Derivative Financial Instruments (Details) - Interest rate swap. $ in Millions	9 Months Ended
Oct. 31, 2015 USD ($)
Derivative Financial Instruments
Notional amount	$ 520.0
Hedge ineffectiveness	0.0
Effective portion of the loss expected to be reclassified from accumulated other comprehensive (loss) income into earnings over the next 12 months	2.4
Designated as hedging instruments
Derivative Financial Instruments
Fair value of the interest rate swap	3.2
Designated as hedging instruments \| Accrued expenses and other current liabilities
Derivative Financial Instruments
Derivative liability	2.4
Designated as hedging instruments \| Other liabilities
Derivative Financial Instruments
Derivative liability	$ 0.8

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)
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- Definition

Fair value of the assets less the liabilities of a derivative or group of derivatives.

+ References

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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-SubTopic 20
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Amount of gain (loss) from the ineffectiveness of the hedge.

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