Note 3 - Revenues 2 (Details Textual) - Construction, Engineering and Installation Services [Member] $ in Millions	Dec. 31, 2020 USD ($)
Revenue, Remaining Performance Obligation, Amount	$ 463.8
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Amount	$ 448.8
Revenue, Remaining Performance Obligation, Percentage	96.80%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Month)	12 months