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Investment In Unconsolidated Affiliate (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Apr. 01, 2021	Mar. 31, 2021
Investments in and Advances to Affiliates [Line Items]
Distributions received from unconsolidated affiliate			$ 68,064	$ 73,241
Company's share in the earnings of equity method investee	$ 35,065	$ 28,276	68,415	58,183
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	47,420		47,420
Distributions received from unconsolidated affiliate			68,064	73,241
Company's share in the earnings of equity method investee	$ 35,065	$ 28,276	$ 68,415	$ 58,183