Insurance Contract, Cumulative Number of Reported Claims | 18,743 |  |  |  |
Specialty Property & Casualty Program | Insurance, Other | Short-Duration Insurance Contract, Accident Year 2024 |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 24,292 | 23,475 |  |  |
Short-Duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 19,489 | 10,802 |  |  |
Short-Duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 1,513 |  |  |  |
Short-Duration Insurance Contract, Cumulative Number of Reported Claims | 57,524 |  |  |  |
Specialty Property & Casualty Program | Insurance, Other | Short-Duration Insurance Contract, Accident Year 2025 |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 3,652 |  |  |  |
Short-Duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 430 |  |  |  |
Short-Duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 1,595 |  |  |  |
Short-Duration Insurance Contract, Cumulative Number of Reported Claims | 2,307 |  |  |  |
Specialty Property & Casualty Program | General Liability |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | $ 12,572 |  |  |  |
Short-Duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 14,423 |  |  |  |
Short-Duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 1,852 |  |  |  |
Short Duration Insurance Contract Liability For Unpaid Clams and Allocated Claim Adjustment Expense Subtotal For Separately Presented | $ 12,572 | 0 |  |  |
Short-Duration Insurance Contracts, Historical Claims Duration, Year One | 0.60% |  |  |  |
Short-Duration Insurance Contracts, Historical Claims Duration, Year Two | 4.20% |  |  |  |
Short-Duration Insurance Contracts, Historical Claims Duration, Year Three | 55.90% |  |  |  |
Short-Duration Insurance Contracts, Historical Claims Duration, Year Four | 0.30% |  |  |  |
Short-Duration Insurance Contracts, Historical Claims Duration, Year Five | 0.00% |  |  |  |
Specialty Property & Casualty Program | General Liability | Short-Duration Insurance Contract, Accident Year 2021 |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 0 | 0 | 0 | 0 | 0
Short-Duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 0 | 0 | 0 | 0 | $ 0
Short-Duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 0 |  |  |  |
Short-Duration Insurance Contract, Cumulative Number of Reported Claims | 0 |  |  |  |
Specialty Property & Casualty Program | General Liability | Short-Duration Insurance Contract, Accident Year 2022 |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 374 | 425 | 217 | 223 |
Short-Duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 266 | 265 | 1 | $ 0 |
Short-Duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 109 |  |  |  |
Short-Duration Insurance Contract, Cumulative Number of Reported Claims | 4 |  |  |  |
Specialty Property & Casualty Program | General Liability | Short-Duration Insurance Contract, Accident Year 2023 |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 1,784 | 1,328 | 2,019 |  |
Short-Duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 791 | 57 | $ 24 |  |
Short-Duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 886 |  |  |  |
Short-Duration Insurance Contract, Cumulative Number of Reported Claims | 26 |  |  |  |
Specialty Property & Casualty Program | General Liability | Short-Duration Insurance Contract, Accident Year 2024 |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 6,955 | 6,915 |  |  |
Short-Duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 780 | 60 |  |  |
Short-Duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 5,205 |  |  |  |
Short-Duration Insurance Contract, Cumulative Number of Reported Claims | 194 |  |  |  |
Specialty Property & Casualty Program | General Liability | Short-Duration Insurance Contract, Accident Year 2025 |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 5,311 |  |  |  |
Short-Duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 15 |  |  |  |
Short-Duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 3,996 |  |  |  |
Short-Duration Insurance Contract, Cumulative Number of Reported Claims | 45 |  |  |  |
Specialty Property & Casualty Program | General Liability | Operating Segments |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | $ 12,572 | 8,286 |  |  |
Specialty Property & Casualty Program | Professional Liability Insurance | Operating Segments |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | 2,851 | 1,807 |  |  |
Specialty Property & Casualty Program | Multi Peril / Business Owners (BOP) | Operating Segments |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | 1,519 | 43 |  |  |
Specialty Property & Casualty Program | Surety Product Line | Operating Segments |  |  |  |  |
Insurance [Line Items] |  |  |  |  |
Short-Duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | $ 94 | $ 6 |  |  |

X
- Definition Insurance [Line Items] + References No definition available. + Details
Name: | ambc_InsuranceLineItems
Namespace Prefix: | ambc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Short Duration Insurance Contract Liability For Unpaid Clams and Allocated Claim Adjustment Expense Subtotal For Separately Presented + References No definition available. + Details
Name: | ambc_ShortDurationInsuranceContractLiabilityForUnpaidClamsAndAllocatedClaimAdjustmentExpenseSubtotalForSeparatelyPresented
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- 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 605 -Name Accounting Standards Codification -Section 55 -Paragraph 11 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477548/944-605-55-11 Reference 2: 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 3: 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 4: 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 5: 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
Name: | us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount, after valuation allowance, recoverable under reinsurance contracts for losses reported to the ceding insurer but not yet paid and amounts expected for incurred losses and settlement expenses, which have not yet been reported to the ceding insurer. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 944 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479838/944-20-50-5 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 944 -SubTopic 310 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477363/944-310-50-2 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 944 -SubTopic 310 -Name Accounting Standards Codification -Section 45 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477409/944-310-45-6 Reference 4: 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 5: 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 6: 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 7: 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 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 4C -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-4C + Details
