Acquisitions (Details) - USD ($) $ in Thousands		12 Months Ended
	Sep. 30, 2014	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2014	Jul. 31, 2013
Business Acquisition [Line Items]
Goodwill acquired			$ 223,732	$ 166,406	$ 165,568
Northern Technical [Member]
Business Acquisition [Line Items]
Percentage of voting interest acquired	100.00%
Total consideration of transaction	$ 97,100
Amount of intangible assets acquired	6,200
Net tangible assets	32,200
Goodwill acquired	$ 60,300
Period from purchase date the purchase price allocation is expected to be finalized			1 year
Northern Technical [Member] | Minimum [Member]
Business Acquisition [Line Items]
Estimated useful life, years			6 months
Northern Technical [Member] | Maximum [Member]
Business Acquisition [Line Items]
Estimated useful life, years			7 years
Engineered Products Company [Member]
Business Acquisition [Line Items]
Revenues			$ 9,000
Ifil [Member] | Minimum [Member] | Scenario Forecast [Member]
Business Acquisition [Line Items]
Revenues		$ 6,000
Ifil [Member] | Maximum [Member] | Scenario Forecast [Member]
Business Acquisition [Line Items]
Revenues		$ 8,000