Income Taxes - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
Oct. 31, 2014	Jul. 31, 2014
Income Taxes [Line Items]
U.S. Federal statutory tax rate	35.00%
Unrecognized tax benefits, accrued interest and penalties	$ 0.7	$ 0.6
Unrecognized tax benefits, for uncertain tax positions	$ 6.9

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

+ References

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-Publisher FASB

-Name Accounting Standards Codification

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- Definition

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

-Glossary Unrecognized Tax Benefit

-URI http://asc.fasb.org/extlink&oid=6527854

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- Definition

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

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