Short-Term Debt - Collateral for Short-Term Debt Facilities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Short-term Debt [Line Items]
Total collateral for financing	$ 1,899,357	$ 2,450,304
Facilities
Short-term Debt [Line Items]
Total real estate securities owned	97,322	99,005
Other assets	1,962	1,962
Total collateral for financing	1,562,735	2,107,451
Servicer advance financing
Short-term Debt [Line Items]
Total collateral for financing	336,622	342,853
Cash	9,615	6,480
Restricted cash	24,170	25,420
Servicer advances	302,837	310,953
Held-for-sale residential loans \| Facilities
Short-term Debt [Line Items]
Market value of loans pledged as collateral under short-term borrowing agreements	1,334,272	1,838,797
Business purpose loans \| Facilities
Short-term Debt [Line Items]
Market value of loans pledged as collateral under short-term borrowing agreements	129,179	167,687
On balance sheet \| Facilities
Short-term Debt [Line Items]
Available-for-sale securities pledged as collateral	5,539	5,823
Sequoia \| Sequoia securities \| Short Term Borrowing Agreement \| Facilities
Short-term Debt [Line Items]
Trading securities pledged as collateral	59,862	61,525
Freddie Mac K-Series \| Sequoia securities \| Short Term Borrowing Agreement \| Facilities
Short-term Debt [Line Items]
Trading securities pledged as collateral	$ 31,921	$ 31,657

Restricted Cash and Other Assets Pledged as Collateral

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Restricted Cash Collateral For Borrowed Securities

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- Definition

Servicer Advances Collateral

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- Definition

Short-term Debt Pledged as Collateral

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Carrying amount as of the balance sheet date of cash collateral held for borrowed securities, for which the cash is restricted as to withdrawal or usage.

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Amount of restricted investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of restricted investment in debt security measured at fair value with change in fair value recognized in net income (trading).

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Carrying amount as of the balance sheet date of loans that have been pledged as collateral for borrowings. If the secured party has the right by contract or custom to sell or re-pledge the collateral, then the debtor reclassifies that asset and report that asset in its statement of financial position separately from other assets not so encumbered.

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The sum of the fair values, as of the date of each statement of financial position presented, of securities that are restricted as collateral for the payment of related debt obligations, primarily secured borrowings and repurchase agreements, and that are reclassified and separately reported in the statement of financial position because the transferee has the right by contract or custom to sell or re-pledge them.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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