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LOANS AND ALLOWANCE FOR LOAN LOSSES - Allowances (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Dec. 31, 2019
Allowance for loan losses, by portfolio segment [Roll Forward]
Beginning balance	$ 24,130	$ 19,656	$ 23,478	$ 18,944
Charge-offs	(326)	(302)	(3,248)	(1,155)
Recoveries	107	128	371	450
Net recoveries (charge-offs)	(219)	(174)	(2,877)	(705)
Provision	679	4,441	3,989	5,684
Ending balance	24,590	23,923	24,590	23,923
Ending allowance balance attributable to loans [Abstract]
Individually evaluated for impairment					$ 5,766	$ 8,097
Collectively evaluated for impairment					18,824	15,381
Total ending allowance balance	24,590	23,923	23,478	18,944	24,590	23,478
Loans [Abstract]
Loans individually evaluated for impairment					16,354	15,665
Loans collectively evaluated for  impairment					1,527,174	1,297,238
Total ending loans balance					1,543,528	1,312,903
Commercial and Agricultural
Allowance for loan losses, by portfolio segment [Roll Forward]
Beginning balance	8,327	5,476	10,227	5,383
Charge-offs	(68)	0	(134)	(55)
Recoveries	18	29	27	44
Net recoveries (charge-offs)	(50)	29	(107)	(11)
Provision	180	4,651	(1,663)	4,784
Ending balance	8,457	10,156	8,457	10,156
Ending allowance balance attributable to loans [Abstract]
Individually evaluated for impairment					5,530	6,000
Collectively evaluated for impairment					2,927	4,227
Total ending allowance balance	8,457	10,156	10,227	5,383	8,457	10,227
Loans [Abstract]
Loans individually evaluated for impairment					7,515	6,147
Loans collectively evaluated for  impairment					398,498	224,775
Total ending loans balance					406,013	230,922
Commercial mortgages:
Allowance for loan losses, by portfolio segment [Roll Forward]
Beginning balance	10,549	9,545	8,869	8,184
Charge-offs	0	0	(2,143)	0
Recoveries	2	0	2	2
Net recoveries (charge-offs)	2	0	(2,141)	2
Provision	361	(285)	4,184	1,074
Ending balance	10,912	9,260	10,912	9,260
Ending allowance balance attributable to loans [Abstract]
Individually evaluated for impairment					184	2,097
Collectively evaluated for impairment					10,728	6,772
Total ending allowance balance	10,912	9,260	8,869	9,260	10,912	8,869
Loans [Abstract]
Loans individually evaluated for impairment					6,750	8,844
Loans collectively evaluated for  impairment					686,185	641,726
Total ending loans balance					692,935	650,570
Residential mortgages
Allowance for loan losses, by portfolio segment [Roll Forward]
Beginning balance	1,891	1,229	1,252	1,226
Charge-offs	(42)	(19)	(56)	(60)
Recoveries	0	0	49	45
Net recoveries (charge-offs)	(42)	(19)	(7)	(15)
Provision	232	(26)	836	(27)
Ending balance	2,081	1,184	2,081	1,184
Ending allowance balance attributable to loans [Abstract]
Individually evaluated for impairment					0	0
Collectively evaluated for impairment					2,081	1,252
Total ending allowance balance	2,081	1,184	2,081	1,226	2,081	1,252
Loans [Abstract]
Loans individually evaluated for impairment					1,277	525
Loans collectively evaluated for  impairment					226,707	188,349
Total ending loans balance					227,984	188,874
Consumer loans:
Allowance for loan losses, by portfolio segment [Roll Forward]
Beginning balance	3,363	3,406	3,130	4,151
Charge-offs	(216)	(283)	(915)	(1,040)
Recoveries	87	99	293	359
Net recoveries (charge-offs)	(129)	(184)	(622)	(681)
Provision	(94)	101	632	(147)
Ending balance	3,140	3,323	3,140	3,323
Ending allowance balance attributable to loans [Abstract]
Individually evaluated for impairment					52	0
Collectively evaluated for impairment					3,088	3,130
Total ending allowance balance	$ 3,140	$ 3,323	$ 3,140	$ 4,151	3,140	3,130
Loans [Abstract]
Loans individually evaluated for impairment					812	149
Loans collectively evaluated for  impairment					215,784	242,388
Total ending loans balance					$ 216,596	$ 242,537

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