Goodwill and Other Intangible Assets (Narrative) (Details) - USD ($)	3 Months Ended	6 Months Ended	9 Months Ended
	Apr. 30, 2015	Jan. 31, 2016	Apr. 30, 2016	Jul. 31, 2015
Indefinite-lived Intangible Assets [Line Items]
Goodwill impairment	$ 0
Goodwill			$ 230,900,000	$ 223,700,000
Reporting unit, percentage of fair value in excess of carrying amount		13.60%	33.80%
Goodwill, impairment test, assumptions used in estimating fair value, terminal growth rate		3.00%
Goodwill, impairment test, assumptions used in estimating fair value, discount rate		12.00%
Goodwill, impairment test, benchmark projected cash flow decrease that would result in potential impairment, percent		90.00%
Goodwill, impairment test, benchmark residual growth rate decrease that would result in potential impairment, percent		6.00%
Goodwill, impairment test, benchmark discount rate increase that would result in potential impairment, percent		3.00%
Intangible assets, net			$ 40,100,000	$ 37,900,000
Amortization of existing intangible assets			4,500,000
Foreign exchange translation decrease of intangible assets			300,000
Northern Technical
Indefinite-lived Intangible Assets [Line Items]
Amount of intangibles acquired			$ 7,000,000
Gas Turbine Systems
Indefinite-lived Intangible Assets [Line Items]
Goodwill		$ 60,200,000