STOCK COMPENSATION (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended			12 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restricted Stock
Shares [Roll Forward]
Nonvested, beginning of period (in shares)	25,522	23,794		23,794
Granted (in shares)				10,161
Vested (in shares)				(7,294)
Forfeited or cancelled (in shares)				(1,139)
Nonvested, end of period (in shares)				25,522	23,794
Weighted-Average Grant Date Fair Value [Roll Forward]
Nonvested, beginning of period (in dollars per share)	$ 38.01	$ 29.90		$ 29.90
Granted (in dollars per share)				49.74
Vested (in dollars per share)				29.15
Forfeitures or cancelled (in dollars per share)				29.97
Nonvested, end of period (in dollars per share)				$ 38.01	$ 29.90
Total unrecognized compensation cost related to nonvested shares granted under the Plan				$ 955
Weighted-average period for recognition				4 years 22 days
Total fair value of shares vested				$ 382	$ 193	$ 314
President and Chief Executive Officer
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Service period				12 months
Directors and President and Chief Executive Officer
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Number of treasury shares reissued to fund stock compensation (in shares)		7,880	9,532
Expense related to stock compensation recognized				$ 301	$ 269	$ 262
Subsequent Event | Directors and President and Chief Executive Officer
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Number of treasury shares reissued to fund stock compensation (in shares)	6,015