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Investment In Unconsolidated Affiliate (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Apr. 01, 2021	Mar. 31, 2021
Investments in and Advances to Affiliates [Line Items]
Distributions received from unconsolidated affiliate			$ 110,559	$ 107,180
Company's share in the earnings of equity method investee	$ 35,005	$ 28,305	103,420	86,488
LSV Asset Management
Investments in and Advances to Affiliates [Line Items]
Equity method investment, ownership percentage					38.70%	38.80%
Total investment in equity method investee	39,872		39,872
Distributions received from unconsolidated affiliate			110,559	107,180
Company's share in the earnings of equity method investee	$ 35,005	$ 28,305	$ 103,420	$ 86,488