Significant accounting policies (Details 1)	12 Months Ended
	Oct. 31, 2011 Year
Patent/technology costs [Member]
Weighted average useful lives for each major category of amortizable intangible assets
Weighted average useful lives for amortizable intangible assets	13.5
Customer relationships [Member]
Weighted average useful lives for each major category of amortizable intangible assets
Weighted average useful lives for amortizable intangible assets	19.5
Noncompete agreements [Member]
Weighted average useful lives for each major category of amortizable intangible assets
Weighted average useful lives for amortizable intangible assets	7.4
Trade names [Member]
Weighted average useful lives for each major category of amortizable intangible assets
Weighted average useful lives for amortizable intangible assets	18.1