SEGMENT AND GEOGRAPHICAL REPORTING - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Identifiable assets at year end	$ 699,962	$ 639,083
Depreciation	9,578	10,520	$ 11,933
Corporate
Segment Reporting Information [Line Items]
Capital expenditures	600	200	500
Identifiable assets at year end	54,700	19,400	18,300
Depreciation	$ 1,500	$ 1,800	$ 1,400