Segment Information - Net Income Reconciliation (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2021	Jul. 31, 2020	Jul. 31, 2019
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total profit from reportable segments	$ 191,992	$ 171,658	$ 187,978
Unallocated amounts:
Administrative costs	(24,865)	(19,814)	(25,550)
Asset Impairment Charges	0	(13,821)	0
Investment and other income	4,333	5,079	5,046
Interest expense	(437)	(2,166)	(2,830)
Income before income taxes and losses of unconsolidated affiliate	171,023	140,936	164,644
Identification Solutions
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total profit from reportable segments	169,238	150,639	164,953
Unallocated amounts:
Asset Impairment Charges		(2,792)
Workplace Safety
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total profit from reportable segments	$ 22,754	21,019	$ 23,025
Unallocated amounts:
Asset Impairment Charges		$ (11,029)