Earnings per Share - Diluted Net Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Diluted Net Income [Abstract]
Less: Net Income Attributable to Non-Controlling Interests	$ 12,910	$ 13,438	$ 24,330	$ 39,209
Net Income of Pzena Investment Management, Inc.	2,664	3,478	4,862	9,944
Diluted Net Income	12,374	13,768	23,119	39,793
Pzena Investment Management, LLC
Diluted Net Income [Abstract]
Net Income Attributable to Non-Controlling Interests	12,827	13,434	24,327	39,039
Less: Assumed Corporate Income Taxes	3,117	3,144	6,070	9,190
Less: Net Income Attributable to Non-Controlling Interests	9,710	10,290	18,257	29,849
Net Income of Pzena Investment Management, Inc.	2,664	3,478	4,862	9,944
Diluted Net Income	$ 12,374	$ 13,768	$ 23,119	$ 39,793