Stock-Based Compensation (Summary Of Stock Options) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
Apr. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Shares, Outstanding, beginning of the year	7,308
Shares, Granted	979
Shares, Exercised	(1,414)
Shares, Forfeited or expired	(2,369)
Shares, Outstanding, end of the year	4,504
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Weighted-Average Exercise Price, Outstanding, beginning of the year (in usd per share)	$ 18.02
Weighted-Average Exercise Price, Granted (in usd per share)	$ 17.95
Weighted-Average Exercise Price, Exercised (in usd per share)	$ 18.08
Weighted-Average Exercise Price, Forfeited or expired (in usd per share)	$ 19.22
Weighted-Average Exercise Price, Outstanding, end of the year (in usd per share)	$ 17.53
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Shares, Exercisable, end of the year	2,646
Shares, Exercisable and expected to vest	4,340
Weighted-Average Exercise Price, Exercisable, end of the year	$ 18.33
Weighted-Average Exercise Price, Exercisable and expected to vest	$ 17.58
Weighted-Average Remaining Contractual Term, Outstanding, end of the year	7 years
Weighted-Average Remaining Contractual Term, Exercisable, end of the year	5 years
Weighted-Average Remaining Contractual Term, Exercisable and expected to vest, years	7 years
Aggregate Intrinsic Value, Outstanding, end of the year	$ 46,202
Aggregate Intrinsic Value, Exercisable, end of the year	25,119
Aggregate Intrinsic Value, Exercisable and expected to vest	$ 44,326

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For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.

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Net number of share options (or share units) granted during the period.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of options outstanding.

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The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance sheet date, including vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of fully vested and expected to vest options that are exercisable.

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The number of exercisable share options (fully vested and expected to vest) that may be converted as of the balance sheet date.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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