EARNINGS PER SHARE - Computation of earnings per share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share [Abstract]
Net income	$ 2,988	$ 2,344	$ 8,126	$ 6,259
Less: Undistributed earnings allocated to participating securities	(48)	(33)	(110)	(74)
Net income allocated to common stock	2,940	2,311	8,016	6,185
Weighted average common shares issued	2,823	2,804	2,815	2,795
Less: Unvested restricted stock awards	(40)	(40)	(34)	(33)
Weighted average common shares outstanding used to calculate basic earnings per common share	2,783	2,764	2,781	2,762
Add: Dilutive effect of stock options	12	15	12	18
Weighted average common shares outstanding used to calculate diluted earnings per common share	$ 2,795	$ 2,779	$ 2,793	$ 2,780
Earnings per common share (basic)	$ 1.06	$ 0.84	$ 2.88	$ 2.24
Earnings per common share (diluted)	$ 1.05	$ 0.83	$ 2.87	$ 2.23

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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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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