Note 4 - Goodwill and Intangible Assets (Detail) - Estimated Useful Lives of Finite Lived Intangible Assets	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2013 Sigma [Member] Estimated Useful Life [Member] Customer Relationships [Member]	Mar. 31, 2013 Sigma [Member] Estimated Useful Life [Member] Computer Software, Intangible Asset [Member]	Mar. 31, 2013 Sigma [Member] Estimated Useful Life [Member] Patented Technology [Member]	Mar. 31, 2013 Sigma [Member] Remaining Estimated Useful Life [Member] Customer Relationships [Member]	Mar. 31, 2013 Sigma [Member] Remaining Estimated Useful Life [Member] Computer Software, Intangible Asset [Member]	Mar. 31, 2013 Sigma [Member] Remaining Estimated Useful Life [Member] Patented Technology [Member]	Mar. 31, 2013 Thermonics [Member] Estimated Useful Life [Member] Customer Relationships [Member]	Mar. 31, 2013 Thermonics [Member] Estimated Useful Life [Member] Patented Technology [Member]	Mar. 31, 2013 Thermonics [Member] Estimated Useful Life [Member] Customer Backlog [Member]	Mar. 31, 2013 Thermonics [Member] Estimated Useful Life [Member] Trade Names [Member]	Mar. 31, 2013 Thermonics [Member] Estimated Useful Life [Member] Noncompete Agreements [Member]	Mar. 31, 2013 Thermonics [Member] Remaining Estimated Useful Life [Member] Customer Relationships [Member]	Mar. 31, 2013 Thermonics [Member] Remaining Estimated Useful Life [Member] Patented Technology [Member]	Mar. 31, 2013 Thermonics [Member] Remaining Estimated Useful Life [Member] Trade Names [Member]	Mar. 31, 2013 Thermonics [Member] Remaining Estimated Useful Life [Member] Noncompete Agreements [Member]	Mar. 31, 2012 Customer Relationships [Member]	Mar. 31, 2012 Patented Technology [Member]	Mar. 31, 2012 Customer Backlog [Member]	Mar. 31, 2012 Trade Names [Member]	Mar. 31, 2012 Noncompete Agreements [Member]
Estimated Useful Life	78 months 9 days	72 months	120 months	60 months				72 months	132 months	3 months	48 months	18 months					72 months	132 months	3 months	48 months	18 months
Remaining Estimated Useful Life					18 months	66 months	6 months						57 months 15 days	117 months 15 days	33 months 15 days	6 months