Consolidated Condensed Statements Of Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Interest and dividend income:
Interest and fees on loans	$ 69,905	$ 63,110	$ 198,803	$ 184,240
Interest and dividends on:
Obligations of U.S. Government, its agencies and other securities	7,691	6,757	22,204	20,787
Interest Income, Securities, State and Municipal	2,205	1,974	6,557	5,098
Other interest income	428	1,383	1,070	2,330
Total interest and dividend income	80,229	73,224	228,634	212,455
Interest on deposits:
Demand and savings deposits	6,412	2,882	13,809	6,787
Time deposits	3,328	2,521	8,765	7,139
Interest on borrowings:
Short-term borrowings	288	197	1,283	616
Long-term debt	2,525	6,073	7,509	17,632
Total interest expense	12,553	11,673	31,366	32,174
Net interest income	67,676	61,551	197,268	180,281
Provision for loan losses	2,940	3,283	4,586	8,740
Net interest income after provision for loan losses	64,736	58,268	192,682	171,541
Noninterest Income [Abstract]
Checkcard fee income	4,352	3,974	12,736	11,775
Bank owned life insurance income	2,585	1,573	4,625	3,790
ATM Fees	500	605	1,534	1,708
OREO valuation adjustments	(77)	(22)	(398)	(367)
Gain on sale of OREO, net	(81)	51	4,093	204
Gain (Loss) on Sale of Investments	0	0	(2,271)	0
Unrealized gain loss on equity securities	(326)	0	3,467	0
Other components of net periodic benefit income	1,705	1,448	5,115	4,344
Other	2,881	3,403	6,330	5,147
Total other income	24,064	23,537	74,209	63,191
Other expense:
Salaries and employee benefits	27,229	23,302	76,652	69,020
Employee Benefits and Share-based Compensation	7,653	5,943	22,312	18,617
Occupancy expense	2,976	2,559	8,482	7,759
Furniture and equipment expense	3,807	3,868	11,969	11,126
Data processing fees	2,580	1,919	6,255	5,560
Professional fees and services	8,065	6,100	20,378	16,947
Marketing	1,364	1,122	3,767	3,262
Insurance	1,388	1,499	4,012	4,586
Communication	1,207	1,110	3,646	3,598
Excise and Sales Taxes	1,000	912	3,063	2,918
Amortization of Intangible Assets	289	0	289	0
Other expense	1,758	2,925	5,333	6,330
Total other expense	59,316	51,259	166,158	149,723
Income before income taxes	29,484	30,546	100,733	85,009
Income taxes	4,722	8,434	16,607	23,598
Net income	24,762	22,112	84,126	61,411
Net income available to common shareholders	$ 24,762	$ 22,112	$ 84,126	$ 61,411
Net income available to common shareholders
Basic	$ 1.58	$ 1.45	$ 5.46	$ 4.01
Diluted	$ 1.56	$ 1.44	$ 5.41	$ 3.99
Weighted average common shares outstanding
Basic	15,686,542	15,287,974	15,420,135	15,299,039
Diluted	15,832,734	15,351,590	15,560,666	15,394,199
Cash dividends declared	$ 0.96	$ 0.94	$ 3.11	$ 2.82
Fiduciary and Trust [Member]
Noninterest Income [Abstract]
Revenue from Contract with Customer, Including Assessed Tax	$ 6,418	$ 5,932	$ 19,479	$ 17,471
Deposit Account [Member]
Noninterest Income [Abstract]
Revenue from Contract with Customer, Including Assessed Tax	2,861	3,216	8,609	9,511
Bank Servicing [Member]
Noninterest Income [Abstract]
Revenue from Contract with Customer, Including Assessed Tax	3,246	3,357	10,890	9,608
Other	$ 3,200	$ 3,400	$ 10,900	$ 9,600