Fair Value of Financial Instruments - Valuation for Level 3 Assets (Details) $ in Thousands	6 Months Ended
Jun. 30, 2022 USD ($) securitization	Jun. 30, 2021 USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 3,935,253	$ 3,471,854
Total (losses)/gains (realized/unrealized)
Included in earnings	(176,272)	38,670
Transfers out	(1,855)	(2,674)
Transfers to securitization trust	0	0
Funding/Contributions	19,191	320
Paydowns/Distributions	(672,386)	(561,143)
Sales	0	(17,944)
Purchases	1,555,737	605,076
Balance at the end of period	4,659,668	3,534,159
Consolidated SLST \| VIE, Primary Beneficiary \| Residential loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	1,070,882	1,266,785
Total (losses)/gains (realized/unrealized)
Included in earnings	(79,292)	(21,788)
Transfers out	0	0
Transfers to securitization trust	0	0
Funding/Contributions	0	0
Paydowns/Distributions	(70,812)	(68,458)
Sales	0	0
Purchases	0	0
Balance at the end of period	920,778	1,176,539
Residential loans \| Residential loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	1,703,290	1,090,930
Total (losses)/gains (realized/unrealized)
Included in earnings	(52,976)	14,494
Transfers out	(875)	(1,259)
Transfers to securitization trust	(676,560)	(160,623)
Funding/Contributions	0	0
Paydowns/Distributions	(293,564)	(306,209)
Sales	0	(15,568)
Purchases	1,514,004	605,076
Balance at the end of period	$ 2,193,319	1,226,841
Number of securitizations completed \| securitization	2
Residential loans held in securitization trusts \| Residential loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 801,429	691,451
Total (losses)/gains (realized/unrealized)
Included in earnings	(65,935)	21,105
Transfers out	(980)	(1,415)
Transfers to securitization trust	676,560	160,623
Funding/Contributions	0	0
Paydowns/Distributions	(237,712)	(70,025)
Sales	0	(2,376)
Purchases	41,733	0
Balance at the end of period	1,215,095	799,363
Multi-family loans \| Multi-family loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	120,021	163,593
Total (losses)/gains (realized/unrealized)
Included in earnings	6,298	10,853
Transfers out	0	0
Transfers to securitization trust	0	0
Funding/Contributions	0	0
Paydowns/Distributions	(19,494)	(47,727)
Sales	0	0
Purchases	0	0
Balance at the end of period	106,825	126,719
Equity investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period		259,095
Total (losses)/gains (realized/unrealized)
Included in earnings		14,006
Funding/Contributions		320
Paydowns/Distributions		(68,724)
Equity investments \| Equity investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	239,631	259,095
Total (losses)/gains (realized/unrealized)
Included in earnings	15,633	14,006
Transfers out	0	0
Transfers to securitization trust	0	0
Funding/Contributions	19,191	320
Paydowns/Distributions	(50,804)	(68,724)
Sales	0	0
Purchases	0	0
Balance at the end of period	$ 223,651	$ 204,697

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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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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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
-Publisher FASB
-Name Accounting Standards Codification
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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.

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

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-Publisher FASB
-Name Accounting Standards Codification
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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.

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