Note 10 - Rentals (Details Textual) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Leases, Rent Expense, Total	$ 2.1	$ 1.1	$ 1.1
Operating Leases, Future Minimum Payments Due, Total	5.8
Operating Leases, Future Minimum Payments, Due in One and Two Years	2.9
Operating Leases, Future Minimum Payments, Due in Three and Four Years	1.9
Operating Leases, Future Minimum Payments, Due in Five to Seven Years	$ 1.0