FAIR VALUE (Estimated fair value financial instruments incl. carrying amounts) (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Securities:
Carried at fair value	$ 1,021,283
Held to maturity	832,098	$ 829,403
Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial assets:
Cash and cash equivalents	362,111	363,087
Time deposits in other financial institutions	1,740	1,740
Securities:
Carried at fair value	31,932	31,699
Held to maturity	0	0
Other investments	0	0
Loans held for sale	0	0
Loans, net	0	0
Cash surrender value on life insurance	0	0
Derivative instruments	0	0
Financial liabilities:
Short term borrowings	0	0
Other borrowings	0	0
Fair Value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Interest rate lock commitments
Securities:
Derivative instruments	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Demand deposits
Financial liabilities:
Deposits	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Savings deposits
Financial liabilities:
Deposits	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Time deposits
Financial liabilities:
Deposits	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Forward commitments
Securities:
Derivative instruments	0	0
Financial liabilities:
Fair Value	0	0
Level 2
Financial assets:
Cash and cash equivalents	0	0
Time deposits in other financial institutions	0	0
Securities:
Carried at fair value	6,064,725	6,115,445
Held to maturity	815,672	776,557
Other investments	72,364	74,567
Loans held for sale	10,425	5,277
Loans, net	10,630,086	10,615,955
Cash surrender value on life insurance	194,419	193,403
Derivative instruments	27,942	46,293
Financial liabilities:
Short term borrowings	92,337	376,117
Other borrowings	373,923	372,473
Fair Value	27,903	46,226
Level 2 | Interest rate lock commitments
Securities:
Derivative instruments	0	0
Level 2 | Demand deposits
Financial liabilities:
Deposits	5,119,554	5,701,340
Level 2 | Savings deposits
Financial liabilities:
Deposits	9,256,609	9,994,391
Level 2 | Time deposits
Financial liabilities:
Deposits	3,305,183	1,817,278
Level 2 | Forward commitments
Securities:
Derivative instruments	241	47
Financial liabilities:
Fair Value	21	99
Significant Unobservable Inputs (Level 3)
Financial assets:
Cash and cash equivalents	0	0
Time deposits in other financial institutions	0	0
Securities:
Carried at fair value	0	0
Held to maturity	0	0
Other investments	0	0
Loans held for sale	0	0
Loans, net	36,540	37,882
Cash surrender value on life insurance	0	0
Derivative instruments	0	0
Financial liabilities:
Short term borrowings	0	0
Other borrowings	0	0
Fair Value	0	0
Significant Unobservable Inputs (Level 3) | Interest rate lock commitments
Securities:
Derivative instruments	449	174
Significant Unobservable Inputs (Level 3) | Demand deposits
Financial liabilities:
Deposits	0	0
Significant Unobservable Inputs (Level 3) | Savings deposits
Financial liabilities:
Deposits	0	0
Significant Unobservable Inputs (Level 3) | Time deposits
Financial liabilities:
Deposits	0	0
Significant Unobservable Inputs (Level 3) | Forward commitments
Securities:
Derivative instruments	0	0
Financial liabilities:
Fair Value	0	0
Commercial and industrial | Quoted Prices in Active Markets for Identical Assets (Level 1) | Commercial and industrial
Securities:
Loans, net	0	0
Commercial and industrial | Quoted Prices in Active Markets for Identical Assets (Level 1) | Paycheck Protection Program ("PPP")
Securities:
Loans, net	0	0
Commercial and industrial | Quoted Prices in Active Markets for Identical Assets (Level 1) | Owner occupied commercial real estate
Securities:
Loans, net	0	0
Commercial and industrial | Quoted Prices in Active Markets for Identical Assets (Level 1) | Non-owner occupied commercial real estate
Securities:
Loans, net	0	0
Commercial and industrial | Quoted Prices in Active Markets for Identical Assets (Level 1) | Real estate construction
Securities:
Loans, net	0	0
Commercial and industrial | Level 2 | Commercial and industrial
Securities:
Loans, net	3,275,913	3,258,085
Commercial and industrial | Level 2 | Paycheck Protection Program ("PPP")
Securities:
Loans, net	8,258	11,025
Commercial and industrial | Level 2 | Owner occupied commercial real estate
Securities:
Loans, net	2,104,906	2,077,109
Commercial and industrial | Level 2 | Non-owner occupied commercial real estate
Securities:
Loans, net	2,254,681	2,173,425
Commercial and industrial | Level 2 | Real estate construction
Securities:
Loans, net	1,063,999	1,037,726
Commercial and industrial | Significant Unobservable Inputs (Level 3) | Commercial and industrial
Securities:
Loans, net	10,810	12,042
Commercial and industrial | Significant Unobservable Inputs (Level 3) | Paycheck Protection Program ("PPP")
Securities:
Loans, net	0	0
Commercial and industrial | Significant Unobservable Inputs (Level 3) | Owner occupied commercial real estate
Securities:
Loans, net	7,408	7,556