Name: | us-gaap_ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount, after reinsurance, of paid claims and allocated claim adjustment expense used in claims development for short-duration insurance contracts. Excludes unallocated claim adjustment expense. + References Reference 1: 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 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 4B -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-4B + Details
Name: | us-gaap_ShortdurationInsuranceContractsCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Percentage of average annual payout, after reinsurance, in the fifth year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 55 -Paragraph 9F -Publisher FASB -URI https://asc.fasb.org/1943274/2147480046/944-40-55-9F Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 4G -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-4G + Details
Name: | us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearFive
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of average annual payout, after reinsurance, in the fourth year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 55 -Paragraph 9F -Publisher FASB -URI https://asc.fasb.org/1943274/2147480046/944-40-55-9F Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 4G -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-4G + Details
Name: | us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearFour
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of average annual payout, after reinsurance, in the first year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 55 -Paragraph 9F -Publisher FASB -URI https://asc.fasb.org/1943274/2147480046/944-40-55-9F Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 4G -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-4G + Details
Name: | us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearOne
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of average annual payout, after reinsurance, in the third year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 55 -Paragraph 9F -Publisher FASB -URI https://asc.fasb.org/1943274/2147480046/944-40-55-9F Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 4G -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-4G + Details
Name: | us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearThree
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of average annual payout, after reinsurance, in the second year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 55 -Paragraph 9F -Publisher FASB -URI https://asc.fasb.org/1943274/2147480046/944-40-55-9F Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 4G -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-4G + Details
Name: | us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearTwo
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Undiscounted amount, after reinsurance, of incurred-but-not-reported (IBNR) liabilities plus expected development on reported claims, for claims and allocated claim adjustment expense for short-duration insurance contracts. Excludes unallocated claim adjustment expense. + References Reference 1: 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 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 4E -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-4E Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 4D -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-4D + Details
Name: | us-gaap_ShortdurationInsuranceContractsIncurredButNotReportedIbnrClaimsLiabilityNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Undiscounted amount, after reinsurance, of incurred claims and allocated claim adjustment expense used in claims development for short-duration insurance contracts. Excludes unallocated claim adjustment expense. + References Reference 1: 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 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 4B -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-4B + Details
Name: | us-gaap_ShortdurationInsuranceContractsIncurredClaimsAndAllocatedClaimAdjustmentExpenseNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Undiscounted amount, after reinsurance, of the liability for unpaid claims and allocated claim adjustment expense for short-duration insurance contracts. Excludes unallocated claim adjustment expense. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 4B -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-4B 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/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 4C -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-4C + Details
Name: | us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Cumulative number of reported claims for short-duration insurance contracts. + References Reference 1: 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 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 4D -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-4D + Details
Name: | us-gaap_ShortdurationInsuranceContractsNumberOfReportedClaims
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | srt_ProductOrServiceAxis=ambc_CommercialAutoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ConsolidationItemsAxis=us-gaap_OperatingSegmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=ambc_UnallocatedLossAdjustmentExpenseReserveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ConsolidationItemsAxis=us-gaap_MaterialReconcilingItemsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=ambc_OtherInsuranceContractsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=ambc_ExcessAndGeneralLiabilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=us-gaap_WorkersCompensationInsuranceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=ambc_NonStandardPersonalAutoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=us-gaap_GeneralLiabilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=us-gaap_ProfessionalLiabilityInsuranceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=ambc_MultiPerilBusinessOwnersBOPMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=us-gaap_SuretySegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=ambc_SpecialtyPropertyCasualtyProgramMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShortdurationInsuranceContractsAccidentYearAxis=us-gaap_ShortDurationInsuranceContractAccidentYear2021Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShortdurationInsuranceContractsAccidentYearAxis=us-gaap_ShortDurationInsuranceContractAccidentYear2022Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShortdurationInsuranceContractsAccidentYearAxis=us-gaap_ShortDurationInsuranceContractAccidentYear2023Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShortdurationInsuranceContractsAccidentYearAxis=us-gaap_ShortDurationInsuranceContractAccidentYear2024Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShortdurationInsuranceContractsAccidentYearAxis=us-gaap_ShortDurationInsuranceContractAccidentYear2025Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=us-gaap_OtherInsuranceProductLineMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |