Segment Reporting (Schedule Of Operating Information, Segment) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Net revenues	[1]	$ 738,342	$ 721,169	$ 2,231,432	$ 2,122,347
Income/(loss) before income taxes		140,530	108,139	378,431	270,356
Global Wealth Management [Member]
Segment Reporting Information [Line Items]
Net revenues	[1]	498,161	453,558	1,481,063	1,348,280
Income/(loss) before income taxes		183,377	161,756	548,043	457,045
Institutional Group [Member]
Segment Reporting Information [Line Items]
Net revenues	[1]	245,952	264,747	768,855	778,367
Income/(loss) before income taxes		34,305	51,717	114,899	144,481
Other [Member]
Segment Reporting Information [Line Items]
Net revenues	[1]	(5,771)	2,864	(18,486)	(4,300)
Income/(loss) before income taxes		$ (77,152)	$ (105,334)	$ (284,511)	$ (331,170)

[1] No individual client accounted for more than 10 percent of total net revenues for the three and nine months ended September 30, 2018 or 2017.