Accrued Expenses and Other Current Liabilities (Details) (USD $)	Oct. 31, 2011	Jul. 31, 2011	Oct. 31, 2010	Jul. 31, 2010
Accrued Expenses and Other Current Liabilities [Abstract]
Accrued wages and benefits	$ 12,248,000	$ 19,751,000
Accrued warranty obligations	9,283,000	9,120,000	9,890,000	10,562,000
Accrued commissions and royalties	4,559,000	3,295,000
Accrued business acquisition payments	913,000	726,000
Other	16,570,000	16,966,000
Accrued expenses and other current liabilities	$ 43,573,000	$ 49,858,000