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Mortgage-Backed Securities - Investment Type (Details) - USD ($) $ in Thousands | Dec. 31, 2024 | Dec. 31, 2023
--- | --- | ---
Debt Securities, Trading and Available-for-sale [Abstract] |  |  |
Par Value |  | $ 7,817,400 | $ 6,143,945
Amortized Cost |  | 7,912,848 | 6,283,185
Non-Agency other, Amortized Cost |  | 1,009,016 | 1,131,769
Fair Value |  | 7,512,087 | 6,038,948
Gross Unrealized Gain |  | 3,283 | 1,324
Gross Unrealized Loss |  | (175,773) | (159,826)
Fair Value |  | 836,526 | 973,267
Amortized Cost |  | 6,903,832 | 5,151,416
Gross Unrealized Gain |  | 11,081 | 48,461
Gross Unrealized Loss |  | (239,352) | (134,196)
Fair Value |  | 6,675,561 | 5,065,681
Residential Mortgage Backed Securities [Member] | Agency MBS |  |  |
Debt Securities, Trading and Available-for-sale [Abstract] |  |  |
Par Value |  | 7,717,764 | 6,022,502
Amortized Cost |  | 7,695,409 | 5,993,922
Non-Agency other, Amortized Cost |  | 827,314 | 898,420
Fair Value |  | 7,302,238 | 5,763,532
Gross Unrealized Gain |  | 0 | 0
Gross Unrealized Loss |  | (167,248) | (148,606)
Fair Value |  | 660,066 | 749,814
Amortized Cost |  | 6,868,095 | 5,095,502
Gross Unrealized Gain |  | 11,081 | 48,459
Gross Unrealized Loss |  | (237,004) | (130,243)
Fair Value |  | 6,642,172 | 5,013,718
Commercial Mortgage Backed Securities [Member] | Agency MBS |  |  |
Debt Securities, Trading and Available-for-sale [Abstract] |  |  |
Par Value |  | 99,636 | 121,293
Amortized Cost |  | 99,848 | 121,799
Non-Agency other, Amortized Cost |  | 99,848 | 106,527
Fair Value |  | 95,463 | 115,595
Gross Unrealized Gain |  | 3 | 28
Gross Unrealized Loss |  | (4,388) | (5,159)
Fair Value |  | 95,463 | 101,396
Amortized Cost |  |  | 15,272
Gross Unrealized Gain |  |  | 0
Gross Unrealized Loss |  |  | (1,073)
Fair Value |  |  | 14,199
Interest-Only-Strip [Member] |  |  |
Debt Securities, Trading and Available-for-sale [Abstract] |  |  |
Amortized Cost | [1] | 117,591 | 167,314
Non-Agency other, Amortized Cost |  | 81,854 | 126,672
Fair Value | [1] | 114,386 | 159,718
Gross Unrealized Gain |  | 3,280 | 1,296
Gross Unrealized Loss |  | (4,137) | (6,014)
Fair Value |  | 80,997 | 121,954
Amortized Cost |  | 35,737 | 40,642
Gross Unrealized Gain |  | 0 | 2
Gross Unrealized Loss |  | (2,348) | (2,880)
Fair Value |  | 33,389 | 37,764
Interest-Only-Strip [Member] | Agency Securities |  |  |
Debt Securities, Trading and Available-for-sale [Abstract] |  |  |
Par Value |  | 6,196,778 | 7,723,379
Interest-Only-Strip, Non-Agency CMBS [Member] |  |  |
Debt Securities, Trading and Available-for-sale [Abstract] |  |  |
Par Value |  | 2,450,398 | 3,860,007
Non-Agency MBS |  |  |
Debt Securities, Trading and Available-for-sale [Abstract] |  |  |
Par Value |  | 0 | 150
Non-Agency other, Amortized Cost |  | 0 | 150
Gross Unrealized Gain |  |  | 0
Gross Unrealized Loss |  |  | (47)
Fair Value |  | $ 0 | $ 103
[1] | (1) The notional balance for Agency CMBS IO and non-Agency CMBS IO was $6,196,778 and $2,450,398, respectively, as of December 31, 2024, and $7,723,379 and $3,860,007, respectively, as of December 31, 2023.

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