Goodwill and Intangible Assets - Changes in Carrying Amount of Goodwill (Detail) $ in Thousands	9 Months Ended
	Apr. 30, 2018 USD ($)
Goodwill [Roll Forward]
Balance as of July 31, 2017	$ 437,697
Goodwill, Translation Adjustments	(2,271)
Balance as of January 31, 2018	435,426
Id Solutions [Member]
Goodwill [Roll Forward]
Balance as of July 31, 2017	391,864
Goodwill, Translation Adjustments	(2,392)
Balance as of January 31, 2018	389,472
Workplace Safety [Member]
Goodwill [Roll Forward]
Balance as of July 31, 2017	45,833
Goodwill, Translation Adjustments	121
Balance as of January 31, 2018	$ 45,954