Goodwill and Identifiable Intangible Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Goodwill and Identifiable Intangible Assets
Goodwill	$ 106,970	$ 106,970
Mutual fund management advisory contracts	42,748	42,753
Mutual fund management subadvisory contracts	8,400	8,400
Total identifiable intangible assets	51,148	51,153
Total goodwill and identifiable intangible assets	$ 158,118	$ 158,123