Investments (Loss) Gain on Securities, Net of Investment Income (Details) (USD $) In Thousands	3 Months Ended				9 Months Ended
	Sep. 30, 2011		Sep. 30, 2010		Sep. 30, 2011		Sep. 30, 2010
(Loss) Gain on Investments [Line Items]
(Loss) gain on securities, net	$ (2,293)	[1]	$ 3,426	[1]	$ 515	[1]	$ 835	[1]
Available-for-sale Securities [Member]
(Loss) Gain on Investments [Line Items]
Realized Gains	223	[2]	10	[2]	2,310	[2]	35	[2]
Realized losses	0	[2]	0	[2]	0	[2]	(2)	[2]
Trading Securities [Member]
(Loss) Gain on Investments [Line Items]
Unrealized (loss) gain	(1,963)		2,201		(1,688)		(438)
Realized Gains	92	[2]	797	[2]	704	[2]	1,986	[2]
Realized losses	(214)	[2]	(58)	[2]	(529)	[2]	(682)	[2]
Derivatives [Member]
(Loss) Gain on Investments [Line Items]
Unrealized (loss) gain	(163)		239		(270)		363
Realized Gains	23	[2],[3]	297	[2],[3]	429	[2],[3]	308	[2],[3]
Realized losses	(291)	[2],[3]	(60)	[2],[3]	(441)	[2],[3]	(735)	[2],[3]
Consolidated Investment Companies [Member]
(Loss) Gain on Investments [Line Items]
(Loss) gain on securities, net	$ (2,300)		$ 2,600		$ (1,700)		$ 100

[1] (Loss) gain on securities, net related to consolidated investment companies totaled $(2.3) million and $2.6 million for the three months ended September 30, 2011 and 2010, respectively, and $(1.7) million and $0.1 million for the nine months ended September 30, 2011 and 2010, respectively.

[2] Realized gains and losses are computed on a specific-identification basis.

[3] These items relate to the settlement of economic derivatives held by certain consolidated sponsored products.