Stock-based compensation (Details 1) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
Oct. 31, 2011 Year
Price Range 11 To 20 [Member]
Summarized information on currently outstanding options
Number outstanding	843
Weighted-average remaining contractual life, in years	4.7
Weighted-average exercise price	$ 15.69
Number exercisable	596
Weighted-average exercise price	$ 16.24
Price Range 21 To 28 [Member]
Summarized information on currently outstanding options
Number outstanding	655
Weighted-average remaining contractual life, in years	6.5
Weighted-average exercise price	$ 26.22
Number exercisable	331
Weighted-average exercise price	$ 25.62
Price Range 29 To 44 [Member]
Summarized information on currently outstanding options
Number outstanding	353
Weighted-average remaining contractual life, in years	8.9
Weighted-average exercise price	$ 40.85
Number exercisable	17
Weighted-average exercise price	$ 30.70

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Weighted average exercise price as of the balance sheet date for those share-based payment arrangements exercisable and outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(1)(c)

+ Details

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- Definition

The number of shares reserved for issuance pertaining to the outstanding exercisable stock options as of the balance-sheet date in the customized range of exercise prices for which the market and performance vesting condition has been satisfied.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(1)(c)

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- Definition

The number of shares reserved for issuance pertaining to the outstanding stock options as of the balance sheet date for all option plans in the customized range of exercise prices.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(1)(a, b)

+ Details

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- Definition

The weighted average price as of the balance-sheet date at which grantees could acquire the underlying shares with respect to all outstanding stock options which are in the customized range of exercise prices.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(1)(a, b)

+ Details

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- Definition

The weighted-average period remaining as of the balance-sheet date until option expiration pertaining to the outstanding stock options for all option plans in the customized range of exercise prices, which may be expressed in a variety of ways (for example, years, months).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph d(1)

+ Details

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