Employee Benefit Plans - Net periodic pension expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Compensation and Retirement Disclosure [Abstract]
Service cost - benefits earned during the period	$ 284	$ 751	$ 845	$ 1,470
Interest cost on benefit obligation	505	757	1,048	1,446
Expected return on plan assets	(843)	(846)	(1,706)	(1,588)
Amortization of net actuarial (gain) loss and prior service costs	105	508	452	892
Settlement cost	1,702		1,702
Net periodic pension expense	$ 1,753	$ 1,170	$ 2,341	$ 2,220