REVENUES (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Disaggregation of Revenue [Line Items]
Revenues	$ 36,781	$ 43,362	$ 66,748	$ 99,422
Revenue remaining performance obligation, practical expedient			true
Eliminations
Disaggregation of Revenue [Line Items]
Revenues	(23)		$ (23)
Towers and Heavy Fabrications
Disaggregation of Revenue [Line Items]
Revenues	24,024	34,327	40,808	83,222
Process Systems
Disaggregation of Revenue [Line Items]
Revenues	4,148	2,964	8,525	6,258
Gearing
Disaggregation of Revenue [Line Items]
Revenues	$ 8,632	$ 6,071	$ 17,438	$ 9,942