Goodwill and Identifiable Intangible Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Goodwill and identifiable intangible assets
Goodwill	$ 106,970	$ 106,970
Other	200	200
Total identifiable intangible assets	40,999	41,599
Total goodwill and identifiable intangible assets	147,969	148,569
Mutual fund management advisory contracts
Goodwill and identifiable intangible assets
Mutual fund contracts	38,699	38,699
Mutual fund management subadvisory contracts
Goodwill and identifiable intangible assets
Mutual fund contracts	$ 2,100	$ 2,700