Derivative Instruments - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Value of right to reclaim cash collateral and posted margin, recorded in Other assets	$ 18,000		$ 18,000		$ 23,000
Gains in change in fair value of the call options	0	$ 0	2,000	$ (3,000)
Net liability fair value of all derivative instruments linked to Ambac's own credit risk	25,000		25,000		35,000
Fair value of posted assets as collateral	44,000		44,000		50,000
Derivative assets	18,000		18,000		26,000
Variable Interest Entity, Primary Beneficiary [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Derivative assets	208,000		208,000		226,000
Warrants [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Derivative assets	$ 1,000		$ 1,000		$ 1,000

Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]

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- Definition

The aggregate fair value of assets that are already posted, at the end of the reporting period, as collateral for derivative instruments with credit-risk-related contingent features.

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- Definition

Amount of right to receive cash collateral under master netting arrangements that have not been offset against derivative liabilities.

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- Definition

Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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- Definition

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

+ References

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- Definition

The aggregate fair value amounts of derivative instruments that contain credit-risk-related contingent features that are in a net liability position at the end of the reporting period. For nonderivative instruments that are designated and qualify as hedging instruments, the fair value amounts are the carrying value of the nonderivative hedging instrument, including the adjustment for the foreign currency transaction gain (loss) on that instrument.

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