FAIR VALUE (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
Impaired Loans, Fair Value Disclosure [Abstract]
Provision for loan and lease losses	$ (709,000)	$ (1,040,000)
Fair value, assets, level 2 to level 1 transfers, amount	0
Recurring
Financial Assets [Abstract]
Obligations of U.S. Government and U.S. Government sponsored enterprises	15,451,000		$ 15,491,000
Mortgage-backed securities, residential	207,819,000		219,909,000
Obligations of states and political subdivisions	51,617,000		53,132,000
Corporate bonds and notes	249,000		251,000
SBA loan pools	3,848,000		4,308,000
Total available for sale securities	278,984,000		293,091,000
Corporate stocks	1,225,000		1,192,000
Derivative assets	1,820,000		974,000
Derivative liabilities	1,870,000		1,049,000
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial Assets [Abstract]
Obligations of U.S. Government and U.S. Government sponsored enterprises	0		0
Mortgage-backed securities, residential	0		0
Obligations of states and political subdivisions	0		0
Corporate bonds and notes	0		0
SBA loan pools	0		0
Total available for sale securities	0		0
Corporate stocks	1,225,000		1,192,000
Derivative assets	0		0
Derivative liabilities	0		0
Recurring | Significant Other Observable Inputs (Level 2)
Financial Assets [Abstract]
Obligations of U.S. Government and U.S. Government sponsored enterprises	15,451,000		15,491,000
Mortgage-backed securities, residential	207,819,000		219,909,000
Obligations of states and political subdivisions	51,617,000		53,132,000
Corporate bonds and notes	249,000		251,000
SBA loan pools	3,848,000		4,308,000
Total available for sale securities	278,984,000		293,091,000
Corporate stocks	0		0
Derivative assets	1,820,000		974,000
Derivative liabilities	1,820,000		974,000
Recurring | Significant Unobservable Inputs (Level 3)
Financial Assets [Abstract]
Obligations of U.S. Government and U.S. Government sponsored enterprises	0		0
Mortgage-backed securities, residential	0		0
Obligations of states and political subdivisions	0		0
Corporate bonds and notes	0		0
SBA loan pools	0		0
Total available for sale securities	0		0
Corporate stocks	0		0
Derivative assets	0		0
Derivative liabilities	50,000		75,000
Impaired Loans: | Non-recurring
Impaired Loans, Fair Value Disclosure [Abstract]
Total impaired loans	350,000		507,000
Provision for loan and lease losses	(59,000)		(175,000)
Impaired Loans: | Non-recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Impaired Loans, Fair Value Disclosure [Abstract]
Total impaired loans	0		0
Impaired Loans: | Non-recurring | Significant Other Observable Inputs (Level 2)
Impaired Loans, Fair Value Disclosure [Abstract]
Total impaired loans	0		0
Impaired Loans: | Non-recurring | Significant Unobservable Inputs (Level 3)
Impaired Loans, Fair Value Disclosure [Abstract]
Total impaired loans	350,000		507,000
Other real estate owned: | Non-recurring
Impaired Loans, Fair Value Disclosure [Abstract]
Total other real estate owned, net	1,832,000		1,940,000
Provision for loan and lease losses	0		(43,000)
Other real estate owned: | Non-recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Impaired Loans, Fair Value Disclosure [Abstract]
Total other real estate owned, net	0		0
Other real estate owned: | Non-recurring | Significant Other Observable Inputs (Level 2)
Impaired Loans, Fair Value Disclosure [Abstract]
Total other real estate owned, net	0		0
Other real estate owned: | Non-recurring | Significant Unobservable Inputs (Level 3)
Impaired Loans, Fair Value Disclosure [Abstract]
Total other real estate owned, net	1,832,000		1,940,000
Commercial mortgages, other | Other real estate owned: | Non-recurring
Impaired Loans, Fair Value Disclosure [Abstract]
Total other real estate owned, net	1,474,000		1,483,000
Provision for loan and lease losses	0		(43,000)
Commercial mortgages, other | Other real estate owned: | Non-recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Impaired Loans, Fair Value Disclosure [Abstract]
Total other real estate owned, net	0		0
Commercial mortgages, other | Other real estate owned: | Non-recurring | Significant Other Observable Inputs (Level 2)
Impaired Loans, Fair Value Disclosure [Abstract]
Total other real estate owned, net	0		0
Commercial mortgages, other | Other real estate owned: | Non-recurring | Significant Unobservable Inputs (Level 3)
Impaired Loans, Fair Value Disclosure [Abstract]
Total other real estate owned, net	1,474,000		1,483,000
Home equity lines and loans | Other real estate owned: | Non-recurring
Impaired Loans, Fair Value Disclosure [Abstract]
