Segments (Schedule Of Financial Information By Segment) (Details)	3 Months Ended		9 Months Ended				12 Months Ended
	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($)		Sep. 30, 2014 USD ($)		Dec. 31, 2014
Segment Reporting Information [Line Items]
Segment Reporting Information, Intersegment Revenue	$ 0	$ 0	$ 0		$ 0
Number of operating segments			3				3
Net interest income	162,038,000	154,716,000	$ 471,833,000		468,275,000
Provision for loan losses	(8,364,000)	(7,652,000)	(19,541,000)		(24,867,000)
Non-interest income	111,148,000	112,286,000	331,666,000		323,676,000
Investment securities gains (losses), net	(378,000)	2,995,000	7,800,000	[1]	10,474,000	[1]
Non-interest expense	(171,262,000)	(161,840,000)	(500,279,000)		(486,355,000)
Income before income taxes	93,182,000	100,505,000	291,479,000		291,203,000
Consumer Segment [Member]
Segment Reporting Information [Line Items]
Net interest income	67,083,000	66,565,000	199,265,000		198,533,000
Provision for loan losses	(8,605,000)	(8,306,000)	(25,500,000)		(25,816,000)
Non-interest income	30,809,000	29,699,000	87,409,000		84,331,000
Investment securities gains (losses), net	0	0	0		0
Non-interest expense	(69,196,000)	(65,900,000)	(203,446,000)		(197,220,000)
Income before income taxes	20,091,000	22,058,000	57,728,000		59,828,000
Commercial Segment [Member]
Segment Reporting Information [Line Items]
Net interest income	74,008,000	72,019,000	218,386,000		214,406,000
Provision for loan losses	166,000	863,000	842,000		803,000
Non-interest income	47,485,000	47,689,000	144,684,000		142,326,000
Investment securities gains (losses), net	0	0	0		0
Non-interest expense	(68,710,000)	(63,542,000)	(199,027,000)		(188,223,000)
Income before income taxes	52,949,000	57,029,000	164,885,000		169,312,000
Wealth Segment [Member]
Segment Reporting Information [Line Items]
Net interest income	10,391,000	9,811,000	31,921,000		29,713,000
Provision for loan losses	106,000	(29,000)	114,000		463,000
Non-interest income	34,042,000	33,368,000	102,336,000		94,870,000
Investment securities gains (losses), net	0	0	0		0
Non-interest expense	(27,211,000)	(23,833,000)	(81,498,000)		(72,606,000)
Income before income taxes	17,328,000	19,317,000	52,873,000		52,440,000
Segment Totals [Member]
Segment Reporting Information [Line Items]
Net interest income	151,482,000	148,395,000	449,572,000		442,652,000
Provision for loan losses	(8,333,000)	(7,472,000)	(24,544,000)		(24,550,000)
Non-interest income	112,336,000	110,756,000	334,429,000		321,527,000
Investment securities gains (losses), net	0	0	0		0
Non-interest expense	(165,117,000)	(153,275,000)	(483,971,000)		(458,049,000)
Income before income taxes	90,368,000	98,404,000	275,486,000		281,580,000
Other Elimination [Member]
Segment Reporting Information [Line Items]
Net interest income	10,556,000	6,321,000	22,261,000		25,623,000
Provision for loan losses	(31,000)	(180,000)	5,003,000		(317,000)
Non-interest income	(1,188,000)	1,530,000	(2,763,000)		2,149,000
Investment securities gains (losses), net	(378,000)	2,995,000	7,800,000		10,474,000
Non-interest expense	(6,145,000)	(8,565,000)	(16,308,000)		(28,306,000)
Income before income taxes	$ 2,814,000	$ 2,101,000	$ 15,993,000		$ 9,623,000

[1] Available for sale and non-marketable securities