Commitments and Guarantees - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		3 Months Ended	12 Months Ended		3 Months Ended	1 Months Ended	3 Months Ended		1 Months Ended		1 Months Ended	12 Months Ended
	Oct. 31, 2012	Jul. 31, 2012	Oct. 31, 2013 Subsequent Event	Jul. 31, 2012 Minimum	Jul. 31, 2012 Maximum	Oct. 31, 2013 Maximum Subsequent Event	Oct. 11, 2011 Credit Agreement	Oct. 31, 2012 Credit Agreement	Oct. 31, 2011 Credit Agreement	Oct. 11, 2011 Credit Agreement Minimum	Jul. 31, 2012 Credit Agreement Minimum	Oct. 11, 2011 Credit Agreement Maximum	Jul. 31, 2012 Credit Agreement Maximum	Oct. 31, 2012 Credit Agreement Other Revolving Credit Facilities	Oct. 11, 2011 Credit Agreement LIBOR Rate Minimum	Oct. 11, 2011 Credit Agreement LIBOR Rate Maximum	Oct. 11, 2011 Credit Agreement Defined Base Rate Minimum	Oct. 11, 2011 Credit Agreement Defined Base Rate Maximum	Oct. 31, 2012 Product Extended Warranty Contracts	Jul. 31, 2012 Product Extended Warranty Contracts
Commitments and Contingencies Disclosure [Line Items]
Standard product warranty term				12 months	26 months
Deferred revenue for product extended warranty contracts	$ 8,585	$ 12,267																	$ 7,008	$ 7,207
Credit facility maximum borrow capacity							100,000
Number of banks							3
Revolving credit agreement period							5 years
Credit agreement expiry date							Oct. 10, 2016
Aggregate available credit amount under specified circumstances							150,000
Percentage of capital stock pledge as collateral							65.00%
Variable interest rate															1.25%	2.00%	0.00%	1.00%
Credit facility commitment fee percentage										0.20%		0.35%
Leverage ratio of total debt to earnings before interest tax depreciation amortization													2.75
Interest coverage ratio											3
Leverage ratio								0.006
Credit facility transaction costs incurred								500
Credit facility, maturity period								5 years
Credit facility available borrow capacity														4,000
Line of credit amount outstanding								0	0
Percentage of revenue					2.00%	0.20%
Employee termination costs	400		75
Business exit cost	$ 997