EARNINGS PER SHARE - Computation of earnings per share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Earnings Per Share [Abstract]
Net income	$ 1,899	$ 1,882	$ 3,915	$ 3,487
Less: Undistributed earnings allocated to participating securities	(22)	(15)	(42)	(26)
Net income allocated to common stock	1,877	1,867	3,873	3,461
Weighted average common shares issued	2,794	2,780	2,790	2,773
Less: Unvested restricted stock awards	(32)	(23)	(30)	(20)
Weighted average common shares outstanding used to calculate basic earnings per common share	2,762	2,757	2,760	2,753
Add: Dilutive effect of stock options	17	18	20	19
Weighted average common shares outstanding used to calculate diluted earnings per common share	$ 2,779	$ 2,775	$ 2,780	$ 2,772
Earnings per common share (basic)	$ 0.68	$ 0.68	$ 1.40	$ 1.26
Earnings per common share (diluted)	$ 0.68	$ 0.67	$ 1.39	$ 1.25

Amount of increase (decrease) to net income used for calculating diluted earnings per share (EPS), resulting from the assumed exercise of stock options or restrictive stock units (RSUs).

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Amount of increase (decrease) to net income used for calculating diluted earnings per share (EPS), resulting from the assumed exercise stock options, restrictive stock units (RSUs), convertible preferred stock of an employee stock ownership plan (ESOP), and other dilutive convertible securities.

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities; of income (loss) available to common shareholders.

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The value of dividends forfeited related to restricted stock awards forfeited.

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Amount of undistributed earnings (loss) allocated to participating securities for the basic earnings (loss) per share or per unit calculation under the two-class method.

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