Employee Benefit Plans - Net periodic pension expense (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2014
Compensation and Retirement Disclosure [Abstract]
Service cost-benefits earned during the year	$ 2,939	$ 2,954	$ 2,457
Interest cost on benefit obligation	2,893	2,618	2,333
Expected return on plan assets	(3,177)	(2,828)	(2,334)
Amortization of net actuarial loss and prior service costs	1,784	1,405	904
Net periodic pension expense	$ 4,439	$ 4,149	$ 3,360