Provision for loan and lease losses			0
Home equity lines & loans				$ 75,000
Home equity lines and loans | Other real estate owned: | Non-recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Impaired Loans, Fair Value Disclosure [Abstract]
Home equity lines & loans				0
Home equity lines and loans | Other real estate owned: | Non-recurring | Significant Other Observable Inputs (Level 2)
Impaired Loans, Fair Value Disclosure [Abstract]
Home equity lines & loans				0
Home equity lines and loans | Other real estate owned: | Non-recurring | Significant Unobservable Inputs (Level 3)
Impaired Loans, Fair Value Disclosure [Abstract]
Home equity lines & loans				$ 75,000
Commercial and agricultural:
Impaired Loans, Fair Value Disclosure [Abstract]
Provision for loan and lease losses	(37,000)	(42,000)
Commercial and agricultural: | Commercial and industrial | Impaired Loans: | Non-recurring
Impaired Loans, Fair Value Disclosure [Abstract]
Total impaired loans	12,000		96,000
Provision for loan and lease losses	0		(70,000)
Commercial and agricultural: | Commercial and industrial | Impaired Loans: | Non-recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Impaired Loans, Fair Value Disclosure [Abstract]
Total impaired loans	0		0
Commercial and agricultural: | Commercial and industrial | Impaired Loans: | Non-recurring | Significant Other Observable Inputs (Level 2)
Impaired Loans, Fair Value Disclosure [Abstract]
Total impaired loans	0		0
Commercial and agricultural: | Commercial and industrial | Impaired Loans: | Non-recurring | Significant Unobservable Inputs (Level 3)
Impaired Loans, Fair Value Disclosure [Abstract]
Total impaired loans	12,000		96,000
Commercial mortgages:
Impaired Loans, Fair Value Disclosure [Abstract]
Provision for loan and lease losses	(125,000)	(478,000)
Commercial mortgages: | Commercial mortgages | Impaired Loans: | Non-recurring
Impaired Loans, Fair Value Disclosure [Abstract]
Total impaired loans	338,000		411,000
Provision for loan and lease losses	(59,000)		(105,000)
Commercial mortgages: | Commercial mortgages | Impaired Loans: | Non-recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Impaired Loans, Fair Value Disclosure [Abstract]
Total impaired loans	0		0
Commercial mortgages: | Commercial mortgages | Impaired Loans: | Non-recurring | Significant Other Observable Inputs (Level 2)
Impaired Loans, Fair Value Disclosure [Abstract]
Total impaired loans	0		0
Commercial mortgages: | Commercial mortgages | Impaired Loans: | Non-recurring | Significant Unobservable Inputs (Level 3)
Impaired Loans, Fair Value Disclosure [Abstract]
Total impaired loans	338,000		411,000
Residential mortgages
Impaired Loans, Fair Value Disclosure [Abstract]
Provision for loan and lease losses	(180,000)	16,000
Residential mortgages | Other real estate owned: | Non-recurring
Impaired Loans, Fair Value Disclosure [Abstract]
Total other real estate owned, net	283,000		382,000
Provision for loan and lease losses	0		0
Residential mortgages | Other real estate owned: | Non-recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Impaired Loans, Fair Value Disclosure [Abstract]
Total other real estate owned, net	0		0
Residential mortgages | Other real estate owned: | Non-recurring | Significant Other Observable Inputs (Level 2)
Impaired Loans, Fair Value Disclosure [Abstract]
Total other real estate owned, net	0		0
Residential mortgages | Other real estate owned: | Non-recurring | Significant Unobservable Inputs (Level 3)
Impaired Loans, Fair Value Disclosure [Abstract]
Total other real estate owned, net	283,000		$ 382,000
Consumer loans:
Impaired Loans, Fair Value Disclosure [Abstract]
Provision for loan and lease losses	(367,000)	$ (536,000)
Consumer loans: | Home equity lines and loans | Other real estate owned: | Non-recurring
Impaired Loans, Fair Value Disclosure [Abstract]
Total other real estate owned, net	75,000
Provision for loan and lease losses	0
Consumer loans: | Home equity lines and loans | Other real estate owned: | Non-recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Impaired Loans, Fair Value Disclosure [Abstract]
Total other real estate owned, net	0
Consumer loans: | Home equity lines and loans | Other real estate owned: | Non-recurring | Significant Other Observable Inputs (Level 2)
Impaired Loans, Fair Value Disclosure [Abstract]
Total other real estate owned, net	0
Consumer loans: | Home equity lines and loans | Other real estate owned: | Non-recurring | Significant Unobservable Inputs (Level 3)
Impaired Loans, Fair Value Disclosure [Abstract]
Total other real estate owned, net	$ 75,000