CONSOLIDATION (Variable Interest Entities) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Variable Interest Entity [Line Items]
Assets of consolidated VIEs	$ 14,928,993		$ 14,928,993		$ 12,014,196
Liabilities of consolidated VIEs	12,458,673		12,458,673		10,155,598
Investments in CLO warehouse
Variable Interest Entity [Line Items]
Maximum exposure to loss attributable to the Company's investment in VIEs	94,000		94,000		104,700
Consolidated Funds
Variable Interest Entity [Line Items]
Net income attributable to non-controlling interests	42,627	$ 15,908	(38,593)	$ 41,878
Non-Consolidated Variable Interest Entities
Variable Interest Entity [Line Items]
Maximum exposure to loss attributable to the Company's investment in VIEs	233,394		233,394		260,520
Consolidated VIEs
Variable Interest Entity [Line Items]
Maximum exposure to loss attributable to the Company's investment in VIEs	168,603		168,603		181,856
Consolidated VIEs | Consolidated Funds
Variable Interest Entity [Line Items]
Assets of consolidated VIEs	11,217,650		11,217,650		9,454,572
Liabilities of consolidated VIEs	$ 10,568,273		$ 10,568,273		$ 8,679,869