The cash inflow associated with the aggregate amount received by the entity through sale or maturity of marketable securities (held-to-maturity or available-for-sale) during the period.

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

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

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Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

+ Details

Marketable Securities (Summary Of Assets Measured At Fair Value On Recurring Basis Using Significant Unobservable Inputs) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Oct. 31, 2011	Oct. 31, 2010	Oct. 31, 2011	Oct. 31, 2010
Sale of securities			$ (22,850)	$ (17,383)
Auction Rate Securities [Member]
Balance, beginning of period				8,200
Auction rate securities put option				(745)
Realized gain included in operations				745
Sale of securities				(8,200)
Balance, end of period