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Residential Mortgage Securities and MSR-Related Assets (Unrealized Losses) (Details) $ in Thousands | Dec. 31, 2020 USD ($) security | Dec. 31, 2019 USD ($)
--- | --- | ---
Fair Value |  |
Less than 12 Months | $ 103,391 |
12 Months or more | 0 |
Total | 103,391 |
Unrealized Losses |  |
Less than 12 Months | 1,183 |
12 Months or more | 0 |
Total | $ 1,183 |
Number of Securities |  |
Less than 12 months (in security) | security | 12 |
12 months or more (in security) | security | 0 |
Fair Value | $ 161,000 | $ 3,983,519
Gross unrealized losses | 1,183 | 18,818
Non-Agency MBS |  |
Fair Value |  |
Less than 12 Months | 41,139 |
12 Months or more | 0 |
Total | 41,139 |
Unrealized Losses |  |
Less than 12 Months | 861 |
12 Months or more | 0 |
Total | $ 861 |
Number of Securities |  |
Less than 12 months (in security) | security | 4 |
12 months or more (in security) | security | 0 |
Fair Value | $ 56,766 | 2,063,529
Gross unrealized losses | 861 | 18
CRT securities |  |
Fair Value |  |
Less than 12 Months | 62,252 |
12 Months or more | 0 |
Total | 62,252 |
Unrealized Losses |  |
Less than 12 Months | 322 |
12 Months or more | 0 |
Total | $ 322 |
Number of Securities |  |
Less than 12 months (in security) | security | 8 |
12 months or more (in security) | security | 0 |
Fair Value | $ 104,234 | 255,408
Gross unrealized losses | 322 | $ 91
CRT in Loss Positions Only, Fair Value Option |  |
Number of Securities |  |
Fair Value | 62,200 |
Gross unrealized losses | $ 322,000 |

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