Benefit Plans - Components of Net Periodic Pension Income (Details) - Pension plans contribution [Member] - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Net periodic pension income
Service cost	$ 404	$ 733
Interest cost	7,657	7,809
Expected return on plan assets	(14,090)	(14,757)
Amortization of transition obligation	23	23
Amortization of prior service cost (credit)	173	(113)
Recognition of actuarial losses	1,710	2,112
Net periodic pension income	$ (4,123)	$ (4,193)