Segment Reporting (Schedule Of Operating Information, Segment) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012 item	Dec. 31, 2011	Dec. 31, 2010
Number of business segments									3
Number of businesses within reportable segment									2
Net revenues	$ 417,830	$ 420,080	$ 374,407	$ 400,333	$ 356,878	$ 334,214	$ 358,857	$ 366,613	$ 1,612,650	$ 1,416,562	$ 1,382,026
Income before income tax expense	61,067	61,677	43,874	59,254	45,026	39,023	3,875	50,684	225,872	138,608	(229)
Net revenues accounted for by individual client, maximum percentage										10.00%
Global Wealth Management [Member]
Net revenues									995,189	908,158	843,269
Income before income tax expense									268,183	235,382	194,023
Institutional Group [Member]
Net revenues									618,536	507,397	541,839
Income before income tax expense									96,167	63,269	129,535
Other [Member]
Net revenues									(1,075)	1,007	(3,082)
Income before income tax expense									$ (138,478)	$ (160,043)	$ (323,787)