ALLOWANCE FOR CREDIT LOSSES AND CREDIT QUALITY - Allowance for loan losses by portfolio segment (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	$ 67,526	$ 71,844	$ 67,773	$ 61,408
Provision for credit losses	0	(1,700)	417	(223)
Loans charged-off	(98)	(267)	(838)	(503)
Recoveries	95	1,836	171	1,981
Net loans (charged-off) recovered	(3)	1,569	(667)	1,478
Ending balance	67,523	71,713	67,523	71,713
Impact of adopting ASC 326 \| ASU 2016-13
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance				9,050
Unallocated
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	482	597	450	3,139
Provision for credit losses	165	(91)	197	248
Loans charged-off	0	0	0	0
Recoveries	0	0	0	0
Net loans (charged-off) recovered	0	0	0	0
Ending balance	647	506	647	506
Unallocated \| Impact of adopting ASC 326 \| ASU 2016-13
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance				(2,881)
Commercial Portfolio Segment \| Commercial and industrial loans:
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	31,322	32,052	30,595	28,333
Provision for credit losses	(139)	(187)	591	(727)
Loans charged-off	(13)	(162)	(32)	(249)
Recoveries	25	1,427	41	1,461
Net loans (charged-off) recovered	12	1,265	9	1,212
Ending balance	31,195	33,130	31,195	33,130
Commercial Portfolio Segment \| Commercial and industrial loans: \| Impact of adopting ASC 326 \| ASU 2016-13
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance				4,312
Commercial Portfolio Segment \| Commercial Real Estate and Multifamily Residential
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	26,257	29,445	26,535	22,907
Provision for credit losses	191	(1,160)	510	1,125
Loans charged-off	0	0	(597)	(71)
Recoveries	0	6	0	14
Net loans (charged-off) recovered	0	6	(597)	(57)
Ending balance	26,448	28,291	26,448	28,291
Commercial Portfolio Segment \| Commercial Real Estate and Multifamily Residential \| Impact of adopting ASC 326 \| ASU 2016-13
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance				4,316
Commercial Portfolio Segment \| Agri-business and agricultural loans:
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	4,761	3,901	5,034	3,043
Provision for credit losses	(8)	(291)	(281)	(493)
Loans charged-off	0	0	0	0
Recoveries	0	320	0	320
Net loans (charged-off) recovered	0	320	0	320
Ending balance	4,753	3,930	4,753	3,930
Commercial Portfolio Segment \| Agri-business and agricultural loans: \| Impact of adopting ASC 326 \| ASU 2016-13
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance				1,060
Commercial Portfolio Segment \| Other Commercial
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	1,058	1,172	1,146	416
Provision for credit losses	(345)	126	(433)	(59)
Loans charged-off	0	0	0	0
Recoveries	0	0	0	0
Net loans (charged-off) recovered	0	0	0	0
Ending balance	713	1,298	713	1,298
Commercial Portfolio Segment \| Other Commercial \| Impact of adopting ASC 326 \| ASU 2016-13
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance				941
Consumer Portfolio Segment \| Consumer 1-4 Family Mortgage
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	2,606	3,384	2,866	2,619
Provision for credit losses	34	(221)	(214)	(454)
Loans charged-off	0	(32)	(22)	(38)
Recoveries	34	34	44	85
Net loans (charged-off) recovered	34	2	22	47
Ending balance	2,674	3,165	2,674	3,165
Consumer Portfolio Segment \| Consumer 1-4 Family Mortgage \| Impact of adopting ASC 326 \| ASU 2016-13
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance				953
Consumer Portfolio Segment \| Other Consumer
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	1,040	1,293	1,147	951
Provision for credit losses	102	124	47	137
Loans charged-off	(85)	(73)	(187)	(145)
Recoveries	36	49	86	101
Net loans (charged-off) recovered	(49)	(24)	(101)	(44)
Ending balance	$ 1,093	$ 1,393	$ 1,093	1,393
Consumer Portfolio Segment \| Other Consumer \| Impact of adopting ASC 326 \| ASU 2016-13
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance				$ 349

Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 45
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=124255206&loc=SL82895884-210446

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Amount, excluding accrued interest, of increase in allowance for credit loss on financing receivable from recovery. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (e)
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919249-210447

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Amount, excluding accrued interest, of decrease in allowance for credit loss on financing receivable from writeoff. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (d)
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919249-210447

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Amount, excluding accrued interest, of decrease (increase) in allowance for credit loss on financing receivable from writeoff (recovery). Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919249-210447

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Amount, excluding accrued interest, of credit loss expense (reversal of expense) on financing receivable. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919249-210447

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