Warranty (Reconciliation Of Warranty Reserves) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Oct. 31, 2011	Oct. 31, 2010
Warranty [Abstract]
Product warranty reserves, beginning balance	$ 19,720	$ 15,707
Accruals for warranties issued during the reporting period	791	2,443
Adjustments related to pre - existing warranties (including changes in estimates)	(535)	2,170
Less settlements made during the period	(3,841)	(988)
Product warranty reserves, ending balance	$ 16,135	$ 19,332

Carrying value as of the balance sheet date of obligations incurred through that date and payable for estimated claims under standard and extended warranty protection rights granted to customers.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 9

-Section 03

-Paragraph 15

-Subparagraph 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 5

-Paragraph 9, 10

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 460

-SubTopic 10

-Section 50

-Paragraph 8

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- Definition

Represents the aggregate decrease in the liability related to payments to satisfy claims for standard and extended product warranties.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 460

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- Definition

Represents the aggregate Increase or Decrease in the liability during the reporting period for accruals related to preexisting standard and extended product warranties (including adjustments for changes in estimates).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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-Paragraph 8

-Subparagraph ((c)(4))

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Represents the aggregate increase in the liability for accruals related to standard and extended product warranties issued during the reporting period.

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-Publisher FASB

-Name Accounting Standards Codification

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