Intangible Assets (Detail) - USD ($) $ in Millions	3 Months Ended
	Oct. 31, 2016	Jul. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Cost	$ 78.9	$ 78.9
Accumulated Amortization	43.3	41.3
Net	$ 35.6	37.6
Developed technologies
Finite-Lived Intangible Assets [Line Items]
Weighted-Average Amortization Period	10 years
Cost	$ 29.9	29.9
Accumulated Amortization	15.9	15.1
Net	$ 14.0	14.8
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Weighted-Average Amortization Period	13 years
Cost	$ 47.1	47.1
Accumulated Amortization	26.4	25.2
Net	$ 20.7	21.9
Trade names
Finite-Lived Intangible Assets [Line Items]
Weighted-Average Amortization Period	3 years
Cost	$ 1.9	1.9
Accumulated Amortization	1.0	1.0
Net	$ 0.9	$ 0.9