INCOME TAXES - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Income tax benefit	$ (3,011)	$ (651)	$ (1,049)
Acquisitions in Canada | Foreign Tax Authority | Canada Revenue Agency
Business Acquisition [Line Items]
Income tax benefit	600	1,300	700
Valuation allowance	$ 700	$ 1,200	$ 700