FAIR VALUE (Fair value measurement non-recurring) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned	$ 5,050	$ 6,914
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	0	0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	65,969	26,748
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	0	0
Fair Value, Measurements, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	31,584	36,464
Loans held for sale	65,969	26,748
Other real estate owned	5,050	6,914
Fair Value, Measurements, Nonrecurring | Mortgage servicing rights
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing rights	4,823	5,621
Fair Value, Measurements, Nonrecurring | Premises, furniture and equipment held for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Premises, furniture and equipment held for sale	567	2,967
Fair Value, Measurements, Nonrecurring | Changes Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	10,718	2,450
Loans held for sale	(2,648)	(980)
Other real estate owned	1,047	947
Fair Value, Measurements, Nonrecurring | Changes Measurement | Mortgage servicing rights
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing rights	1,676	911
Fair Value, Measurements, Nonrecurring | Changes Measurement | Premises, furniture and equipment held for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Premises, furniture and equipment held for sale	0	735
Fair Value, Measurements, Nonrecurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Loans held for sale	0	0
Other real estate owned	0	0
Fair Value, Measurements, Nonrecurring | Level 1 | Mortgage servicing rights
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing rights	0	0
Fair Value, Measurements, Nonrecurring | Level 1 | Premises, furniture and equipment held for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Premises, furniture and equipment held for sale	0	0
Fair Value, Measurements, Nonrecurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Loans held for sale	65,969	26,748
Other real estate owned	0	0
Fair Value, Measurements, Nonrecurring | Level 2 | Mortgage servicing rights
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing rights	0	0
Fair Value, Measurements, Nonrecurring | Level 2 | Premises, furniture and equipment held for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Premises, furniture and equipment held for sale	0	0
Fair Value, Measurements, Nonrecurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	31,584	36,464
Loans held for sale	0	0
Other real estate owned	5,050	6,914
Fair Value, Measurements, Nonrecurring | Level 3 | Mortgage servicing rights
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing rights	4,823	5,621
Fair Value, Measurements, Nonrecurring | Level 3 | Premises, furniture and equipment held for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Premises, furniture and equipment held for sale	567	2,967
Fair Value, Measurements, Nonrecurring | Agricultural and agricultural real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	13,923	12,623
Fair Value, Measurements, Nonrecurring | Agricultural and agricultural real estate | Changes Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	781	1,254
Fair Value, Measurements, Nonrecurring | Agricultural and agricultural real estate | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Fair Value, Measurements, Nonrecurring | Agricultural and agricultural real estate | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Fair Value, Measurements, Nonrecurring | Agricultural and agricultural real estate | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	13,923	12,623
Fair Value, Measurements, Nonrecurring | Residential real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	376	4,978
Fair Value, Measurements, Nonrecurring | Residential real estate | Changes Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	36	82
Fair Value, Measurements, Nonrecurring | Residential real estate | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Fair Value, Measurements, Nonrecurring | Residential real estate | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Fair Value, Measurements, Nonrecurring | Residential real estate | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	376	4,978
Fair Value, Measurements, Nonrecurring | Consumer
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	250	1,033
Fair Value, Measurements, Nonrecurring | Consumer | Changes Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Fair Value, Measurements, Nonrecurring | Consumer | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Fair Value, Measurements, Nonrecurring | Consumer | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Fair Value, Measurements, Nonrecurring | Consumer | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	250	1,033
Commercial and industrial | Fair Value, Measurements, Nonrecurring | Commercial and industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	9,602	15,173
Commercial and industrial | Fair Value, Measurements, Nonrecurring | Commercial and industrial | Changes Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	445	1,114
Commercial and industrial | Fair Value, Measurements, Nonrecurring | Commercial and industrial | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Commercial and industrial | Fair Value, Measurements, Nonrecurring | Commercial and industrial | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Commercial and industrial | Fair Value, Measurements, Nonrecurring | Commercial and industrial | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	9,602	15,173
Commercial and industrial | Fair Value, Measurements, Nonrecurring | Owner occupied commercial real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	5,949	1,352
Commercial and industrial | Fair Value, Measurements, Nonrecurring | Owner occupied commercial real estate | Changes Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	9,456	0
Commercial and industrial | Fair Value, Measurements, Nonrecurring | Owner occupied commercial real estate | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Commercial and industrial | Fair Value, Measurements, Nonrecurring | Owner occupied commercial real estate | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Commercial and industrial | Fair Value, Measurements, Nonrecurring | Owner occupied commercial real estate | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	5,949	1,352
Commercial and industrial | Fair Value, Measurements, Nonrecurring | Non-owner occupied commercial real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	1,035	1,305
Commercial and industrial | Fair Value, Measurements, Nonrecurring | Non-owner occupied commercial real estate | Changes Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Commercial and industrial | Fair Value, Measurements, Nonrecurring | Non-owner occupied commercial real estate | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Commercial and industrial | Fair Value, Measurements, Nonrecurring | Non-owner occupied commercial real estate | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Commercial and industrial | Fair Value, Measurements, Nonrecurring | Non-owner occupied commercial real estate | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	1,035	1,305
Real estate construction | Fair Value, Measurements, Nonrecurring | Commercial and industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	449	0
Real estate construction | Fair Value, Measurements, Nonrecurring | Commercial and industrial | Changes Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Real estate construction | Fair Value, Measurements, Nonrecurring | Commercial and industrial | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Real estate construction | Fair Value, Measurements, Nonrecurring | Commercial and industrial | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Real estate construction | Fair Value, Measurements, Nonrecurring | Commercial and industrial | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	$ 449	$ 0