Intangible Assets and Goodwill - Estimated of Amortization Expenses (Detail) (USD $) In Thousands, unless otherwise specified	Apr. 30, 2013
Finite-Lived Intangible Assets [Line Items]
Intangible amortization expenses for 2014	$ 2,216
Intangible amortization expenses for 2015	1,907
Intangible amortization expenses for 2016	1,525
Intangible amortization expenses for 2017	1,262
Intangible amortization expenses for 2018	1,309
Intangible amortization expenses for Thereafter	$ 3,455

Amount of amortization expense expected to be recognized during the next fiscal year following the latest fiscal year for assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

Reference 1: 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=7658586&loc=d3e16323-109275

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Amount of amortization expense expected to be recognized after the fifth rolling twelve months following the latest balance sheet presented for assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

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Amount of amortization expense expected to be recognized during the fifth fiscal year following the latest fiscal year for assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount of amortization expense expected to be recognized during the fourth fiscal year following the latest fiscal year for assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount of amortization expense expected to be recognized during the third fiscal year following the latest fiscal year for assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount of amortization expense expected to be recognized during the second fiscal year following the latest fiscal year for assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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