Note M - Pension and Other Postretirement Benefit Plans - Net Funded Status of Pension and Postretirement Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Net amount recognized	$ (31,463)	$ (43,576)
Pension Plan [Member]
Benefit obligation, beginning of year	105,520	107,322
Service cost	608	653
Interest cost	2,516	3,305
Prior service cost	65	0
Actuarial (gain) loss	(1,577)	3,161
Contributions by plan participants	114	93
Benefits paid	(8,546)	(9,014)
Benefit obligation, end of year	98,700	105,520
Fair value of assets, Balance	83,284	87,291
Actual return on plan assets	15,325	3,541
Employer contribution	2,253	1,373
Contributions by plan participants	114	93
Benefits paid	(8,546)	(9,014)
Fair value of assets, Balance	92,430	83,284
Funded status	(6,270)	(22,236)
Other assets - noncurrent	60	0
Accrued liabilities - current	(423)	(276)
Accrued retirement benefits - noncurrent	(5,907)	(21,960)
Net amount recognized	(6,270)	(22,236)
Net transition obligation	133	158
Prior service cost	94	104
Actuarial net loss	31,563	43,548
Net amount recognized	31,790	43,810
Other Postretirement Benefits Plan [Member]
Benefit obligation, beginning of year	7,059	7,451
Service cost	16	17
Interest cost	154	219
Prior service cost	0	0
Actuarial (gain) loss	(395)	211
Contributions by plan participants	269	352
Benefits paid	(1,001)	(1,191)
Benefit obligation, end of year	6,102	7,059
Fair value of assets, Balance	0	0
Actual return on plan assets	0	0
Employer contribution	732	839
Contributions by plan participants	269	352
Benefits paid	(1,001)	(1,191)
Fair value of assets, Balance	0	0
Funded status	(6,102)	(7,059)
Other assets - noncurrent	0	0
Accrued liabilities - current	(833)	(1,081)
Accrued retirement benefits - noncurrent	(5,269)	(5,978)
Net amount recognized	(6,102)	(7,059)
Net transition obligation	0	0
Prior service cost	(487)	(697)
Actuarial net loss	160	463
Net amount recognized	$ (327)	$ (234)