Earnings per Share - Diluted Net Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Diluted Net Income [Abstract]
Less: Net Income Attributable to Non-Controlling Interests	$ 22,474	$ 10,651	$ 43,316	$ 11,420
Net Income of Pzena Investment Management, Inc.	4,603	2,198	8,790	2,198
Diluted Net Income	21,176	9,997	40,906	10,749
Pzena Investment Management, LLC
Diluted Net Income [Abstract]
Net Income Attributable to Non-Controlling Interests	22,225	10,417	42,873	11,500
Less: Assumed Corporate Income Taxes	5,652	2,618	10,757	2,949
Less: Net Income Attributable to Non-Controlling Interests	16,573	7,799	32,116	8,551
Net Income of Pzena Investment Management, Inc.	4,603	2,198	8,790	2,198
Diluted Net Income	$ 21,176	$ 9,997	$ 40,906	$ 10,749