Acquisitions (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
	Sep. 30, 2014	Jul. 31, 2016	Apr. 30, 2016	Jan. 31, 2016	Oct. 31, 2015	Jul. 31, 2015	Apr. 30, 2015	Jan. 31, 2015	Oct. 31, 2014	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2014	Aug. 31, 2015
Business Acquisition [Line Items]
Net sales		$ 593.8	$ 571.3	$ 517.2	$ 538.0	$ 610.6	$ 575.6	$ 588.5	$ 596.5	$ 2,220.3	$ 2,371.2	$ 2,473.5
Goodwill acquired		$ 229.3				$ 223.7				$ 229.3	$ 223.7	$ 166.4
Northern Technical
Business Acquisition [Line Items]
Percentage of voting interest acquired	100.00%
Business Combination, Consideration Transferred	$ 97.1
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	6.2
Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Net Tangible Assets	32.2
Goodwill acquired	$ 60.3
Northern Technical | Minimum
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life										6 months
Northern Technical | Maximum
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life										7 years
Engineered Products Company
Business Acquisition [Line Items]
Percentage of voting interest acquired													100.00%