XML 77 R64.htm IDEA: XBRL DOCUMENT
v3.25.1

Insurance Contracts - Summary of Information Related to Policies Currently Included in Ambac's Loss Reserves or Subrogation Recoverable (Phantom) (Details) - USD ($) $ in Thousands | Mar. 31, 2025 | Dec. 31, 2024 | Mar. 31, 2024 | Dec. 31, 2023
--- | --- | --- | --- | ---
Financial Guarantee Insurance Contracts, Claim Liability [Line Items] |  |  |  |
Liability for Claims and Claims Adjustment Expense | $ 373,105 | $ 349,062 |  |
Liability for Claims | 373,105 | 349,062 |  |
Ceded Loss And Loss Expenses Paid Not Yet Recovered |  |  | $ 15,088 |
Short-Duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | 78,185 |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments | 294,920 | $ 270,081 | $ 182,892 | $ 156,232
Specialty Property & Casualty Program |  |  |  |
Financial Guarantee Insurance Contracts, Claim Liability [Line Items] |  |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments | 294,920 |  |  |
Operating Segments | Specialty Property & Casualty Program |  |  |  |
Financial Guarantee Insurance Contracts, Claim Liability [Line Items] |  |  |  |
Liability for Claims and Claims Adjustment Expense | 373,105 |  |  |
Liability for Claims | 373,105 |  |  |
Operating Segments | Commercial Auto |  |  |  |
Financial Guarantee Insurance Contracts, Claim Liability [Line Items] |  |  |  |
Liability for Claims and Claims Adjustment Expense | 155,383 |  |  |
Liability for Claims | 155,383 |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments | 127,775 |  |  |
Operating Segments | Commercial Auto | Specialty Property & Casualty Program |  |  |  |
Financial Guarantee Insurance Contracts, Claim Liability [Line Items] |  |  |  |
Short-Duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | 27,608 |  |  |
Operating Segments | Excess and General Liability |  |  |  |
Financial Guarantee Insurance Contracts, Claim Liability [Line Items] |  |  |  |
Liability for Claims and Claims Adjustment Expense | 65,845 |  |  |
Liability for Claims | 65,845 |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments | 56,775 |  |  |
Operating Segments | Excess and General Liability | Specialty Property & Casualty Program |  |  |  |
Financial Guarantee Insurance Contracts, Claim Liability [Line Items] |  |  |  |
Short-Duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | 9,070 |  |  |
Operating Segments | Workers' Compensation Insurance |  |  |  |
Financial Guarantee Insurance Contracts, Claim Liability [Line Items] |  |  |  |
Liability for Claims and Claims Adjustment Expense | 14,602 |  |  |
Liability for Claims | 14,602 |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments | 0 |  |  |
Operating Segments | Workers' Compensation Insurance | Specialty Property & Casualty Program |  |  |  |
Financial Guarantee Insurance Contracts, Claim Liability [Line Items] |  |  |  |
Short-Duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | 14,602 |  |  |
Operating Segments | Non-standard Personal Auto |  |  |  |
Financial Guarantee Insurance Contracts, Claim Liability [Line Items] |  |  |  |
Liability for Claims and Claims Adjustment Expense | 9,149 |  |  |
Liability for Claims | 9,149 |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments | 396 |  |  |
Operating Segments | Non-standard Personal Auto | Specialty Property & Casualty Program |  |  |  |
Financial Guarantee Insurance Contracts, Claim Liability [Line Items] |  |  |  |
Short-Duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | 8,753 |  |  |
Operating Segments | General Liability |  |  |  |
Financial Guarantee Insurance Contracts, Claim Liability [Line Items] |  |  |  |
Liability for Claims and Claims Adjustment Expense | 44,208 |  |  |
Liability for Claims | 44,208 |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments | 35,157 |  |  |
Operating Segments | General Liability | Specialty Property & Casualty Program |  |  |  |
Financial Guarantee Insurance Contracts, Claim Liability [Line Items] |  |  |  |
Short-Duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | 9,051 |  |  |
Operating Segments | Professional Liability Insurance |  |  |  |
Financial Guarantee Insurance Contracts, Claim Liability [Line Items] |  |  |  |
Liability for Claims and Claims Adjustment Expense | 23,373 |  |  |
Liability for Claims | 23,373 |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments | 21,561 |  |  |
Operating Segments | Professional Liability Insurance | Specialty Property & Casualty Program |  |  |  |
Financial Guarantee Insurance Contracts, Claim Liability [Line Items] |  |  |  |
Short-Duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | 1,812 |  |  |
Operating Segments | Surety Product Line |  |  |  |
Financial Guarantee Insurance Contracts, Claim Liability [Line Items] |  |  |  |
Liability for Claims and Claims Adjustment Expense | 10,558 |  |  |
