Stock Options Transactions (Detail) (Stock Options, USD $)	12 Months Ended
Apr. 30, 2014	Apr. 30, 2013	Apr. 30, 2012
Stock Options
Options
Outstanding, beginning of year	1,100,000	1,492,000	1,833,000
Granted	0	0	48,000
Exercised	(655,000)	(238,000)	(235,000)
Forfeited/expired	(49,000)	(154,000)	(154,000)
Outstanding, end of year	396,000	1,100,000	1,492,000
Exercisable, end of year	337,000	864,000	1,061,000
Weighted Average Exercise Price
Outstanding, beginning of year	$ 14.72	$ 14.00	$ 13.78
Granted			$ 22.71
Exercised	$ 13.88	$ 9.32	$ 12.76
Forfeited/expired	$ 13.42	$ 16.87	$ 15.63
Outstanding, end of year	$ 16.23	$ 14.72	$ 14.00
Exercisable, end of year	$ 16.11	$ 15.01	$ 14.33

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iii)

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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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.

+ References

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

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-SubTopic 10

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

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Number of options outstanding, including both vested and non-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 price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Number of share options (or share units) exercised during the current period.

+ References

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-Publisher SEC

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