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Insurance Contracts Financial Guarantee Insurance Contracts - Components of Loss and Loss Expense Reserves and Subrogation Recoverable (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024	Dec. 31, 2023
Components of Loss and Loss Expense Reserves and Subrogation Recoverable [Line Items]
Ceded Loss And Loss Expenses Paid Not Yet Recovered		$ 41,225
Policyholder Benefits and Claims Incurred, Ceded	$ 166,959	72,160
Liability for Claims and Claims Adjustment Expense	437,539		$ 349,062
Liability for Claim and Claim Adjustment Expenses Net of Subrogation recoverables	$ 437,539	$ 323,231	$ 349,062	$ 197,089

X

- Definition

Ceded Loss And Loss Expenses Paid Not Yet Recovered

+ References

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- Definition

[Line Items] for Components of Loss and Loss Expense Reserves and Subrogation Recoverable [Table]

+ References

No definition available.

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- Definition

Liability for Claim and Claim Adjustment Expenses Net of Subrogation recoverables

+ References

No definition available.

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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

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- Definition

Amount of reduction of provision for policy benefits and costs incurred for policies ceded.

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