Note N - Pension and Other Postretirement Benefit Plans - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Pension Plan [Member]
Service cost	$ 648	$ 792
Interest cost	3,304	4,019
Expected return on plan assets	(4,894)	(5,238)
Amortization of transition obligation	35	34
Amortization of prior service cost	45	64
Amortization of actuarial net loss	2,982	2,710
Net periodic benefit cost	2,120	2,381
Other Postretirement Benefits Plan [Member]
Service cost	17	18
Interest cost	219	304
Amortization of prior service cost	(274)	(274)
Net periodic benefit cost	$ (38)	$ 48