Consolidated Sponsored Investment Products - Derivatives, Net Gains (Losses) (Details) - Consolidated Sponsored Investment Products [Member] - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses)	$ 878	$ 2,031
Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses)	(217)	(75)
Foreign Exchange Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses)	263	666
Equity Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses)	633	1,414
Commodity Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses)	212	126
Credit Risk Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses)	$ (13)	$ (100)