Income Taxes - Schedule of Deferred Tax Assets (Liabilities) (Details) - USD ($) $ in Thousands	Jul. 31, 2015	Jul. 31, 2014
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Inventory	$ 4,387	$ 5,460
Deferred Tax Asset Prepaid Catalog Costs	0	30
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Benefits	1,612	1,533
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Allowance for Doubtful Accounts	1,136	852
Deferred Tax Assets, Other	8,524	8,700
Deferred Tax Assets, Gross, Current	15,659	16,575
Deferred Tax Assets, Property, Plant and Equipment	3,344	2,431
Deferred Tax Assets, Goodwill and Intangible Assets	1,242	1,706
Deferred Tax Assets, capitalized R&D	1,140	1,425
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost	19,549	21,733
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Postretirement Benefits	3,563	5,002
Deferred Tax Assets, Valuation Allowance	(39,922)	(37,409)
Deferred Tax Assets, Tax Deferred Expense, Other	1,014	1,411
Deferred Tax Assets, Gross, Noncurrent	56,674	55,169
Deferred Tax Assets, Gross	72,333	71,744
Deferred Tax Liabilities, Inventory	(197)	(126)
Deferred Tax Liabilities, Prepaid Expenses	(2,179)	(3,180)
Deferred Tax Liabilities Tax Deferred Expense Compensation And Benefits Employee Benefits	0	(27)
Deferred Tax Liabilities Accounts Receivable	(14)	(9)
Deferred Tax Liabilities Current Other	(1,510)	(1,015)
Deferred Tax Liabilities, Gross, Current	(3,900)	(4,357)
Deferred Tax Liabilities, Property, Plant and Equipment	(3,213)	(4,587)
Deferred Tax Liabilities, Intangible Assets	(26,570)	(27,381)
Deferred Tax Liabilities, Deferred Expense, Capitalized Research and Development Costs	0	0
Deferred Tax Liability, Deferred Expense, Deferred Compensation	0	0
Deferred Tax Liabilities, Deferred Tax Expense, Postretirement Benefits	0	(4)
Deferred Tax Liabilities Tax Credit Carryforwards And Net Operating Losses	0	0
Deferred Tax Liability, Valuation Allowance	0	0
Deferred Tax Liabilities, Other	(10,965)	(6,499)
Deferred Tax Liabilities, Gross, Noncurrent	40,748	38,471
Deferred Tax Liabilities, Gross	(44,648)	(42,828)
Deferred Tax Assets, Net, Deferred Expense, Compensation and Benefits, Postretirement Benefits		4,998
Deferred Tax Assets, Tax Credit Carryforwards	66,744	58,870
Deferred Tax Assets, Net		28,916
Net of liabilities [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Inventory	4,190	5,334
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Benefits	1,612	1,506
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Allowance for Doubtful Accounts	1,122	843
Deferred Tax Assets, Other	7,014	7,685
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Postretirement Benefits	3,563
Deferred Tax Liabilities, Intangible Assets		(25,675)
Deferred Tax Assets, Net, Current	11,759	12,218
Deferred Tax Assets, Tax Credit Carryforwards	66,744	58,870
Deferred Tax Assets, Net, Noncurrent	15,926	16,698
Deferred Tax Assets, Net	27,685
Net of assets [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Liabilities, Prepaid Expenses	(2,179)	(3,150)
Deferred Tax Liabilities, Property, Plant and Equipment	131	(2,156)
Deferred Tax Liabilities, Intangible Assets	(25,328)
Deferred Tax Liabilities, Other	$ (9,951)	$ (5,088)