Employee Benefit Plans - Schedule of Net Periodic Benefit Cost (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2011
Net periodic postretirement benefit cost included the following components:
Service cost	$ 770	$ 644	$ 666
Prior service credit	(203)	(203)	(82)
Interest cost	476	633	694
Amortization of unrecognized gain	(47)	(189)	(76)
Periodic postretirement benefit cost	$ 996	$ 885	$ 1,202