FAIR VALUE (Estimated fair value financial instruments incl. carrying amounts) (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Securities:
Carried at fair value	$ 913,083
Held to maturity	10,923,532	$ 9,954,572
Total	830,247	84,709
Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial assets:
Cash and cash equivalents	399,860	435,599
Time deposits in other financial institutions	1,740	2,894
Securities:
Carried at fair value	26,737	1,008
Held to maturity		0
Other investments	0	0
Total	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	6,033,294	7,529,366
Held to maturity		94,139
Other investments	80,286	82,567
Total	782,805
Loans held for sale	9,570	21,640
Loans, net	10,351,017	9,809,915
Cash surrender value on life insurance	193,184	191,722
Derivative instruments	48,893	23,891
Financial liabilities:
Short term borrowings	147,000	131,597
Other borrowings	372,308	373,194
Fair Value	48,837	25,099
Level 2 \| Interest rate lock commitments
Securities:
Derivative instruments	0	0
Level 2 \| Demand deposits
Financial liabilities:
Deposits	6,083,563	6,495,326
Level 2 \| Savings deposits
Financial liabilities:
Deposits	10,060,523	8,897,909
Level 2 \| Time deposits
Financial liabilities:
Deposits	1,123,035	1,024,020
Level 2 \| Forward commitments
Securities:
Derivative instruments	829	32
Financial liabilities:
Fair Value	11	95
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
Other investments	0	0
Total	0
Loans held for sale	0	0
Loans, net	43,949	41,641
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	231	1,306
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 \| Commercial and industrial
Securities:
Held to maturity	3,278,703	2,645,085
Commercial and industrial \| Paycheck Protection Program ("PPP")
Securities:
Held to maturity	13,506	199,883
Commercial and industrial \| Owner occupied commercial real estate
Securities:
Held to maturity	2,285,973	2,240,334
Commercial and industrial \| Non-owner occupied commercial real estate
Securities:
Held to maturity	2,219,542	2,010,591
Commercial and industrial \| Real estate construction
Securities:
Held to maturity	996,017	856,119
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	3,117,330	2,594,012
Commercial and industrial \| Level 2 \| Paycheck Protection Program ("PPP")
Securities:
Loans, net	13,506	199,883
Commercial and industrial \| Level 2 \| Owner occupied commercial real estate
Securities:
Loans, net	2,139,649	2,213,583
Commercial and industrial \| Level 2 \| Non-owner occupied commercial real estate
Securities:
Loans, net	2,101,258	1,986,215
Commercial and industrial \| Level 2 \| Real estate construction
Securities:
Loans, net	966,796	844,578
Commercial and industrial \| Significant Unobservable Inputs (Level 3) \| Commercial and industrial
Securities:
Loans, net	14,436	8,989
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	8,486	8,447
Commercial and industrial \| Significant Unobservable Inputs (Level 3) \| Non-owner occupied commercial real estate
Securities:
Loans, net	11,643	11,946
Commercial and industrial \| Significant Unobservable Inputs (Level 3) \| Real estate construction
Securities:
Loans, net	1,547	0
Agricultural and agricultural real estate
Securities:
Held to maturity	781,354	753,753
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	722,299	737,834
Agricultural and agricultural real estate \| Significant Unobservable Inputs (Level 3)
Securities:
Loans, net	6,215	11,404
Residential real estate
Securities:
Held to maturity	852,928	829,283
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	809,211	818,323
Residential real estate \| Significant Unobservable Inputs (Level 3)
Securities:
Loans, net	1,622	855
Consumer
Securities:
Held to maturity	495,509	419,524
Consumer \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Securities:
Loans, net	0	0
Consumer \| Level 2
Securities:
Loans, net	480,968	415,487
Consumer \| Significant Unobservable Inputs (Level 3)
