Note M - Pension and Other Postretirement Benefit Plans - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Pension Plan [Member]
Service cost	$ 615	$ 648
Interest cost	2,516	3,304
Prior service cost	65	0
Expected return on plan assets	(4,552)	(4,894)
Amortization of transition obligation	40	35
Amortization of prior service cost	47	45
Amortization of actuarial net loss	3,246	2,982
Net periodic benefit cost	1,977	2,120
Other Postretirement Benefits Plan [Member]
Service cost	16	17
Interest cost	154	219
Prior service cost	0	0
Amortization of prior service cost	(274)	(274)
Net periodic benefit cost	$ (104)	$ (38)