Income Taxes - Schedule of Deferred Tax Assets (Liabilities) (Details) - USD ($)	12 Months Ended
	Jul. 31, 2017	Jul. 31, 2016
Operating Loss Carryforwards [Line Items]
Tax Benefits Associated with Closure of Tax Audits	$ 320
Deferred Tax Assets, Inventory	4,516,000	$ 5,142,000
Deferred Tax Asset Prepaid Catalog Costs	0	0
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Benefits	8,932,000	6,347,000
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Allowance for Doubtful Accounts	1,141,000	1,619,000
Deferred Tax Assets, Property, Plant and Equipment	2,819,000	2,847,000
Deferred Tax Assets, Goodwill and Intangible Assets	1,187,000	1,144,000
Deferred Tax Assets, capitalized R&D	570,000	855,000
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost	16,743,000	20,549,000
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Postretirement Benefits	4,144,000	4,152,000
Deferred Tax Assets, Valuation Allowance	(38,563,000)	(37,992,000)
Deferred Tax Assets, Tax Deferred Expense, Other	12,060,000	10,918,000
Deferred Tax Assets, Gross	83,677,000	72,371,000
Deferred Tax Liabilities, Inventory	(1,000)	(153,000)
Deferred Tax Liabilities, Prepaid Expenses	(1,107,000)	(1,577,000)
Deferred Tax Liabilities Tax Deferred Expense Compensation And Benefits Employee Benefits	0	0
Deferred Tax Liabilities Accounts Receivable	(11,000)	(15,000)
Deferred Tax Liabilities, Property, Plant and Equipment	(3,884,000)	(2,695,000)
Deferred Tax Liabilities, Intangible Assets	(37,681,000)	(31,777,000)
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	0
Deferred Tax Liabilities Tax Credit Carryforwards And Net Operating Losses	0	0
Deferred Tax Liability, Valuation Allowance	0	0
Deferred Tax Liabilities, Other	(10,798,000)	(15,173,000)
Deferred Tax Liabilities, Gross	(53,482,000)	(51,390,000)
Deferred Tax Assets, Net, Deferred Expense, Compensation and Benefits, Postretirement Benefits		4,152,000
Deferred Tax Assets, Tax Credit Carryforwards	70,128,000	56,790,000
Deferred Tax Assets, Net		20,981,000
Net of liabilities [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Inventory	4,515,000	4,989,000
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Benefits	8,932,000	6,347,000
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Allowance for Doubtful Accounts	1,130,000	1,604,000
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Postretirement Benefits	4,144,000
Deferred Tax Liabilities, Intangible Assets		(30,633,000)
Deferred Tax Assets, Tax Credit Carryforwards	70,128,000	56,790,000
Deferred Tax Assets, Net	30,195,000
Net of assets [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Liabilities, Prepaid Expenses	(1,107,000)	(1,577,000)
Deferred Tax Liabilities, Property, Plant and Equipment	(1,065,000)	152,000
Deferred Tax Liabilities, Intangible Assets	(36,494,000)
Deferred Tax Liabilities, Other	$ 1,262,000	$ (4,255,000)