FAIR VALUE - Financial Instruments by Fair-value Hierarchy Level (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	$ 11,913	$ 6,890
Derivative liabilities	(27,475)	(4,254)
Oaktree Capital Group Excluding Consolidated Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments	29,736	34,934
Oaktree Capital Group Excluding Consolidated Funds | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	40,655	44,260
Oaktree Capital Group Excluding Consolidated Funds | Fair Value, Measurements, Recurring | Foreign-currency forward contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	3,295	0
Derivative liabilities	0	(1,703)
Oaktree Capital Group Excluding Consolidated Funds | Fair Value, Measurements, Recurring | U.S. Treasury and other securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments	8,611	9,232
Oaktree Capital Group Excluding Consolidated Funds | Fair Value, Measurements, Recurring | Corporate investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments	28,749	35,028
Oaktree Capital Group Excluding Consolidated Funds | Fair Value, Measurements, Recurring | Level I
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	8,611	9,232
Oaktree Capital Group Excluding Consolidated Funds | Fair Value, Measurements, Recurring | Level I | Foreign-currency forward contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Oaktree Capital Group Excluding Consolidated Funds | Fair Value, Measurements, Recurring | Level I | U.S. Treasury and other securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments	8,611	9,232
Oaktree Capital Group Excluding Consolidated Funds | Fair Value, Measurements, Recurring | Level I | Corporate investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments	0	0
Oaktree Capital Group Excluding Consolidated Funds | Fair Value, Measurements, Recurring | Level II
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	6,361	4,717
Oaktree Capital Group Excluding Consolidated Funds | Fair Value, Measurements, Recurring | Level II | Foreign-currency forward contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	3,295	0
Derivative liabilities	0	(1,703)
Oaktree Capital Group Excluding Consolidated Funds | Fair Value, Measurements, Recurring | Level II | Foreign-currency forward contracts | Corporate investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities		(94)
Oaktree Capital Group Excluding Consolidated Funds | Fair Value, Measurements, Recurring | Level II | U.S. Treasury and other securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments	0	0
Oaktree Capital Group Excluding Consolidated Funds | Fair Value, Measurements, Recurring | Level II | Corporate investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments	3,066	4,717
Oaktree Capital Group Excluding Consolidated Funds | Fair Value, Measurements, Recurring | Level III
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	25,683	30,311
Oaktree Capital Group Excluding Consolidated Funds | Fair Value, Measurements, Recurring | Level III | Foreign-currency forward contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Oaktree Capital Group Excluding Consolidated Funds | Fair Value, Measurements, Recurring | Level III | U.S. Treasury and other securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments	0	0
Oaktree Capital Group Excluding Consolidated Funds | Fair Value, Measurements, Recurring | Level III | Corporate investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments	$ 25,683	$ 30,311