Contracts Accounted for as Insurance - Additional Information (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Guarantor Obligations [Line Items]
Weighted average risk-free rates for U.S. dollar denominated financial guaranty insurance obligations	3.79%	4.17%
Minimum
Guarantor Obligations [Line Items]
Weighted average risk-free rates for U.S. dollar denominated financial guaranty insurance obligations	3.52%	3.79%
Maximum
Guarantor Obligations [Line Items]
Weighted average risk-free rates for U.S. dollar denominated financial guaranty insurance obligations	4.96%	5.40%
Foreign Currency Concentration Risk | Premiums Receivable | Premiums Receivable
Guarantor Obligations [Line Items]
Percentage of installment premiums denominated in currencies other than the U.S. dollar	69.00%	70.00%