Mortgage-Backed Securities - Schedule of Investment Portfolio (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025
Debt Securities, Available-for-sale [Line Items]
Principal/ Notional Balance	$ 7,354,216	$ 6,606,785
Unamortized Premium (Discount)	(461,639)	(464,118)
Amortized Cost	6,892,577	6,142,667
Unrealized Gain/ (Loss), net	57,332	133,942
Fair Value	$ 6,949,909	$ 6,276,609
Period-end Weighted Average Yield	5.29%	5.37%
30 year fixed-rate pass-through
Debt Securities, Available-for-sale [Line Items]
Principal/ Notional Balance	$ 5,981,029	$ 5,223,764
Unamortized Premium (Discount)	(49,466)	(33,396)
Amortized Cost	5,931,563	5,190,368
Unrealized Gain/ (Loss), net	52,066	118,792
Fair Value	$ 5,983,629	$ 5,309,160
Period-end Weighted Average Yield	5.36%	5.46%
Agency CMO
Debt Securities, Available-for-sale [Line Items]
Principal/ Notional Balance	$ 463,522	$ 484,974
Unamortized Premium (Discount)	(406,504)	(424,405)
Amortized Cost	57,018	60,569
Unrealized Gain/ (Loss), net	7,368	8,751
Fair Value	$ 64,386	$ 69,320
Period-end Weighted Average Yield	8.83%	9.18%
Agency CMBS
Debt Securities, Available-for-sale [Line Items]
Principal/ Notional Balance	$ 909,665	$ 898,047
Unamortized Premium (Discount)	(5,669)	(6,317)
Amortized Cost	903,996	891,730
Unrealized Gain/ (Loss), net	(2,102)	6,399
Fair Value	$ 901,894	$ 898,129
Period-end Weighted Average Yield	4.62%	4.62%