Consolidated Condensed Statements Of Income - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Interest and dividend income:
Interest and fees on loans	$ 103,258,000	$ 83,522,000	$ 291,300,000	$ 233,725,000
Interest and dividends on:
Obligations of U.S. Government, its agencies and other securities	13,321,000	10,319,000	39,731,000	24,073,000
Interest Income, Securities, State and Municipal	2,900,000	2,923,000	8,718,000	8,046,000
Other interest income	1,410,000	3,180,000	6,715,000	3,593,000
Total interest and dividend income	120,889,000	99,944,000	346,464,000	269,437,000
Interest on deposits:
Demand and savings deposits	20,029,000	5,757,000	52,309,000	7,441,000
Time deposits	3,097,000	825,000	6,410,000	2,253,000
Interest on borrowings:
Short-term borrowings	1,136,000	306,000	2,688,000	740,000
Long-term debt	2,358,000	2,228,000	7,018,000	6,550,000
Total interest expense	26,620,000	9,116,000	68,425,000	16,984,000
Net interest income	94,269,000	90,828,000	278,039,000	252,453,000
Provision for credit losses	(1,580,000)	3,190,000	1,095,000	1,576,000
Net interest income after provision for credit losses	95,849,000	87,638,000	276,944,000	250,877,000
Noninterest Income [Abstract]
Debit card fee income	6,652,000	6,514,000	19,939,000	19,371,000
Bank owned life insurance income	1,448,000	1,185,000	3,965,000	4,734,000
ATM Fees	575,000	610,000	1,661,000	1,725,000
Gains (Losses) on Sales of Other Real Estate	(6,000)	5,607,000	(3,000)	5,611,000
Real Estate Owned, Valuation Allowance, Valuation Increase	0	12,009,000	15,000	12,039,000
Gain on equity securities, net	998,000	58,000	618,000	3,120,000
Other components of net periodic benefit income	1,893,000	3,027,000	5,679,000	9,081,000
Other	2,329,000	3,653,000	4,368,000	7,779,000
Total other income	27,713,000	46,694,000	77,115,000	109,543,000
Other expense:
Salaries and employee benefits	34,525,000	37,889,000	103,045,000	99,462,000
Employee Benefits and Share-based Compensation	10,822,000	9,897,000	32,176,000	30,595,000
Occupancy expense	3,203,000	3,455,000	9,770,000	9,709,000
Furniture and equipment expense	3,060,000	2,912,000	9,409,000	8,783,000
Data processing fees	9,700,000	8,170,000	28,032,000	24,090,000
Professional fees and services	7,572,000	8,359,000	22,158,000	20,992,000
Marketing	1,197,000	1,595,000	3,755,000	3,931,000
Insurance	2,158,000	1,237,000	5,932,000	3,887,000
Communication	1,135,000	1,098,000	3,217,000	2,923,000
Excise and Sales Taxes	1,125,000	1,186,000	3,499,000	3,545,000
Amortization of Intangible Assets	334,000	341,000	989,000	1,146,000
Foundation contribution expense	0	4,000,000	0	4,000,000
Other expense	2,977,000	2,764,000	8,214,000	7,261,000
Total other expense	77,808,000	82,903,000	230,196,000	220,324,000
Income before income taxes	45,754,000	51,429,000	123,863,000	140,096,000
Income taxes	8,837,000	9,361,000	21,629,000	24,829,000
Net income	$ 36,917,000	$ 42,068,000	$ 102,234,000	$ 115,267,000
Net income available to common shareholders
Basic	$ 2.29	$ 2.59	$ 6.32	$ 7.10
Diluted	$ 2.28	$ 2.57	$ 6.29	$ 7.05
Weighted average common shares outstanding
Basic	16,133,310	16,253,704	16,180,261	16,240,966
Diluted	16,217,880	16,374,982	16,261,109	16,355,790
Quarterly Dividend
Weighted average common shares outstanding
Cash dividends declared	$ 1.05	$ 1.04	$ 3.15	$ 3.12
Fiduciary and Trust [Member]
Noninterest Income [Abstract]
Revenue from Contract with Customer, Including Assessed Tax	$ 9,100,000	$ 8,216,000	$ 26,531,000	$ 25,872,000
Deposit Account [Member]
Noninterest Income [Abstract]
Revenue from Contract with Customer, Including Assessed Tax	2,109,000	2,859,000	6,391,000	7,496,000
Bank Servicing [Member]
Noninterest Income [Abstract]
Revenue from Contract with Customer, Including Assessed Tax	$ 2,615,000	$ 2,956,000	$ 7,951,000	$ 12,715,000