Note M - Pension and Other Postretirement Benefit Plans - Net Funded Status of Pension and Postretirement Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Net amount recognized	$ 30,877	$ 38,801
Pension Plan [Member]
Benefit obligation, beginning of year	118,170	129,056
Service cost	861	1,009
Interest cost	3,979	4,213
Actuarial (gain) loss	(8,690)	(6,980)
Contributions by plan participants	105	139
Benefits paid	(9,413)	(9,267)
Benefit obligation, end of year	105,012	118,170
Fair value of assets, Balance	94,372	94,164
Actual return on plan assets	2,894	7,967
Employer contribution	2,300	1,369
Contributions by plan participants	105	139
Benefits paid	(9,413)	(9,267)
Fair value of assets, Balance	90,258	94,372
Funded status	(14,754)	(23,798)
Other assets - noncurrent	157	694
Accrued liabilities - current	(679)	(706)
Accrued retirement benefits - noncurrent	(14,232)	(23,786)
Net amount recognized	(14,754)	(23,798)
Net transition obligation	564	790
Actuarial net loss	31,146	37,140
Net amount recognized	31,710	37,930
Other Postretirement Benefits Plan [Member]
Benefit obligation, beginning of year	11,574	15,933
Service cost	20	20
Interest cost	325	420
Actuarial (gain) loss	(2,608)	(3,380)
Contributions by plan participants	440	472
Benefits paid	(1,674)	(1,891)
Benefit obligation, end of year	8,077	11,574
Fair value of assets, Balance
Actual return on plan assets
Employer contribution	1,234	1,419
Contributions by plan participants	440	472
Benefits paid	(1,674)	(1,891)
Fair value of assets, Balance
Funded status	(8,077)	(11,574)
Other assets - noncurrent
Accrued liabilities - current	(1,241)	(1,654)
Accrued retirement benefits - noncurrent	(6,836)	(9,920)
Net amount recognized	(8,077)	(11,574)
Net transition obligation
Actuarial net loss	(833)	871
Net amount recognized	$ (833)	$ 871