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Goodwill And Intangible Assets (Narrative) (Detail) (USD $) In Millions, unless otherwise specified | 12 Months Ended
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Apr. 30, 2012 | Apr. 30, 2011 | Apr. 30, 2010
Goodwill And Intangible Assets [Abstract] |  |  |
Amortization expense | $ 2.2 | $ 2.4 | $ 1.7

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- Definition Aggregate amount of intangible asset amortization recognized as expense during the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 142 -Paragraph 45 -Subparagraph a(2) -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=6905858&loc=d3e16323-109275 + Details
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- Details
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