Business Segment Information (Amounts Of Consolidated Revenue, Expense, Tax And Assets) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Segment Reporting Information [Line Items]
Net interest income	$ 189,708	$ 172,074
Provision/(provision credit) for loan losses	(1,000)	3,000
Noninterest income	116,939	134,305
Noninterest expense	222,205	226,927
Income/(loss) before income taxes	85,442	76,452
Provision/(benefit) for income taxes	27,054	24,239
Net income/(loss)	58,388	52,213
Average assets	28,806,106	26,618,694
Regional Banking [Member]
Segment Reporting Information [Line Items]
Net interest income	193,389	172,312
Provision/(provision credit) for loan losses	3,098	14,767
Noninterest income	58,976	59,276
Noninterest expense	148,065	145,399
Income/(loss) before income taxes	101,202	71,422
Provision/(benefit) for income taxes	36,623	25,407
Net income/(loss)	64,579	46,015
Average assets	17,955,319	15,945,192
Fixed Income [Member]
Segment Reporting Information [Line Items]
Net interest income	1,151	2,667
Noninterest income	50,822	67,122
Noninterest expense	48,685	58,623
Income/(loss) before income taxes	3,288	11,166
Provision/(benefit) for income taxes	1,024	3,892
Net income/(loss)	2,264	7,274
Average assets	1,875,708	2,269,678
Corporate [Member]
Segment Reporting Information [Line Items]
Net interest income	(14,100)	(14,363)
Noninterest income	5,476	5,723
Noninterest expense	16,880	13,461
Income/(loss) before income taxes	(25,504)	(22,101)
Provision/(benefit) for income taxes	(13,093)	(11,246)
Net income/(loss)	(12,411)	(10,855)
Average assets	7,359,015	6,362,224
Non Strategic [Member]
Segment Reporting Information [Line Items]
Net interest income	9,268	11,458
Provision/(provision credit) for loan losses	(4,098)	(11,767)
Noninterest income	1,665	2,184
Noninterest expense	8,575	9,444
Income/(loss) before income taxes	6,456	15,965
Provision/(benefit) for income taxes	2,500	6,186
Net income/(loss)	3,956	9,779
Average assets	$ 1,616,064	$ 2,041,600