LOANS - Corporate Debt Held for Investment (Details) - Corporate Loans - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance		$ 2,239,930	$ 2,152,213
Originations & advances	$ 1,572,718	1,061,644
Sales and transfers	(1,205,965)	(353,090)
Principal payments	(661,941)	(576,759)
Amortization & accretion of (premium) discounts	12,617	12,206
Loan restructuring		(16,732)
Allowance for loan losses
Beginning allowance	(39,552)	(7,363)
Current period (allowance) reversal	11,632	(14,429)
Write offs		11,893
Ending allowance	(27,920)	(39,552)
Net carrying value	1,968,991	2,239,930
Cumulative effect of change in accounting principle for credit losses
Allowance for loan losses
Beginning allowance		(29,653)
First lien loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance		1,489,125	1,403,503
Originations & advances	1,506,705	834,211
Sales and transfers	(1,122,275)	(273,887)
Principal payments	(492,884)	(444,759)
Amortization & accretion of (premium) discounts	9,120	8,374
Loan restructuring		(19,550)
Allowance for loan losses
Beginning allowance	(18,767)	(7,363)
Current period (allowance) reversal	1,426	(12,510)
Write offs		11,893
Ending allowance	(17,341)	(18,767)
Net carrying value	1,391,217	1,489,125
First lien loans \| Cumulative effect of change in accounting principle for credit losses
Allowance for loan losses
Beginning allowance		(10,787)
Second Lien
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance		750,805	$ 748,710
Originations & advances	66,013	227,433
Sales and transfers	(83,690)	(79,203)
Principal payments	(169,057)	(132,000)
Amortization & accretion of (premium) discounts	3,497	3,832
Loan restructuring		2,818
Allowance for loan losses
Beginning allowance	(20,785)	0
Current period (allowance) reversal	10,206	(1,919)
Write offs		0
Ending allowance	(10,579)	(20,785)
Net carrying value	$ 577,774	750,805
Second Lien \| Cumulative effect of change in accounting principle for credit losses
Allowance for loan losses
Beginning allowance		$ (18,866)

Mortgage Loans on Real Estate, Restructuring

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- Definition

SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Excluding Loan Loss Allowance

+ References

No definition available.

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- Definition

Amount of decrease in investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate, from collection of principal.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Footnote 6
-Subsection 29

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 948
-SubTopic 310
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Footnote 6))
-URI http://asc.fasb.org/extlink&oid=120402547&loc=d3e617274-123014

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- Definition

The net increase(decrease) in interest income during the period representing the allocation of deferred loan origination fees less deferred loan origination costs using the effective interest method over the term of the debt arrangement to which they pertain taking into account the effect of prepayments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 20
-Section 35
-Paragraph 2
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3602-108585

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Amount of allowance for credit loss for debt security measured at amortized cost (held-to-maturity).

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
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-Paragraph 13
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Amount of writeoff of investment in debt security, measured at amortized cost (held-to-maturity), charged against allowance for credit loss.

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- Definition

Amount of expense (reversal of expense) for expected credit loss on investment in debt security measured at amortized cost (held-to-maturity).

+ References

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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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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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- Definition

Amount of investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 948
-SubTopic 310
-Section S99
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- Definition

Amount of decrease in investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate, from sale.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 310
-Section S99
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- Definition

Amount of addition to investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate, classified as other.

+ References

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-Publisher FASB
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