Commitments And Contingencies (Schedule Of Deferred Revenue Related To The Peace Of Mind Program) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Jul. 31, 2013	Jul. 31, 2012
Movement in Deferred Revenue [Roll Forward]
Balance, beginning of the period	$ 146,286	$ 141,080
Amounts deferred for new guarantees issued	737	573
Revenue recognized on previous deferrals	(27,826)	(26,983)
Balance, end of the period	$ 119,197	$ 114,670

Amount of deferred revenue as of balance sheet date. Deferred revenue represents collections of cash or other assets related to a revenue producing activity for which revenue has not yet been recognized. Generally, an entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP.

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Amount of deferred revenue recognized for transactions arising during the current reporting period. Deferred revenue is a liability as of the balance sheet date related to a revenue producing activity for which revenue has not yet been recognized. Generally, an Entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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Amount of previously reported deferred or unearned revenue that was recognized as revenue during the period. Deferred revenue is a liability related to a revenue producing activity for which revenue has not yet been recognized. Generally, an entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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