Commercial and industrial | Significant Unobservable Inputs (Level 3) | Non-owner occupied commercial real estate
Securities:
Loans, net	10,983	11,371
Commercial and industrial | Significant Unobservable Inputs (Level 3) | Real estate construction
Securities:
Loans, net	1,498	1,518
Agricultural and agricultural real estate | Quoted Prices in Active Markets for Identical Assets (Level 1)
Securities:
Loans, net	0	0
Agricultural and agricultural real estate | Level 2
Securities:
Loans, net	730,438	838,849
Agricultural and agricultural real estate | Significant Unobservable Inputs (Level 3)
Securities:
Loans, net	5,053	3,788
Residential real estate | Quoted Prices in Active Markets for Identical Assets (Level 1)
Securities:
Loans, net	0	0
Residential real estate | Level 2
Securities:
Loans, net	717,493	739,718
Residential real estate | Significant Unobservable Inputs (Level 3)
Securities:
Loans, net	788	1,607
Consumer | Quoted Prices in Active Markets for Identical Assets (Level 1)
Securities:
Loans, net	0	0
Consumer | Level 2
Securities:
Loans, net	474,398	480,018
Consumer | Significant Unobservable Inputs (Level 3)
Securities:
Loans, net	0	0
Carrying Amount
Financial assets:
Cash and cash equivalents	362,111	363,087
Time deposits in other financial institutions	1,740	1,740
Securities:
Carried at fair value	6,096,657	6,147,144
Held to maturity	832,098	829,403
Other investments	72,364	74,567
Loans held for sale	10,425	5,277
Loans, net	11,382,646	11,318,869
Cash surrender value on life insurance	194,419	193,403
Derivative instruments	27,942	46,293
Financial liabilities:
Short term borrowings	92,337	376,117
Other borrowings	372,097	371,753
Fair Value	27,903	46,226
Carrying Amount | Interest rate lock commitments
Securities:
Derivative instruments	449	174
Carrying Amount | Demand deposits
Financial liabilities:
Deposits	5,119,554	5,701,340
Carrying Amount | Savings deposits
Financial liabilities:
Deposits	9,256,609	9,994,391
Carrying Amount | Time deposits
Financial liabilities:
Deposits	3,305,183	1,817,278
Carrying Amount | Forward commitments
Securities:
Derivative instruments	241	47
Financial liabilities:
Fair Value	21	99
Carrying Amount | Commercial and industrial | Commercial and industrial
Securities:
Loans, net	3,466,522	3,435,343
Carrying Amount | Commercial and industrial | Paycheck Protection Program ("PPP")
Securities:
Loans, net	8,258	11,025
Carrying Amount | Commercial and industrial | Owner occupied commercial real estate
Securities:
Loans, net	2,298,387	2,251,359
Carrying Amount | Commercial and industrial | Non-owner occupied commercial real estate
Securities:
Loans, net	2,404,279	2,314,401
Carrying Amount | Commercial and industrial | Real estate construction
Securities:
Loans, net	1,072,048	1,046,084
Carrying Amount | Agricultural and agricultural real estate
Securities:
Loans, net	807,637	917,876
Carrying Amount | Residential real estate
Securities:
Loans, net	833,520	845,650
Carrying Amount | Consumer
Securities:
Loans, net	491,995	497,131
Estimated Fair Value
Financial assets:
Cash and cash equivalents	362,111	363,087
Time deposits in other financial institutions	1,740	1,740
Securities:
Carried at fair value	6,096,657	6,147,144
Held to maturity	815,672	776,557
Other investments	72,364	74,567
Loans held for sale	10,425	5,277
Loans, net	10,666,626	10,653,837
Cash surrender value on life insurance	194,419	193,403
Derivative instruments	27,942	46,293
Financial liabilities:
Short term borrowings	92,337	376,117
Other borrowings	373,923	372,473
Fair Value	27,903	46,226
Estimated Fair Value | Interest rate lock commitments
Securities:
Derivative instruments	449	174
Estimated Fair Value | Demand deposits
Financial liabilities:
Deposits	5,119,554	5,701,340
Estimated Fair Value | Savings deposits
Financial liabilities:
Deposits	9,256,609	9,994,391
Estimated Fair Value | Time deposits
Financial liabilities:
Deposits	3,305,183	1,817,278
Estimated Fair Value | Forward commitments
Securities:
Derivative instruments	241	47
Financial liabilities:
Fair Value	21	99
Estimated Fair Value | Commercial and industrial | Commercial and industrial
Securities:
Loans, net	3,286,723	3,270,127
Estimated Fair Value | Commercial and industrial | Paycheck Protection Program ("PPP")
Securities:
Loans, net	8,258	11,025
Estimated Fair Value | Commercial and industrial | Owner occupied commercial real estate
Securities:
Loans, net	2,112,314	2,084,665
Estimated Fair Value | Commercial and industrial | Non-owner occupied commercial real estate
Securities:
Loans, net	2,265,664	2,184,796
Estimated Fair Value | Commercial and industrial | Real estate construction
Securities:
Loans, net	1,065,497	1,039,244
Estimated Fair Value | Agricultural and agricultural real estate
Securities:
Loans, net	735,491	842,637
Estimated Fair Value | Residential real estate
Securities:
Loans, net	718,281	741,325
Estimated Fair Value | Consumer
Securities:
Loans, net	$ 474,398	$ 480,018