Investment In Unconsolidated Affiliate (Statement of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Schedule of Equity Method Investments [Line Items]
Revenues	$ 424,927	$ 416,254	$ 1,240,335	$ 1,226,660
Equity Method Investment, Nonconsolidated Investee | LSV Asset Management
Schedule of Equity Method Investments [Line Items]
Revenues	94,902	121,232	289,546	365,164
Net income	$ 70,440	$ 96,699	$ 220,184	$ 289,918