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Mortgage-Backed Securities - Unrealized Gain (Loss) on Investments (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
Investments [Line Items] |  |  |
Unrealized gain (loss) on investments, net | $ 142,501 | $ (213,022) | $ (14,814)
Residential Mortgage Backed Securities [Member] | Agency MBS |  |  |
Investments [Line Items] |  |  |
Unrealized loss on debt securities |  | (208,129) | (14,917)
Residential Mortgage Backed Securities [Member] | Agency MBS |  |  |
Investments [Line Items] |  |  |
Unrealized loss on debt securities | 141,263 |  |
Commercial Mortgage Backed Securities [Member] | Agency MBS |  |  |
Investments [Line Items] |  |  |
Unrealized loss on debt securities |  | (1,169) | 0
Commercial Mortgage Backed Securities [Member] | Agency MBS |  |  |
Investments [Line Items] |  |  |
Unrealized loss on debt securities | 96 |  |
Interest-Only-Strip [Member] |  |  |
Investments [Line Items] |  |  |
Unrealized loss on debt securities | 1,111 | (3,924) | (65)
Asset-backed Securities, Securitized Loans and Receivables |  |  |
Investments [Line Items] |  |  |
Unrealized gain (loss) on other investments | $ 31 | $ 200 | $ 168

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