SHAREHOLDERS' EQUITY - Accumulated Other Comprehensive Income (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2018 USD ($)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
December 31, 2017	$ 40,241
Current-period change	(1,757)
September 30, 2018	27,872
Accumulated Other Comprehensive Income, Net
AOCI Attributable to Parent, Net of Tax [Roll Forward]
December 31, 2017	5,984
September 30, 2018	4,227
Foreign Currency Translation
AOCI Attributable to Parent, Net of Tax [Roll Forward]
December 31, 2017	5,703
Current-period change	(1,757)
September 30, 2018	3,946
Pension Postretirement Benefit Obligation
AOCI Attributable to Parent, Net of Tax [Roll Forward]
December 31, 2017	281
Current-period change	0
September 30, 2018	$ 281