Reportable Segments Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jan. 31, 2013		Jan. 31, 2012		Jan. 31, 2013		Jan. 31, 2012		Jul. 31, 2012
Net revenue:
Revenues	$ 138,554		$ 126,433		$ 258,421		$ 244,290
Income from operations before income taxes:
Income (loss) from operations	13,803		7,791		21,238		13,375
Total other (expense) income, net	(402)		2,955		(1,308)		3,266
Income from continuing operations before income taxes	13,401		10,746		19,930		16,641
Identifiable assets:
Assets	560,689				560,689				557,996
Total	560,689				560,689				557,996
Share-based compensation:
Share based compensation	3,310		3,150		5,954		5,401
Depreciation and amortization:
Depreciation and amortization	4,044		4,489		8,043		9,205
Medical Imaging
Net revenue:
Revenues	80,668		75,263		156,676		147,937
Income from operations before income taxes:
Income (loss) from operations	8,535	[1]	2,530	[1]	15,934	[1]	8,012	[1]
Share-based compensation:
Share based compensation	2,101		1,751		3,682		2,959
Depreciation and amortization:
Depreciation and amortization	2,750		2,846		5,622		5,873
Ultrasound
Net revenue:
Revenues	40,450		41,078		72,144		75,679
Income from operations before income taxes:
Income (loss) from operations	3,527		4,704		2,733		4,363
Share-based compensation:
Share based compensation	585		963		1,178		1,688
Depreciation and amortization:
Depreciation and amortization	980		1,368		1,836		2,778
Security Technology
Net revenue:
Revenues	17,436		10,092		29,601		20,674
Income from operations before income taxes:
Income (loss) from operations	1,741	[2]	557	[2]	2,571	[2]	1,000	[2]
Share-based compensation:
Share based compensation	624		436		1,094		754
Depreciation and amortization:
Depreciation and amortization	314		275		585		554
Reportable segment assets
Identifiable assets:
Assets	385,648				385,648				362,669
Reportable segment assets | Medical Imaging
Identifiable assets:
Assets	214,160				214,160				199,512
Reportable segment assets | Ultrasound
Identifiable assets:
Assets	140,761				140,761				136,388
Reportable segment assets | Security Technology
Identifiable assets:
Assets	30,727				30,727				26,769
Corporate assets
Identifiable assets:
Assets	$ 175,041	[3]			$ 175,041	[3]			$ 195,327	[3]

[1] Includes $2,198 of contingent consulting fees related to the tax refund and related interest received in the three and six months ended January 31, 2012, respectively.

[2] Includes $516 of contingent consulting fees related to the tax refund and related interest received in the three and six months ended January 31, 2012, respectively.

[3] Includes cash and cash equivalents of $131,824 and $153,122 at January 31, 2013 and July 31, 2012, respectively.