Non-Controlling Interests (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Noncontrolling Interest [Line Items]
Net Income Attributable to Non-Controlling Interests	$ 12,931	$ 13,885	$ 25,771	$ 28,028
Non-Controlling Interests of Pzena Investment Management, LLC
Noncontrolling Interest [Line Items]
Net Income Attributable to Non-Controlling Interests	12,893	13,918	25,605	28,031
Non-Controlling Interests of Consolidated Subsidiaries
Noncontrolling Interest [Line Items]
Net Income Attributable to Non-Controlling Interests	$ 38	$ (33)	$ 166	$ (3)