NET DEFERRED TAX ASSET AND INCOME TAXES - Components of net deferred tax assets (Details) - Components of net deferred tax assets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Allowance for loan losses	$ 2,174	$ 1,916
Interest on non-performing loans	244	233
Accrued deferred compensation	493	334
Post-retirement benefits	11	11
Other real estate owned write-downs	30
Restricted stock awards	220	162
Net unrealized holding loss on available-for-sale securities		58
Write-down of securities	2	4
Other	139	282
Gross deferred tax assets	3,313	3,000
Deferred loan costs, net	(329)	(344)
Mark-to-market purchase accounting adjustments	(44)	(37)
Goodwill and core deposit intangible asset	(570)	(545)
Accelerated depreciation	(703)	(698)
Other real estate owned write-downs		(45)
Mortgage servicing rights	(58)	(55)
Net unrealized holding gain on available-for-sale securities	(360)
Gross deferred tax liabilities	(2,064)	(1,724)
Net deferred tax asset	$ 1,249	$ 1,276