Note 3 - Revenues 2 (Details Textual) - Construction, Engineering and Installation Services [Member] $ in Millions	Dec. 31, 2019 USD ($)
Revenue, Remaining Performance Obligation, Amount	$ 464.6
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Amount	$ 452.8
Revenue, Remaining Performance Obligation, Percentage	97.50%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	12 months