Restructuring and Related Charges by Segment (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				12 Months Ended
	Jul. 31, 2013	Apr. 30, 2013	Jul. 31, 2011	Oct. 31, 2010	Jul. 31, 2013	Jul. 31, 2011
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges, net	$ 3,023	$ 496	$ 3,587	$ 3,562	$ 3,519	$ 7,066
Medical Imaging
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges, net					1,099	2,829
Ultrasound
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges, net					2,209	3,668
Security Technology
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges, net					$ 211	$ 569