Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Interest Income
Interest and fees on loans	$ 142,055	$ 125,752	$ 118,138
Interest on investment securities:
Taxable	17,337	14,387	12,392
Tax-exempt	2,843	2,706	1,622
Interest Income, Deposits with Financial Institutions	1,666	85	0
Total Interest Income	163,901	142,930	132,152
Interest Expense
Interest on deposits	21,397	14,826	12,052
Interest on short-term borrowings	3,415	1,214	472
Interest on long-term debt	880	765	683
Total Interest Expense	25,692	16,805	13,207
Net Interest Income	138,209	126,125	118,945
Provision for loan losses	(2,310)	3,006	4,395
Net Interest Income After Provision for Loan Losses	140,519	123,119	114,550
Non-interest Income
Gains on sale of investment securities	0	4,476	3,513
Equity Securities, FV-NI, Unrealized Gain (Loss)	(90)
Revenue from Contract with Customer, Including Assessed Tax	57,453
Bank owned life insurance	3,090	4,212	3,326
Other income	2,962	2,956	3,195
Total Non-interest Income	60,564	63,607	58,825
Non-interest Expense
Salaries and employee benefits	54,385	51,057	50,883
Occupancy related expenses	9,323	9,557	10,119
Equipment and software related expenses	7,729	7,732	7,211
FDIC insurance expense	1,251	1,348	1,622
Advertising	2,974	2,914	2,606
Bankcard expenses	4,503	3,924	4,458
Postage, delivery, and statement mailings	2,157	2,094	2,080
Office supplies	1,319	1,437	1,364
Legal and professional fees	1,847	1,956	1,882
Telecommunications	1,750	1,988	1,813
Repossessed asset losses, net of expenses	845	735	890
Merger related costs	13,257	0	0
Other expenses	11,726	11,239	11,236
Total Non-interest Expense	113,066	95,981	96,164
Income Before Income Taxes	88,017	90,745	77,211
Income tax expense	18,015	36,435	25,083
Net Income Available to Common Shareholders	$ 70,002	$ 54,310	$ 52,128
Average shares outstanding, basic	15,421	15,412	14,900
Effect of dilutive securities	18	24	13
Average shares outstanding, diluted	15,439	15,436	14,913
Basic earnings per common share	$ 4.50	$ 3.49	$ 3.46
Diluted earnings per common share	4.49	3.48	3.45
Dividends declared per common share	$ 1.98	$ 1.78	$ 1.72
Deposit Account [Member]
Non-interest Income
Revenue from Contract with Customer, Including Assessed Tax	$ 29,704	$ 28,574	$ 26,703
Debit Card [Member]
Non-interest Income
Revenue from Contract with Customer, Including Assessed Tax	18,369	17,120	16,515
Fiduciary and Trust [Member]
Non-interest Income
Revenue from Contract with Customer, Including Assessed Tax	$ 6,529	$ 6,269	$ 5,573