New Accounting Guidance (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred Taxes
Available-for-sale Securities	$ 41,377	$ 161,270
Accounting Standards Update 2015-17 | Adjustments for New Accounting Principle, Early Adoption | Scenario, Previously Reported
Deferred Taxes
Current deferred tax assets		7,500
Non Current deferred tax assets		20,000
Accounting Standards Update 2015-17 | Adjustments for New Accounting Principle, Early Adoption | Restatement Adjustment
Deferred Taxes
Non Current deferred tax assets		27,500
Sponsored privately offered funds measured at net asset value
Deferred Taxes
Available-for-sale Securities	$ 825	3,810
Sponsored privately offered funds measured at net asset value | Accounting Standards Update 2015-07 | Adjustments for New Accounting Principle, Early Adoption | Scenario, Previously Reported
Deferred Taxes
Available-for-sale Securities		3,800
Sponsored privately offered funds measured at net asset value | Accounting Standards Update 2015-07 | Adjustments for New Accounting Principle, Early Adoption | Restatement Adjustment
Deferred Taxes
Available-for-sale Securities		$ 3,800