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, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Segment Reporting Information [Line Items]
Total net interest income	$ 132,575	$ 118,410	$ 386,740	$ 336,730
Total net interest income, Change in Contribution	14,165		50,010
Total net interest income, Change in Contribution Percentage	12.00%		15.00%
Total non-interest income	62,945	67,247	160,903	144,786
Total non-interest income, Change in Contribution	(4,302)		16,117
Total non-interest income, Change in Contribution Percentage	(6.00%)		11.00%
Total net revenue	195,520	185,657	547,643	481,516
Total net revenue, Change in Contribution	9,863		66,127
Total net revenue, Change in Contribution Percentage	5.00%		14.00%
Total segment profit	32,302	30,202	81,107	58,354
Total segment profit, Change in Contribution	2,100		22,753
Total segment profit, Change in Contribution Percentage	7.00%		39.00%
Total segment assets	17,018,592	15,914,804	17,018,592	15,914,804	15,893,808
Total segment assets, Change in Contribution	1,103,788
Total segment assets, Change in Contribution Percentage	7.00%
Community Banking [Member]
Segment Reporting Information [Line Items]
Total net interest income	124,684	109,242	368,834	312,053
Total net interest income, Change in Contribution	15,442		56,781
Total net interest income, Change in Contribution Percentage	14.00%		18.00%
Total non-interest income	48,912	55,714	117,717	109,172
Total non-interest income, Change in Contribution	(6,802)		8,545
Total non-interest income, Change in Contribution Percentage	(12.00%)		8.00%
Total net revenue	173,596	164,956	486,551	421,225
Total net revenue, Change in Contribution	8,640		65,326
Total net revenue, Change in Contribution Percentage	5.00%		16.00%
Total segment profit	39,663	32,887	96,052	61,158
Total segment profit, Change in Contribution	6,776		34,894
Total segment profit, Change in Contribution Percentage	21.00%		57.00%
Total segment assets	16,877,673	15,110,396	16,877,673	15,110,396
Total segment assets, Change in Contribution	1,767,277
Total segment assets, Change in Contribution Percentage	12.00%
Specialty Finance [Member]
Segment Reporting Information [Line Items]
Total net interest income	33,125	28,802	90,750	84,808
Total net interest income, Change in Contribution	4,323		5,942
Total net interest income, Change in Contribution Percentage	15.00%		7.00%
Total non-interest income	131	784	1,724	2,282
Total non-interest income, Change in Contribution	(653)		(558)
Total non-interest income, Change in Contribution Percentage	(83.00%)		(24.00%)
Total net revenue	33,256	29,586	92,474	87,090
Total net revenue, Change in Contribution	3,670		5,384
Total net revenue, Change in Contribution Percentage	12.00%		6.00%
Total segment profit	12,967	12,765	36,401	40,730
Total segment profit, Change in Contribution	202		(4,329)
Total segment profit, Change in Contribution Percentage	2.00%		(11.00%)
Total segment assets	3,796,745	3,255,916	3,796,745	3,255,916
Total segment assets, Change in Contribution	540,829
Total segment assets, Change in Contribution Percentage	17.00%
Wealth Management [Member]
Segment Reporting Information [Line Items]
Total net interest income	524	2,883	4,940	6,322
Total net interest income, Change in Contribution	(2,359)		(1,382)
Total net interest income, Change in Contribution Percentage	(82.00%)		(22.00%)
Total non-interest income	16,115	14,304	47,316	40,734
Total non-interest income, Change in Contribution	1,811		6,582
Total non-interest income, Change in Contribution Percentage	13.00%		16.00%
Total net revenue	16,639	17,187	52,256	47,056
Total net revenue, Change in Contribution	(548)		5,200
Total net revenue, Change in Contribution Percentage	(3.00%)		11.00%
Total segment profit	1,317	2,357	5,297	5,060
Total segment profit, Change in Contribution	(1,040)		237
Total segment profit, Change in Contribution Percentage	(44.00%)		5.00%
Total segment assets	95,128	88,551	95,128	88,551
Total segment assets, Change in Contribution	6,577
Total segment assets, Change in Contribution Percentage	7.00%
Intersegment Elimination [Member]
Segment Reporting Information [Line Items]
Total net interest income	(25,758)	(22,517)	(77,784)	(66,453)
Total net interest income, Change in Contribution	(3,241)		(11,331)
Total net interest income, Change in Contribution Percentage	(14.00%)		(17.00%)
Total non-interest income	(2,213)	(3,555)	(5,854)	(7,402)
Total non-interest income, Change in Contribution	1,342		1,548
Total non-interest income, Change in Contribution Percentage	38.00%		21.00%
Total net revenue	(27,971)	(26,072)	(83,638)	(73,855)
Total net revenue, Change in Contribution	(1,899)		(9,783)
Total net revenue, Change in Contribution Percentage	(7.00%)		(13.00%)
Total segment profit	(21,645)	(17,807)	(56,643)	(48,594)
Total segment profit, Change in Contribution	(3,838)		(8,049)
Total segment profit, Change in Contribution Percentage	(22.00%)		(17.00%)
Total segment assets	(3,750,954)	(2,540,059)	(3,750,954)	(2,540,059)
Total segment assets, Change in Contribution	$ (1,210,895)
Total segment assets, Change in Contribution Percentage	(48.00%)