FAIR VALUE MEASUREMENTS - Carrying value and estimated fair values of financial instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Carrying value
Financial Assets
Cash and cash equivalents	$ 35,485	$ 62,118
Securities available-for-sale	79,623	76,694
Federal Home Loan Bank stock	3,211	3,176
Loans held-for-sale		763
Loans receivable, net	763,184	699,018
Accrued interest receivable	2,424	2,307
Cash surrender value of life insurance	14,038	13,685
Financial Liabilities
Demand (non-interest-bearing)	218,420	201,340
Demand (interest-bearing)	127,854	125,465
Money market	182,476	183,783
Savings and other	135,435	119,651
Certificates of deposit	117,585	124,294
Deposits	781,770	754,533
Repurchase agreements	5,535	3,914
FHLBB advances	37,188	26,979
Subordinated debt	9,788	9,764
Note payable	344	376
Capital lease liability	418	422
Accrued interest payable	89	150
Estimated fair value
Financial Assets
Cash and cash equivalents	35,485	62,118
Securities available-for-sale	79,623	76,694
Federal Home Loan Bank stock	3,211	3,176
Loans held-for-sale		778
Loans receivable, net	774,442	707,154
Accrued interest receivable	2,424	2,307
Cash surrender value of life insurance	14,038	13,685
Financial Liabilities
Demand (non-interest-bearing)	218,420	201,340
Demand (interest-bearing)	127,854	125,465
Money market	182,476	183,783
Savings and other	135,435	119,651
Certificates of deposit	118,610	125,437
Deposits	782,795	755,676
Repurchase agreements	5,535	3,914
FHLBB advances	38,440	28,559
Subordinated debt	10,378	9,764
Note payable	377	405
Capital lease liability	841	870
Accrued interest payable	89	150
Fair Value Measurements Using - Level 1
Financial Assets
Cash and cash equivalents	35,485	62,118
Securities available-for-sale	1,040	1,010
Federal Home Loan Bank stock
Loans held-for-sale
Loans receivable, net
Accrued interest receivable
Cash surrender value of life insurance	14,038	13,685
Financial Liabilities
Demand (non-interest-bearing)
Demand (interest-bearing)
Money market
Savings and other
Certificates of deposit
Deposits
Repurchase agreements
FHLBB advances
Subordinated debt
Note payable
Capital lease liability
Accrued interest payable
Fair Value Measurements Using - Level 2
Financial Assets
Cash and cash equivalents
Securities available-for-sale	78,583	75,684
Federal Home Loan Bank stock	3,211	3,176
Loans held-for-sale
Loans receivable, net
Accrued interest receivable
Cash surrender value of life insurance
Financial Liabilities
Demand (non-interest-bearing)
Demand (interest-bearing)
Money market
Savings and other
Certificates of deposit
Deposits
Repurchase agreements
FHLBB advances
Subordinated debt
Note payable
Capital lease liability
Accrued interest payable
Fair Value Measurements Using - Level 3
Financial Assets
Cash and cash equivalents
Securities available-for-sale
Federal Home Loan Bank stock
Loans held-for-sale		788
Loans receivable, net	774,442	707,154
Accrued interest receivable	2,424	2,307
Cash surrender value of life insurance
Financial Liabilities
Demand (non-interest-bearing)	218,420	201,340
Demand (interest-bearing)	127,854	125,465
Money market	182,476	183,783
Savings and other	135,435	119,651
Certificates of deposit	118,610	125,437
Deposits	782,795	755,676
Repurchase agreements	5,535	3,914
FHLBB advances	38,440	28,559
Subordinated debt	10,378	9,764
Note payable	377	405
Capital lease liability	841	870
Accrued interest payable	$ 89	$ 150