Segment Information - Schedule of Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Segment Reporting Information [Line Items]
Net interest income	$ 94,740	$ 97,392
Provision for loan losses, net	3,552	2,132
Noninterest income	43,276	42,363
Noninterest expense	98,944	99,216
Income Before Income Taxes	35,520	38,407
Income taxes	8,517	9,259
Net Income	27,003	29,148
Selected Financial Information
Average assets	12,741,506	12,125,303
Depreciation and amortization	8,721	9,080
General Banking [Member]
Segment Reporting Information [Line Items]
Net interest income	94,442	97,260
Provision for loan losses, net	3,552	2,132
Noninterest income	27,394	25,740
Noninterest expense	85,893	85,517
Income Before Income Taxes	32,391	35,351
Income taxes	7,319	8,084
Net Income	25,072	27,267
Selected Financial Information
Average assets	12,667,616	12,053,721
Depreciation and amortization	8,485	8,875
Wealth Management [Member]
Segment Reporting Information [Line Items]
Net interest income	245	55
Noninterest income	7,288	8,007
Noninterest expense	5,891	6,770
Income Before Income Taxes	1,642	1,292
Income taxes	628	513
Net Income	1,014	779
Selected Financial Information
Average assets	5,907	3,263
Depreciation and amortization	44	46
Insurance [Member]
Segment Reporting Information [Line Items]
Net interest income	53	77
Noninterest income	8,594	8,616
Noninterest expense	7,160	6,929
Income Before Income Taxes	1,487	1,764
Income taxes	570	662
Net Income	917	1,102
Selected Financial Information
Average assets	67,983	68,319
Depreciation and amortization	$ 192	$ 159