PENSION PLAN - Plan Assets at Fair Value (Details) - Pension Plan - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	$ 6,165	$ 5,238	$ 5,166
Level I
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	5,179	4,348
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	986	890
Cash
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	247	262
Cash | Level I
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	247	262
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	1,418	1,257
Fixed income | Level I
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	1,418	1,257
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	925	890
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	925	890
Domestic equities
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	2,034	1,624
Domestic equities | Level I
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	2,034	1,624
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	1,480	1,205
Foreign equities | Level I
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	1,480	1,205
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
Real estate investment trusts
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	61
Real estate investment trusts | Level I
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	0
Real estate investment trusts | Level II
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	0
Real estate investment trusts | Level III
Plan's assets at fair value by level, within the fair value hierarchy
Total assets at fair value	$ 61