Income Taxes - Schedule of Deferred Tax Assets (Liabilities) (Details) - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2017
Operating Loss Carryforwards [Line Items]
Tax Benefits Associated with Closure of Tax Audits		$ 1,742
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 2,850
Deferred Tax Assets, Inventory		3,095	$ 4,516
Deferred Tax Asset Prepaid Catalog Costs		0	0
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Benefits		3,772	8,932
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Allowance for Doubtful Accounts		828	1,141
Deferred Tax Assets, Property, Plant and Equipment		2,959	2,819
Deferred Tax Assets, Goodwill and Intangible Assets		1,073	1,187
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost		10,656	16,743
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Postretirement Benefits		3,280	4,144
Deferred Tax Assets, Valuation Allowance		(56,866)	(38,563)
Deferred Tax Assets, Tax Deferred Expense, Other		8,548	12,630
Deferred Tax Assets, Gross		41,693	83,677
Deferred Tax Liabilities, Inventory		(53)	(1)
Deferred Tax Liabilities, Prepaid Expenses		(978)	(1,107)
Deferred Tax Liabilities Tax Deferred Expense Compensation And Benefits Employee Benefits		(91)	0
Deferred Tax Liabilities Accounts Receivable		(1)	(11)
Deferred Tax Liabilities, Property, Plant and Equipment		(4,911)	(3,884)
Deferred Tax Liabilities, Intangible Assets		(29,630)	(37,681)
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		(8,962)	(10,798)
Deferred Tax Liabilities, Gross		(44,626)	(53,482)
Deferred Tax Assets, Net, Deferred Expense, Compensation and Benefits, Postretirement Benefits			4,144
Deferred Tax Assets, Tax Credit Carryforwards		64,348	70,128
Deferred Tax Assets, Net			30,195
Net of liabilities [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Inventory		3,042	4,515
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Benefits		3,681	8,932
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Allowance for Doubtful Accounts		827	1,130
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Postretirement Benefits		3,280
Deferred Tax Liabilities, Intangible Assets			(36,494)
Deferred Tax Assets, Tax Credit Carryforwards		64,348	70,128
Deferred Tax Liabilities, Net		(2,933)
Net of assets [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Liabilities, Prepaid Expenses		(978)	(1,107)
Deferred Tax Liabilities, Property, Plant and Equipment		(1,952)	(1,065)
Deferred Tax Liabilities, Intangible Assets		(28,557)
Deferred Tax Liabilities, Other		$ (414)	$ 1,832