Consolidated Sponsored Investment Products - Derivative Instruments (Details) - Consolidated Sponsored Investment Products [Member] $ in Thousands	Dec. 31, 2015 USD ($)
Options [Member] | Long [Member]
Derivative [Line Items]
Volume	$ 3,015
Options [Member] | Short [Member]
Derivative [Line Items]
Volume	755
Futures [Member]
Derivative [Line Items]
Volume	278
Forward foreign currency exchange [Member] | Long [Member]
Derivative [Line Items]
Volume	5,591
Forward foreign currency exchange [Member] | Short [Member]
Derivative [Line Items]
Volume	29,069
Interest rate swaps [Member]
Derivative [Line Items]
Volume	69,094
Other swaps [Member]
Derivative [Line Items]
Volume	$ 35,180