Segment Reporting (Schedule Of Operating Information, Segment) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 item	Sep. 30, 2011
Number of business segments			3
Number of businesses within reportable segment			2
Net revenues	$ 420,080	$ 334,214	$ 1,194,820	$ 1,059,684
Income before income tax expense	61,677	39,023	164,805	93,582
Net revenues accounted for by individual client, maximum percentage	10.00%	10.00%	10.00%	10.00%
Global Wealth Management [Member]
Net revenues	251,728	219,498	740,105	683,589
Income before income tax expense	68,370	55,612	198,901	172,510
Institutional Group [Member]
Net revenues	169,679	113,259	453,480	373,168
Income before income tax expense	33,427	9,152	74,677	52,496
Other [Member]
Net revenues	(1,327)	1,457	1,235	2,927
Income before income tax expense	$ (40,120)	$ (25,741)	$ (108,773)	$ (131,424)