Note N - Pension and Other Postretirement Benefit Plans (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Defined Benefit Plan, Cost of Premium for Health Coverage Plan, Percentage	100.00%
Defined Benefit Plan, Accumulated Benefit Obligation	$ 105,520	$ 107,322
Defined Benefit Plan, Weighted Average Healthcare Cost, Trend Rate	6.25%
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate	5.00%
Defined Benefit Plan, Percentage of Increase in Assumed HealthCare Cost Trend Rate	1.00%
Defined Benefit Plan, Effect of One Percentage Point Increase on Accumulated Postretirement Benefit Obligation	$ 84
Defined Benefit Plan, Effect of One Percentage Point Increase on Service and Interest Cost Components	$ 3
Defined Benefit Plan, Percentage of Decrease in Assumed Healthcare Cost Trend Rate	1.00%
Defined Benefit Plan, Effect of One Percentage Point Decrease on Accumulated Postretirement Benefit Obligation	$ 71
Defined Benefit Plan, Effect of One Percentage Point Decrease on Service and Interest Cost Components	$ 3
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	100.00%	100.00%
Defined Benefit Plan, Expected Long-term Return on Plan Assets	5.89%
Defined Contribution Plan, Cost	$ 1,949	$ 2,276
Pension Plan [Member]
Defined Benefit Plan, Expected Future Employer Contributions, Current Fiscal Year	$ 2,346
UNITED STATES
Defined Benefit Plan, Expected Long-term Return on Plan Assets	6.10%
Common Stock Held by U.S Pension Plans [Member]
Defined Benefit Plan, Plan Assets, Employer, Related Party, Number of Shares (in shares)	98,211	98,211
Defined Benefit Plan, Plan Assets, Employer, Related Party, Amount	$ 544	$ 1,483
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	0.70%	1.70%