Pension and Other Postretirement Benefits - Components of Net Periodic Pension Income (Details) - Pension plans contribution [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Net periodic pension income
Service cost	$ 406	$ 414	$ 1,224	$ 1,224
Interest cost	7,979	7,716	23,939	23,051
Expected return on plan assets	(13,456)	(14,188)	(40,352)	(42,410)
Amortization of transition obligation	23	24	68	70
Amortization of prior service (credit) cost	(5)	(42)	(15)	90
Recognition of actuarial losses	1,682	1,746	5,056	5,174
Net periodic pension income	$ (3,371)	$ (4,330)	$ (10,080)	$ (12,801)