Real Estate Securities - Trading Securities by Collateral Type (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Debt and Equity Securities, FV-NI [Line Items]
Real estate securities, at fair value	$ 102,220		$ 40,424
Unpaid principal balance	16,370		16,567
Fair value of securities acquired	47,526	$ 1,700
Fair value of securities sold	0	3,509
Net market valuation gains (losses) recorded	14,475	$ 1,961
Senior
Debt and Equity Securities, FV-NI [Line Items]
Real estate securities, at fair value	97,955		36,109
Unpaid principal balance	0		0
Subordinate
Debt and Equity Securities, FV-NI [Line Items]
Real estate securities, at fair value	4,265		4,315
Unpaid principal balance	16,370		16,567
Interest-only securities \| Senior
Debt and Equity Securities, FV-NI [Line Items]
Real estate securities, at fair value	97,955		36,109
Interest-only securities \| Senior \| Sequoia
Debt and Equity Securities, FV-NI [Line Items]
Real estate securities, at fair value	32,000		28,000
Multifamily securities \| Subordinate
Debt and Equity Securities, FV-NI [Line Items]
Real estate securities, at fair value	2,714		2,641
Other third-party residential securities \| Subordinate
Debt and Equity Securities, FV-NI [Line Items]
Real estate securities, at fair value	$ 1,551		$ 1,674

Amount of increase (decrease) of investment in debt and equity securities, measured at fair value with changes in fair value recognized in net income.

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Amount of principal of investment owned.

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Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading) and investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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