SEGMENT REPORTING (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) facility item MW	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)
SEGMENT REPORTING
Revenues from external customers	$ 36,781		$ 66,748
Revenues	36,781	$ 43,362	66,748	$ 99,422
Operating profit (loss)	(5,736)	(516)	(10,273)	1,087
Depreciation and amortization	2,349	2,203	4,706	4,304
Capital expenditures	1,447	1,043	1,676	4,304
Total Assets	108,653		$ 108,653		$ 112,350
Towers and Heavy Fabrications
SEGMENT REPORTING
Number of facilities | facility			2
Revenues from external customers	24,001		$ 40,785
Intersegment revenues	23		23
Revenues	24,024	34,327	40,808	83,222
Operating profit (loss)	724	2,801	(780)	8,649
Depreciation and amortization	1,280	1,070	2,537	2,161
Capital expenditures	1,198	729	$ 1,198	3,389
Towers and Heavy Fabrications | Maximum
SEGMENT REPORTING
Annual tower production capacity (in towers) | item			550
Towers and Heavy Fabrications | Minimum
SEGMENT REPORTING
Power generating capacity of turbines that towers produced annually can support (in megawatts) | MW			1,100
Gearing
SEGMENT REPORTING
Revenues from external customers	8,632		$ 17,438
Revenues	8,632	6,071	17,438	9,942
Operating profit (loss)	(662)	(634)	(1,288)	(2,165)
Depreciation and amortization	586	612	1,176	1,238
Capital expenditures	247	132	467	332
Process Systems
SEGMENT REPORTING
Revenues from external customers	4,148		8,525
Revenues	4,148	2,964	8,525	6,258
Operating profit (loss)	(5,772)	(1,099)	(6,664)	(1,921)
Depreciation and amortization	423	468	874	801
Capital expenditures		138		410
Corporate
SEGMENT REPORTING
Operating profit (loss)	(26)	(1,584)	(1,541)	(3,476)
Depreciation and amortization	60	53	119	104
Capital expenditures	2	$ 44	11	$ 173
Operating segments
SEGMENT REPORTING
Total Assets	108,653		108,653		112,350
Operating segments | Towers and Heavy Fabrications
SEGMENT REPORTING
Total Assets	34,717		34,717		27,958
Operating segments | Gearing
SEGMENT REPORTING
Total Assets	34,870		34,870		37,456
Operating segments | Process Systems
SEGMENT REPORTING
Total Assets	21,201		21,201		26,442
Operating segments | Assets held for sale
SEGMENT REPORTING
Total Assets	579		579		580
Operating segments | Corporate
SEGMENT REPORTING
Total Assets	251,370		251,370		249,326
Eliminations
SEGMENT REPORTING
Intersegment revenues	(23)		(23)
Revenues	(23)		(23)
Total Assets	$ (234,084)		$ (234,084)		$ (229,412)