EQUITY COMPENSATION - Equity Incentive Plan (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Jan. 01, 2021
Equity compensation
Equity-based compensation expense	$ 65,991	$ 30,336	$ 191,144	$ 91,576
Restricted units
Equity compensation
Equity-based compensation expense	36,390	30,036	127,219	86,804
Restricted units with a market condition
Equity compensation
Equity-based compensation expense	29,601	300	63,925	4,729
Options
Equity compensation
Equity-based compensation expense	$ 0	$ 0	$ 0	$ 43
Ares Management L.P
Equity compensation
Total number of shares available for grant under the equity incentive plan (in shares)	38,972,964		38,972,964		44,510,451