Ceded Loss And Loss Expenses Paid Not Yet Recovered

No definition available.

Name:	ambc_CededLossAndLossExpensesPaidNotYetRecovered
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Includes the unexpired portion of financial guarantee premiums ceded on policies as of the balance sheet date and reinsurance recoverables on claims or claim adjustment expense paid by the ceding insurer.

+ References

No definition available.

+ Details

Name:	ambc_DeferredCededPremiumsAndReinsuranceRecoverables
Namespace Prefix:	ambc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Number of Reinsurers Covering Majority

+ References

No definition available.

+ Details

Name:	ambc_NumberOfReinsurersCoveringMajority
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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of Ceded Reinsurance Recoverable Represented by Top Three

+ References

No definition available.

+ Details

Name:	ambc_PercentageOfCededReinsuranceRecoverableRepresentedByTopThree
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Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Reinsurance Recoverable, Gross, All Other

+ References

No definition available.

+ Details

Name:	ambc_ReinsuranceRecoverableGrossAllOther
Namespace Prefix:	ambc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Summary of Ceded Par and Net Unsecured Reinsurance Recoverable [Line Items]

+ References

No definition available.

+ Details

Name:	ambc_SummaryOfCededParAndNetUnsecuredReinsuranceRecoverableLineItems
Namespace Prefix:	ambc_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Uncollateralized Credit Exposure Supoorted by Unlimited Uncapped Indemnity

+ References

No definition available.

+ Details

Name:	ambc_UncollateralizedCreditExposureSupoortedByUnlimitedUncappedIndemnity
Namespace Prefix:	ambc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Unsecured Reinsurance Recoverable, All Other

+ References

No definition available.

+ Details

Name:	ambc_UnsecuredReinsuranceRecoverableAllOther
Namespace Prefix:	ambc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents reinsurance recoverables on paid and unpaid losses and deferred ceded premiums, net of ceded premiums payables due to reinsurers, letters of credit, and collateral posted for the benefit of the cedant.

+ References

No definition available.

+ Details

Name:	ambc_UnsecuredReinsuranceRecoverables
Namespace Prefix:	ambc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of allowance for credit loss on reinsurance recoverable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-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/2003/role/disclosureRef
-Topic 944
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
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-URI https://asc.fasb.org/1943274/2147479344/326-20-45-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
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-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount before valuation allowance recoverable under reinsurance contracts. Examples include, but are not limited to, settled and unsettled claims, incurred but not reported losses, loss adjustment expense, premium paid, policy benefits and policy reserves.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481962/310-10-50-7A

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
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-Section 50
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
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-Name Accounting Standards Codification
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-Paragraph 1
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
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-Name Accounting Standards Codification
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-URI https://asc.fasb.org/1943274/2147477409/944-310-45-5

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
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-Name Accounting Standards Codification
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-14

+ Details

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Balance Type:	debit
Period Type:	instant

- Details

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- Details

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- Details

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- Details

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- Details

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Insurance - Summary of Percentage Ceded to Reinsurers and Reinsurance Recoverable and Rating Levels (Details) $ in Thousands	Mar. 31, 2025 USD ($)	Dec. 31, 2024 USD ($)	Mar. 31, 2024 USD ($)
Summary of Ceded Par and Net Unsecured Reinsurance Recoverable [Line Items]
Ceded Loss And Loss Expenses Paid Not Yet Recovered			$ 15,088
Reinsurance Recoverable, Allowance for Credit Loss	$ 100	$ 100
Reinsurance Recoverables, Gross	351,110
Unsecured Reinsurance Recoverables	242,613
Reinsurance Recoverable, Gross, All Other	112,497
Unsecured Reinsurance Recoverable, All Other	47,489
Letters of Credit Outstanding, Amount	$ 66,954
Number of Reinsurers Covering Majority	5
Percentage of Ceded Reinsurance Recoverable Represented by Top Three	68.00%
Uncollateralized Credit Exposure Supoorted by Unlimited Uncapped Indemnity	$ 34,724	$ 35,146
Deferred Ceded Premiums And Reinsurance Recoverables	496,024
QBE Insurance Corporation \| Property and Casualty, Commercial Insurance \| Standard & Poor's, A Rating
Summary of Ceded Par and Net Unsecured Reinsurance Recoverable [Line Items]
Reinsurance Recoverables, Gross	31,002
Unsecured Reinsurance Recoverables	31,002
Assured Guaranty Re Ltd \| Financial Guarantee \| Standard & Poor's, A+ Rating
Summary of Ceded Par and Net Unsecured Reinsurance Recoverable [Line Items]
Reinsurance Recoverables, Gross	28,184
Unsecured Reinsurance Recoverables	18,894
General Reinsurance Company \| Property and Casualty, Commercial Insurance \| Standard & Poor's, AA+ Rating
Summary of Ceded Par and Net Unsecured Reinsurance Recoverable [Line Items]
Reinsurance Recoverables, Gross	150,484
Unsecured Reinsurance Recoverables	129,496
Swiss Reinsurance America Corporation \| Financial Guarantee \| Standard & Poor's, A+ Rating
Summary of Ceded Par and Net Unsecured Reinsurance Recoverable [Line Items]
Reinsurance Recoverables, Gross	17,147
Unsecured Reinsurance Recoverables	15,732
Swiss Reinsurance America Corporation \| Financial Guarantee \| Standard & Poors, No Rating
Summary of Ceded Par and Net Unsecured Reinsurance Recoverable [Line Items]
Reinsurance Recoverables, Gross	11,796
Unsecured Reinsurance Recoverables	$ 0