Fair Value Disclosures - Narrative (Details) $ in Millions	9 Months Ended	12 Months Ended
Sep. 30, 2024 USD ($)	Dec. 31, 2023 USD ($)
Fair Value, Inputs, Level 3 \| Fair Value, Measurements, Nonrecurring
Fair Value Assets Measured On Non Recurring Basis Unobservable Input Reconciliation [Line Items]
Loans held for investment, net	$ 20.7	$ 38.3
Impaired loans, carrying value	47.1	58.3
Allowance allocations	$ 26.4	$ 20.0
CRT securities \| Minimum
Fair Value Assets Measured On Non Recurring Basis Unobservable Input Reconciliation [Line Items]
Debt securities, available-for-sale, term	4 years 7 months 17 days
CRT securities \| Maximum
Fair Value Assets Measured On Non Recurring Basis Unobservable Input Reconciliation [Line Items]
Debt securities, available-for-sale, term	6 years 10 months 28 days
Measurement Input, Discount Rate \| CRT securities \| Minimum
Fair Value Assets Measured On Non Recurring Basis Unobservable Input Reconciliation [Line Items]
Debt securities, available-for-sale, measurement input	0.0452
Measurement Input, Discount Rate \| CRT securities \| Maximum
Fair Value Assets Measured On Non Recurring Basis Unobservable Input Reconciliation [Line Items]
Debt securities, available-for-sale, measurement input	0.0609
Measurement Input, Discount Rate \| CRT securities \| Weighted Average
Fair Value Assets Measured On Non Recurring Basis Unobservable Input Reconciliation [Line Items]
Debt securities, available-for-sale, measurement input	0.0512	0.0657
Debt securities, available-for-sale, term	5 years 6 months	6 years 21 days

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Fair Value Measurement With Unobservable Inputs Reconciliation Non Recurring Basis Asset Gain Loss Included In Earnings

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- Definition

Value of input used to measure investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

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