Income Taxes - Reconciliation of Tax Rate (Details)
6 Months Ended
Jan. 31, 2016
Jan. 31, 2015
Reconciliation of consolidated income tax rate    
Consolidated effective tax rate (as a percent) 36.30% 38.30%
Differential attributable to:    
Acquisition related items, net (0.70%)  
New tax legislation (0.70%)  
International operations (0.40%)  
Other (0.20%)  
United States    
Reconciliation of consolidated income tax rate    
Consolidated effective tax rate (as a percent) 36.30% 36.40%