Pension and Other Postretirement Benefits - Funded Status of Other Postretirement Benefit Plans and Amounts Recognized in the Consolidated Balance Sheets (Details) - Other Postretirement Benefit Plan, Defined Benefit [Member] - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Change in Benefit Obligation
Benefit Obligation, Beginning of Year	$ 18,160	$ 20,542
Interest Cost	629	673	$ 840
Actuarial Losses	(323)	(747)
Benefit Obligation, End of Year	15,323	18,160	$ 20,542
Funded Status of Plans	(15,323)	(18,160)
Amounts Recognized in Balance Sheet
Short-term Accrued Benefit Obligation	(1,598)	(1,254)
Accrued Postretirement Benefits	(13,725)	(16,906)
Net Amount Recognized	(15,323)	(18,160)
Benefits and expenses paid	(2,208)	(2,308)
Plan Amendments	$ (935)	$ 0