Segment Information - Schedule of Segment Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Net interest income	$ 387,533	$ 391,765	$ 405,336
Provision for loan losses, net	14,714	11,800	7,382
Noninterest income	173,943	173,149	173,142
Noninterest expense	407,298	401,662	409,005
Income Before Income Taxes	139,464	151,452	162,091
Income taxes	31,053	35,414	38,529
Net Income	108,411	116,038	123,562
Selected Financial Information
Average assets	12,938,020	12,270,195	12,028,030
Depreciation and amortization	36,613	37,056	36,072
General Banking [Member]
Segment Reporting Information [Line Items]
Net interest income	386,596	391,092	404,214
Provision for loan losses, net	14,714	11,800	7,382
Noninterest income	107,059	105,477	107,457
Noninterest expense	354,555	348,270	355,693
Income Before Income Taxes	124,386	136,499	148,596
Income taxes	25,303	29,761	33,726
Net Income	99,083	106,738	114,870
Selected Financial Information
Average assets	12,872,123	12,196,144	11,957,761
Depreciation and amortization	35,692	36,072	35,038
Wealth Management [Member]
Segment Reporting Information [Line Items]
Net interest income	726	337	851
Noninterest income	30,117	31,245	32,209
Noninterest expense	24,165	25,346	26,733
Income Before Income Taxes	6,678	6,236	6,327
Income taxes	2,554	2,386	2,105
Net Income	4,124	3,850	4,222
Selected Financial Information
Average assets	6,087	4,034	1,821
Depreciation and amortization	174	183	190
Insurance [Member]
Segment Reporting Information [Line Items]
Net interest income	211	336	271
Noninterest income	36,767	36,427	33,476
Noninterest expense	28,578	28,046	26,579
Income Before Income Taxes	8,400	8,717	7,168
Income taxes	3,196	3,267	2,698
Net Income	5,204	5,450	4,470
Selected Financial Information
Average assets	59,810	70,017	68,448
Depreciation and amortization	$ 747	$ 801	$ 844