Components of Total Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2015
Income Tax Disclosure [Abstract]
Unrecognized tax benefits	$ 13,004	$ 12,671	$ 13,269	$ 13,156
Reduction to unrecognized tax benefits for tax credit carry forward	(955)	(1,882)
Accrued interest and penalties	1,290	1,209
Total unrecognized tax benefits	13,339	11,998
Short-term, included in "Income and other taxes"	893	1,735
Long-term	12,446	10,263
Total unrecognized tax benefits	$ 13,339	$ 11,998