Restructuring and Related Charges by Segment (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges, net	$ 3.5	$ 3.5	$ 0
Medical Imaging
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges, net	1.7	1.1
Ultrasound
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges, net	1.4	2.2
Security Technology
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges, net	$ 0.4	$ 0.2