Segment Information (Summary Of Certain Operating Information For Reportable Segments) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Segment Reporting Information [Line Items]
Total net interest income	$ 141,782	$ 132,575	$ 408,319	$ 386,740
Total net interest income, Change in Contribution	9,207		21,579
Total net interest income, Change in Contribution Percentage	7.00%		6.00%
Total non-interest income	54,662	62,945	176,036	160,903
Total non-interest income, Change in Contribution	(8,283)		15,133
Total non-interest income, Change in Contribution Percentage	(13.00%)		9.00%
Total net revenue	196,444	195,520	584,355	547,643
Total net revenue, Change in Contribution	924		36,712
Total net revenue, Change in Contribution Percentage	0.00%		7.00%
Total segment profit	35,563	32,302	101,922	81,107
Total segment profit, Change in Contribution	3,261		20,815
Total segment profit, Change in Contribution Percentage	10.00%		26.00%
Total assets	17,682,548	17,018,592	17,682,548	17,018,592	17,519,613
Total segment assets, Change in Contribution	663,956
Total segment assets, Change in Contribution Percentage	4.00%
Operating Segments [Member] | Community banking
Segment Reporting Information [Line Items]
Total net interest income	133,378	124,684	384,327	368,834
Total net interest income, Change in Contribution	8,694		15,493
Total net interest income, Change in Contribution Percentage	7.00%		4.00%
Total non-interest income	37,727	48,912	120,211	117,717
Total non-interest income, Change in Contribution	(11,185)		2,494
Total non-interest income, Change in Contribution Percentage	(23.00%)		2.00%
Total net revenue	171,105	173,596	504,538	486,551
Total net revenue, Change in Contribution	(2,491)		17,987
Total net revenue, Change in Contribution Percentage	(1.00%)		4.00%
Total segment profit	36,279	39,663	104,153	96,052
Total segment profit, Change in Contribution	(3,384)		8,101
Total segment profit, Change in Contribution Percentage	(9.00%)		8.00%
Total assets	17,375,033	16,877,673	17,375,033	16,877,673
Total segment assets, Change in Contribution	497,360
Total segment assets, Change in Contribution Percentage	3.00%
Operating Segments [Member] | Specialty finance
Segment Reporting Information [Line Items]
Total net interest income	32,742	32,182	95,292	88,462
Total net interest income, Change in Contribution	560		6,830
Total net interest income, Change in Contribution Percentage	2.00%		8.00%
Total non-interest income	2,125	1,074	5,607	4,012
Total non-interest income, Change in Contribution	1,051		1,595
Total non-interest income, Change in Contribution Percentage	98.00%		40.00%
Total net revenue	34,867	33,256	100,899	92,474
Total net revenue, Change in Contribution	1,611		8,425
Total net revenue, Change in Contribution Percentage	5.00%		9.00%
Total segment profit	14,826	12,967	42,438	36,401
Total segment profit, Change in Contribution	1,859		6,037
Total segment profit, Change in Contribution Percentage	14.00%		17.00%
Total assets	4,222,537	3,796,745	4,222,537	3,796,745
Total segment assets, Change in Contribution	425,792
Total segment assets, Change in Contribution Percentage	11.00%
Operating Segments [Member] | Wealth management
Segment Reporting Information [Line Items]
Total net interest income	1,624	524	5,284	4,940
Total net interest income, Change in Contribution	1,100		344
Net Interest income Not Meaningful Variance	NM
Total net interest income, Change in Contribution Percentage			7.00%
Total non-interest income	19,044	16,115	55,971	47,316
Total non-interest income, Change in Contribution	2,929		8,655
Total non-interest income, Change in Contribution Percentage	18.00%		18.00%
Total net revenue	20,668	16,639	61,255	52,256
Total net revenue, Change in Contribution	4,029		8,999
Total net revenue, Change in Contribution Percentage	24.00%		17.00%
Total segment profit	2,702	1,317	8,093	5,297
Total segment profit, Change in Contribution	1,385		2,796
Operating Income Loss Not Meaningful Variance	NM
Total segment profit, Change in Contribution Percentage			53.00%
Total assets	101,707	95,128	101,707	95,128
Total segment assets, Change in Contribution	6,579
Total segment assets, Change in Contribution Percentage	7.00%
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Total net interest income	(25,962)	(24,815)	(76,584)	(75,496)
Total net interest income, Change in Contribution	(1,147)		(1,088)
Total net interest income, Change in Contribution Percentage	(5.00%)		(1.00%)
Total non-interest income	(4,234)	(3,156)	(5,753)	(8,142)
Total non-interest income, Change in Contribution	(1,078)		2,389
Total non-interest income, Change in Contribution Percentage	(34.00%)		29.00%
Total net revenue	(30,196)	(27,971)	(82,337)	(83,638)
Total net revenue, Change in Contribution	(2,225)		1,301
Total net revenue, Change in Contribution Percentage	(8.00%)		2.00%
Total segment profit	(18,244)	(21,645)	(52,762)	(56,643)
Total segment profit, Change in Contribution	3,401		3,881
Total segment profit, Change in Contribution Percentage	16.00%		7.00%
Total assets	(4,016,729)	(3,750,954)	(4,016,729)	(3,750,954)
Total segment assets, Change in Contribution	$ (265,775)
Total segment assets, Change in Contribution Percentage	(7.00%)