Income Taxes - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Apr. 30, 2015	Apr. 30, 2014	Jan. 31, 2015
Disclosure Income Taxes Additional Information [Abstract]
Income tax expense	$ (1,512)us-gaap_IncomeTaxExpenseBenefit	$ (174)us-gaap_IncomeTaxExpenseBenefit
Effective tax rate	12.60%	5.40%
Period specific items benefit	246ment_PeriodSpecificTaxItems
Effective income tax rate forecast	17.00%ment_EffectiveIncomeTaxRateForecast
U.S. federal statutory rate	35.00%
Income taxes associated with uncertain income tax positions	19,343us-gaap_UnrecognizedTaxBenefits
Liability for uncertain tax positions, current	238
Income tax liability	$ 19,105		$ 19,279

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-- A ratio calculated by dividing the forecast amount of income tax expense attributable to continuing operations by forecasted GAAP-basis pretax income from continuing operations. --

+ References

No definition available.

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- Definition

-- The net amount of all increases and decreases in the period of discrete tax items --

+ References

No definition available.

+ Details

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- Definition

Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

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-Topic 235

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-Section S99

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-Subparagraph (SX 210.4-08.(h)(2))

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- Definition

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

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-Paragraph 1

-Subparagraph (SAB TOPIC 6.I)

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- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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-Glossary Income Tax Expense (or Benefit)

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- Definition

The current portion of the amount recognized for uncertain tax positions as of the balance sheet date.

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-Name Accounting Standards Codification

-Topic 210

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-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.20)

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- Definition

The noncurrent portion of the amount recognized for uncertain tax positions as of the balance sheet date.

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-Subparagraph (SX 210.5-02.24)

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- Definition

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

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-Glossary Unrecognized Tax Benefit

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