Segment Information - Net Income Reconciliation (Detail) - USD ($) $ in Thousands	3 Months Ended
	Oct. 31, 2021	Oct. 31, 2020
Segment Reconciliation [Abstract]
Total profit from reportable segments	$ 51,109	$ 48,267
Unallocated amounts:
Administrative costs	(6,774)	(6,079)
Investment and other income	543	155
Interest expense	(182)	(106)
Income before income taxes and losses of unconsolidated affiliate	$ 44,696	$ 42,237