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Summary of Significant Accounting Policies - Residential Whole Loans (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2025	Dec. 31, 2024
Accounts, Notes, Loans and Financing Receivable [Line Items]
LTV ratio (as a percent)	80.00%
Residential whole loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
LTV ratio (as a percent)	64.00%
Residential whole loans | Business purpose loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
LTV ratio (as a percent)	67.00%	67.00%
Residential whole loans | Business purpose loans | Multifamily Properties
Accounts, Notes, Loans and Financing Receivable [Line Items]
Threshold balance (below)	$ 10

X

- Definition

Financing Receivable, Threshold Balance

+ References

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- Definition

The LTV of which the Company has assessed its residential whole loans at carrying value will have a higher likelihood of default than newly originated mortgage loans

+ References

No definition available.

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 310
-SubTopic 20
-Name Accounting Standards Codification
-Section 40
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481628/310-20-40-7

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481990/310-10-45-2

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