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Securities, at Fair Value (Residential Mortgage Securities) (Details) - USD ($) $ in Thousands | Sep. 30, 2021 | Dec. 31, 2020
--- | --- | ---
Debt Securities, Available-for-sale [Line Items] |  |  |
Fair Value | [1] | $ 283,037 | $ 399,999
Residential Mortgage Securities |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Principal/ Current Face |  | 102,307 | 161,878
Purchase Premiums |  | 6,163 | 3,022
Accretable Purchase Discounts |  | (59) | (8,206)
Discount Designated as Credit Reserve and OTTI |  | (20,768) | (21,437)
Amortized Cost |  | 87,643 | 135,257
Gross Unrealized Gains |  | 17,853 | 26,926
Gross Unrealized Losses |  | (8) | (1,183)
Net Unrealized Gain/(Loss) |  | 17,845 | 25,743
Fair Value |  | 105,488 | 161,000
RPL/NPL MBS |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Principal/ Current Face |  |  | 55,000
Amortized Cost |  |  | 46,900
Fair Value |  |  | $ 53,900
Expected to Recover Less Than Par |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Percentage of current face amount of Non-Agency MBS to be recovered |  |  | 99.00%
CRT, Fair Value Option |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Gross Unrealized Gains |  | 2,200 | $ 551
Gross Unrealized Losses |  | (8) | (322)
Fair Value |  | $ 68,000 | $ 66,200
[1] | See Note 6 for information regarding the Company’s pledged assets.

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