Fair Value of Financial Instruments - Level 3 Liabilities (Details) - Level 3 - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Weighted Average | Residential whole loan | Liquidation timeline (in years) | Liquidation model
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Inputs, Liquidation Timeline		1 year 10 months 24 days		1 year 9 months 18 days
Minimum | Residential whole loan | Liquidation timeline (in years) | Liquidation model
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Inputs, Liquidation Timeline		1 month 6 days		9 months 18 days
Maximum | Residential whole loan | Liquidation timeline (in years) | Liquidation model
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Inputs, Liquidation Timeline		4 years 6 months		4 years 6 months
Recurring basis | Agreements with Non-mark-to-market Collateral Provisions
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 377,252	$ 469,424	$ 440,106	$ 469,424	$ 578,879
Issuances	0		107,230	112,740	379,625
Payment of principal	(154,989)		(145,983)	(359,901)	(557,151)
Change in unrealized losses	0		0	0	0
Balance at end of period	222,263		401,353	222,263	401,353
Recurring basis | Agreements with Mark-to-market Collateral Provisions
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	290,228	$ 178,864	553,162	178,864	884,495
Issuances	12,323		56,330	126,924	78,348
Payment of principal	(108,427)		(103,745)	(111,664)	(457,096)
Change in unrealized losses	0		0	0	0
Balance at end of period	$ 194,124		$ 505,747	$ 194,124	$ 505,747