Business Segment Information (Amounts Of Consolidated Revenue, Expense, Tax And Assets) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Segment Reporting Information [Line Items]
Net interest income	$ 172,074,000	$ 156,866,000
Provision/(provision credit) for loan losses	3,000,000	5,000,000
Noninterest income	134,305,000	129,689,000
Noninterest expense	226,927,000	376,221,000
Income/(loss) before income taxes	76,452,000	(94,666,000)
Provision/(benefit) for income taxes	24,239,000	(22,261,000)
Net income/(loss)	52,213,000	(72,405,000)
Average assets	26,618,694,000	25,641,934,000
Regional Banking [Member]
Segment Reporting Information [Line Items]
Net interest income	172,326,000	154,412,000
Provision/(provision credit) for loan losses	14,767,000	4,915,000
Noninterest income	59,275,000	60,180,000
Noninterest expense	145,355,000	135,444,000
Income/(loss) before income taxes	71,479,000	74,233,000
Provision/(benefit) for income taxes	25,429,000	26,504,000
Net income/(loss)	46,050,000	47,729,000
Average assets	15,944,097,000	14,225,092,000
Fixed Income [Member]
Segment Reporting Information [Line Items]
Net interest income	2,664,000	4,319,000
Noninterest income	67,122,000	61,564,000
Noninterest expense	58,668,000	54,741,000
Income/(loss) before income taxes	11,118,000	11,142,000
Provision/(benefit) for income taxes	3,874,000	4,143,000
Net income/(loss)	7,244,000	6,999,000
Average assets	2,270,144,000	2,447,259,000
Corporate [Member]
Segment Reporting Information [Line Items]
Net interest income	(14,374,000)	(16,080,000)
Noninterest income	5,723,000	5,385,000
Noninterest expense	13,477,000	14,362,000
Income/(loss) before income taxes	(22,128,000)	(25,057,000)
Provision/(benefit) for income taxes	(11,257,000)	(11,714,000)
Net income/(loss)	(10,871,000)	(13,343,000)
Average assets	6,362,533,000	6,412,346,000
Non Strategic [Member]
Segment Reporting Information [Line Items]
Net interest income	11,458,000	14,215,000
Provision/(provision credit) for loan losses	(11,767,000)	85,000
Noninterest income	2,185,000	2,560,000
Noninterest expense	9,427,000	171,674,000
Income/(loss) before income taxes	15,983,000	(154,984,000)
Provision/(benefit) for income taxes	6,193,000	(41,194,000)
Net income/(loss)	9,790,000	(113,790,000)
Average assets	$ 2,041,920,000	$ 2,557,237,000