SECURITIES - Composition of Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Amortized cost (1)
Available-for-sale
Municipal bonds	$ 12,816	$ 15,800
Mortgage-backed securities, U.S. Government agencies and U.S. Government-sponsored enterprises	49,217	53,407
Collateralized mortgage obligations, U.S. Government Agencies	6,360	1,470
Collateralized mortgage obligations, Non-agency	2,997	3,327
SBA bonds	1,876	2,056
CRA mutual funds	838	834
Corporate bonds	2,000	2,000
Preferred stock	7	7
Total securities available-for-sale	76,111	78,901
Non-marketable securities
Federal Home Loan Bank of Boston stock	3,510	3,211
Gross unrealized gains
Available-for-sale
Municipal bonds	137	197
Mortgage-backed securities, U.S. Government agencies and U.S. Government-sponsored enterprises	221	229
Collateralized mortgage obligations, U.S. Government Agencies	3	4
Collateralized mortgage obligations, Non-agency	419	414
SBA bonds	7	9
CRA mutual funds
Corporate bonds	41	16
Preferred stock	165	215
Total securities available-for-sale	993	1,084
Non-marketable securities
Federal Home Loan Bank of Boston stock
Gross unrealized losses
Available-for-sale
Municipal bonds		1
Mortgage-backed securities, U.S. Government agencies and U.S. Government-sponsored enterprises	229	335
Collateralized mortgage obligations, U.S. Government Agencies
Collateralized mortgage obligations, Non-agency	9	6
SBA bonds	1	1
CRA mutual funds	16	16
Corporate bonds		3
Preferred stock
Total securities available-for-sale	255	362
Non-marketable securities
Federal Home Loan Bank of Boston stock
Fair value
Available-for-sale
Municipal bonds	12,953	15,996
Mortgage-backed securities, U.S. Government agencies and U.S. Government-sponsored enterprises	49,209	53,301
Collateralized mortgage obligations, U.S. Government Agencies	6,363	1,474
Collateralized mortgage obligations, Non-agency	3,407	3,735
SBA bonds	1,882	2,064
CRA mutual funds	822	818
Corporate bonds	2,041	2,013
Preferred stock	172	222
Total securities available-for-sale	76,849	79,623
Non-marketable securities
Federal Home Loan Bank of Boston stock	$ 3,510	$ 3,211

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Investments in notes or bonds that are collateralized by a specific group of underlying assets owned by the issuer of the notes or bonds which are short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Cash Equivalents
-URI http://asc.fasb.org/extlink&oid=6507016

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
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Amount of securities, mortgage loans, or other financial instruments pledged as collateral for deposits.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
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-Section 50
-Paragraph 1
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Amount of Federal Home Loan Bank (FHLB) and Federal Reserve Bank stock.

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For an unclassified balance sheet, this item represents investments in common and preferred stocks and other forms of securities that provide ownership interests in a corporation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
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Investment in short-term money-market instruments (such as commercial paper, banker's acceptances, repurchase agreements, government securities, certificates of deposit, and so forth) which are highly liquid (that is, readily convertible to known amounts of cash) and so near their maturity that they present an insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify as cash equivalents by definition. Original maturity means an original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Cash Equivalents
-URI http://asc.fasb.org/extlink&oid=6507016

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Fair value of securitized, pay-through debt securities collateralized by real estate mortgage loans classified as available-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Mortgage-Backed Securities
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- Definition

Bonds or similar securities issued by state, city, or local governments or the agencies operated by state, city, or local governments which are short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

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-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=6507016

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Carrying value as of the balance sheet date of the portion of long-term, collateralized debt obligations due within one year or the operating cycle, if longer. Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.20)
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-Name Regulation S-X (SX)
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-Section 02
-Paragraph 19, 20
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