Stock-Based Compensation - Expense (Details) - USD ($)	3 Months Ended		9 Months Ended
	Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2016	Apr. 30, 2015
Income statement components of stock-based compensation expense recognized in Consolidated Statements of Income
Stock-based compensation before income taxes	$ 2,242,000	$ 1,353,000	$ 5,837,000	$ 4,354,000
Income tax benefits	(797,000)	(479,000)	(2,071,000)	(1,525,000)
Total stock-based compensation expense, net of tax	1,445,000	874,000	3,766,000	2,829,000
Cost of sales
Income statement components of stock-based compensation expense recognized in Consolidated Statements of Income
Stock-based compensation before income taxes	120,000	64,000	320,000	226,000
Operating expenses: Selling
Income statement components of stock-based compensation expense recognized in Consolidated Statements of Income
Stock-based compensation before income taxes	246,000	138,000	684,000	444,000
Operating expenses: General and administrative
Income statement components of stock-based compensation expense recognized in Consolidated Statements of Income
Stock-based compensation before income taxes	1,847,000	1,137,000	4,750,000	3,639,000
Operating expenses: Research and development
Income statement components of stock-based compensation expense recognized in Consolidated Statements of Income
Stock-based compensation before income taxes	29,000	14,000	83,000	45,000
Total operating expenses
Income statement components of stock-based compensation expense recognized in Consolidated Statements of Income
Stock-based compensation before income taxes	$ 2,122,000	$ 1,289,000	$ 5,517,000	$ 4,128,000