Note 9 - Segment Information (Details) - Segment Information (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Net revenues from unaffiliated customers:
Net revenues from unaffiliated customers	$ 10,188	$ 8,797
Earnings (loss) before income tax expense (benefit):
Earnings (loss) before income tax expense (benefit)	671	411
Net earnings (loss):
Net earnings (loss)	438	286
Thermal Products [Member]
Net revenues from unaffiliated customers:
Net revenues from unaffiliated customers	5,717	5,243
Earnings (loss) before income tax expense (benefit):
Earnings (loss) before income tax expense (benefit)	1,029	811
Net earnings (loss):
Net earnings (loss)	672	564
Mechanical Products [Member]
Net revenues from unaffiliated customers:
Net revenues from unaffiliated customers	2,435	2,047
Earnings (loss) before income tax expense (benefit):
Earnings (loss) before income tax expense (benefit)	(285)	(283)
Net earnings (loss):
Net earnings (loss)	(186)	(197)
Electrical Products [Member]
Net revenues from unaffiliated customers:
Net revenues from unaffiliated customers	2,036	1,507
Earnings (loss) before income tax expense (benefit):
Earnings (loss) before income tax expense (benefit)	319	5
Net earnings (loss):
Net earnings (loss)	208	4
Corporate Segment [Member]
Earnings (loss) before income tax expense (benefit):
Earnings (loss) before income tax expense (benefit)	(392)	(122)
Net earnings (loss):
Net earnings (loss)	$ (256)	$ (85)