Residential Whole Loans - Net Gain/(Loss) on Residential Whole Loans Measured at Fair Value Through Earnings (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Financing Receivable, Allowance for Credit Loss [Line Items]
Total	$ (203,991)	$ 31,241	$ (288,605)	$ 105,690
Residential whole loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Fair value realized and unrealized gain/(loss)	(185,052)	41,293	(240,829)	129,284
Realized credit losses, net of recoveries	(18,939)	(10,052)	(47,776)	(23,594)
Total	(203,991)	31,241	(288,605)	105,690
Residential whole loans \| Non-QM loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Fair value realized and unrealized gain/(loss)	(134,923)	31,465	(177,207)	104,783
Realized credit losses, net of recoveries	(616)	(80)	(1,163)	(866)
Residential whole loans \| Business purpose loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Fair value realized and unrealized gain/(loss)	(29,406)	7,169	(35,664)	19,985
Realized credit losses, net of recoveries	(18,309)	(9,788)	(45,350)	(21,904)
Residential whole loans \| Business purpose loans \| Single-family rental loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Fair value realized and unrealized gain/(loss)	(34,754)	16,878	(35,505)	45,888
Realized credit losses, net of recoveries	(387)	(7,489)	(988)	(11,833)
Residential whole loans \| Business purpose loans \| Single-family transitional loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Fair value realized and unrealized gain/(loss)	850	(1,770)	(2,819)	(16,488)
Realized credit losses, net of recoveries	(2,860)	(946)	(7,295)	(4,469)
Residential whole loans \| Business purpose loans \| Multifamily transitional loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Fair value realized and unrealized gain/(loss)	4,498	(7,939)	2,660	(9,415)
Realized credit losses, net of recoveries	(15,062)	(1,353)	(37,067)	(5,602)
Residential whole loans \| Seasoned RPL/NPL loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Fair value realized and unrealized gain/(loss)	(17,775)	1,769	(24,414)	1,885
Realized credit losses, net of recoveries	(14)	(184)	(1,263)	(824)
Residential whole loans \| Other loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Fair value realized and unrealized gain/(loss)	(2,948)	890	(3,544)	2,631
Realized credit losses, net of recoveries	$ 0	$ 0	$ 0	$ 0