Acquisitions - Additional Information (Detail) - USD ($)	12 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2016
Business Acquisition Actual Revenue And Pre Tax Income Loss [Line Items]
Proceeds from Divestiture of Businesses	$ 19,141
Gain (Loss) on Disposition of Business	(4,666,000)	$ 0	$ 0
Interest expense	3,168,000	5,504,000	7,824,000
Income tax expense (benefit)	60,955,000	30,987,000	29,235,000
Pre-tax amortization of intangible assets	$ 6,433,000	$ 7,113,000	$ 9,056,000