Valuation and Qualifying Accounts and Reserves (Details) - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2015	Jul. 31, 2014	Jul. 31, 2013
Inventory Reserves [Member]
Balance at Beginning of Period	$ 2,136	$ 1,760	$ 1,864
Charged to Costs and Expenses	2,643	2,279	2,203
Deductions	(2,864)	(1,903)	(2,307)
Balance at End of Period	1,915	2,136	1,760
Valuation Allowance On Income Taxes [Member]
Balance at Beginning of Period	3,017	3,062	1,588
Charged to Costs and Expenses	470	0	1,474
Deductions		45	0
Balance at End of Period		3,017	3,062
Trade Receivable Allowances [Member]
Balance at Beginning of Period	681	478	4,553
Charged to Costs and Expenses	1,303	914	773
Deductions	(1,238)	(711)	(4,848)
Balance at End of Period	$ 746	$ 681	$ 478