Non-Controlling Interests (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Noncontrolling Interest [Line Items]
Net Income Attributable to Non-Controlling Interests	$ 13,438	$ 15,185	$ 39,209	$ 43,213
Non-Controlling Interests of Pzena Investment Management, LLC
Noncontrolling Interest [Line Items]
Net Income Attributable to Non-Controlling Interests	13,434	15,169	39,039	43,200
Non-Controlling Interests of Consolidated Subsidiaries
Noncontrolling Interest [Line Items]
Net Income Attributable to Non-Controlling Interests	$ 4	$ 16	$ 170	$ 13