Segment Reporting (Schedule Of Operating Information, Segment) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Net revenues	[1]	$ 913,034	$ 770,420
Income/(loss) before income taxes		115,106	137,809
Global Wealth Management [Member]
Segment Reporting Information [Line Items]
Net revenues	[1]	582,956	510,610
Income/(loss) before income taxes		194,167	194,490
Institutional Group [Member]
Segment Reporting Information [Line Items]
Net revenues	[1]	332,238	261,286
Income/(loss) before income taxes		41,740	32,204
Other Segments [Member]
Segment Reporting Information [Line Items]
Net revenues	[1]	(2,160)	(1,476)
Income/(loss) before income taxes		$ (120,801)	$ (88,885)

[1] No individual client accounted for more than 10 percent of total net revenues for the three months ended March 31, 2020 or 2019.