Ceded Loss And Loss Expenses Paid Not Yet Recovered

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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- 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

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Balance Type:	debit
Period Type:	instant

- Definition

Number of Reinsurers Covering Majority

+ References

No definition available.

+ Details

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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

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- Definition

Reinsurance Recoverable Credit Exposure

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Reinsurance Recoverable, Gross, All Other

+ References

No definition available.

+ Details

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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

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Uncollateralized Credit Exposure Supoorted by Unlimited Uncapped Indemnity

+ References

No definition available.

+ Details

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

- Definition

Unsecured Reinsurance Recoverable, All Other

+ References

No definition available.

+ Details

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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

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of allowance for credit loss on reinsurance recoverable.

+ References

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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

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- Details

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Insurance - Summary of Percentage Ceded to Reinsurers and Reinsurance Recoverable and Rating Levels (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024	Sep. 30, 2024
Summary of Ceded Par and Net Unsecured Reinsurance Recoverable [Line Items]
Ceded Loss And Loss Expenses Paid Not Yet Recovered			$ 41,225
Reinsurance Recoverable, Allowance for Credit Loss	$ 100	$ 100
Reinsurance Recoverables, Gross	440,462
Unsecured Reinsurance Recoverables	304,283
Reinsurance Recoverable, Gross, All Other	175,331
Unsecured Reinsurance Recoverable, All Other	98,083
Letters of Credit Outstanding, Amount	$ 72,454
Number of Reinsurers Covering Majority	5
Percentage of Ceded Reinsurance Recoverable Represented by Top Three	60.20%
Uncollateralized Credit Exposure Supoorted by Unlimited Uncapped Indemnity	$ 28,999	35,146
Deferred Ceded Premiums And Reinsurance Recoverables	601,368
Reinsurance Recoverable Credit Exposure	304,283	$ 232,310
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	27,255
Unsecured Reinsurance Recoverables	27,255
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	49,677
Unsecured Reinsurance Recoverables	32,540
General Reinsurance Company \| Property and Casualty, Commercial Insurance \| Standard Poors A Plus Plus Rating
Summary of Ceded Par and Net Unsecured Reinsurance Recoverable [Line Items]
Reinsurance Recoverables, Gross	148,776
Unsecured Reinsurance Recoverables	130,515
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	17,486
Unsecured Reinsurance Recoverables	15,890
Swiss Reinsurance America Corporation \| Financial Guarantee \| Standard & Poors, No Rating
Summary of Ceded Par and Net Unsecured Reinsurance Recoverable [Line Items]
Reinsurance Recoverables, Gross	21,937
Unsecured Reinsurance Recoverables	$ 0