Income Taxes - Schedule of Deferred Tax Assets (Liabilities) (Details) - USD ($) $ in Thousands	Jul. 31, 2020	Jul. 31, 2019
Tax Credit Carryforward [Line Items]
Deferred Tax Liabilities, Gross	$ 43,649	$ 47,270
Deferred Tax Assets, Gross	34,208	36,687
Deferred Tax Liabilities, Other	4,700	7,961
Deferred Tax Assets, Tax Deferred Expense, Other	11,786	7,406
Deferred Tax Liability, Valuation Allowance	0	0
Deferred Tax Assets, Valuation Allowance	58,809	60,073
Deferred Tax Liabilities Tax Credit Carryforwards And Net Operating Losses	0	0
Deferred Tax Assets, Tax Credit Carryforwards	56,447	62,966
Deferred tax liabilities, deferred tax expense, postretirement benefits	31	71
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Postretirement Benefits	3,002	2,659
Deferred Tax Liability, Deferred Expense, Deferred Compensation	0	0
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost	7,851	7,352
Deferred Tax Liabilities, Intangible Assets	31,488	31,415
Deferred Tax Assets, Goodwill and Intangible Assets	1,026	1,432
Deferred Tax Liabilities, Property, Plant and Equipment	7,285	6,869
Deferred Tax Assets, Property, Plant and Equipment	3,663	3,125
Deferred Tax Liabilities Accounts Receivable	0	233
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Allowance for Doubtful Accounts	1,518	943
Deferred Tax Liabilities Tax Deferred Expense Compensation And Benefits Employee Benefits	72	89
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Benefits	3,339	7,021
Deferred Tax Liabilities, Prepaid Expenses	15	631
Deferred Tax Asset Prepaid Catalog Costs	0	0
Deferred Tax Liabilities, Inventory	58	1
Deferred Tax Assets, Inventory	4,385	3,856
Net of liabilities [Member]
Tax Credit Carryforward [Line Items]
Deferred Tax Assets, Valuation Allowance	58,809
Deferred Tax Assets, Tax Credit Carryforwards	56,447
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Postretirement Benefits	2,971
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost	7,851
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Allowance for Doubtful Accounts	1,518
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Benefits	3,267
Deferred Tax Assets, Inventory	4,327
Net of assets [Member]
Tax Credit Carryforward [Line Items]
Deferred Tax Liabilities, Net	9,441	10,583
Deferred Tax Liabilities, Other	7,086
Deferred Tax Liabilities, Intangible Assets	30,462
Deferred Tax Liabilities, Property, Plant and Equipment	3,622
Deferred Tax Liabilities, Prepaid Expenses	$ 15
Net of liabilities [Member]
Tax Credit Carryforward [Line Items]
Deferred Tax Assets, Net, Deferred Expense, Compensation and Benefits, Postretirement Benefits		2,588
Deferred Tax Assets, Valuation Allowance		60,073
Deferred Tax Assets, Tax Credit Carryforwards		62,966
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost		7,352
Deferred Tax Liabilities, Intangible Assets		29,983
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Allowance for Doubtful Accounts		710
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Benefits		6,932
Deferred Tax Assets, Inventory		3,855
Net of assets [Member]
Tax Credit Carryforward [Line Items]
Deferred Tax Liabilities, Other		555
Deferred Tax Liabilities, Property, Plant and Equipment		3,744
Deferred Tax Liabilities, Prepaid Expenses		$ 631