DERIVATIVES AND HEDGING - Impact of Derivatives Held by Consolidated Funds on Income (Details) - Not Designated as Hedging Instrument - Consolidated Funds - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Foreign-currency forward contracts
Derivatives, Fair Value [Line Items]
Net Realized Gain (Loss) on Investments	$ 214	$ (2,507)	$ 2,340	$ (1,068)
Net Change in Unrealized Appreciation (Depreciation) on Investments	1,158	(465)	688	(1,176)
Total-return and interest-rate swaps
Derivatives, Fair Value [Line Items]
Net Realized Gain (Loss) on Investments	0	838	0	858
Net Change in Unrealized Appreciation (Depreciation) on Investments	0	115	0	29
Options and futures
Derivatives, Fair Value [Line Items]
Net Realized Gain (Loss) on Investments	0	(1,771)	0	47
Net Change in Unrealized Appreciation (Depreciation) on Investments	$ 0	$ 960	$ 0	$ (113)

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=109980867&loc=SL5618551-113959

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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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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=118932676&loc=d3e3602-108585

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