Segment Reporting (Schedule of Operating Information, Segment) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2011		Jun. 30, 2010		Jun. 30, 2011		Jun. 30, 2010
Net revenues	$ 358,857	[1]	$ 328,009	[1]	$ 725,470	[1]	$ 640,039	[1]
Income/(loss) before income taxes	3,875		35,945		54,559		75,510
Maximum Percentage of Total Net Revenues	10.00%		10.00%		10.00%		10.00%
Global Wealth Management [Member]
Net revenues	225,645	[1]	199,940	[1]	464,091	[1]	399,361	[1]
Income/(loss) before income taxes	55,426		40,441		116,898		79,599
Institutional Group [Member]
Net revenues	132,915	[1]	124,602	[1]	259,909	[1]	237,894	[1]
Income/(loss) before income taxes	21,951		30,769		43,344		58,225
Other [Member]
Net revenues	297	[1]	3,467	[1]	1,470	[1]	2,784	[1]
Income/(loss) before income taxes	$ (73,502)		$ (35,265)		$ (105,683)		$ (62,314)

[1] No individual client accounted for more than 10 percent of total net revenues for the three and six months ended June 30, 2011 or 2010.