Business Segment Information (Amounts Of Consolidated Revenue, Expense, Tax And Assets) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Segment Reporting Information [Line Items]
Net interest income	$ 166,640,000	$ 156,768,000	$ 323,506,000	$ 309,127,000
Provision for loan losses	2,000,000	5,000,000	7,000,000	15,000,000
Noninterest income	130,301,000	126,901,000	259,990,000	272,631,000
Noninterest expense	218,394,000	163,162,000	594,615,000	381,206,000
Income/(loss) before income taxes	76,547,000	115,507,000	(18,119,000)	185,552,000
Provision/(benefit) for income taxes	21,590,000	33,578,000	(671,000)	53,644,000
Net income/(loss)	54,957,000	81,929,000	(17,448,000)	131,908,000
Average assets	25,414,048,000	23,647,298,000	25,528,689,000	23,778,347,000
Regional Banking [Member]
Segment Reporting Information [Line Items]
Net interest income	165,908,000	148,675,000	320,317,000	290,701,000
Provision for loan losses	17,078,000	8,425,000	21,993,000	21,415,000
Noninterest income	65,989,000	66,227,000	126,193,000	126,219,000
Noninterest expense	144,203,000	132,996,000	279,983,000	265,539,000
Income/(loss) before income taxes	70,616,000	73,481,000	144,534,000	129,966,000
Provision/(benefit) for income taxes	24,996,000	26,070,000	51,377,000	46,153,000
Net income/(loss)	45,620,000	47,411,000	93,157,000	83,813,000
Average assets	15,023,869,000	13,053,129,000	14,628,188,000	12,835,470,000
Fixed Income [Member]
Segment Reporting Information [Line Items]
Net interest income	4,297,000	2,587,000	8,620,000	6,063,000
Noninterest income	56,001,000	47,564,000	117,566,000	104,323,000
Noninterest expense	51,214,000	116,000	105,897,000	52,714,000
Income/(loss) before income taxes	9,084,000	50,035,000	20,289,000	57,672,000
Provision/(benefit) for income taxes	3,171,000	19,143,000	7,338,000	21,986,000
Net income/(loss)	5,913,000	30,892,000	12,951,000	35,686,000
Average assets	2,416,132,000	2,074,593,000	2,431,118,000	2,056,581,000
Corporate [Member]
Segment Reporting Information [Line Items]
Net interest income	(17,376,000)	(11,968,000)	(33,460,000)	(21,891,000)
Noninterest income	3,901,000	5,215,000	9,286,000	18,430,000
Noninterest expense	13,770,000	13,532,000	27,939,000	30,859,000
Income/(loss) before income taxes	(27,245,000)	(20,285,000)	(52,113,000)	(34,320,000)
Provision/(benefit) for income taxes	(15,882,000)	(16,369,000)	(27,522,000)	(26,997,000)
Net income/(loss)	(11,363,000)	(3,916,000)	(24,591,000)	(7,323,000)
Average assets	5,565,279,000	5,341,568,000	5,987,666,000	5,595,768,000
Non Strategic [Member]
Segment Reporting Information [Line Items]
Net interest income	13,811,000	17,474,000	28,029,000	34,254,000
Provision for loan losses	(15,078,000)	(3,425,000)	(14,993,000)	(6,415,000)
Noninterest income	4,410,000	7,895,000	6,945,000	23,659,000
Noninterest expense	9,207,000	16,518,000	180,796,000	32,094,000
Income/(loss) before income taxes	24,092,000	12,276,000	(130,829,000)	32,234,000
Provision/(benefit) for income taxes	9,305,000	4,734,000	(31,864,000)	12,502,000
Net income/(loss)	14,787,000	7,542,000	(98,965,000)	19,732,000
Average assets	$ 2,408,768,000	$ 3,178,008,000	$ 2,481,717,000	$ 3,290,528,000