Employee Benefit Plans - Schedule of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2014
Net periodic postretirement benefit (gain) cost included the following components:
Service cost	$ 9	$ 210	$ 674
Interest cost	114	222	534
Amortization of prior service credit	(1,035)	(1,169)	(203)
Amortization of net actuarial gain	(646)	(804)	(265)
Curtailment gain	0	(4,296)	0
Periodic postretirement benefit (gain) cost	$ (1,558)	$ (5,837)	$ 740