Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Interest income:
Interest and fees on loans	$ 246,015	$ 231,469	$ 220,687
Interest and dividends on investment securities:
Taxable	30,861	29,900	31,237
Exempt from federal taxes	3,998	4,357	4,728
Interest on deposits in banks	1,537	1,334	992
Interest on federal funds sold	12	7	18
Total interest income	282,423	267,067	257,662
Interest expense:
Interest on deposits	13,107	13,779	15,800
Interest on securities sold under repurchase agreements	231	237	294
Interest on long-term debt	2,300	2,016	1,936
Interest in preferred stock pending redemption	0	0	159
Interest on subordinated debentures held by subsidiary trusts	2,422	2,574	2,506
Total interest expense	18,060	18,606	20,695
Net interest income	264,363	248,461	236,967
Provision for loan losses	6,822	(6,622)	(6,125)
Net interest income after provision for loan losses	257,541	255,083	243,092
Non-interest income:
Other service charges, commissions and fees	43,154	40,742	35,977
Income from the origination and sale of loans	29,973	23,940	34,254
Wealth management revenues	19,907	18,996	17,085
Service charges on deposit accounts	17,031	16,567	16,837
Investment securities gains, net	137	61	1
Other income	10,727	11,095	7,525
Total non-interest income	120,929	111,401	111,679
Non-interest expense:
Salaries and wages	101,451	96,513	94,002
Employee benefits	30,738	30,130	30,338
Occupancy, net	17,879	17,796	16,587
Furniture and equipment	15,524	13,816	12,554
Outsourced technology services	10,124	9,423	9,029
FDIC insurance premiums	4,858	4,608	5,057
Professional fees	6,458	4,882	4,773
OREO expense, net of income	(1,475)	(272)	2,291
Mortgage servicing rights amortization	2,434	2,361	2,787
Mortgage servicing rights impairment recovery	(97)	(136)	(99)
Core deposit intangibles amortization	3,388	2,251	1,418
Other expenses	50,936	47,480	43,332
Loss Contingency Expense	5,000	4,000	0
Acquisition Expense	795	4,017	0
Total non-interest expense	248,013	236,869	222,069
Income before income tax expense	130,457	129,615	132,702
Income tax expense	43,662	45,214	46,566
Net income	$ 86,795	$ 84,401	$ 86,136
Basic earnings per common share	$ 1.92	$ 1.89	$ 1.98
Diluted earnings per common share	$ 1.90	$ 1.87	$ 1.96