DERIVATIVES AND HEDGING - Impact of Derivatives Held by Consolidated Funds on Income (Details) - Consolidated Funds - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Foreign-currency forward contracts
Derivatives, Fair Value [Line Items]
Net Realized Gain (Loss) on Investments	$ 192	$ (4,300)	$ (11,200)	$ (1,960)
Net Change in Unrealized Appreciation (Depreciation) on Investments	417	(276)	(23,483)	412
Options and futures
Derivatives, Fair Value [Line Items]
Net Realized Gain (Loss) on Investments	(114)	0	(4)	0
Net Change in Unrealized Appreciation (Depreciation) on Investments	(40)	0	(157)	0
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Net Realized Gain (Loss) on Investments	146	(4,300)	(11,136)	(1,960)
Net Change in Unrealized Appreciation (Depreciation) on Investments	371	(276)	(23,646)	412
Not Designated as Hedging Instrument \| Foreign-currency forward contracts
Derivatives, Fair Value [Line Items]
Net Realized Gain (Loss) on Investments	192	(4,300)	(11,200)	(1,960)
Net Change in Unrealized Appreciation (Depreciation) on Investments	417	(276)	(23,483)	412
Not Designated as Hedging Instrument \| Total-return and interest-rate and credit default swaps
Derivatives, Fair Value [Line Items]
Net Realized Gain (Loss) on Investments	68	0	68	0
Net Change in Unrealized Appreciation (Depreciation) on Investments	(6)	0	(6)	0
Not Designated as Hedging Instrument \| Options and futures
Derivatives, Fair Value [Line Items]
Net Realized Gain (Loss) on Investments	(114)	0	(4)	0
Net Change in Unrealized Appreciation (Depreciation) on Investments	$ (40)	$ 0	$ (157)	$ 0

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5618551-113959

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The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of derivative instruments, including options, swaps, futures, and forward contracts, held at each balance sheet date, that was included in earnings for the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

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