Note M - Pension and Other Postretirement Benefit Plans - Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Pension Plan [Member]
Net gain	$ (5,643)	$ (9,057)	$ 15,514
Prior service cost		(10)	58
Amortization of transition asset	(34)	(35)	(33)
Amortization of prior service (cost) benefit	(67)	(66)	(59)
Amortization of net (loss) gain	(2,952)	(3,613)	(3,627)
Total recognized in other comprehensive income	(8,696)	(12,781)	11,853
Net periodic benefit cost	1,932	3,012	2,583
Total recognized in net periodic benefit cost and other comprehensive income	(6,764)	(9,769)	14,436
Net loss	(5,643)	(9,057)	15,514
Prior service cost		(10)	58
Amortization of transition asset	(34)	(35)	(33)
Amortization of prior service cost	(67)	(66)	(59)
Amortization of net (loss) gain	(2,952)	(3,613)	(3,627)
Net periodic benefit cost	1,932	3,012	2,583
Other Postretirement Benefits Plan [Member]
Net gain	(940)	(3,380)	496
Prior service cost	(1,668)
Amortization of transition asset
Amortization of prior service (cost) benefit	206
Amortization of net (loss) gain	(32)	(230)	(728)
Total recognized in other comprehensive income	(2,434)	(3,610)	(232)
Net periodic benefit cost	171	671	1,360
Total recognized in net periodic benefit cost and other comprehensive income	(2,263)	(2,939)	1,128
Net loss	(940)	(3,380)	496
Prior service cost	(1,668)
Amortization of transition asset
Amortization of prior service cost	206
Amortization of net (loss) gain	(32)	(230)	(728)
Net periodic benefit cost	$ 171	$ 671	$ 1,360