Segment Information (Summary Of Certain Operating Information For Reportable Segments) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Segment Reporting Information [Line Items]
Total net interest income	$ 130,713	$ 125,895
Total net interest income, Change in Contribution	4,818
Total net interest income, Change in Contribution Percentage	4.00%
Total non-interest income	57,379	47,023
Total non-interest income, Change in Contribution	10,356
Total non-interest income, Change in Contribution Percentage	22.00%
Total net revenue	188,092	172,918
Total net revenue, Change in Contribution	15,174
Total net revenue, Change in Contribution Percentage	9.00%
Total segment profit	32,052	23,210
Total segment profit, Change in Contribution	8,842
Total segment profit, Change in Contribution Percentage	38.00%
Total assets	17,074,247	16,172,018	17,519,613
Total segment assets, Change in Contribution	902,229
Total segment assets, Change in Contribution Percentage	6.00%
Community Banking [Member]
Segment Reporting Information [Line Items]
Total net interest income	123,434	121,134
Total net interest income, Change in Contribution	2,300
Total net interest income, Change in Contribution Percentage	2.00%
Total non-interest income	39,882	31,786
Total non-interest income, Change in Contribution	8,096
Total non-interest income, Change in Contribution Percentage	25.00%
Total net revenue	163,316	152,920
Total net revenue, Change in Contribution	10,396
Total net revenue, Change in Contribution Percentage	7.00%
Total segment profit	33,647	26,975
Total segment profit, Change in Contribution	6,672
Total segment profit, Change in Contribution Percentage	25.00%
Total assets	16,743,196	15,640,198
Total segment assets, Change in Contribution	1,102,998
Total segment assets, Change in Contribution Percentage	7.00%
Specialty Finance [Member]
Segment Reporting Information [Line Items]
Total net interest income	31,090	27,586
Total net interest income, Change in Contribution	3,504
Total net interest income, Change in Contribution Percentage	13.00%
Total non-interest income	1,693	1,371
Total non-interest income, Change in Contribution	322
Total non-interest income, Change in Contribution Percentage	23.00%
Total net revenue	32,783	28,957
Total net revenue, Change in Contribution	3,826
Total net revenue, Change in Contribution Percentage	13.00%
Total segment profit	13,774	12,465
Total segment profit, Change in Contribution	1,309
Total segment profit, Change in Contribution Percentage	11.00%
Total assets	3,932,552	3,387,001
Total segment assets, Change in Contribution	545,551
Total segment assets, Change in Contribution Percentage	16.00%
Wealth Management [Member]
Segment Reporting Information [Line Items]
Total net interest income	1,264	1,724
Total net interest income, Change in Contribution	(460)
Total net interest income, Change in Contribution Percentage	(27.00%)
Total non-interest income	17,856	15,237
Total non-interest income, Change in Contribution	2,619
Total non-interest income, Change in Contribution Percentage	17.00%
Total net revenue	19,120	16,961
Total net revenue, Change in Contribution	2,159
Total net revenue, Change in Contribution Percentage	13.00%
Total segment profit	2,237	1,496
Total segment profit, Change in Contribution	741
Total segment profit, Change in Contribution Percentage	50.00%
Total assets	94,918	95,275
Total segment assets, Change in Contribution	(357)
Total segment assets, Change in Contribution Percentage	0.00%
Intersegment Elimination [Member]
Segment Reporting Information [Line Items]
Total net interest income	(25,075)	(24,549)
Total net interest income, Change in Contribution	(526)
Total net interest income, Change in Contribution Percentage	(2.00%)
Total non-interest income	(2,052)	(1,371)
Total non-interest income, Change in Contribution	(681)
Total non-interest income, Change in Contribution Percentage	(50.00%)
Total net revenue	(27,127)	(25,920)
Total net revenue, Change in Contribution	(1,207)
Total net revenue, Change in Contribution Percentage	(5.00%)
Total segment profit	(17,606)	(17,726)
Total segment profit, Change in Contribution	120
Total segment profit, Change in Contribution Percentage	1.00%
Total assets	(3,696,419)	(2,950,456)
Total segment assets, Change in Contribution	$ (745,963)
Total segment assets, Change in Contribution Percentage	(25.00%)