EARNINGS PER CLASS A SHARE (Schedule of Basic and Diluted Net Loss per Share of Class A Common Stock) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Numerator
Net loss attributable to Medley Management Inc.	$ (122)	$ (516)	$ (2,066)	$ (770)
Less: Fair value adjustment to redeemable non-controlling interest (Note 17)	0	0	(147)	0
Participating Securities
Numerator
Less: Allocation of earnings to participating securities		8	72	1
Common Class A
Numerator
Net loss available to Class A common stockholders	$ (122)	$ (508)	$ (2,141)	$ (769)
Denominator
Weighted average shares of Class A common stock outstanding (in shares)	639,216	589,933	631,620	583,449
Net income (loss) per Class A common stock, Basic (in dollars per share)	$ (0.19)	$ (0.86)	$ (3.39)	$ (1.32)