ALLOWANCE FOR LOAN LOSSES AND CREDIT QUALITY INFORMATION - Analysis of Impaired Loans (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Ending Loan Balances	$ 57,348	$ 62,106
Loans with No Related Reserve	28,006	32,172
Loans with Related Reserve	29,342	29,934
Related Reserve	3,956	5,017
Contractual Principal Balances	73,718	78,982
Average Loan Balances	60,672	60,743
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Ending Loan Balances	17,935	20,842
Loans with No Related Reserve	2,781	3,422
Loans with Related Reserve	15,154	17,420
Related Reserve	2,369	3,861
Contractual Principal Balances	21,035	23,815
Average Loan Balances	17,818	15,072
Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Ending Loan Balances	12,493	14,181
Loans with No Related Reserve	7,513	8,282
Loans with Related Reserve	4,980	5,899
Related Reserve	628	796
Contractual Principal Balances	14,863	17,015
Average Loan Balances	13,832	14,533
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Ending Loan Balances	7,844	7,819
Loans with No Related Reserve	6,577	6,304
Loans with Related Reserve	1,267	1,515
Related Reserve	192	203
Contractual Principal Balances	8,710	8,977
Average Loan Balances	7,891	8,158
Owner-occupied commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Ending Loan Balances	4,919	5,374
Loans with No Related Reserve	3,224	3,654
Loans with Related Reserve	1,695	1,720
Related Reserve	18	12
Contractual Principal Balances	5,542	5,717
Average Loan Balances	5,845	5,827
Commercial mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Ending Loan Balances	8,372	7,598
Loans with No Related Reserve	6,565	4,487
Loans with Related Reserve	1,807	3,111
Related Reserve	147	112
Contractual Principal Balances	17,314	16,658
Average Loan Balances	9,882	12,630
Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Ending Loan Balances	5,785	6,292
Loans with No Related Reserve	1,346	6,023
Loans with Related Reserve	4,439	269
Related Reserve	602	33
Contractual Principal Balances	6,254	6,800
Average Loan Balances	$ 5,404	$ 4,523