Debt Saudi revolver (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Apr. 30, 2013
Foreign line of credit facility [Line Items]
Foreign Line of Credit Facility, Interest Rate Description	(a) a margin in effect plus prime rate; or (b) a margin in effect plus the LIBOR rate for the corresponding interest period.
SAUDI ARABIA
Foreign line of credit facility [Line Items]
Saudi foreign revolver	2.7
Foreign Line of Credit Facility, Interest Rate Description	SIBOR (Singapore Interbank Offered Rate) plus a margin of 3.5%

Description of the interest rate for the amounts borrowed under the credit facility, including the terms and the method for determining the interest rate (for example, fixed or variable, LIBOR plus a percentage, increasing rate, timing of interest rate resets, remarketing provisions).

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 129

-Paragraph 2, 4

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: 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

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration