Pension and Postretirement Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Pension Plans [Member]
Components of Net Periodic Benefit Costs [Abstract]
Service cost	$ 3,137	$ 2,977
Interest cost	1,225	1,469
Expected return on plan assets	(2,298)	(2,746)
Prior service cost (credit) amortization	48	49
Actuarial loss (gain) amortization	897	157
Net periodic benefit credit	3,009	1,906
Postretirement Benefit Plans [Member]
Components of Net Periodic Benefit Costs [Abstract]
Service cost	23	25
Interest cost	80	96
Prior service cost (credit) amortization	(98)	(107)
Actuarial loss (gain) amortization	(78)	(169)
Net periodic benefit credit	$ (73)	$ (155)