Consolidated Condensed Statements Of Income - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Interest and dividend income:
Interest and fees on loans	$ 83,522,000	$ 78,127,000	$ 233,725,000	$ 238,040,000
Interest and dividends on:
Obligations of U.S. Government, its agencies and other securities	10,319,000	4,904,000	24,073,000	13,760,000
Interest Income, Securities, State and Municipal	2,923,000	2,029,000	8,046,000	6,098,000
Other interest income	3,180,000	360,000	3,593,000	689,000
Total interest and dividend income	99,944,000	85,420,000	269,437,000	258,587,000
Interest on deposits:
Demand and savings deposits	5,757,000	435,000	7,441,000	1,222,000
Time deposits	825,000	1,011,000	2,253,000	3,880,000
Interest on borrowings:
Short-term borrowings	306,000	187,000	740,000	552,000
Long-term debt	2,228,000	2,185,000	6,550,000	6,746,000
Total interest expense	9,116,000	3,818,000	16,984,000	12,400,000
Net interest income	90,828,000	81,602,000	252,453,000	246,187,000
Provision for (recovery of) credit losses	3,190,000	1,972,000	1,576,000	(6,923,000)
Net interest income after provision for credit losses	87,638,000	79,630,000	250,877,000	253,110,000
Noninterest Income [Abstract]
Debit card fee income	6,514,000	6,453,000	19,371,000	19,297,000
Bank owned life insurance income	1,185,000	1,462,000	4,734,000	3,776,000
ATM Fees	610,000	622,000	1,725,000	1,807,000
Gains (Losses) on Sales of Other Real Estate	5,607,000	3,000	5,611,000	(26,000)
Real Estate Owned, Valuation Allowance, Valuation Increase	12,009,000	0	12,039,000	13,000
Gain on equity securities, net	58,000	609,000	3,120,000	2,886,000
Other components of net periodic benefit income	3,027,000	2,038,000	9,081,000	6,114,000
Other	3,653,000	3,347,000	7,779,000	8,390,000
Total other income	46,694,000	32,411,000	109,543,000	97,738,000
Other expense:
Salaries and employee benefits	37,889,000	29,433,000	99,462,000	89,632,000
Employee Benefits and Share-based Compensation	9,897,000	10,640,000	30,595,000	30,897,000
Occupancy expense	3,455,000	3,211,000	9,709,000	9,878,000
Furniture and equipment expense	2,912,000	2,797,000	8,783,000	8,163,000
Data processing fees	8,170,000	7,817,000	24,090,000	22,679,000
Professional fees and services	8,359,000	6,973,000	20,992,000	19,610,000
Marketing	1,595,000	1,574,000	3,931,000	4,355,000
Insurance	1,237,000	1,403,000	3,887,000	4,370,000
Communication	1,098,000	796,000	2,923,000	2,688,000
Excise and Sales Taxes	1,186,000	1,113,000	3,545,000	3,324,000
Amortization of Intangible Assets	341,000	420,000	1,146,000	1,378,000
Foundation contribution expense	4,000,000	0	4,000,000	4,000,000
Other expense	2,764,000	2,312,000	7,261,000	6,780,000
Total other expense	82,903,000	68,489,000	220,324,000	207,754,000
Income before income taxes	51,429,000	43,552,000	140,096,000	143,094,000
Income taxes	9,361,000	8,118,000	24,829,000	25,697,000
Net income	$ 42,068,000	$ 35,434,000	$ 115,267,000	$ 117,397,000
Net income available to common shareholders
Basic	$ 2.59	$ 2.17	$ 7.10	$ 7.20
Diluted	$ 2.57	$ 2.16	$ 7.05	$ 7.14
Weighted average common shares outstanding
Basic	16,253,704	16,292,312	16,240,966	16,315,996
Diluted	16,374,982	16,423,912	16,355,790	16,445,568
Quarterly Dividend
Weighted average common shares outstanding
Cash dividends declared	$ 1.04	$ 1.03	$ 3.12	$ 3.09
Special Dividend
Weighted average common shares outstanding
Cash dividends declared	$ 0	$ 0	$ 0	$ 200
Fiduciary and Trust [Member]
Noninterest Income [Abstract]
Revenue from Contract with Customer, Including Assessed Tax	$ 8,216,000	$ 8,820,000	$ 25,872,000	$ 25,562,000
Deposit Account [Member]
Noninterest Income [Abstract]
Revenue from Contract with Customer, Including Assessed Tax	2,859,000	2,389,000	7,496,000	6,475,000
Bank Servicing [Member]
Noninterest Income [Abstract]
Revenue from Contract with Customer, Including Assessed Tax	$ 2,956,000	$ 6,668,000	$ 12,715,000	$ 23,444,000