Commitments (Purchase Commitments) (Details)	12 Months Ended
Jan. 31, 2019 USD ($)
Raw Materials [Member]
Long-term Purchase Commitment [Line Items]
Purchase commitment	$ 11,296,000

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.

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