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LOANS AND ALLOWANCE FOR LOAN LOSSES - Allowances (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Allowance for loan losses, by portfolio segment [Roll Forward]
Beginning balance	$ 20,909	$ 26,233	$ 20,924	$ 23,478
Charge-offs	(227)	(2,489)	(416)	(2,921)
Recoveries	144	126	577	263
Net recoveries (charge-offs)	(83)	(2,363)	161	(2,658)
Provision	(150)	260	(409)	3,310
Ending balance	20,676	24,130	20,676	24,130
Ending allowance balance attributable to loans:
Individually evaluated for impairment	3,244		3,244		$ 1,527
Collectively evaluated for impairment	17,432		17,432		19,397
Total ending allowance balance	20,676	24,130	20,676	24,130	20,924
Loans:
Loans individually evaluated for impairment	13,128		13,128		10,589
Loans collectively evaluated for  impairment	1,549,694		1,549,694		1,530,909
Total ending loans balance	1,562,822		1,562,822		1,541,498
Commercial and Agricultural
Allowance for loan losses, by portfolio segment [Roll Forward]
Beginning balance	4,337	11,191	4,493	10,227
Charge-offs	(25)	(36)	(25)	(65)
Recoveries	10	5	275	8
Net recoveries (charge-offs)	(15)	(31)	250	(57)
Provision	(694)	(2,833)	(1,115)	(1,843)
Ending balance	3,628	8,327	3,628	8,327
Ending allowance balance attributable to loans:
Individually evaluated for impairment	1,389		1,389		1,401
Collectively evaluated for impairment	2,239		2,239		3,092
Total ending allowance balance	3,628	8,327	3,628	8,327	4,493
Loans:
Loans individually evaluated for impairment	3,263		3,263		3,400
Loans collectively evaluated for  impairment	338,731		338,731		366,852
Total ending loans balance	341,994		341,994		370,252
Commercial mortgages:
Allowance for loan losses, by portfolio segment [Roll Forward]
Beginning balance	11,787	10,472	11,496	8,869
Charge-offs	0	(2,143)	0	(2,143)
Recoveries	1	0	1	0
Net recoveries (charge-offs)	1	(2,143)	1	(2,143)
Provision	1,175	2,220	1,466	3,823
Ending balance	12,963	10,549	12,963	10,549
Ending allowance balance attributable to loans:
Individually evaluated for impairment	1,781		1,781		74
Collectively evaluated for impairment	11,182		11,182		11,422
Total ending allowance balance	12,963	10,549	12,963	10,549	11,496
Loans:
Loans individually evaluated for impairment	8,565		8,565		5,117
Loans collectively evaluated for  impairment	758,635		758,635		714,028
Total ending loans balance	767,200		767,200		719,145
Residential mortgages
Allowance for loan losses, by portfolio segment [Roll Forward]
Beginning balance	2,115	1,421	2,079	1,252
Charge-offs	(46)	(13)	(71)	(13)
Recoveries	10	49	10	48
Net recoveries (charge-offs)	(36)	36	(61)	35
Provision	(288)	434	(227)	604
Ending balance	1,791	1,891	1,791	1,891
Ending allowance balance attributable to loans:
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	1,791		1,791		2,079
Total ending allowance balance	1,791	1,891	1,791	1,891	2,079
Loans:
Loans individually evaluated for impairment	954		954		1,271
Loans collectively evaluated for  impairment	246,355		246,355		238,742
Total ending loans balance	247,309		247,309		240,013
Consumer loans:
Allowance for loan losses, by portfolio segment [Roll Forward]
Beginning balance	2,670	3,149	2,856	3,130
Charge-offs	(156)	(297)	(320)	(700)
Recoveries	123	72	291	207
Net recoveries (charge-offs)	(33)	(225)	(29)	(493)
Provision	(343)	439	(533)	726
Ending balance	2,294	3,363	2,294	3,363
Ending allowance balance attributable to loans:
Individually evaluated for impairment	74		74		52
Collectively evaluated for impairment	2,220		2,220		2,804
Total ending allowance balance	2,294	$ 3,363	2,294	$ 3,363	2,856
Loans:
Loans individually evaluated for impairment	346		346		801
Loans collectively evaluated for  impairment	205,973		205,973		211,287
Total ending loans balance	$ 206,319		$ 206,319		$ 212,088

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