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Stock-Based Compensation - Stock Option Assumptions (Detail) - $ / shares
9 Months Ended
Apr. 30, 2017
Apr. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Expected term 6 years 1 month 10 days 6 years 1 month 10 days
Expected volatility 29.55% 29.95%
Expected dividend yield 2.70% 2.59%
Risk-free interest rate 1.26% 1.64%
Weighted-average market value of underlying stock at grant date $ 35.14 $ 20.02
Options, Grants in Period, Weighted Average Exercise Price 35.14 20.02
Weighted-average fair value of options granted during the period $ 7.56 $ 4.58