FAIR VALUE (Fair value measurement non-recurring) (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned	$ 6,314	$ 6,624
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	33,248	57,949
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	41,445	34,488
Loans held for sale	33,248	57,949
Other real estate owned	6,314	6,624
Fair Value, Measurements, Nonrecurring | Mortgage servicing rights
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing rights	5,559	5,189
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	6,925	6,499
Fair Value, Measurements, Nonrecurring | Changes Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	1,851	12,082
Loans held for sale	(1,304)	(982)
Other real estate owned	(88)	1,044
Fair Value, Measurements, Nonrecurring | Changes Measurement | Mortgage servicing rights
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing rights	(391)	1,778
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	(44)	3,288
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	33,248	57,949
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	41,445	34,488
Loans held for sale	0	0
Other real estate owned	6,314	6,624
Fair Value, Measurements, Nonrecurring | Level 3 | Mortgage servicing rights
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing rights	5,559	5,189
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	6,925	6,499
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	14,161	12,451
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	0	0
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	14,161	12,451
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	8,969	11,256
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	214	451
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	8,969	11,256
Owner occupied commercial real estate | Fair Value, Measurements, Nonrecurring | Commercial and industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	3,573	5,874
Owner occupied commercial real estate | 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	11,631
Owner occupied commercial real estate | 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
Owner occupied commercial real estate | 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
Owner occupied commercial real estate | 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	3,573	5,874
Non-owner occupied commercial real estate | Fair Value, Measurements, Nonrecurring | Commercial and industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	14,742	4,907
Non-owner occupied commercial real estate | 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	1,637	0
Non-owner occupied commercial real estate | 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
Non-owner occupied commercial real estate | 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
Non-owner occupied commercial real estate | 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	$ 14,742	$ 4,907