Note 3 - Revenues 2 (Details Textual) - Construction, Engineering and Installation Services [Member] $ in Millions	Sep. 30, 2019 USD ($)
Revenue, Remaining Performance Obligation, Amount	$ 497.0
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-10-01
Revenue, Remaining Performance Obligation, Amount	$ 488.2
Revenue, Remaining Performance Obligation, Percentage	98.20%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	12 months