Note 4 - Inventories (Details Textual) - USD ($) $ in Millions	6 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Sep. 30, 2017	Jun. 30, 2017
LIFO Inventory Amount			$ 8.5	$ 7.7
Inventory Difference Using FIFO Basis			$ 26.4	$ 26.2
Cost of Sales [Member]
Inventory, LIFO Reserve, Effect on Income, Net	$ 0.2	$ 0.5