Summary of Business Operations and Significant Accounting Policies - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended				3 Months Ended	12 Months Ended	3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended		12 Months Ended
	Jul. 31, 2012 Segment	Jul. 31, 2011	Jul. 31, 2010	Jul. 31, 2009	Apr. 30, 2012 Reclassifications	Jul. 31, 2011 Reclassifications	Oct. 31, 2011 Increase (Decrease) Effect of Exchange Rates on Cash	Jan. 31, 2012 Increase (Decrease) Effect of Exchange Rates on Cash	Oct. 31, 2011 Increase (Decrease) Net Cash Provided By Used In Operating Activities	Jan. 31, 2012 Increase (Decrease) Net Cash Provided By Used In Operating Activities	Jan. 31, 2012 Increase (Decrease) Net Cash Provided By Used In Financing Activities	Jul. 31, 2012 Computer Software, Intangible Asset	Jul. 31, 2011 Computer Software, Intangible Asset	Jul. 31, 2010 Computer Software, Intangible Asset	Jul. 31, 2012 Minimum	Jul. 31, 2012 Maximum
Significant Accounting Policies [Line Items]
Ownership interests															10.00%	50.00%
Depreciation of property, plant, and equipment	$ 13,439	$ 12,770	$ 11,962
Standard product warranty term															12 months	26 months
Estimated lives of software development												3 years			6 months	14 years
Amortization expense of development expense	3,063	3,088	2,931									1,273	1,940	1,921
Unamortized balance of capitalized software	192	1,594
Cash and cash equivalents	187,011	169,656	169,254	119,855
Percentage of certificates of deposit instruments that are insured by the FDIC	100.00%
Reportable segment	3
Foreign exchange losses	668	678	612
Effect of exchange rate on cash	(1,929)	1,647	(2,097)		620	1,685
Prior period reclassification adjustment							$ 910	$ 620	$ (910)	$ (654)	$ (34)