Credit Risk Assessment for Long-term Receivables (Details) - USD ($) $ in Thousands	Jan. 31, 2016	Jan. 31, 2015
Accounts and Financing Receivable [Line Items]
Term receivables, long-term	$ 268,657	$ 301,862
S&P credit rating, AAA+ through BBB-
Accounts and Financing Receivable [Line Items]
Term receivables, long-term	195,764	192,430
S&P credit rating, BB+ and lower
Accounts and Financing Receivable [Line Items]
Term receivables, long-term	22,520	31,939
S&P credit rating
Accounts and Financing Receivable [Line Items]
Term receivables, long-term	218,284	224,369
Internal Credit Rating
Accounts and Financing Receivable [Line Items]
Term receivables, long-term	$ 50,373	$ 77,493

Amount due from customers or clients, more than one year from the balance sheet date, for goods or services that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.

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 210.5-02.17)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 3
-Article 5

Name:	us-gaap_AccountsReceivableNetNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant