Note 2 - Summary of Significant Accounting Policies (Details Textual) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Jan. 01, 2019 USD ($)
Customer Concentration Risk [Member] | Sales Revenue, Net [Member] | Commercial Air Handling [Member]
Number of Customers	2
Customer Concentration Risk [Member] | Sales Revenue, Net [Member] | Commercial Air Handling [Member] | Two Customers [Member]
Concentration Risk, Percentage	22.00%
Customer Concentration Risk [Member] | Sales Revenue, Net [Member] | Aerospace [Member]
Number of Customers		1
Customer Concentration Risk [Member] | Sales Revenue, Net [Member] | Aerospace [Member] | One Customer [Member]
Concentration Risk, Percentage		18.00%
Accounting Standards Update 2016-02 [Member] | Scenario, Forecast [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption			$ 14