Segment Reporting (Schedule of Operating Information, Segment) (Details) (USD $) In Thousands	3 Months Ended				9 Months Ended
	Sep. 30, 2011		Sep. 30, 2010		Sep. 30, 2011		Sep. 30, 2010
Net revenues	$ 334,214	[1]	$ 340,388	[1]	$ 1,059,684	[1]	$ 980,427	[1]
Income/(loss) before income taxes	39,023		(142,556)		93,582		(67,046)
Global Wealth Management [Member]
Net revenues	219,498	[1]	207,484	[1]	683,589	[1]	606,845	[1]
Income/(loss) before income taxes	55,612		51,707		172,510		131,306
Institutional Group [Member]
Net revenues	113,259	[1]	138,043	[1]	373,168	[1]	375,937	[1]
Income/(loss) before income taxes	9,152		27,654		52,496		85,879
Other [Member]
Net revenues	1,457	[1]	(5,139)	[1]	2,927	[1]	(2,355)	[1]
Income/(loss) before income taxes	$ (25,741)		$ (221,917)		$ (131,424)		$ (284,231)

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