Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Oct. 19, 2017
Entity Registrant Name	Moelis & Co
Entity Central Index Key	0001596967
Document Type	10-Q
Document Period End Date	Sep. 30, 2017
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	Q3
Class A common stock
Entity Common Stock, Shares Outstanding		33,297,858
Class B common stock
Entity Common Stock, Shares Outstanding		20,045,736