Note 9 - Segment Information (Details) - Segment Information (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Segment Reporting Information [Line Items]
Net revenues from unaffiliated customers	$ 10,794	$ 9,900	$ 31,934	$ 30,091
Earnings (loss) before income tax expense (benefit):
Earnings (loss) before income tax expense (benefit)	1,268	1,114	3,733	2,971
Net earnings (loss):
Net earnings (loss)	837	1,090	2,480	2,385
Thermal Products [Member]
Segment Reporting Information [Line Items]
Net revenues from unaffiliated customers	5,908	5,844	17,267	17,514
Earnings (loss) before income tax expense (benefit):
Earnings (loss) before income tax expense (benefit)	1,304	1,232	3,322	3,468
Net earnings (loss):
Net earnings (loss)	861	1,206	2,222	2,847
Mechanical Products [Member]
Segment Reporting Information [Line Items]
Net revenues from unaffiliated customers	3,077	2,193	9,261	7,784
Earnings (loss) before income tax expense (benefit):
Earnings (loss) before income tax expense (benefit)	(109)	(346)	245	(742)
Net earnings (loss):
Net earnings (loss)	(72)	(339)	152	(686)
Electrical Products [Member]
Segment Reporting Information [Line Items]
Net revenues from unaffiliated customers	1,809	1,863	5,406	4,793
Earnings (loss) before income tax expense (benefit):
Earnings (loss) before income tax expense (benefit)	203	294	608	493
Net earnings (loss):
Net earnings (loss)	134	288	402	422
Corporate Segment [Member]
Earnings (loss) before income tax expense (benefit):
Earnings (loss) before income tax expense (benefit)	(130)	(66)	(442)	(248)
Net earnings (loss):
Net earnings (loss)	$ (86)	$ (65)	$ (296)	$ (198)