Summary of Charges Related to Accrued Restructuring Activities (Detail) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Apr. 30, 2017
Apr. 30, 2017
Restructuring Cost and Reserve [Line Items]    
Balance at beginning period $ 1.4 $ 5.2
Restructuring charge 2.1 2.5
Adjustments   (0.1)
Cash payments (1.1) (5.2)
Balance at end period 2.4 2.4
Employee Severance and Benefits    
Restructuring Cost and Reserve [Line Items]    
Balance at beginning period 1.4 [1] 5.2 [2]
Restructuring charge 2.1 [1] 2.5 [2]
Adjustments [2]   (0.1)
Cash payments (1.1) [1] (5.2) [2]
Balance at end period [1],[2] $ 2.4 $ 2.4
[1] Restructuring charges in fiscal year 2017 includes $2.1 million with respect to the Fiscal Year 2017 Restructuring Plan. All other activity pertains to the Fiscal Year 2016 Restructuring Plan.
[2] Restructuring charges in fiscal year 2017 includes $2.4 million with respect to the Fiscal Year 2017 Restructuring Plan. All other activity pertains to the Fiscal Year 2016 Restructuring Plan.