Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 Segment	Jun. 30, 2012
Segment Reporting Information [Line Items]
Number of segments in which the business operates			3
Net interest income	$ 99,228	$ 86,448	$ 188,203	$ 173,392
Provision for loan losses, net	(6,398)	2,322	(9,236)	5,421
Noninterest income	43,714	43,760	88,053	87,545
Noninterest expense	107,195	87,959	209,340	173,733
Income Before Income Taxes	42,145	39,927	76,152	81,783
Income taxes	11,024	10,578	20,165	22,114
Net Income	31,121	29,349	55,987	59,669
Selected Financial Information [Abstract]
Average assets	11,782,650	9,826,939	11,294,023	9,790,973
Depreciation and amortization	9,937	7,267	18,317	13,856
General Banking [Member]
Segment Reporting Information [Line Items]
Net interest income	98,112	85,293	185,924	171,059
Provision for loan losses, net	(6,395)	2,300	(9,231)	5,401
Noninterest income	28,694	30,768	58,883	62,339
Noninterest expense	94,030	77,091	184,336	152,227
Income Before Income Taxes	39,171	36,670	69,702	75,770
Income taxes	9,954	9,452	17,887	20,017
Net Income	29,217	27,218	51,815	55,753
Selected Financial Information [Abstract]
Average assets	11,645,336	9,681,451	11,154,636	9,647,614
Depreciation and amortization	9,636	6,912	17,715	13,135
Wealth Management [Member]
Segment Reporting Information [Line Items]
Net interest income	1,046	1,082	2,144	2,189
Provision for loan losses, net	(3)	22	(5)	20
Noninterest income	6,999	5,844	13,905	11,432
Noninterest expense	7,117	5,450	12,947	10,937
Income Before Income Taxes	931	1,454	3,107	2,664
Income taxes	298	453	1,021	848
Net Income	633	1,001	2,086	1,816
Selected Financial Information [Abstract]
Average assets	71,369	80,579	73,785	79,030
Depreciation and amortization	41	43	83	90
Insurance [Member]
Segment Reporting Information [Line Items]
Net interest income	70	73	135	144
Provision for loan losses, net	0	0	0	0
Noninterest income	8,021	7,148	15,265	13,774
Noninterest expense	6,048	5,418	12,057	10,569
Income Before Income Taxes	2,043	1,803	3,343	3,349
Income taxes	772	673	1,257	1,249
Net Income	1,271	1,130	2,086	2,100
Selected Financial Information [Abstract]
Average assets	65,945	64,909	65,602	64,329
Depreciation and amortization	$ 260	$ 312	$ 519	$ 631