Goodwill and intangible assets (Details 1) (USD $) In Thousands, unless otherwise specified	Oct. 31, 2011	Oct. 31, 2010
Summary of intangible assets subject to amortization
Carrying Amount	$ 150,181	$ 63,157
Accumulated Amortization	29,482	23,329
Net Book Value	120,699	39,828
Patent/technology costs [Member]
Summary of intangible assets subject to amortization
Carrying Amount	43,235	23,429
Accumulated Amortization	11,571	9,084
Net Book Value	31,664	14,345
Customer relationships [Member]
Summary of intangible assets subject to amortization
Carrying Amount	78,324	30,630
Accumulated Amortization	11,843	8,273
Net Book Value	66,481	22,357
Noncompete agreements [Member]
Summary of intangible assets subject to amortization
Carrying Amount	5,042	5,982
Accumulated Amortization	3,727	4,857
Net Book Value	1,315	1,125
Trade names [Member]
Summary of intangible assets subject to amortization
Carrying Amount	22,143	1,684
Accumulated Amortization	1,530	479
Net Book Value	20,613	1,205
Other [Member]
Summary of intangible assets subject to amortization
Carrying Amount	1,437	1,432
Accumulated Amortization	811	636
Net Book Value	$ 626	$ 796