Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
INTEREST INCOME
Loans, including fees	$ 204,467	$ 190,292	$ 182,972
Securities:
Taxable	5,229	5,492	5,727
Tax-exempt	964	982	1,061
Federal funds sold	1	14	2
Interest-bearing deposits with banks	7,908	4,265	4,391
Total interest income	218,569	201,045	194,153
INTEREST EXPENSE
Deposits	12,638	10,251	10,795
Short-term borrowings	7	4	16
Long-term borrowings		32	25
Junior subordinated debentures	2,096	1,966	1,966
Total interest expense	14,741	12,253	12,802
Net interest income	203,828	188,792	181,351
Provision for loan losses	11,519	7,675	3,072
Net interest income after provision for loan losses	192,309	181,117	178,279
NONINTEREST INCOME
Trust revenue	10,630	9,091	9,180
Service charges on deposits	62,233	57,651	56,389
Securities transactions (includes accumulated other comprehensive income reclassifications of $15, $3,814 and $533, respectively)	(59)	9,269	1,641
Income from sales of loans	2,825	1,968	1,813
Insurance commissions	15,559	14,791	14,642
Cash management	10,616	7,510	6,741
Gain on sale of other assets	46	79	335
Other	5,182	5,449	5,672
Total noninterest income	107,032	105,808	96,413
NONINTEREST EXPENSE
Salaries and employee benefits	119,662	113,083	108,640
Occupancy, net	12,313	11,512	11,610
Depreciation	10,114	9,966	9,595
Amortization of intangible assets	2,269	1,935	1,754
Data processing services	4,796	4,579	4,689
Net (income) expense from other real estate owned	(747)	324	511
Marketing and business promotion	7,236	6,986	7,024
Deposit insurance	2,904	3,358	3,291
Other	32,857	33,972	36,407
Total noninterest expense	191,404	185,715	183,521
Income before taxes	107,937	101,210	91,171
Income tax expense	37,263	35,040	27,284
Net income	$ 70,674	$ 66,170	$ 63,887
NET INCOME PER COMMON SHARE
Basic	$ 4.53	$ 4.25	$ 4.14
Diluted	$ 4.44	$ 4.17	$ 4.04
OTHER COMPREHENSIVE INCOME
Reclassification adjustment for gains included in net income, net of tax of $6, $1,475 and $206, respectively	$ (9)	$ (2,339)	$ (327)
Unrealized (losses) gains on securities, net of tax of $897, $207 and $(747), respectively	(1,424)	(327)	613
Other comprehensive (loss) gain, net of tax of $903, $1,682 and $(541), respectively	(1,433)	(2,666)	286
Comprehensive income	$ 69,241	$ 63,504	$ 64,173