FAIR VALUE OF ASSETS AND LIABILITIES - Carrying value and estimated fair values of financial instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Carrying value
Financial Assets
Cash and cash equivalents	$ 42,638	$ 62,118
Securities available-for-sale	76,801	76,694
Federal Home Loan Bank stock	2,937	3,176
Loans held-for-sale	837	763
Loans receivable, net	753,623	699,018
Accrued interest receivable	2,260	2,307
Cash surrender value of life insurance	13,952	13,685
Mortgage servicing rights	359	597
Financial Liabilities
Demand (non-interest-bearing)	210,396	201,340
Demand (interest-bearing)	126,064	125,465
Money market	201,504	183,783
Savings and other	127,595	119,651
Certificates of deposit	121,171	124,294
Deposits	786,730	754,533
Repurchase agreements	3,581	3,914
FHLBB advances	27,134	26,979
Subordinated debt	9,782	9,764
Note payable	351	376
Capital lease liability	419	422
Accrued interest payable	275	150
Estimated fair value
Financial Assets
Cash and cash equivalents	42,638	62,118
Securities available-for-sale	76,801	76,694
Federal Home Loan Bank stock	2,937	3,176
Loans held-for-sale	852	778
Loans receivable, net	765,433	707,154
Accrued interest receivable	2,260	2,307
Cash surrender value of life insurance	13,952	13,685
Mortgage servicing rights	962	1,383
Financial Liabilities
Demand (non-interest-bearing)	210,396	201,340
Demand (interest-bearing)	126,064	125,465
Money market	201,504	183,783
Savings and other	127,595	119,651
Certificates of deposit	122,448	125,437
Deposits	788,007	755,676
Repurchase agreements	3,581	3,914
FHLBB advances	28,004	28,559
Subordinated debt	10,432	9,764
Note payable	385	405
Capital lease liability	903	870
Accrued interest payable	275	150
Fair Value Measurements Using - Level 1
Financial Assets
Cash and cash equivalents	42,638	62,118
Securities available-for-sale	241	246
Federal Home Loan Bank stock
Loans held-for-sale
Loans receivable, net
Accrued interest receivable	2,260	2,307
Cash surrender value of life insurance	13,952	13,685
Mortgage servicing rights
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	275	150
Fair Value Measurements Using - Level 2
Financial Assets
Cash and cash equivalents
Securities available-for-sale	76,560	76,448
Federal Home Loan Bank stock	2,937	3,176
Loans held-for-sale
Loans receivable, net
Accrued interest receivable
Cash surrender value of life insurance
Mortgage servicing rights	962	1,383
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	852	778
Loans receivable, net	765,433	707,154
Accrued interest receivable
Cash surrender value of life insurance
Mortgage servicing rights
Financial Liabilities
Demand (non-interest-bearing)	210,396	201,340
Demand (interest-bearing)	126,064	125,465
Money market	201,504	183,783
Savings and other	127,595	119,651
Certificates of deposit	122,448	125,437
Deposits	788,007	755,676
Repurchase agreements	3,581	3,914
FHLBB advances	28,004	28,559
Subordinated debt	10,432	9,764
Note payable	385	405
Capital lease liability	903	870
Accrued interest payable