Note 14 - Segment Information (Details) - Segment Information (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Net revenues from unaffiliated customers	$ 9,862	$ 10,794	$ 12,343	$ 8,797	$ 9,335	$ 9,900	$ 11,218	$ 8,973	$ 41,796	$ 39,426
Depreciation/amortization									879	847
Operating Income (loss)									4,916	3,962
Earnings (loss) before income tax expense (benefit)	1,176	1,268	2,054	411	1,037	1,114	1,487	370	4,909	4,008
Income tax expense (benefit)	217	431	697	125	345	24	484	78	1,470	931
Net earnings (loss)	959	837	1,357	286	692	1,090	1,003	292	3,439	3,077
Capital expenditures									831	424
Thermal Products [Member]
Segment Reporting Information [Line Items]
Net revenues from unaffiliated customers									23,446	22,962
Depreciation/amortization									720	695
Operating Income (loss)									4,740	4,322
Earnings (loss) before income tax expense (benefit)									4,699	4,327
Income tax expense (benefit)									1,407	1,005
Net earnings (loss)									3,292	3,322
Capital expenditures									595	349
Mechanical Products [Member]
Segment Reporting Information [Line Items]
Net revenues from unaffiliated customers									11,245	9,962
Depreciation/amortization									87	79
Operating Income (loss)									(18)	(784)
Earnings (loss) before income tax expense (benefit)									(5)	(772)
Income tax expense (benefit)									(2)	(179)
Net earnings (loss)									(3)	(593)
Capital expenditures									96	16
Electrical Products [Member]
Segment Reporting Information [Line Items]
Net revenues from unaffiliated customers									7,105	6,502
Depreciation/amortization									72	73
Operating Income (loss)									781	722
Earnings (loss) before income tax expense (benefit)									802	751
Income tax expense (benefit)									240	174
Net earnings (loss)									562	577
Capital expenditures									140	59
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Operating Income (loss)									(587)	(298)
Earnings (loss) before income tax expense (benefit)									(587)	(298)
Income tax expense (benefit)									(175)	(69)
Net earnings (loss)									$ (412)	$ (229)