Net Periodic Benefit Cost (Detail) - USD ($) $ in Millions	12 Months Ended
	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0.6	$ 1.3	$ 1.1
Interest cost	0.7	0.7	0.6
Expected return on plan assets	(0.9)	(0.9)	(0.8)
Amortization of net actuarial loss recognized	0.1	0.2	0.1
Total net periodic benefit cost	$ 0.5	$ 1.3	$ 1.0