Segment Information (Summary Of Certain Operating Information For Reportable Segments) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Segment Reporting Information [Line Items]
Total net interest income	$ 144,006	$ 130,713
Total net interest income, Change in Contribution	13,293
Total net interest income, Change in Contribution Percentage	10.00%
Total non-interest income	45,529	57,379
Total non-interest income, Change in Contribution	(11,850)
Total non-interest income, Change in Contribution Percentage	(21.00%)
Total net revenue	189,535	188,092
Total net revenue, Change in Contribution	1,443
Total net revenue, Change in Contribution Percentage	1.00%
Total segment profit	34,500	32,052
Total segment profit, Change in Contribution	2,448
Total segment profit, Change in Contribution Percentage	8.00%
Total assets	18,221,163	17,074,247	18,097,783
Total segment assets, Change in Contribution	1,146,916
Total segment assets, Change in Contribution Percentage	7.00%
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total net interest income	140,066	127,159
Total net interest income, Change in Contribution	12,907
Total net interest income, Change in Contribution Percentage	10.00%
Total non-interest income	52,141	63,348
Total non-interest income, Change in Contribution	(11,207)
Total non-interest income, Change in Contribution Percentage	(18.00%)
Total net revenue	192,207	190,507
Total net revenue, Change in Contribution	1,700
Total net revenue, Change in Contribution Percentage	1.00%
Operating Segments [Member] | Community banking
Segment Reporting Information [Line Items]
Total net interest income	116,755	106,230
Total net interest income, Change in Contribution	10,525
Total net interest income, Change in Contribution Percentage	10.00%
Total non-interest income	27,319	40,601
Total non-interest income, Change in Contribution	(13,282)
Total non-interest income, Change in Contribution Percentage	(33.00%)
Total net revenue	144,074	146,831
Total net revenue, Change in Contribution	(2,757)
Total net revenue, Change in Contribution Percentage	(2.00%)
Total segment profit	22,581	20,979
Total segment profit, Change in Contribution	1,602
Total segment profit, Change in Contribution Percentage	8.00%
Total assets	15,160,507	14,295,418
Total segment assets, Change in Contribution	865,089
Total segment assets, Change in Contribution Percentage	6.00%
Operating Segments [Member] | Specialty finance
Segment Reporting Information [Line Items]
Total net interest income	19,212	17,482
Total net interest income, Change in Contribution	1,730
Total net interest income, Change in Contribution Percentage	10.00%
Total non-interest income	7,881	7,305
Total non-interest income, Change in Contribution	576
Total non-interest income, Change in Contribution Percentage	8.00%
Total net revenue	27,093	24,787
Total net revenue, Change in Contribution	2,306
Total net revenue, Change in Contribution Percentage	9.00%
Total segment profit	8,982	8,629
Total segment profit, Change in Contribution	353
Total segment profit, Change in Contribution Percentage	4.00%
Total assets	2,532,362	2,291,140
Total segment assets, Change in Contribution	241,222
Total segment assets, Change in Contribution Percentage	11.00%
Operating Segments [Member] | Wealth management
Segment Reporting Information [Line Items]
Total net interest income	4,099	3,447
Total net interest income, Change in Contribution	652
Total net interest income, Change in Contribution Percentage	19.00%
Total non-interest income	16,941	15,442
Total non-interest income, Change in Contribution	1,499
Total non-interest income, Change in Contribution Percentage	10.00%
Total net revenue	21,040	18,889
Total net revenue, Change in Contribution	2,151
Total net revenue, Change in Contribution Percentage	11.00%
Total segment profit	2,937	2,444
Total segment profit, Change in Contribution	493
Total segment profit, Change in Contribution Percentage	20.00%
Total assets	528,294	487,689
Total segment assets, Change in Contribution	40,605
Total segment assets, Change in Contribution Percentage	8.00%
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Total net interest income	3,940	3,554
Total net interest income, Change in Contribution	386
Total net interest income, Change in Contribution Percentage	11.00%
Total non-interest income	(6,612)	(5,969)
Total non-interest income, Change in Contribution	(643)
Total non-interest income, Change in Contribution Percentage	(11.00%)
Total net revenue	(2,672)	(2,415)
Total net revenue, Change in Contribution	$ (257)
Total net revenue, Change in Contribution Percentage	(11.00%)