Segment Reporting (Schedule Of Operating Information, Segment) (Details) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($) Segment	Sep. 30, 2015 USD ($)
Segment Reporting Information [Line Items]
Number of business segments | Segment				3
Net revenues	[1]	$ 641,986	$ 591,575	$ 1,914,105	$ 1,750,308
Income/(loss) before income taxes		$ 27,982	$ 22,348	$ 87,688	$ 130,485
Net revenues accounted for by individual client, maximum percentage		10.00%	10.00%	10.00%	10.00%
Global Wealth Management [Member]
Segment Reporting Information [Line Items]
Number of businesses within reportable segment | Segment				2
Net revenues	[1]	$ 390,032	$ 357,306	$ 1,155,875	$ 1,030,097
Income/(loss) before income taxes		109,079	97,227	307,466	290,049
Institutional Group [Member]
Segment Reporting Information [Line Items]
Net revenues	[1]	258,800	232,125	760,996	729,269
Income/(loss) before income taxes		44,923	25,853	116,628	100,124
Other [Member]
Segment Reporting Information [Line Items]
Net revenues	[1]	(6,846)	2,144	(2,766)	(9,058)
Income/(loss) before income taxes		$ (126,020)	$ (100,732)	$ (336,406)	$ (259,688)

[1] No individual client accounted for more than 10 percent of total net revenues for the three and nine months ended September 30, 2016 or 2015.