Document And Entity Information - shares	9 Months Ended
	Sep. 30, 2020	Nov. 10, 2020
Document Information [Line Items]
Entity Registrant Name	MEDLEY MANAGEMENT INC.
Entity Central Index Key	0001611110
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Entity Emerging Growth Company	false
Entity Small Business	true
Common Class A
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		669,753
Common Class B
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		100