FAIR VALUE (Quantitative Information about Level 3 fair value measurements) (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Interest rate lock commitments | Recurring Basis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	$ 1,857	$ 1,827
Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0	0
Level 3 | Interest rate lock commitments
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	1,857	1,827
Level 3 | Discounted cash flows
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing rights	6,218	5,189
Level 3 | Modified appraised value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other real estate owned	6,236	6,624
Level 3 | Modified appraised value | Agricultural and agricultural real estate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Collateral dependent impaired loans	7,271	12,451
Level 3 | Modified appraised value | Premises, furniture and equipment held for sale
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Premises, furniture and equipment held for sale	7,633
Level 3 | Modified appraised value | Premises, furniture and equipment held for sale | Recurring Basis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Premises, furniture and equipment held for sale		6,499
Level 3 | Interest rate lock commitments | Recurring Basis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	1,857	1,827
Level 3 | Interest rate lock commitments | Discounted cash flows
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	$ 1,857	$ 1,827
Closing ratio | Level 3 | Discounted cash flows | Weighted Average | Interest rate lock commitments
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	0.88	0.86
Closing ratio | Level 3 | Discounted cash flows | Minimum | Interest rate lock commitments
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	0	0
Closing ratio | Level 3 | Discounted cash flows | Maximum | Interest rate lock commitments
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	0.99	0.99
Appraisal discount | Level 3 | Modified appraised value | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing assets, discount rate	0.00%	0.00%
Appraisal discount | Level 3 | Modified appraised value | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing assets, discount rate	10.00%	10.00%
Appraisal discount | Level 3 | Modified appraised value | Premises, furniture and equipment held for sale | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing assets, discount rate		0.00%
Appraisal discount | Level 3 | Modified appraised value | Premises, furniture and equipment held for sale | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing assets, discount rate	10.00%	10.00%
Commercial and industrial | Level 3 | Modified appraised value | Commercial and industrial
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Collateral dependent impaired loans	$ 10,621	$ 11,256
Commercial and industrial | Level 3 | Modified appraised value | Owner occupied commercial real estate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Collateral dependent impaired loans	1,233	5,874
Commercial and industrial | Level 3 | Modified appraised value | Non-owner occupied commercial real estate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Collateral dependent impaired loans	$ 12,050	$ 4,907
Commercial and industrial | Appraisal discount | Level 3 | Modified appraised value | Commercial and industrial | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing assets, discount rate	0.00%	0.00%
Commercial and industrial | Appraisal discount | Level 3 | Modified appraised value | Commercial and industrial | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing assets, discount rate	7.00%	8.00%
Commercial and industrial | Appraisal discount | Level 3 | Modified appraised value | Owner occupied commercial real estate | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing assets, discount rate	0.00%	0.00%
Commercial and industrial | Appraisal discount | Level 3 | Modified appraised value | Owner occupied commercial real estate | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing assets, discount rate	12.00%	12.00%
Commercial and industrial | Appraisal discount | Level 3 | Modified appraised value | Non-owner occupied commercial real estate | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing assets, discount rate	0.00%	0.00%
Commercial and industrial | Appraisal discount | Level 3 | Modified appraised value | Non-owner occupied commercial real estate | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing assets, discount rate	10.00%	10.00%
Agricultural and agricultural real estate | Appraisal discount | Level 3 | Modified appraised value | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing assets, discount rate	0.00%	0.00%
Agricultural and agricultural real estate | Appraisal discount | Level 3 | Modified appraised value | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing assets, discount rate	9.00%	10.00%