Note M - Pension and Other Postretirement Benefit Plans (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Defined Benefit Plan, Cost of Premium for Health Coverage Plan, Percentage	100.00%
Defined Benefit Plan, Accumulated Benefit Obligation	$ 98,700	$ 105,520
Defined Benefit Plan, Weighted Average Healthcare Cost, Trend Rate	6.00%
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	$ 81
Defined Benefit Plan, Effect of One Percentage Point Increase on Service and Interest Cost Components	$ 2
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	$ 2
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	100.00%	100.00%
Defined Benefit Plan, Expected Long-term Return on Plan Assets	5.69%
Defined Contribution Plan, Cost	$ 2,162	$ 1,949
Pension Plan [Member]
Defined Benefit Plan, Expected Future Employer Contributions, Current Fiscal Year	$ 733
UNITED STATES
Defined Benefit Plan, Expected Long-term Return on Plan Assets	5.90%
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	$ 1,398	$ 544
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	1.50%	0.70%