Pension and Other Postretirement Benefits - Components of Net Periodic Pension Income (Details) - Pension plans contribution [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Net periodic pension income
Service cost	$ 407	$ 406	$ 818	$ 810
Interest cost	7,970	7,678	15,960	15,335
Expected return on plan assets	(13,434)	(14,132)	(26,896)	(28,221)
Amortization of transition obligation	23	23	45	46
Amortization of prior service (credit) cost	(5)	(41)	(10)	132
Recognition of actuarial losses	1,679	1,718	3,374	3,428
Net periodic pension income	$ (3,360)	$ (4,348)	$ (6,709)	$ (8,470)