Employee Benefit Plans - Schedule of Assumptions Used (Details)	12 Months Ended
	Jul. 31, 2015	Jul. 31, 2014	Jul. 31, 2013
Compensation and Retirement Disclosure [Abstract]
Weighted average discount rate used in determining accumulated postretirement benefit obligation	3.00%	3.50%	4.00%
Weighted average discount rate used in determining net periodic benefit cost	3.41%	4.00%	3.25%
Assumed health care trend rate used to measure APBO at July 31	7.00%	7.50%	8.00%
Rate to which cost trend rate is assumed to decline (the ultimate trend rate)	5.50%	5.50%	5.50%
Fiscal year the ultimate trend rate is reached	2018	2018	2018