Fair Value of Analogic Canada Plan Pension Assets by Assets Category (Detail) - USD ($) $ in Millions	Jul. 31, 2017	[1]	Jul. 31, 2016	[1]	Jul. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension assets	$ 16.7		$ 15.3		$ 15.0
Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension assets	$ 16.7		$ 15.3		$ 15.0

[1] This comprises units of segregated pooled funds with an insurance company. These funds have underlying values primarily derived from mutual funds that have debt and equity securities, which are traded on an active market based on the closing price of each trading day.