Consolidated Sponsored Investment Products - Derivative Instruments (Details) - Consolidated Sponsored Investment Products [Member] $ in Thousands	Sep. 30, 2015 USD ($)
Options [Member] | Long [Member]
Derivative [Line Items]
Volume	$ 3,527
Options [Member] | Short [Member]
Derivative [Line Items]
Volume	2,499
Futures [Member]
Derivative [Line Items]
Volume	109,286
Forward foreign currency exchange [Member] | Long [Member]
Derivative [Line Items]
Volume	2,294
Forward foreign currency exchange [Member] | Short [Member]
Derivative [Line Items]
Volume	26,565
Interest rate swaps [Member]
Derivative [Line Items]
Volume	31,603
Other swaps [Member]
Derivative [Line Items]
Volume	$ 27,956