SHAREHOLDERS' EQUITY Share Repurchase Program (Details) (USD $) In Millions, except Share data	3 Months Ended
Jul. 31, 2011
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Authorized Amount	$ 150.0
Stock Repurchased and Retired During Period, Shares	1,527,196
Stock Repurchased and Retired During Period, Value	34.1
Repurchase of Equity [Member]
Equity, Class of Treasury Stock [Line Items]
Maximum Broker Authorization to Purchase on Our Behalf	40.0
Stock Repurchased and Retired Subsequent to Period End, Shares	1,598,500
Stock Repurchased and Retired Subsequent to Period End, Value	$ 31.0

Maximum Broker Authorization to Purchase on Our Behalf

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Stock Repurchased and Retired Subsequent to Period End, Shares

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Stock Repurchased and Retired Subsequent to Period End, Value

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Number of shares that have been repurchased and retired during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 12
-Paragraph 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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Article 3

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 29, 30
-Article 5

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Equity impact of the value of stock that has been repurchased and retired during the period. The excess of the purchase price over par value can be charged against retained earnings (once the excess is fully allocated to additional paid in capital).

+ References

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The amount authorized by an entity's Board of Directors under a stock repurchase plan.

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