Mortgage-Backed Securities - Collateral Characteristics of Non-Agency Residential MBS (Details) - Non-Agency RMBS - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Debt Securities, Available-for-sale [Line Items]
Weighted average maturity (years)	18 years 7 months 6 days	19 years 6 months
Weighted average amortized loan to value	56.30%	57.10%
Weighted average FICO	706	707
Weighted average loan balance (in thousands)	$ 249	$ 252
Weighted average percentage owner-occupied	83.70%	84.50%
Weighted average percentage single family residence	60.30%	61.40%
Weighted average current credit enhancement	1.20%	1.30%
CA
Debt Securities, Available-for-sale [Line Items]
Weighted average geographic concentration of top four states	32.80%	33.10%
NY
Debt Securities, Available-for-sale [Line Items]
Weighted average geographic concentration of top four states	11.80%	11.60%
FL
Debt Securities, Available-for-sale [Line Items]
Weighted average geographic concentration of top four states	7.60%	7.60%
NJ
Debt Securities, Available-for-sale [Line Items]
Weighted average geographic concentration of top four states	4.60%	4.50%