DISCONTINUED OPERATIONS - Discontinued Operations Included in Statement of Operations (Details) - MEGTEC and Universal Businesses - Discontinued Operations, Held-for-sale - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenue	$ 58,257	$ 116,439
Cost of operations	45,521	90,189
Selling, general and administrative	7,597	17,024
Goodwill impairment	72,309	72,309
Research and development	390	756
Operating income (loss)	(67,560)	(63,839)
Net loss	$ (55,932)	$ (59,428)