VARIABLE INTEREST ENTITIES - Additional Information (Details) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020 USD ($) entity	Dec. 31, 2019 USD ($) entity
Variable Interest Entity [Line Items]
Consolidated VIEs representing funds and CLOs, assets	$ 9,118,704	$ 9,264,762
Consolidated VIEs representing funds and CLOs, liabilities	$ 6,861,274	$ 6,696,371
Consolidated VIEs
Variable Interest Entity [Line Items]
Number of VIE's consolidated (in entity) | entity	22	22
Consolidated VIEs representing funds and CLOs, assets	$ 7,400,000
Consolidated VIEs representing funds and CLOs, liabilities	6,600,000
Maximum exposure to loss	$ 538,600
Number of fund managed by Oaktree | Consolidated VIEs
Variable Interest Entity [Line Items]
Number of VIE's consolidated (in entity) | entity	9
Number of CLO's for which Oaktree acts as collateral manager | Consolidated VIEs
Variable Interest Entity [Line Items]
Number of VIE's consolidated (in entity) | entity	13
Number of remaining variable interest entities | Consolidated VIEs
Variable Interest Entity [Line Items]
Number of VIE's consolidated (in entity) | entity	22