Finite-Lived Intangible Assets (Detail) - USD ($) $ in Millions	12 Months Ended
	Jul. 31, 2017	Jul. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Cost	$ 62.3	$ 78.9
Accumulated Amortization	44.0	41.3
Net	$ 18.3	37.6
Developed technologies
Finite-Lived Intangible Assets [Line Items]
Weighted-Average Amortization Period	10 years
Cost	$ 17.7	29.9
Accumulated Amortization	14.4	15.1
Net	$ 3.3	14.8
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Weighted-Average Amortization Period	13 years
Cost	$ 43.7	47.1
Accumulated Amortization	28.7	25.2
Net	$ 15.0	21.9
Trade names
Finite-Lived Intangible Assets [Line Items]
Weighted-Average Amortization Period	3 years
Cost	$ 0.9	1.9
Accumulated Amortization	$ 0.9	1.0
Net		$ 0.9