Note 9 - Segment Information (Details) - Segment Information - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Net revenues:
Net revenues	$ 11,559	$ 12,343	$ 21,747	$ 21,140
Earnings (loss) before income tax expense (benefit):
Earnings (loss) before income tax expense (benefit)	1,659	2,054	2,330	2,465
Net earnings (loss):
Net earnings (loss)	1,080	1,357	1,518	1,643
Thermal Products [Member]
Net revenues:
Net revenues	6,659	6,116	12,376	11,359
Earnings (loss) before income tax expense (benefit):
Earnings (loss) before income tax expense (benefit)	1,537	1,207	2,566	2,018
Net earnings (loss):
Net earnings (loss)	1,001	797	1,673	1,361
Mechanical Products [Member]
Net revenues:
Net revenues	2,487	4,137	4,922	6,184
Earnings (loss) before income tax expense (benefit):
Earnings (loss) before income tax expense (benefit)	(196)	637	(481)	354
Net earnings (loss):
Net earnings (loss)	(128)	421	(314)	224
Electrical Products [Member]
Net revenues:
Net revenues	2,413	2,090	4,449	3,597
Earnings (loss) before income tax expense (benefit):
Earnings (loss) before income tax expense (benefit)	477	400	796	405
Net earnings (loss):
Net earnings (loss)	311	264	519	268
Corporate Segment [Member]
Earnings (loss) before income tax expense (benefit):
Earnings (loss) before income tax expense (benefit)	(159)	(190)	(551)	(312)
Net earnings (loss):
Net earnings (loss)	$ (104)	$ (125)	$ (360)	$ (210)