SECURITIES - Aggreggate fair value and gross unrealized loss of securities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Less Than 12 Months, Fair value
Available-for-sale
Municipal bonds	$ 479	$ 517
Mortgage-backed securities	15,914	34,758
Collateralized mortgage obligations, U.S. Government agencies	9,317
Collateralized mortgage obligations, Non-agency		60
SBA bonds	8,519	475
CRA mutual funds	835	818
Corporate bonds	1,491	498
Total temporarily impaired securities	36,555	37,126
Other than temporarily impaired securities, Collateralized mortgage obligations, Non-agency	101	174
Total temporarily impaired and other-than-temporarily impaired securities	36,656	37,300
Less Than 12 Months, Unrealized losses
Available-for-sale
Municipal bonds	1	1
Mortgage-backed securities	99	329
Collateralized mortgage obligations, U.S. Government agencies	87
Collateralized mortgage obligations, Non-agency
SBA bonds	20	1
CRA mutual funds	16	16
Corporate bonds	9	3
Total temporarily impaired securities	232	350
Other than temporarily impaired securities, Collateralized mortgage obligations, Non-agency	14	1
Total temporarily impaired and other-than-temporarily impaired securities	246	351
12 Months or Longer, Fair value
Available-for-sale
Municipal bonds
Mortgage-backed securities	17,892	249
Collateralized mortgage obligations, U.S. Government agencies
Collateralized mortgage obligations, Non-agency	77	339
SBA bonds
CRA mutual funds
Corporate bonds
Total temporarily impaired securities	17,969	588
Other than temporarily impaired securities, Collateralized mortgage obligations, Non-agency
Total temporarily impaired and other-than-temporarily impaired securities	17,969	599
12 Months or Longer, Unrealized losses
Available-for-sale
Municipal bonds
Mortgage-backed securities	168	6
Collateralized mortgage obligations, U.S. Government agencies
Collateralized mortgage obligations, Non-agency	3	5
SBA bonds
CRA mutual funds
Corporate bonds
Total temporarily impaired securities	171	11
Other than temporarily impaired securities, Collateralized mortgage obligations, Non-agency
Total temporarily impaired and other-than-temporarily impaired securities	171	11
Total, Fair value
Available-for-sale
Municipal bonds	479	517
Mortgage-backed securities	33,806	35,007
Collateralized mortgage obligations, U.S. Government agencies	9,317
Collateralized mortgage obligations, Non-agency	77	399
SBA bonds	8,519	475
CRA mutual funds	835	818
Corporate bonds	1,491	498
Total temporarily impaired securities	54,524	37,714
Other than temporarily impaired securities, Collateralized mortgage obligations, Non-agency	101	174
Total temporarily impaired and other-than-temporarily impaired securities	54,625	37,888
Total, Unrealized losses
Available-for-sale
Municipal bonds	1	1
Mortgage-backed securities	267	335
Collateralized mortgage obligations, U.S. Government agencies	87
Collateralized mortgage obligations, Non-agency	3	5
SBA bonds	20	1
CRA mutual funds	16	16
Corporate bonds	9	3
Total temporarily impaired securities	403	361
Other than temporarily impaired securities, Collateralized mortgage obligations, Non-agency	14	1
Total temporarily impaired and other-than-temporarily impaired securities	$ 417	$ 362

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Accumulated other comprehensive loss related to portion of other than temporary impairment (OTTI) due to factors other than credit losses on debt securities categorized as available-for-sale that an entity does not intend to sell and which it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis of the debt security. The amount represented by this item is net of tax, as applicable.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 9A
-URI http://asc.fasb.org/extlink&oid=82896770&loc=SL6284427-111562

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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-Section 50
-Paragraph 2
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 14A
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Total of accumulated other comprehensive loss related to that portion of other than temporary impairment (OTTI) due to factors other than credit losses on debt securities categorized either as available-for-sale or held-to-maturity that an entity does not intend to sell and which it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis of the debt security. The amount represented by this item is net of tax, as applicable.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
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-URI http://asc.fasb.org/extlink&oid=84228862&loc=SL7669686-108580

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- Definition

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.

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Amount of securities that are debt instruments (corporate or municipal bonds) that typically have long-term nominal maturities for which the interest rate is reset through an auction process.

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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
-SubTopic 405
-Section 50
-Paragraph 1
-Subparagraph (b)
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The aggregate fair value as of the balance sheet date of financial instruments and other positions owned by the entity including: (1) mortgages, mortgage-backed and asset backed securities; (2) US government and agency obligations; (3) state and municipal government obligations; (4) other sovereign government debt; (5) corporate obligations; (6) corporate equities; (7) principal investments; (8) derivative contracts; and (9) physical commodities. Includes both pledged and unpledged holdings.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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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.

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

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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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