Reportable Segment Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended										12 Months Ended
	Jul. 31, 2014		Apr. 30, 2014	Jan. 31, 2014	Oct. 31, 2013	Jul. 31, 2013		Apr. 30, 2013	Jan. 31, 2013	Oct. 31, 2012	Jul. 31, 2014		Jul. 31, 2013		Jul. 31, 2012
Product Revenue:
Product Revenue											$ 509,527		$ 526,725		$ 494,675
Engineering Revenue:
Engineering Revenue											8,021		23,638		21,896
Net revenue:
Total net revenue	142,000		124,000	141,400	110,100	166,200		125,800	138,500	119,900	517,548		550,363		516,571
Income (loss) before income taxes:
Income from operations											29,088		45,375		39,963
Total other (expense) income, net											(50)		(1,278)		4,236
Income before income taxes											29,038		44,097		44,199
Assets by segment:
Assets	614,342					587,784					614,342		587,784
Goodwill by segment:
Goodwill	56,955					50,073					56,955		50,073
Share-based compensation expense:
Share based compensation											11,512		11,601		13,396
Depreciation and amortization:
Depreciation and amortization											22,057		17,275		17,775
Reportable segment assets
Assets by segment:
Assets	489,000					488,900					489,000		488,900
Corporate assets
Assets by segment:
Assets	125,300	[1]				98,900	[1]				125,300	[1]	98,900	[1]
Medical Imaging
Product Revenue:
Product Revenue											291,300		305,600		290,700
Engineering Revenue:
Engineering Revenue											4,300		13,000		11,100
Net revenue:
Total net revenue											295,600		318,600		301,800
Income (loss) before income taxes:
Income from operations											31,000	[2]	31,900	[2]	18,900	[2]
Share-based compensation expense:
Share based compensation											6,600		7,600		7,800
Depreciation and amortization:
Depreciation and amortization											11,500		11,500		11,500
Medical Imaging | Reportable segment assets
Assets by segment:
Assets	218,500	[3]				217,100	[3]				218,500	[3]	217,100	[3]
Goodwill by segment:
Goodwill	1,900					1,900					1,900		1,900
Ultrasound
Product Revenue:
Product Revenue											152,300		149,600		151,200
Engineering Revenue:
Engineering Revenue											200		200
Net revenue:
Total net revenue											152,500		149,800		151,200
Income (loss) before income taxes:
Income from operations											(6,800)	[4]	(3,700)	[4]	10,800	[4]
Share-based compensation expense:
Share based compensation											2,800		2,100		3,600
Depreciation and amortization:
Depreciation and amortization											9,100		4,700		5,100
Ultrasound | Reportable segment assets
Assets by segment:
Assets	235,500	[5]				218,500	[5]				235,500	[5]	218,500	[5]
Goodwill by segment:
Goodwill	55,100					48,200					55,100		48,200
Security Technology
Product Revenue:
Product Revenue											65,900		71,600		52,800
Engineering Revenue:
Engineering Revenue											3,500		10,400		10,800
Net revenue:
Total net revenue											69,400		82,000		63,600
Income (loss) before income taxes:
Income from operations											4,900	[6]	17,200	[6]	10,300	[6]
Share-based compensation expense:
Share based compensation											2,100		1,900		2,000
Depreciation and amortization:
Depreciation and amortization											1,500		1,100		1,200
Security Technology | Reportable segment assets
Assets by segment:
Assets	$ 35,000					$ 53,300					$ 35,000		$ 53,300

[1] Includes cash, cash equivalents and marketable securities of $60.9 million and $57.4 million, as of July 31, 2014 and 2013, respectively.

[2] Includes restructuring charges of $1.7 million and $1.1 million for fiscal years 2014 and 2013, respectively. Includes $2.2 million of contingent consulting fees related to the tax refund and related interest received in fiscal year 2012.

[3] Includes net intangible assets from acquisitions of $26.0 million and $29.4 million, respectively at July 31, 2014 and 2013.

[4] Includes restructuring charges of $1.4 million and $2.2 million for fiscal year 2014 and 2013, respectively.

[5] Includes net intangible assets from acquisitions of $19.9 million and $24.2 million, respectively at July 31, 2014 and 2013, relating to our acquisition of Ultrasonix during the third quarter of fiscal year 2013.

[6] Includes restructuring charges of $0.4 million and $0.2 million for fiscal year 2014 and 2013, respectively. Includes $0.5 million of contingent consulting fees related to the tax refund and related interest received in fiscal year 2012.