Income Taxes (Schedule of Deferred Tax Assets and Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Oct. 31, 2013	Jul. 31, 2013	Oct. 31, 2012
Deferred tax assets:
Accounts receivable, principally due to allowances for doubtful accounts	$ 1,145		$ 1,073
Inventories	4,812		4,916
Litigation settlements	184		199
Accrued liabilities, reserves and compensation accruals	36,377		41,760
Restricted stock	19,925		19,395
Net operating loss carryforwards	5,514		3,563
Plant and equipment	3,555		3,999
Research and experimental expenses - Section 59(e)	5,318		6,815
Tax credit carryforwards	11,091		8,700
Total gross deferred tax assets	87,921		90,420
Less valuation allowance	(968)	(1,000)	(1,107)
Deferred tax assets	86,953		89,313
Deferred tax liabilities:
Tax deductible goodwill	(21,575)		(19,038)
Transaction cost	(1,144)		(1,144)
Foreign deferred tax liabilities	(10,179)		(19,365)
Other intangible assets	(20,195)		(24,548)
Bonus adjustments under new accounting method	(1,300)		(2,601)
Total gross deferred tax liabilities	(54,393)		(66,696)
Net deferred tax assets	$ 32,560		$ 22,617