Mortgage-Backed Securities - Unrealized Gain (Loss) on Investments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Investments [Line Items]
Unrealized loss on investments, net	$ (179,100)	$ (69,197)	$ (121,491)	$ (245,551)
Residential Mortgage Backed Securities [Member]
Investments [Line Items]
Unrealized loss on debt securities	(177,768)	(65,723)	(120,735)	(240,322)
Commercial Mortgage Backed Securities [Member]
Investments [Line Items]
Unrealized loss on debt securities	(777)	(1,432)	(815)	(1,432)
Interest-Only-Strip [Member]
Investments [Line Items]
Unrealized loss on debt securities	(591)	(2,033)	36	(3,874)
Asset-backed Securities, Securitized Loans and Receivables
Investments [Line Items]
Unrealized gain (loss) on other investments	$ 36	$ (9)	$ 23	$ 77