Note 14 - Segment Reporting - Segment Reporting (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Revenues from external customers	$ 54,614	$ 46,138	$ 158,174	$ 128,967
Revenue from Contract with Customer, Including Assessed Tax	54,614	46,138	158,174	128,967
Operating profit (loss)	(475)	(258)	2,240	(958)
Depreciation and amortization	1,567	1,616	4,761	5,006
Capital expenditures	668	593	1,597	1,776
Assets	126,056		126,056		$ 122,866
Consolidation, Eliminations [Member]
Revenues from external customers
Revenue from Contract with Customer, Including Assessed Tax	(32)	(2)	(39)	(2)
Operating profit (loss)
Depreciation and amortization
Capital expenditures
Assets	(204,185)		(204,185)		(214,110)
Intersegment Eliminations [Member]
Revenue from Contract with Customer, Including Assessed Tax
Heavy Fabrications [Member] | Operating Segments [Member]
Revenues from external customers	43,434	33,834	125,418	91,098
Revenue from Contract with Customer, Including Assessed Tax	43,440	33,834	125,424	91,098
Operating profit (loss)	2,020	693	8,760	789
Depreciation and amortization	928	951	2,831	3,024
Capital expenditures	601	346	1,199	855
Assets	43,256		43,256		41,432
Heavy Fabrications [Member] | Intersegment Eliminations [Member]
Revenue from Contract with Customer, Including Assessed Tax	6		6
Gearing [Member] | Operating Segments [Member]
Revenues from external customers	7,100	7,989	20,241	27,282
Revenue from Contract with Customer, Including Assessed Tax	7,125	7,989	20,273	27,282
Operating profit (loss)	(1,023)	496	(1,935)	2,797
Depreciation and amortization	488	508	1,503	1,472
Capital expenditures	42	235	211	875
Assets	45,742		45,742		47,022
Gearing [Member] | Intersegment Eliminations [Member]
Revenue from Contract with Customer, Including Assessed Tax	25		32
Industrial Solutions [Member] | Operating Segments [Member]
Revenues from external customers	4,080	4,315	12,515	10,587
Revenue from Contract with Customer, Including Assessed Tax	4,081	4,317	12,516	10,589
Operating profit (loss)	87	141	496	(116)
Depreciation and amortization	109	123	319	368
Capital expenditures	7	8	134	22
Assets	10,563		10,563		8,893
Industrial Solutions [Member] | Intersegment Eliminations [Member]
Revenue from Contract with Customer, Including Assessed Tax	1	2	1	2
Corporate Segment [Member] | Operating Segments [Member]
Revenues from external customers
Revenue from Contract with Customer, Including Assessed Tax
Operating profit (loss)	(1,559)	(1,588)	(5,081)	(4,428)
Depreciation and amortization	42	34	108	142
Capital expenditures	18	4	53	24
Assets	230,680		230,680		$ 239,629
Corporate Segment [Member] | Intersegment Eliminations [Member]
Revenue from Contract with Customer, Including Assessed Tax