ACCUMULATED OTHER COMPREHENSIVE LOSS - Summary of accumulated other comprehensive (loss) income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income Loss [Roll Forward]
Balance	$ (1,901)	$ (1,969)
Change during period:
Before-tax amount	(557)	76
Tax benefit (expense)	197	(27)
Reclassification adjustment, net of taxes
Amortization of net loss	54	48
Net realized gain (loss)	25	(29)
Total activity in period	(281)	68
Balance	(2,182)	(1,901)
Pension Adjustment
Accumulated Other Comprehensive Income Loss [Roll Forward]
Balance	(1,899)	(2,024)
Change during period:
Before-tax amount	(474)	119
Tax benefit (expense)	168	(42)
Reclassification adjustment, net of taxes
Amortization of net loss	54	48
Net realized gain (loss)
Total activity in period	(252)	125
Balance	(2,151)	(1,899)
Unrealized (Loss) gain on Securities
Accumulated Other Comprehensive Income Loss [Roll Forward]
Balance	(2)	55
Change during period:
Before-tax amount	(83)	(43)
Tax benefit (expense)	29	15
Reclassification adjustment, net of taxes
Amortization of net loss
Net realized gain (loss)	25	(29)
Total activity in period	(29)	(57)
Balance	$ (31)	$ (2)