Segment Information - Net Income Reconciliation (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2018
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total profit from reportable segments	$ 171,658	$ 187,978	$ 175,123
Unallocated amounts:
Administrative costs	(19,814)	(25,550)	(27,093)
Gain (Loss) on Disposition of Business	0	0	(4,666)
Investment and other income	5,079	5,046	2,487
Interest expense	(2,166)	(2,830)	(3,168)
Income before income taxes and losses of unconsolidated affiliate	140,936	164,644	152,015
Asset Impairment Charges	(13,821)	0	0
Workplace Safety
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total profit from reportable segments	21,019	23,025	31,712
Identification Solutions
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total profit from reportable segments	$ 150,639	$ 164,953	$ 143,411