FAIR VALUE (Estimated fair value financial instruments incl. carrying amounts) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Securities:
Held to maturity	$ 99,619	$ 100,484
Level 1
Financial assets:
Cash and cash equivalents	331,665	378,734
Time deposits in other financial institutions	3,129	3,564
Securities:
Carried at fair value	2,035	8,503
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 assets	0	0
Financial liabilities:
Short term borrowings	0	0
Other borrowings	0	0
Derivative liabilities	0	0
Level 1 \| Interest rate lock commitments
Securities:
Derivative assets	0	0
Level 1 \| Demand deposits
Financial liabilities:
Deposits	0	0
Level 1 \| Savings deposits
Financial liabilities:
Deposits	0	0
Level 1 \| Time deposits
Financial liabilities:
Deposits	0	0
Level 1 \| Forward commitments
Financial liabilities:
Derivative liabilities	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	4,948,663	3,304,293
Held to maturity	99,619	100,484
Other investments	35,940	31,321
Loans held for sale	65,969	26,748
Loans, net	8,889,019	8,206,879
Cash surrender value on life insurance	173,111	171,625
Derivative assets	50,387	17,527
Financial liabilities:
Short term borrowings	306,706	182,626
Other borrowings	525,388	278,169
Derivative liabilities	59,328	21,462
Level 2 \| Interest rate lock commitments
Securities:
Derivative assets	0	0
Level 2 \| Demand deposits
Financial liabilities:
Deposits	5,022,567	3,543,863
Level 2 \| Savings deposits
Financial liabilities:
Deposits	6,742,151	6,307,425
Level 2 \| Time deposits
Financial liabilities:
Deposits	1,002,392	1,193,043
Level 2 \| Forward commitments
Financial liabilities:
Derivative liabilities	352	113
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	31,584	36,464
Cash surrender value on life insurance	0	0
Derivative assets	0	0
Financial liabilities:
Short term borrowings	0	0
Other borrowings	0	0
Derivative liabilities	0	0
Level 3 \| Interest rate lock commitments
Securities:
Derivative assets	2,255	681
Level 3 \| Demand deposits
Financial liabilities:
Deposits	0	0
Level 3 \| Savings deposits
Financial liabilities:
Deposits	0	0
Level 3 \| Time deposits
Financial liabilities:
Deposits	0	0
Level 3 \| Forward commitments
Financial liabilities:
Derivative liabilities	0	0
Commercial and industrial \| Level 1 \| Commercial and industrial
Securities:
Loans, net	0	0
Commercial and industrial \| Level 1 \| Real estate construction
Securities:
Loans, net	0	0
Commercial and industrial \| Level 2 \| Commercial and industrial
Securities:
Loans, net	2,219,880	2,606,080
Commercial and industrial \| Level 2 \| Real estate construction
Securities:
Loans, net	907,470	924,041
Commercial and industrial \| Level 3 \| Commercial and industrial
Securities:
Loans, net	9,602	15,173
Commercial and industrial \| Level 3 \| Real estate construction
Securities:
Loans, net	449	0
Paycheck Protection Program ("PPP") \| Level 1 \| Commercial and industrial
Securities:
Loans, net	0
Paycheck Protection Program ("PPP") \| Level 2 \| Commercial and industrial
Securities:
Loans, net	1,128,035
Paycheck Protection Program ("PPP") \| Level 3 \| Commercial and industrial
Securities:
Loans, net	0
Owner occupied commercial real estate \| Level 1 \| Commercial and industrial
Securities:
Loans, net	0	0
Owner occupied commercial real estate \| Level 2 \| Commercial and industrial
Securities:
Loans, net	1,464,643	1,408,036
Owner occupied commercial real estate \| Level 3 \| Commercial and industrial
Securities:
Loans, net	5,949	1,352
Non-owner occupied commercial real estate \| Level 1 \| Commercial and industrial
Securities:
Loans, net	0	0
Non-owner occupied commercial real estate \| Level 2 \| Commercial and industrial
Securities:
Loans, net	1,633,306	1,396,222
Non-owner occupied commercial real estate \| Level 3 \| Commercial and industrial
Securities:
Loans, net	1,035	1,305
Agricultural and agricultural real estate \| Level 1
Securities:
Loans, net	0	0
Agricultural and agricultural real estate \| Level 2
Securities:
Loans, net	470,734	564,198
Agricultural and agricultural real estate \| Level 3
Securities:
Loans, net	13,923	12,623
Residential real estate \| Level 1
Securities:
Loans, net	0	0
Residential real estate \| Level 2
Securities:
Loans, net	690,369	838,365
Residential real estate \| Level 3
Securities:
Loans, net	376	3,088
