Goodwill And Intangible Assets (Estimated Annual Amortization Expense Related To Amortizing Intangible Assets) (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Apr. 30, 2012
Goodwill And Intangible Assets [Abstract]
2013	$ 2,183
2014	2,119
2015	1,855
2016	1,594
2017	980
Thereafter	7,892
Total estimated amortization expense	$ 16,623

The aggregate estimated amortization expense for succeeding fiscal years for intangible assets subject to amortization.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

-Paragraph 45

-Subparagraph a(3)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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)(3)

-URI http://asc.fasb.org/extlink&oid=6905858&loc=d3e16323-109275

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- Definition

The amount of amortization expense expected to be recognized for the remainder of the finite-lived intangible asset useful life after the fifth succeeding fiscal year.

+ References

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The amount of amortization expense expected to be recognized during year five of the five succeeding fiscal years.

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The amount of amortization expense expected to be recognized during year four of the five succeeding fiscal years.

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- Definition

The amount of amortization expense expected to be recognized during year one of the five succeeding fiscal years.

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- Definition

The amount of amortization expense expected to be recognized during year three of the five succeeding fiscal years.

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The amount of amortization expense expected to be recognized during year two of the five succeeding fiscal years.

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