Segment Information - Net Income Reconciliation (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2017
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total profit from reportable segments	$ 187,978	$ 175,123	$ 156,126
Unallocated amounts:
Administrative costs	25,550	27,093	25,111
Gain (Loss) on Disposition of Business	0	(4,666)	0
Investment and other income	(5,046)	(2,487)	(1,121)
Interest Expense	2,830	3,168	5,504
Income before income taxes	164,644	152,015	126,632
Workplace Safety
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total profit from reportable segments	23,025	31,712	25,554
Identification Solutions
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total profit from reportable segments	$ 164,953	$ 143,411	$ 130,572