Employee Benefit Plans - Schedule of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2016
Net periodic postretirement benefit gain included the following components:
Service cost	$ 0	$ 0	$ 9
Interest cost	79	89	114
Amortization of prior service credit	0	0	(1,035)
Amortization of net actuarial gain	(520)	(544)	(646)
Periodic postretirement benefit gain	$ (441)	$ (455)	$ (1,558)