Note N - Pension and Other Postretirement Benefit Plans - Net Funded Status of Pension and Postretirement Plans (Details) - USD ($)	12 Months Ended
	Jun. 30, 2025	Jun. 30, 2024
Return on plan assets	$ (1,808)
Net amount recognized	(11,461,000)	$ (8,062,000)
Pension Plan [Member]
Benefit obligation, beginning of year	68,110,000	72,242,000
Service cost	352,000	373,000
Interest cost	3,404,000	3,609,000
Prior service cost	21,000	0
Actuarial loss (gain)	1,753,000	254,000
Contributions by plan participants	137,000	116,000
Benefits paid	(7,353,000)	(8,484,000)
Benefit obligation, end of year	66,424,000	68,110,000
Fair value of assets, Balance	62,660,000	67,338,000
Actual return on plan assets	2,616,000	3,101,000
Employer contribution	608,000	589,000
Contributions by plan participants	137,000	116,000
Benefits paid	(7,353,000)	(8,484,000)
Fair value of assets, Balance	56,860,000	62,660,000
Funded status	(9,564,000)	(5,450,000)
Other assets - noncurrent	15,000	0
Accrued liabilities - current	(380,000)	(260,000)
Accrued retirement benefits - noncurrent	(9,199,000)	(5,190,000)
Net amount recognized	(9,564,000)	(5,450,000)
Net transition obligation	26,000	53,000
Prior service benefit	(185,000)	(145,000)
Actuarial net loss (gain)	11,937,000	8,768,000
Net amount recognized	11,778,000	8,676,000
Other Postretirement Benefits Plan [Member]
Benefit obligation, beginning of year	3,169,000	3,685,000
Service cost	7,000	8,000
Interest cost	165,000	191,000
Prior service cost	0	0
Actuarial loss (gain)	33,000	(166,000)
Contributions by plan participants	155,000	0
Benefits paid	(659,000)	(549,000)
Benefit obligation, end of year	2,870,000	3,169,000
Fair value of assets, Balance	0	0
Actual return on plan assets	0	0
Employer contribution	504,000	549,000
Contributions by plan participants	155,000	0
Benefits paid	(659,000)	(549,000)
Fair value of assets, Balance	0	0
Funded status	(2,870,000)	(3,169,000)
Other assets - noncurrent	0	0
Accrued liabilities - current	(237,000)	(505,000)
Accrued retirement benefits - noncurrent	(2,633,000)	(2,664,000)
Net amount recognized	(2,870,000)	(3,169,000)
Net transition obligation	0	0
Prior service benefit	0	0
Actuarial net loss (gain)	(317,000)	(614,000)
Net amount recognized	$ (317,000)	$ (614,000)