LOANS AND ALLOWANCE FOR LOAN LOSSES - Aging (Details)	12 Months Ended
	Dec. 31, 2017 USD ($) quarter component	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Aging categories of performing loans and nonaccrual loans
Current	$ 1,095,474,000	$ 1,044,311,000
Total Past Due	9,832,000	7,657,000
Total Loans	1,105,306,000	1,051,968,000
Non-Accrual	9,699,000	6,229,000
90 Days Still Accruing	0	0
Increased amount of interest income on loans	$ 423,000	396,000	$ 639,000
Allowance for loan losses, number of evaluation components | component	2
Impaired loans collectively evaluated	$ 1,300,000	0
Number of rolling quarters utilized in charge-off factor calculation | quarter	12
Liability for unfunded commitments	$ 284,000	284,000
Commercial
Aging categories of performing loans and nonaccrual loans
Current	777,756,000	752,664,000
Total Past Due	6,153,000	3,955,000
Total Loans	783,909,000	756,619,000
Non-Accrual	8,350,000	4,975,000
90 Days Still Accruing	0	0
Commercial | Commercial Business
Aging categories of performing loans and nonaccrual loans
Current	377,901,000	386,311,000
Total Past Due	2,462,000	258,000
Total Loans	380,363,000	386,569,000
Non-Accrual	1,027,000	74,000
90 Days Still Accruing	0	0
Commercial | Commercial Real Estate
Aging categories of performing loans and nonaccrual loans
Current	300,282,000	270,339,000
Total Past Due	1,574,000	1,121,000
Total Loans	301,856,000	271,460,000
Non-Accrual	5,206,000	1,375,000
90 Days Still Accruing	0	0
Commercial | Acquisition & Development
Aging categories of performing loans and nonaccrual loans
Current	99,573,000	96,014,000
Total Past Due	2,117,000	2,576,000
Total Loans	101,690,000	98,590,000
Non-Accrual	2,117,000	3,526,000
90 Days Still Accruing	0	0
Residential
Aging categories of performing loans and nonaccrual loans
Current	243,177,000	212,502,000
Total Past Due	3,037,000	2,950,000
Total Loans	246,214,000	215,452,000
Non-Accrual	1,157,000	1,072,000
90 Days Still Accruing	0	0
Home Equity
Aging categories of performing loans and nonaccrual loans
Current	61,907,000	64,791,000
Total Past Due	493,000	595,000
Total Loans	62,400,000	65,386,000
Non-Accrual	13,000	104,000
90 Days Still Accruing	0	0
Consumer
Aging categories of performing loans and nonaccrual loans
Current	12,634,000	14,354,000
Total Past Due	149,000	157,000
Total Loans	12,783,000	14,511,000
Non-Accrual	179,000	78,000
90 Days Still Accruing	0	0
Financing Receivables, 30 to 59 Days Past Due
Aging categories of performing loans and nonaccrual loans
Total Past Due	2,687,000	2,891,000
Financing Receivables, 30 to 59 Days Past Due | Commercial
Aging categories of performing loans and nonaccrual loans
Total Past Due	557,000	244,000
Financing Receivables, 30 to 59 Days Past Due | Commercial | Commercial Business
Aging categories of performing loans and nonaccrual loans
Total Past Due	512,000	15,000
Financing Receivables, 30 to 59 Days Past Due | Commercial | Commercial Real Estate
Aging categories of performing loans and nonaccrual loans
Total Past Due	45,000	229,000
Financing Receivables, 30 to 59 Days Past Due | Commercial | Acquisition & Development
Aging categories of performing loans and nonaccrual loans
Total Past Due	0	0
Financing Receivables, 30 to 59 Days Past Due | Residential
Aging categories of performing loans and nonaccrual loans
Total Past Due	1,879,000	2,067,000
Financing Receivables, 30 to 59 Days Past Due | Home Equity
Aging categories of performing loans and nonaccrual loans
Total Past Due	240,000	525,000
Financing Receivables, 30 to 59 Days Past Due | Consumer
Aging categories of performing loans and nonaccrual loans
Total Past Due	11,000	55,000
Financing Receivables, 60 to 89 Days Past Due
Aging categories of performing loans and nonaccrual loans
Total Past Due	4,338,000	622,000
Financing Receivables, 60 to 89 Days Past Due | Commercial
Aging categories of performing loans and nonaccrual loans
Total Past Due	3,391,000	169,000
Financing Receivables, 60 to 89 Days Past Due | Commercial | Commercial Business
Aging categories of performing loans and nonaccrual loans
Total Past Due	1,368,000	169,000
Financing Receivables, 60 to 89 Days Past Due | Commercial | Commercial Real Estate
Aging categories of performing loans and nonaccrual loans
Total Past Due	1,149,000	0
Financing Receivables, 60 to 89 Days Past Due | Commercial | Acquisition & Development
Aging categories of performing loans and nonaccrual loans
Total Past Due	874,000	0
Financing Receivables, 60 to 89 Days Past Due | Residential
Aging categories of performing loans and nonaccrual loans
Total Past Due	707,000	419,000
Financing Receivables, 60 to 89 Days Past Due | Home Equity
Aging categories of performing loans and nonaccrual loans
Total Past Due	240,000	0
Financing Receivables, 60 to 89 Days Past Due | Consumer
Aging categories of performing loans and nonaccrual loans
Total Past Due	0	34,000
Financing Receivables, Equal to Greater than 90 Days Past Due
Aging categories of performing loans and nonaccrual loans
Total Past Due	2,807,000	4,144,000
Financing Receivables, Equal to Greater than 90 Days Past Due | Commercial
Aging categories of performing loans and nonaccrual loans
Total Past Due	2,205,000	3,542,000
Financing Receivables, Equal to Greater than 90 Days Past Due | Commercial | Commercial Business
Aging categories of performing loans and nonaccrual loans
Total Past Due	582,000	74,000
Financing Receivables, Equal to Greater than 90 Days Past Due | Commercial | Commercial Real Estate
Aging categories of performing loans and nonaccrual loans
Total Past Due	380,000	892,000
Financing Receivables, Equal to Greater than 90 Days Past Due | Commercial | Acquisition & Development
Aging categories of performing loans and nonaccrual loans
Total Past Due	1,243,000	2,576,000
Financing Receivables, Equal to Greater than 90 Days Past Due | Residential
Aging categories of performing loans and nonaccrual loans
Total Past Due	451,000	464,000
Financing Receivables, Equal to Greater than 90 Days Past Due | Home Equity
Aging categories of performing loans and nonaccrual loans
Total Past Due	13,000	70,000
Financing Receivables, Equal to Greater than 90 Days Past Due | Consumer
Aging categories of performing loans and nonaccrual loans
Total Past Due	$ 138,000	$ 68,000