ALLOWANCE FOR CREDIT LOSSES AND CREDIT QUALITY - Allowance for loan losses by portfolio segment (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	$ 67,773	$ 61,408
Provision for credit losses	417	1,477
Loans charged-off	(740)	(236)
Recoveries	76	145
Net loans (charged-off) recovered	(664)	(91)
Ending balance	67,526	71,844
Impact of adopting ASC 326 \| ASU 2016-13
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance		9,050
Commercial and Industrial \| Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	30,595	28,333
Provision for credit losses	730	(540)
Loans charged-off	(19)	(87)
Recoveries	16	34
Net loans (charged-off) recovered	(3)	(53)
Ending balance	31,322	32,052
Commercial and Industrial \| Impact of adopting ASC 326 \| ASU 2016-13 \| Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance		4,312
Commercial Real Estate and Multifamily Residential \| Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	26,535	22,907
Provision for credit losses	319	2,285
Loans charged-off	(597)	(71)
Recoveries	0	8
Net loans (charged-off) recovered	(597)	(63)
Ending balance	26,257	29,445
Commercial Real Estate and Multifamily Residential \| Impact of adopting ASC 326 \| ASU 2016-13 \| Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance		4,316
Agri-business and Agricultural \| Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	5,034	3,043
Provision for credit losses	(273)	(202)
Loans charged-off	0	0
Recoveries	0	0
Net loans (charged-off) recovered	0	0
Ending balance	4,761	3,901
Agri-business and Agricultural \| Impact of adopting ASC 326 \| ASU 2016-13 \| Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance		1,060
Other Commercial \| Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	1,146	416
Provision for credit losses	(88)	(185)
Loans charged-off	0	0
Recoveries	0	0
Net loans (charged-off) recovered	0	0
Ending balance	1,058	1,172
Other Commercial \| Impact of adopting ASC 326 \| ASU 2016-13 \| Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance		941
Consumer 1-4 Family Mortgage \| Consumer Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	2,866	2,619
Provision for credit losses	(248)	(233)
Loans charged-off	(22)	(6)
Recoveries	10	51
Net loans (charged-off) recovered	(12)	45
Ending balance	2,606	3,384
Consumer 1-4 Family Mortgage \| Impact of adopting ASC 326 \| ASU 2016-13 \| Consumer Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance		953
Other Consumer \| Consumer Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	1,147	951
Provision for credit losses	(55)	13
Loans charged-off	(102)	(72)
Recoveries	50	52
Net loans (charged-off) recovered	(52)	(20)
Ending balance	1,040	1,293
Other Consumer \| Impact of adopting ASC 326 \| ASU 2016-13 \| Consumer Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance		349
Unallocated
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	450	3,139
Provision for credit losses	32	339
Loans charged-off	0	0
Recoveries	0	0
Net loans (charged-off) recovered	0	0
Ending balance	$ 482	597
Unallocated \| Impact of adopting ASC 326 \| ASU 2016-13
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance		$ (2,881)

Amount excluding accrued interest, of allowance for credit loss on financing receivable.

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-Name Accounting Standards Codification
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Amount, after recovery, of writeoff of financing receivable, charged against allowance for credit loss.

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Amount of increase in allowance for credit loss on financing receivable from recovery.

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