Segment Reporting (Schedule Of Operating Information, Segment) (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Segment Reporting Information [Line Items]
Net revenues		$ 793,449	$ 738,342	$ 742,732	$ 750,358	$ 804,085	$ 721,169	$ 725,647	$ 675,531	$ 3,024,881	[1]	$ 2,926,432	[1]	$ 2,575,496	[1]
Income/(loss) before income taxes										534,362		269,536		142,582
Global Wealth Management [Member]
Segment Reporting Information [Line Items]
Net revenues	[1]									1,990,319		1,822,218		1,563,410
Income/(loss) before income taxes										737,003		626,906		430,318
Institutional Group [Member]
Segment Reporting Information [Line Items]
Net revenues	[1]									1,055,495		1,110,768		1,014,164
Income/(loss) before income taxes										157,051		217,981		164,143
Other Segments [Member]
Segment Reporting Information [Line Items]
Net revenues	[1]									(20,933)		(6,554)		(2,078)
Income/(loss) before income taxes										$ (359,692)		$ (575,351)		$ (451,879)

[1] No individual client accounted for more than 10 percent of total net revenues for the years ended December 31, 2018, 2017, and 2016.