Fair Value of Financial Instruments - Valuation for Level 3 Assets (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2024	Mar. 31, 2023
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 3,327,211	$ 3,801,370
Fair Value, Assets and Liabilities Measured on Recurring Basis, Gain (Loss) Included in Earnings [Abstract]
Included in earnings	(9,009)	54,963
Transfers out	(21,066)	(326)
Transfers to securitization trust, net	0	0
Funding/Contributions		21,948
Paydowns/Distributions	(241,006)	(294,927)
Sales	(28,912)	(166)
Purchases	305,735	88,521
Balance at the end of period	$ 3,332,953	$ 3,671,383
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Operating Income (Expense), Net	Other Operating Income (Expense), Net
Residential loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 827,535	$ 1,081,384
Fair Value, Assets and Liabilities Measured on Recurring Basis, Gain (Loss) Included in Earnings [Abstract]
Included in earnings	(2,924)	(599)
Transfers out	(18,180)	(93)
Transfers to securitization trust, net	(370,804)	(86,110)
Funding/Contributions		0
Paydowns/Distributions	(62,718)	(141,355)
Sales	(22,204)	(166)
Purchases	290,024	67,939
Balance at the end of period	640,729	921,000
Residential loans \| Consolidated SLST \| VIE, Primary Beneficiary
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	754,860	827,582
Fair Value, Assets and Liabilities Measured on Recurring Basis, Gain (Loss) Included in Earnings [Abstract]
Included in earnings	(138)	15,121
Transfers out	0	0
Transfers to securitization trust, net	0	0
Funding/Contributions		0
Paydowns/Distributions	(16,596)	(13,550)
Sales	0	0
Purchases	0	0
Balance at the end of period	738,126	829,153
Residential loans held in securitization trusts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	1,501,908	1,616,114
Fair Value, Assets and Liabilities Measured on Recurring Basis, Gain (Loss) Included in Earnings [Abstract]
Included in earnings	(1,773)	33,041
Transfers out	(2,886)	(233)
Transfers to securitization trust, net	370,804	86,110
Funding/Contributions		0
Paydowns/Distributions	(152,806)	(130,911)
Sales	(6,708)	0
Purchases	15,711	20,582
Balance at the end of period	1,724,250	1,624,703
Multi-family loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	95,792	87,534
Fair Value, Assets and Liabilities Measured on Recurring Basis, Gain (Loss) Included in Earnings [Abstract]
Included in earnings	(2,137)	2,889
Transfers out	0	0
Transfers to securitization trust, net	0	0
Funding/Contributions		6,420
Paydowns/Distributions	(1,750)	(1,534)
Sales	0	0
Purchases	0	0
Balance at the end of period	91,905	95,309
Equity investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	147,116	179,746
Fair Value, Assets and Liabilities Measured on Recurring Basis, Gain (Loss) Included in Earnings [Abstract]
Included in earnings	(2,037)	3,451
Transfers out	0	0
Transfers to securitization trust, net	0	0
Funding/Contributions		15,528
Paydowns/Distributions	(7,136)	(7,577)
Sales	0	0
Purchases	0	0
Balance at the end of period	$ 137,943	191,148
Equity investments in disposal group held for sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period		9,010
Fair Value, Assets and Liabilities Measured on Recurring Basis, Gain (Loss) Included in Earnings [Abstract]
Included in earnings		1,060
Transfers out		0
Transfers to securitization trust, net		0
Funding/Contributions		0
Paydowns/Distributions		0
Sales		0
Purchases		0
Balance at the end of period		$ 10,070

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Funding/Contributions

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- Definition

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers Out of Level 3 to Out of Securitization Trust, Net

+ References

No definition available.

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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- Definition

Amount of gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

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- Definition

Amount of purchases of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

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- Definition

Amount of sale of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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- Definition

Amount of settlement of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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- Definition

Amount of transfers of financial instrument classified as an asset out of level 3 of the fair value hierarchy.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(3)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

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- Definition

Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-SubTopic 10
-Topic 820
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

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- Definition

Indicates line item in statement in which net income is reported that includes gain (loss) from asset measured at fair value using unobservable input (level 3).

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