Segment Information (Details) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
OPERATIONS:
Net interest income	$ 117,443	$ 116,767	$ 239,269	$ 207,161
Provision for loan losses	17,619	20,366	39,968	45,859
Other income	51,491	53,209	104,247	103,109
Other expenses	110,068	105,723	224,514	199,736
Net income	41,247	43,620	79,034	64,408
Commercial [Member]
OPERATIONS:
Net interest income	64,587	54,649	132,162	97,683
Provision for loan losses	15,090	12,676	25,107	21,030
Other income	12,620	12,766	27,413	22,970
Other expenses	35,732	27,956	73,346	53,053
Net income	17,150	24,427	39,729	37,287
Commercial [Member] | YTD [Member]
AVERAGES :
Assets	6,114,006	4,837,737	6,114,006	4,837,737
Commercial [Member] | Second Quarter [Member]
AVERAGES :
Assets	6,133,210	5,443,648	6,133,210	5,443,648
Retail [Member]
OPERATIONS:
Net interest income	56,272	59,941	112,043	108,196
Provision for loan losses	6,517	10,482	12,466	20,208
Other income	25,785	27,990	49,976	52,773
Other expenses	58,539	55,866	119,370	107,800
Net income	11,050	14,968	19,619	22,364
Retail [Member] | YTD [Member]
AVERAGES :
Assets	2,944,264	2,863,282	2,944,264	2,863,282
Retail [Member] | Second Quarter [Member]
AVERAGES :
Assets	2,934,633	2,928,728	2,934,633	2,928,728
Wealth [Member]
OPERATIONS:
Net interest income	4,707	4,859	9,531	9,563
Provision for loan losses	707	1,104	1,326	1,886
Other income	8,089	8,442	16,282	16,161
Other expenses	10,140	9,596	20,437	18,948
Net income	1,267	1,750	2,632	3,237
Wealth [Member] | YTD [Member]
AVERAGES :
Assets	242,586	291,671	242,586	291,671
Wealth [Member] | Second Quarter [Member]
AVERAGES :
Assets	241,929	289,357	241,929	289,357
Other [Member]
OPERATIONS:
Net interest income	(8,123)	(2,682)	(14,467)	(8,281)
Provision for loan losses	(4,695)	(3,629)	1,069	3,002
Other income	4,997	4,011	10,576	16,396
Other expenses	5,657	12,305	11,361	19,935
Net income	296	(9,652)	4,656	(12,631)
Other [Member] | YTD [Member]
AVERAGES :
Assets	5,074,596	4,429,044	5,074,596	4,429,044
Other [Member] | Second Quarter [Member]
AVERAGES :
Assets	5,171,436	4,810,446	5,171,436	4,810,446
YTD [Member]
AVERAGES :
Assets	14,375,452	12,493,446	14,375,452	12,493,446
Second Quarter [Member]
AVERAGES :
Assets	$ 14,481,208	$ 13,426,271	$ 14,481,208	$ 13,426,271