Liability for Claims | 10,558 |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments | 10,558 |  |  |
Operating Segments | Surety Product Line | Specialty Property & Casualty Program |  |  |  |
Financial Guarantee Insurance Contracts, Claim Liability [Line Items] |  |  |  |
Short-Duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | 0 |  |  |
Segment Reporting, Reconciling Item, Excluding Corporate Nonsegment | Unallocated Loss Adjustment Expense Reserve |  |  |  |
Financial Guarantee Insurance Contracts, Claim Liability [Line Items] |  |  |  |
Liability for Claims and Claims Adjustment Expense | 13,159 |  |  |
Liability for Claims | 13,159 |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments | 6,668 |  |  |
Segment Reporting, Reconciling Item, Excluding Corporate Nonsegment | Unallocated Loss Adjustment Expense Reserve | Specialty Property & Casualty Program |  |  |  |
Financial Guarantee Insurance Contracts, Claim Liability [Line Items] |  |  |  |
Short-Duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | 6,491 |  |  |
Segment Reporting, Reconciling Item, Excluding Corporate Nonsegment | Other Insurance Contracts |  |  |  |
Financial Guarantee Insurance Contracts, Claim Liability [Line Items] |  |  |  |
Liability for Claims and Claims Adjustment Expense | 36,828 |  |  |
Liability for Claims | 36,828 |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments | 36,030 |  |  |
Segment Reporting, Reconciling Item, Excluding Corporate Nonsegment | Other Insurance Contracts | Specialty Property & Casualty Program |  |  |  |
Financial Guarantee Insurance Contracts, Claim Liability [Line Items] |  |  |  |
Short-Duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | $ 798 |  |  |

X
- Definition Ceded Loss And Loss Expenses Paid Not Yet Recovered + References No definition available. + Details
Name: | ambc_CededLossAndLossExpensesPaidNotYetRecovered
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Subparagraph (a)(4) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-9 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 55 -Paragraph 34 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480046/944-40-55-34 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Subparagraph (a)(5)(ix) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-9 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Subparagraph (a)(5)(viii) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-9 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Subparagraph (a)(5)(vii) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-9 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Subparagraph (a)(5)(vi) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-9 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Subparagraph (a)(5)(v) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-9 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Subparagraph (a)(5)(iv) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-9 Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Subparagraph (a)(5)(iii) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-9 Reference 10: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Subparagraph (a)(5)(ii) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-9 Reference 11: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Subparagraph (a)(5)(i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-9 + Details
Name: | us-gaap_FinancialGuaranteeInsuranceContractsClaimLiabilityAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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 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
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/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/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 4: 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 5: 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 Reference 6: 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 7: 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 8: 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 + Details
Name: | us-gaap_ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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/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 4C -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-4C Reference 3: 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 + Details
Name: | us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=ambc_SpecialtyPropertyCasualtyProgramMember
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_CommercialAutoMember
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=us-gaap_SuretySegmentMember
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_UnallocatedLossAdjustmentExpenseReserveMember
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: |