Investment In Unconsolidated Affiliate (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Investments in and Advances to Affiliates [Line Items]
Distributions received from unconsolidated affiliate			$ 138,216	$ 117,447
Company's share in the earnings of equity method investee	$ 41,726	$ 39,333	$ 123,406	109,213
LSV Asset Management
Investments in and Advances to Affiliates [Line Items]
Equity method investment, ownership percentage	38.90%		38.90%
Total investment in equity method investee	$ 44,682		$ 44,682
Distributions received from unconsolidated affiliate			138,216	117,447
Company's share in the earnings of equity method investee	$ 41,726	$ 39,333	$ 123,406	$ 109,213

Amount of distribution received from equity method investee for return on investment, classified as operating activities. Excludes distribution for return of investment, classified as investing activities.

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