Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013 Segment	Mar. 31, 2012
Segment Reporting Information [Line Items]
Number of segments in which the business operates	3
Net interest income	$ 88,975	$ 86,944
Provision for loan losses, net	(2,838)	3,099
Noninterest income	44,339	43,785
Noninterest expense	102,145	85,774
Income Before Income Taxes	34,007	41,856
Income taxes	9,141	11,536
Net Income	24,866	30,320
Selected Financial Information [Abstract]
Average assets	10,799,967	9,755,006
Depreciation and amortization	8,380	6,589
General Banking [Member]
Segment Reporting Information [Line Items]
Net interest income	87,812	85,766
Provision for loan losses, net	(2,836)	3,101
Noninterest income	30,189	31,571
Noninterest expense	90,306	75,136
Income Before Income Taxes	30,531	39,100
Income taxes	7,933	10,565
Net Income	22,598	28,535
Selected Financial Information [Abstract]
Average assets	10,658,486	9,613,776
Depreciation and amortization	8,079	6,223
Wealth Management [Member]
Segment Reporting Information [Line Items]
Net interest income	1,098	1,107
Provision for loan losses, net	(2)	(2)
Noninterest income	6,906	5,588
Noninterest expense	5,830	5,487
Income Before Income Taxes	2,176	1,210
Income taxes	723	395
Net Income	1,453	815
Selected Financial Information [Abstract]
Average assets	76,227	77,481
Depreciation and amortization	42	47
Insurance [Member]
Segment Reporting Information [Line Items]
Net interest income	65	71
Noninterest income	7,244	6,626
Noninterest expense	6,009	5,151
Income Before Income Taxes	1,300	1,546
Income taxes	485	576
Net Income	815	970
Selected Financial Information [Abstract]
Average assets	65,254	63,749
Depreciation and amortization	$ 259	$ 319