Business and Summary of Significant Accounting Policies - Derivative Financial Instruments (Details)	12 Months Ended
Jan. 31, 2017
Minimum
Derivative [Line Items]
Derivative, term of contract	1 month
Maximum
Derivative [Line Items]
Derivative, term of contract	12 months

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.

No definition available.

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