Goodwill and Other Intangible Assets (Narrative) (Details) - USD ($)	3 Months Ended	6 Months Ended
	Apr. 30, 2015	Jan. 31, 2016	Jul. 31, 2015
Indefinite-lived Intangible Assets [Line Items]
Goodwill impairment	$ 0
Goodwill		$ 228,500,000	$ 223,700,000
Long-term revenue growth rate		3.00%
Discount rate		12.00%
Intangible assets, net		$ 41,700,000	$ 37,900,000
Amortization of existing intangible assets		3,000,000
Foreign exchange translation decrease of intangible assets		$ 1,100,000
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%
Northern Technical
Indefinite-lived Intangible Assets [Line Items]
Amount of intangibles acquired		$ 7,000,000
Industrial Product segment
Indefinite-lived Intangible Assets [Line Items]
Goodwill		$ 60,200,000
Percentage of fair value in excess of carrying amount		14.00%