Note 12 - Employee Benefit and Retirement Plans - Actual Asset Allocation For The Assets Within The Company's Plans (Details)	Jun. 30, 2020	Jun. 30, 2019
Asset allocation	100.00%	100.00%
Cash and Cash Equivalents [Member]
Asset allocation	4.00%	2.00%
Fixed Income Securities [Member]
Asset allocation	27.00%	31.00%
Equity Securities [Member]
Asset allocation	40.00%	35.00%
Mutual and Pooled Funds [Member]
Asset allocation	29.00%	32.00%