Securities:
Loans, net	0	0
Carrying Amount
Financial assets:
Cash and cash equivalents	399,860	435,599
Time deposits in other financial institutions	1,740	2,894
Securities:
Carried at fair value	6,060,331	7,530,374
Held to maturity		84,709
Other investments	80,286	82,567
Total	830,247
Loans held for sale	9,570	21,640
Loans, net	10,817,817	9,844,484
Cash surrender value on life insurance	193,184	191,722
Derivative instruments	48,893	23,891
Financial liabilities:
Short term borrowings	147,000	131,597
Other borrowings	371,446	372,072
Fair Value	48,837	25,099
Carrying Amount \| Interest rate lock commitments
Securities:
Derivative instruments	231	1,306
Carrying Amount \| Demand deposits
Financial liabilities:
Deposits	6,083,563	6,495,326
Carrying Amount \| Savings deposits
Financial liabilities:
Deposits	10,060,523	8,897,909
Carrying Amount \| Time deposits
Financial liabilities:
Deposits	1,123,035	1,024,020
Carrying Amount \| Forward commitments
Securities:
Derivative instruments	829	32
Financial liabilities:
Fair Value	11	95
Carrying Amount \| Commercial and industrial \| Commercial and industrial
Securities:
Loans, net	3,248,440	2,617,347
Carrying Amount \| Commercial and industrial \| Paycheck Protection Program ("PPP")
Securities:
Loans, net	13,506	199,883
Carrying Amount \| Commercial and industrial \| Owner occupied commercial real estate
Securities:
Loans, net	2,269,001	2,221,120
Carrying Amount \| Commercial and industrial \| Non-owner occupied commercial real estate
Securities:
Loans, net	2,204,733	1,992,683
Carrying Amount \| Commercial and industrial \| Real estate construction
Securities:
Loans, net	971,747	833,581
Carrying Amount \| Agricultural and agricultural real estate
Securities:
Loans, net	778,787	748,540
Carrying Amount \| Residential real estate
Securities:
Loans, net	845,502	820,856
Carrying Amount \| Consumer
Securities:
Loans, net	486,101	410,474
Estimated Fair Value
Financial assets:
Cash and cash equivalents	399,860	435,599
Time deposits in other financial institutions	1,740	2,894
Securities:
Carried at fair value	6,060,031	7,530,374
Held to maturity		94,139
Other investments	80,286	82,567
Total	782,805
Loans held for sale	9,570	21,640
Loans, net	10,394,966	9,851,556
Cash surrender value on life insurance	193,184	191,722
Derivative instruments	48,893	23,891
Financial liabilities:
Short term borrowings	147,000	131,597
Other borrowings	372,308	373,194
Fair Value	48,837	25,099
Estimated Fair Value \| Interest rate lock commitments
Securities:
Derivative instruments	231	1,306
Estimated Fair Value \| Demand deposits
Financial liabilities:
Deposits	6,083,563	6,495,326
Estimated Fair Value \| Savings deposits
Financial liabilities:
Deposits	10,060,523	8,897,909
Estimated Fair Value \| Time deposits
Financial liabilities:
Deposits	1,123,035	1,024,020
Estimated Fair Value \| Forward commitments
Securities:
Derivative instruments	829	32
Financial liabilities:
Fair Value	11	95
Estimated Fair Value \| Commercial and industrial \| Commercial and industrial
Securities:
Loans, net	3,131,766	2,603,001
Estimated Fair Value \| Commercial and industrial \| Paycheck Protection Program ("PPP")
Securities:
Loans, net	13,506	199,883
Estimated Fair Value \| Commercial and industrial \| Owner occupied commercial real estate
Securities:
Loans, net	2,148,135	2,222,030
Estimated Fair Value \| Commercial and industrial \| Non-owner occupied commercial real estate
Securities:
Loans, net	2,112,901	1,998,161
Estimated Fair Value \| Commercial and industrial \| Real estate construction
Securities:
Loans, net	968,343	844,578
Estimated Fair Value \| Agricultural and agricultural real estate
Securities:
Loans, net	728,514	749,238
Estimated Fair Value \| Residential real estate
Securities:
Loans, net	810,833	819,178
Estimated Fair Value \| Consumer
Securities:
Loans, net	$ 480,968	$ 415,487

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