Consolidated Condensed Statements Of Income - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Interest and dividend income:
Interest and fees on loans	$ 80,687,000	$ 72,003,000
Interest and dividends on:
Obligations of U.S. Government, its agencies and other securities	5,531,000	6,995,000
Interest Income, Securities, State and Municipal	2,200,000	2,217,000
Other interest income	491,000	641,000
Total interest and dividend income	88,909,000	81,856,000
Interest on deposits:
Demand and savings deposits	6,342,000	7,093,000
Time deposits	4,285,000	3,777,000
Interest on borrowings:
Short-term borrowings	462,000	739,000
Long-term debt	1,537,000	2,471,000
Total interest expense	12,626,000	14,080,000
Net interest income	76,283,000	67,776,000
Provision for loan losses	5,153,000	2,498,000
Net interest income after provision for loan losses	71,130,000	65,278,000
Noninterest Income [Abstract]
Debit card fee income	4,960,000	4,369,000
Bank owned life insurance income	1,248,000	1,006,000
ATM Fees	412,000	440,000
Gains (Losses) on Sales of Other Real Estate	(196,000)	(12,000)
Loss (gain) on equity securities, net	(973,000)	1,742,000
Other components of net periodic benefit income	1,988,000	1,183,000
Other	1,640,000	1,197,000
Total other income	22,486,000	22,025,000
Other expense:
Salaries and employee benefits	28,429,000	25,805,000
Employee Benefits and Share-based Compensation	10,043,000	8,430,000
Occupancy expense	3,480,000	3,011,000
Furniture and equipment expense	4,319,000	4,150,000
Data processing fees	2,492,000	2,133,000
Professional fees and services	7,066,000	6,006,000
Marketing	1,486,000	1,226,000
Insurance	1,550,000	1,156,000
Communication	1,155,000	1,333,000
Excise and Sales Taxes	1,145,000	1,005,000
Amortization of Intangible Assets	606,000	289,000
Other expense	4,505,000	2,283,000
Total other expense	66,276,000	56,827,000
Income before income taxes	27,340,000	30,476,000
Income taxes	4,968,000	5,021,000
Net income	$ 22,372,000	$ 25,455,000
Net income available to common shareholders
Basic	$ 1.37	$ 1.63
Diluted	$ 1.36	$ 1.62
Weighted average common shares outstanding
Basic	16,303,602	15,651,541
Diluted	16,425,881	15,744,777
Cash dividends declared	$ 1.22	$ 1.21
Fiduciary and Trust [Member]
Noninterest Income [Abstract]
Revenue from Contract with Customer, Including Assessed Tax	$ 7,113,000	$ 6,723,000
Deposit Account [Member]
Noninterest Income [Abstract]
Revenue from Contract with Customer, Including Assessed Tax	2,528,000	2,559,000
Bank Servicing [Member]
Noninterest Income [Abstract]
Revenue from Contract with Customer, Including Assessed Tax	$ 3,766,000	$ 2,818,000