Consumer \| Level 1
Securities:
Loans, net	0	0
Consumer \| Level 2
Securities:
Loans, net	374,582	469,939
Consumer \| Level 3
Securities:
Loans, net	250	988
Carrying Amount
Financial assets:
Cash and cash equivalents	331,655	378,734
Time deposits in other financial institutions	3,129	3,564
Securities:
Carried at fair value	4,950,698	3,312,796
Held to maturity	88,700	91,324
Other investments	35,940	31,321
Loans held for sale	65,969	26,748
Loans, net	8,996,269	8,297,522
Cash surrender value on life insurance	173,111	171,625
Derivative assets	50,387	17,527
Financial liabilities:
Short term borrowings	306,706	182,626
Other borrowings	524,045	275,773
Derivative liabilities	59,328	21,462
Carrying Amount \| Interest rate lock commitments
Securities:
Derivative assets	2,255	681
Carrying Amount \| Demand deposits
Financial liabilities:
Deposits	5,022,567	3,543,863
Carrying Amount \| Savings deposits
Financial liabilities:
Deposits	6,742,151	6,307,425
Carrying Amount \| Time deposits
Financial liabilities:
Deposits	1,002,392	1,193,043
Carrying Amount \| Forward commitments
Financial liabilities:
Derivative liabilities	352	113
Carrying Amount \| Commercial and industrial \| Commercial and industrial
Securities:
Loans, net	2,269,048	2,530,809
Carrying Amount \| Commercial and industrial \| Real estate construction
Securities:
Loans, net	896,978	1,027,081
Carrying Amount \| Paycheck Protection Program ("PPP") \| Commercial and industrial
Securities:
Loans, net	1,128,035
Carrying Amount \| Owner occupied commercial real estate \| Commercial and industrial
Securities:
Loans, net	1,483,673	1,472,704
Carrying Amount \| Non-owner occupied commercial real estate \| Commercial and industrial
Securities:
Loans, net	1,647,556	1,495,877
Carrying Amount \| Agricultural and agricultural real estate
Securities:
Loans, net	502,717	565,837
Carrying Amount \| Residential real estate
Securities:
Loans, net	692,228	832,277
Carrying Amount \| Consumer
Securities:
Loans, net	376,034	443,332
Estimated Fair Value
Financial assets:
Cash and cash equivalents	331,665	378,734
Time deposits in other financial institutions	3,129	3,564
Securities:
Carried at fair value	4,950,698	3,312,796
Held to maturity	99,619	100,484
Other investments	35,940	31,321
Loans held for sale	65,969	26,748
Loans, net	8,920,603	8,243,343
Cash surrender value on life insurance	173,111	171,625
Derivative assets	50,387	17,527
Financial liabilities:
Short term borrowings	306,706	182,626
Other borrowings	525,388	278,169
Derivative liabilities	59,328	21,462
Estimated Fair Value \| Interest rate lock commitments
Securities:
Derivative assets	2,255	681
Estimated Fair Value \| Demand deposits
Financial liabilities:
Deposits	5,022,567	3,543,863
Estimated Fair Value \| Savings deposits
Financial liabilities:
Deposits	6,742,151	6,307,425
Estimated Fair Value \| Time deposits
Financial liabilities:
Deposits	1,002,392	1,193,043
Estimated Fair Value \| Forward commitments
Financial liabilities:
Derivative liabilities	352	113
Estimated Fair Value \| Commercial and industrial \| Commercial and industrial
Securities:
Loans, net	2,229,482	2,621,253
Estimated Fair Value \| Commercial and industrial \| Real estate construction
Securities:
Loans, net	907,919	924,041
Estimated Fair Value \| Paycheck Protection Program ("PPP") \| Commercial and industrial
Securities:
Loans, net	1,128,035
Estimated Fair Value \| Owner occupied commercial real estate \| Commercial and industrial
Securities:
Loans, net	1,470,592	1,409,388
Estimated Fair Value \| Non-owner occupied commercial real estate \| Commercial and industrial
Securities:
Loans, net	1,634,341	1,397,527
Estimated Fair Value \| Agricultural and agricultural real estate
Securities:
Loans, net	484,657	576,821
Estimated Fair Value \| Residential real estate
Securities:
Loans, net	690,745	841,453
Estimated Fair Value \| Consumer
Securities:
Loans, net	374,832	$ 470,927
Forward commitments \| Level 1
Securities:
Derivative assets	0
Forward commitments \| Level 2
Securities:
Derivative assets	27
Forward commitments \| Level 3
Securities:
Derivative assets	0
Forward commitments \| Carrying Amount
Securities:
Derivative assets	27
Forward commitments \| Estimated Fair Value
Securities:
Derivative assets	$ 27

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