Fair Value Measurements - Additional Information (Detail) - USD ($)	12 Months Ended
	Jul. 31, 2015	Apr. 30, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill, Carrying Value	$ 26,194
Other Intangible Assets, Estimated Fair Value	19,543
Goodwill and Intangible Asset Impairment	6,651
Debt, Fair Value	252,254,000	$ 244,000
Debt, Carrying Value	243,288,000	$ 236,000
WPS APAC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill, Impairment Loss	26,000
Workplace Safety Americas [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill, Impairment Loss	11,000
Workplace Safety [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill, Impairment Loss	$ 37,000