Notes Payable (Detail Textuals) - USD ($) $ in Thousands	9 Months Ended
Oct. 31, 2015	Oct. 31, 2014
Debt Instrument [Line Items]
Notes payable under credit agreement	$ 171,840	$ 153,853
Senior secured credit facility
Debt Instrument [Line Items]
Term of senior secured credit facility	5 years
Senior secured credit facility	$ 450,000
Amount available under credit agreement	$ 264,900
Senior secured credit facility \| LIBOR plus \| Minimum
Debt Instrument [Line Items]
Spread interest rate	1.50%
Senior secured credit facility \| LIBOR plus \| Maximum
Debt Instrument [Line Items]
Spread interest rate	2.00%
Senior secured credit facility \| Prime plus \| Minimum
Debt Instrument [Line Items]
Spread interest rate	0.50%
Senior secured credit facility \| Prime plus \| Maximum
Debt Instrument [Line Items]
Spread interest rate	1.00%

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

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- Definition

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.

+ References

No definition available.

+ Details

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- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Sum of the carrying values as of the balance sheet date of the portions of long-term notes payable due within one year or the operating cycle if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19,20)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Period Type:	instant

- Details

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- Details

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