Accrued Expenses and Other Current Liabilities (Product Warranty Rollforward) (Details) - USD ($)	6 Months Ended
	Jan. 31, 2021	Jan. 31, 2020
Changes in Product Warranty Liability
Balance at beginning of period	$ 15,200,000	$ 15,968,000
Provision for warranty obligations	2,329,000	1,937,000
Additions (in connection with acquisitions)	500,000	1,000,000
Charges incurred	(1,355,000)	(2,479,000)
Warranty settlement and reclass	0	302,000
Balance at end of period	$ 16,674,000	$ 16,728,000