Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	3 Months Ended
Jul. 31, 2016	Jul. 31, 2015	Apr. 30, 2016
Income Tax Disclosure [Abstract]
Unrecognized tax benefits	$ 6,957		$ 6,484
Unrecognized tax benefits that would impact effective tax rate	4,559
Accrued interest and penalties related to unrecognized tax benefits	244		$ 217
Net interest and penalties included in income tax expense	28	$ 119
Expected decrease in unrecognized tax benefits	$ 3,221

Amount of decrease reasonably possible in the next twelve months for the unrecognized tax benefit.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (d)(3)
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32718-109319

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The sum of the amounts of estimated penalties and interest recognized in the period arising from income tax examinations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32718-109319

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Amount of unrecognized tax benefits pertaining to uncertain tax positions taken in tax returns.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15A
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6907707&loc=SL6600010-109319

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Unrecognized Tax Benefit
-URI http://asc.fasb.org/extlink&oid=6527854

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Amount accrued for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32718-109319

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The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate.

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