CONSOLIDATION (Variable Interest Entities) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Variable Interest Entity [Line Items]
Assets of consolidated VIEs	$ 12,014,196	$ 10,154,692	$ 8,563,522
Liabilities of consolidated VIEs	10,155,598	8,760,351	7,103,230
Net income attributable to non-controlling interests related to consolidated VIEs			35,915
Investments in CLO warehouse
Variable Interest Entity [Line Items]
Maximum exposure to loss attributable to the Company's investment in VIEs	104,700
Consolidated Funds
Variable Interest Entity [Line Items]
Net income attributable to non-controlling interests related to consolidated VIEs	39,704	20,512	$ 60,818
Non-Consolidated Variable Interest Entities
Variable Interest Entity [Line Items]
Maximum exposure to loss attributable to the Company's investment in VIEs	260,520	222,477
Consolidated VIEs
Variable Interest Entity [Line Items]
Maximum exposure to loss attributable to the Company's investment in VIEs	181,856	186,455
Consolidated VIEs | Consolidated Funds
Variable Interest Entity [Line Items]
Assets of consolidated VIEs	9,454,572	8,141,280
Liabilities of consolidated VIEs	$ 8,679,869	$ 7,479,383