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, 2017	Dec. 31, 2016
Allowance for loan losses	$ 1,499	$ 2,023
Interest on non-performing loans	210	362
Accrued deferred compensation	248	268
Post-retirement benefits	11	17
Other real estate owned write-downs	6	184
Restricted stock awards	77	62
Mark-to-market purchase accounting adjustments	122	513
Write-down of securities	154	588
Other	51	64
Gross deferred tax assets	2,378	4,081
Deferred loan costs, net	(312)	(457)
Goodwill and core deposit intangible asset	(534)	(848)
Accelerated depreciation	(752)	(1,048)
Mortgage servicing rights	(56)	(116)
Net unrealized holding gain on available-for-sale securities	(47)	(245)
Gross deferred tax liabilities	(1,701)	(2,714)
Net deferred tax asset	$ 677	$ 1,367