FAIR VALUE (Fair Value Measurement Non-recurring) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Benefit to provision for loan losses	$ (17,072)	$ (1,678)	$ (26,796)	$ (21,520)	$ (4,903)	$ (5,201)	$ (4,918)	$ (1,635)	$ (67,066)	$ (16,657)	$ (24,013)
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	0				0				0	0
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	57,949				26,748				57,949	26,748
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	0				0				0	0
Nonrecurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	34,488				36,464				34,488	36,464
Loans held for sale	57,949				26,748				57,949	26,748
Other real estate owned	6,624				6,914				6,624	6,914
Premises, furniture and equipment held for sale	6,499				2,967				6,499	2,967
Nonrecurring Basis | Agricultural and agricultural real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	12,451								12,451
Nonrecurring Basis | Consumer
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0								0
Nonrecurring Basis | Residential real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0								0
Nonrecurring Basis | (Gains)/Losses
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	12,082				2,450				12,082	2,450
Loans held for sale	(982)				(980)				(982)	(980)
Other real estate owned	1,044				947				1,044	947
Premises, furniture and equipment held for sale	3,288				735				3,288	735
Nonrecurring Basis | Commercial and industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	11,256				15,173				11,256	15,173
Nonrecurring Basis | Commercial and industrial | Owner occupied commercial real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	5,874				1,352				5,874	1,352
Nonrecurring Basis | Commercial and industrial | Non-owner occupied commercial real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	4,907				1,305				4,907	1,305
Nonrecurring Basis | Commercial and industrial | (Gains)/Losses
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	451				1,114				451	1,114
Nonrecurring Basis | Commercial and industrial | (Gains)/Losses | Owner occupied commercial real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	11,631				0				11,631	0
Nonrecurring Basis | Commercial and industrial | (Gains)/Losses | Non-owner occupied commercial real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Nonrecurring Basis | Owner occupied commercial real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Nonrecurring Basis | Owner occupied commercial real estate | (Gains)/Losses
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Nonrecurring Basis | Agricultural and agricultural real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans					12,623					12,623
Nonrecurring Basis | Agricultural and agricultural real estate | (Gains)/Losses
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				1,254				0	1,254
Nonrecurring Basis | Residential real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans					4,978					4,978
Nonrecurring Basis | Residential real estate | (Gains)/Losses
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				82				0	82
Nonrecurring Basis | Consumer
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans					1,033					1,033
Nonrecurring Basis | Consumer | (Gains)/Losses
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Nonrecurring Basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Loans held for sale	0				0				0	0
Other real estate owned	0				0				0	0
Premises, furniture and equipment held for sale	0				0				0	0
Nonrecurring Basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Commercial and industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Nonrecurring Basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Commercial and industrial | Owner occupied commercial real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Nonrecurring Basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Commercial and industrial | Non-owner occupied commercial real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Nonrecurring Basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Owner occupied commercial real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Nonrecurring Basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Agricultural and agricultural real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Nonrecurring Basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Residential real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Nonrecurring Basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Consumer
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Nonrecurring Basis | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Loans held for sale	57,949				26,748				57,949	26,748
Other real estate owned	0				0				0	0
Premises, furniture and equipment held for sale	0				0				0	0
Nonrecurring Basis | Significant Other Observable Inputs (Level 2) | Commercial and industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Nonrecurring Basis | Significant Other Observable Inputs (Level 2) | Commercial and industrial | Owner occupied commercial real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Nonrecurring Basis | Significant Other Observable Inputs (Level 2) | Commercial and industrial | Non-owner occupied commercial real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Nonrecurring Basis | Significant Other Observable Inputs (Level 2) | Owner occupied commercial real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Nonrecurring Basis | Significant Other Observable Inputs (Level 2) | Agricultural and agricultural real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Nonrecurring Basis | Significant Other Observable Inputs (Level 2) | Residential real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Nonrecurring Basis | Significant Other Observable Inputs (Level 2) | Consumer
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Nonrecurring Basis | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	34,488				36,464				34,488	36,464
Loans held for sale	0				0				0	0
Other real estate owned	6,624				6,914				6,624	6,914
Premises, furniture and equipment held for sale	6,499				2,967				6,499	2,967
Nonrecurring Basis | Significant Unobservable Inputs (Level 3) | Commercial and industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	11,256				15,173				11,256	15,173
Nonrecurring Basis | Significant Unobservable Inputs (Level 3) | Commercial and industrial | Owner occupied commercial real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	5,874				1,352				5,874	1,352
Nonrecurring Basis | Significant Unobservable Inputs (Level 3) | Commercial and industrial | Non-owner occupied commercial real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	4,907				1,305				4,907	1,305
Nonrecurring Basis | Significant Unobservable Inputs (Level 3) | Owner occupied commercial real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Nonrecurring Basis | Significant Unobservable Inputs (Level 3) | Agricultural and agricultural real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	12,451				12,623				12,451	12,623
Nonrecurring Basis | Significant Unobservable Inputs (Level 3) | Residential real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				4,978				0	4,978
Nonrecurring Basis | Significant Unobservable Inputs (Level 3) | Consumer
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				1,033				0	1,033
Nonrecurring Basis | Commercial Servicing Rights
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing rights	5,189				5,621				5,189	5,621
Nonrecurring Basis | Commercial Servicing Rights | (Gains)/Losses
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing rights	1,778				911				1,778	911
Nonrecurring Basis | Commercial Servicing Rights | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing rights	0				0				0	0
Nonrecurring Basis | Commercial Servicing Rights | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing rights	0				0				0	0
Nonrecurring Basis | Commercial Servicing Rights | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing rights	$ 5,189				$ 5,621				$ 5,189	$ 5,621