Residential Whole Loans - Allowance for Credit Losses (Details) - Residential whole loans - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 10,665	$ 20,451
Current provision/(reversal)	145	(460)
Write-offs	(616)	(379)
Ending balance	10,194	19,612
Business purpose loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	3,139,060		$ 3,396,181
Business purpose loans \| Single-family transitional loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	1,389	2,587
Current provision/(reversal)	(88)	(472)
Write-offs	(436)	(416)
Ending balance	865	1,699
Business purpose loans \| Single-family transitional loans \| Collateral Dependent Methodology
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	11,000	21,900
Business purpose loans \| Single-family rental loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	1,312,993		1,356,400
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	366	4,355
Current provision/(reversal)	614	228
Write-offs	0	59
Ending balance	980	4,642
Business purpose loans \| Single-family rental loans \| Collateral Dependent Methodology
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans		10,600
Non-QM loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	4,540,553		4,291,086
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	2,125	1,871
Current provision/(reversal)	(197)	(190)
Write-offs	0	0
Ending balance	1,928	1,681
Legacy RPL/NPL loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	1,061,802		$ 1,082,549
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	6,785	11,638
Current provision/(reversal)	(184)	(26)
Write-offs	(180)	(22)
Ending balance	6,421	11,590
Legacy RPL/NPL loans \| Collateral Dependent Methodology
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	$ 37,000	$ 50,500

Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease.

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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/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph c
-Publisher SEC

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

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+ References

No definition available.

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- Definition

Amount, excluding accrued interest, of decrease (increase) in allowance for credit loss on financing receivable from writeoff (recovery). Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

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- Definition

Amortized cost excluding accrued interest, before allowance for credit loss, of financing receivable. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479344/326-20-45-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-3B

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-5

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- Definition

Amount, excluding accrued interest, of credit loss expense (reversal of expense) on financing receivable. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

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