Residential Loans and Residential Loans Held for Sale, at Fair Value - Schedule of Residential Mortgage Loans Held in Securitization Trusts, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2026	Dec. 31, 2025
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Principal	$ 5,271,155	$ 4,619,015
Premium / (Discount)	(69,920)	(85,324)
Change in fair value	(261,327)	(94,809)
Carrying value	4,939,908	4,438,882
Consolidated SLST \| VIE, Primary Beneficiary
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Principal	1,234,659	1,307,770
Premium / (Discount)	(59,435)	(61,606)
Change in fair value	(127,666)	(80,487)
Carrying value	1,047,558	1,165,677
Residential loans
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Principal	803,867	575,565
Premium / (Discount)	3,885	3,389
Change in fair value	(25,994)	5,009
Carrying value	781,758	583,963
Residential loans held in securitization trusts
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Principal	3,085,038	2,656,765
Premium / (Discount)	(14,370)	(27,107)
Change in fair value	(111,045)	(21,123)
Carrying value	2,959,623	2,608,535
Total Residential loans
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Principal	5,123,564	4,540,100
Premium / (Discount)	(69,920)	(85,324)
Change in fair value	(264,705)	(96,601)
Carrying value	4,788,939	4,358,175
Residential loans held for sale
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Principal	147,591	78,915
Premium / (Discount)	0	0
Change in fair value	3,378	1,792
Carrying value	$ 150,969	$ 80,707