Equity Method Investments - Summary of Financial Information Related to Moelis Australia (Details) - USD ($) $ in Thousands		12 Months Ended
	Apr. 10, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Equity Method Investments
Income (loss) from equity method investments		$ 7,162	$ 8,341	$ 5,076
Moelis Australia Holdings
Equity Method Investments
Total revenues		91,222	83,602	41,292
Total expenses		(69,688)	(62,187)	(34,526)
Net Income (loss)		21,534	21,415	6,766
Income (loss) from equity method investments	$ (2,400)	7,162	8,366	$ 3,383
Total assets		261,513	222,514
Total liabilities		(91,799)	(54,100)
Net equity		$ 169,714	$ 168,414