Note 7 - Intangible Assets - Summary of Intangible Assets (Details) - USD ($) $ in Thousands		Dec. 31, 2018	Dec. 31, 2017
Gross Carrying Amount		$ 2,710	$ 3,848
Accumulated Amortization		(1,157)	(1,945)
Intangible Assets, Net		1,553	1,903
Customer Relationships [Member]
Gross Carrying Amount		1,378	1,378
Accumulated Amortization		(689)	(551)
Intangible Assets, Net		689	827
Trademarks and Trade Names [Member]
Gross Carrying Amount		1,132	1,132
Accumulated Amortization		(377)	(302)
Intangible Assets, Net		755	830
Backlog [Member]
Gross Carrying Amount	[1]	200
Accumulated Amortization	[1]	(91)
Intangible Assets, Net	[1]	$ 109
Patents [Member]
Gross Carrying Amount			1,162
Accumulated Amortization			(929)
Intangible Assets, Net			233
Other Intangible Assets [Member]
Gross Carrying Amount	[2]		176
Accumulated Amortization	[2]		(163)
Intangible Assets, Net	[2]		$ 13

[1] Backlog, included in the July 2018 acquisition of Ameron, has a weighted-average amortization period of eleven months.

[2] Other intangibles consist of favorable lease contracts and non-compete agreements.