Goodwill and Other Intangible Assets (Narrative) (Details)	3 Months Ended	6 Months Ended	9 Months Ended	12 Months Ended
	Apr. 30, 2015 USD ($)	Jan. 31, 2016 USD ($)	Apr. 30, 2016 reporting_unit	Jul. 31, 2016 USD ($)	Jul. 31, 2015 USD ($)	Jul. 31, 2014 USD ($)
Indefinite-lived Intangible Assets [Line Items]
Number of Reporting Units | reporting_unit			5
Intangible assets, net				$ 38,500,000	$ 37,900,000
Reporting Unit, Percentage of Fair Value in Excess of Carrying Amount			34.00%
Goodwill				229,300,000	223,700,000	$ 166,400,000
Fair Value Inputs, Long-term Revenue Growth Rate		3.00%
Fair Value Inputs, Discount Rate		12.00%
Goodwill, Impairment Test, Benchmark Projected Cash Flow Decrease That Would Result in Potential Impairment, Percent		25.00%
Goodwill, Impairment Test, Benchmark Residual Growth Rate Decrease That Would Result in Potential Impairment, Percent		4.50%
Goodwill, Impairment Test, Benchmark Discount Rate Increase That Would Result in Potential Impairment, Percent		1.20%
Goodwill, Impairment Loss	$ 0
Patents Trademarks And Tradenames
Indefinite-lived Intangible Assets [Line Items]
Intangible assets, net				$ 7,800,000	8,800,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				7 years 4 months 24 days
Customer Relationships
Indefinite-lived Intangible Assets [Line Items]
Intangible assets, net				$ 30,700,000	$ 29,100,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				12 years 4 months 24 days
Gas Turbine Systems
Indefinite-lived Intangible Assets [Line Items]
Reporting Unit, Percentage of Fair Value in Excess of Carrying Amount		38.00%
Goodwill		$ 60,200,000