Product Warranty (Schedule Of Warranty Liability) (Details) - USD ($) $ in Thousands	9 Months Ended
Jan. 31, 2017	Jan. 31, 2016
Product Warranties Disclosures [Abstract]
Warranty claims period	2 months
Movement in Standard and Extended Product Warranty, Increase (Decrease) [Roll Forward]
Beginning balance	$ 2,926	$ 2,643
Accrual	13,460	11,668
Settlements	(13,376)	(11,755)
Ending balance	$ 3,010	$ 2,556

Product Warranty Claims, Period

No definition available.

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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- References

No definition available.

+ Details

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=68068213&loc=d3e12565-110249

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (c)(5)
-URI http://asc.fasb.org/extlink&oid=68068213&loc=d3e12565-110249

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.15(5))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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- Definition

Amount of decrease in the standard and extended product warranty accrual from payments made in cash or in kind to satisfy claims under the terms of the standard and extended product warranty.

+ References

+ Details

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Balance Type:	debit
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- Definition

Amount of increase in the standard and extended product warranty accrual from warranties issued.

+ References

+ Details

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