Note 5 - Inventories (Details Textual) - USD ($)	12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Inventory, Net, Total	$ 52,987,000	$ 61,790,000
Inventory, LIFO Reserve	24,541,000	23,280,000
FIFO Inventory Amount	33,100	33,200,000
LIFO Inventory Amount	8,600,000	9,800,000
Cost of Sales [Member]
Inventory, LIFO Reserve, Effect on Income, Net, Total	$ 1,300,000	$ 1,600,000