Note N - Pension and Other Postretirement Benefit Plans - Net Funded Status of Pension and Postretirement Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Net amount recognized	$ 43,576	$ 41,901
Pension Plan [Member]
Benefit obligation, beginning of year	107,322	105,012
Service cost	653	795
Interest cost	3,305	4,020
Actuarial loss	3,161	6,718
Contributions by plan participants	93	103
Benefits paid	(9,014)	(9,326)
Benefit obligation, end of year	105,520	107,322
Fair value of assets, Balance	87,291	90,258
Actual return on plan assets	3,541	4,125
Employer contribution	1,373	2,131
Contributions by plan participants	93	103
Benefits paid	(9,014)	(9,326)
Fair value of assets, Balance	83,284	87,291
Funded status	(22,236)	(20,031)
Other assets - noncurrent		3
Accrued liabilities - current	(276)	(645)
Accrued retirement benefits - noncurrent	(21,960)	(19,389)
Net amount recognized	(22,236)	(20,031)
Net transition obligation	158	178
Prior service cost	104	144
Actuarial net loss	43,548	42,185
Net amount recognized	43,810	42,507
Other Postretirement Benefits Plan [Member]
Benefit obligation, beginning of year	7,451	8,077
Service cost	17	19
Interest cost	219	305
Actuarial loss	211	18
Contributions by plan participants	352	389
Benefits paid	(1,191)	(1,357)
Benefit obligation, end of year	7,059	7,451
Fair value of assets, Balance
Actual return on plan assets
Employer contribution	839	968
Contributions by plan participants	352	389
Benefits paid	(1,191)	(1,357)
Fair value of assets, Balance
Funded status	(7,059)	(7,451)
Other assets - noncurrent
Accrued liabilities - current	(1,081)	(962)
Accrued retirement benefits - noncurrent	(5,978)	(6,489)
Net amount recognized	(7,059)	(7,451)
Net transition obligation
Prior service cost	(697)	(908)
Actuarial net loss	463	302
Net amount recognized	$ (234)	$ (606)