LOANS (Impaired loans) (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Receivables [Abstract]
Threshold period past due, nonperforming status of loans and leases	90 days	90 days
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired loans with a related allowance		$ 17,721
Impaired loans without a related allowance		75,171
Total impaired loans held to maturity		92,892
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired loans with a related allowance		17,189
Impaired loans without a related allowance		69,863
Total impaired loans held to maturity		87,052
Impaired Financing Receivable, Related Allowance		8,172
Avg. Loan Balance
Impaired loans with a related allowance		18,217
Impaired loans without a related allowance		67,721
Total impaired loans held to maturity		85,938
Interest Income Recognized
Impaired loans with a related allowance		39
Impaired loans without a related allowance		1,596
Total impaired loans held to maturity		1,635
Commercial and industrial
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired loans with a related allowance		17
Impaired loans without a related allowance		668
Total impaired loans held to maturity		685
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired loans with a related allowance		17
Impaired loans without a related allowance		668
Total impaired loans held to maturity		685
Impaired Financing Receivable, Related Allowance		0
Avg. Loan Balance
Impaired loans with a related allowance		0
Impaired loans without a related allowance		636
Total impaired loans held to maturity		636
Interest Income Recognized
Impaired loans with a related allowance		0
Impaired loans without a related allowance		26
Total impaired loans held to maturity		26
Commercial and industrial | Commercial and industrial
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired loans with a related allowance		11,727
Impaired loans without a related allowance		22,525
Total impaired loans held to maturity		34,252
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired loans with a related allowance		11,710
Impaired loans without a related allowance		20,104
Total impaired loans held to maturity		31,814
Impaired Financing Receivable, Related Allowance		6,276
Avg. Loan Balance
Impaired loans with a related allowance		11,757
Impaired loans without a related allowance		19,141
Total impaired loans held to maturity		30,898
Interest Income Recognized
Impaired loans with a related allowance		6
Impaired loans without a related allowance		782
Total impaired loans held to maturity		788
Commercial and industrial | Owner occupied commercial real estate
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired loans with a related allowance		712
Impaired loans without a related allowance		8,756
Total impaired loans held to maturity		9,468
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired loans with a related allowance		712
Impaired loans without a related allowance		8,756
Total impaired loans held to maturity		9,468
Impaired Financing Receivable, Related Allowance		352
Avg. Loan Balance
Impaired loans with a related allowance		1,435
Impaired loans without a related allowance		8,337
Total impaired loans held to maturity		9,772
Interest Income Recognized
Impaired loans with a related allowance		22
Impaired loans without a related allowance		341
Total impaired loans held to maturity		363
Commercial and industrial | Non-owner occupied commercial real estate
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired loans with a related allowance		138
Impaired loans without a related allowance		1,592
Total impaired loans held to maturity		1,730
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired loans with a related allowance		138
Impaired loans without a related allowance		1,592
Total impaired loans held to maturity		1,730
Impaired Financing Receivable, Related Allowance		33
Avg. Loan Balance
Impaired loans with a related allowance		0
Impaired loans without a related allowance		1,515
Total impaired loans held to maturity		1,515
Interest Income Recognized
Impaired loans with a related allowance		0
Impaired loans without a related allowance		62
Total impaired loans held to maturity		62
Agricultural and agricultural real estate
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired loans with a related allowance		2,751
Impaired loans without a related allowance		19,113
Total impaired loans held to maturity		21,864
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired loans with a related allowance		2,237
Impaired loans without a related allowance		16,317
Total impaired loans held to maturity		18,554
Impaired Financing Receivable, Related Allowance		916
Avg. Loan Balance
Impaired loans with a related allowance		2,739
Impaired loans without a related allowance		16,837
Total impaired loans held to maturity		19,576
Interest Income Recognized
Impaired loans with a related allowance		0
Impaired loans without a related allowance		60
Total impaired loans held to maturity		60
Residential real estate
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired loans with a related allowance		1,378
Impaired loans without a related allowance		19,382
Total impaired loans held to maturity		20,760
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired loans with a related allowance		1,378
Impaired loans without a related allowance		19,300
Total impaired loans held to maturity		20,678
Impaired Financing Receivable, Related Allowance		176
Avg. Loan Balance
Impaired loans with a related allowance		1,116
Impaired loans without a related allowance		17,073
Total impaired loans held to maturity		18,189
Interest Income Recognized
Impaired loans with a related allowance		0
Impaired loans without a related allowance		280
Total impaired loans held to maturity		280
Consumer
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired loans with a related allowance		998
Impaired loans without a related allowance		3,135
Total impaired loans held to maturity		4,133
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired loans with a related allowance		997
Impaired loans without a related allowance		3,126
Total impaired loans held to maturity		4,123
Impaired Financing Receivable, Related Allowance		419
Avg. Loan Balance
Impaired loans with a related allowance		1,170
Impaired loans without a related allowance		4,182
Total impaired loans held to maturity		5,352
Interest Income Recognized
Impaired loans with a related allowance		11
Impaired loans without a related allowance		45
Total impaired loans held to maturity		$ 56