Segment Reporting (Schedule Of Operating Information, Segment) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended	9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Jun. 30, 2013 item	Sep. 30, 2013		Sep. 30, 2012
Number of business segments					3
Number of businesses within reportable segment					2
Net revenues	$ 478,639	[1]	$ 414,157	[1]		$ 1,410,921	[1]	$ 1,182,830	[1]
Income before income tax expense	31,008		61,174			107,241		169,396
Net revenues accounted for by individual client, maximum percentage						10.00%
Global Wealth Management [Member]
Net revenues	274,669	[1]	250,914	[1]		824,344	[1]	737,822	[1]
Income before income tax expense	72,128		68,020			220,551		197,933
Institutional Group [Member]
Net revenues	205,132	[1]	164,611	[1]		593,875	[1]	443,961	[1]
Income before income tax expense	34,986		33,201			94,298		79,809
Other [Member]
Net revenues	(1,162)	[1]	(1,368)	[1]		(7,298)	[1]	1,047	[1]
Income before income tax expense	$ (76,106)		$ (40,047)			$ (207,608)		$ (108,346)

[1] No individual client accounted for more than 10 percent of total net revenues for the three and nine months ended September 30, 2013 or 2012.