Plan Assets Held in Trust (Detail)	12 Months Ended
	Jul. 31, 2014	Jul. 31, 2013
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target allocation percentage	100.00%
Actual allocation percentage	100.00%	100.00%
Equity Securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target allocation percentage	60.00%
Actual allocation percentage	60.90%	65.80%
Debt Securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target allocation percentage	40.00%
Actual allocation percentage	39.10%	34.20%