Schedule of Fair Value, Assets Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Jul. 31, 2018	Jul. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred compensation plan assets	$ 43,316	$ 28,095
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	230,319	176,663
Deferred compensation plan assets	$ 43,316	$ 28,095