PENSION PLAN - Plan Assets at Fair Value (Details) - Pension Plan - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	$ 5,238	$ 5,166	$ 4,573
Level I
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	4,348	4,494
Level II
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	0	0
Level III
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	890	672
Cash
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	262	465
Cash | Level I
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	262	465
Cash | Level II
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	0	0
Cash | Level III
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	0	0
Fixed income
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	1,257	1,188
Fixed income | Level I
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	1,257	1,188
Fixed income | Level II
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	0	0
Fixed income | Level III
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	0	0
Alternative investments
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	890	672
Alternative investments | Level I
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	0	0
Alternative investments | Level II
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	0	0
Alternative investments | Level III
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	890	672
Domestic equities
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	1,624	1,653
Domestic equities | Level I
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	1,624	1,653
Domestic equities | Level II
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	0	0
Domestic equities | Level III
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	0	0
Foreign equities
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	1,205	1,188
Foreign equities | Level I
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	1,205	1,188
Foreign equities | Level II
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	0	0
Foreign equities | Level III
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	$ 0	$ 0