Subsequent events (Details)	12 Months Ended
Jan. 31, 2016
Subsequent Event [Line Items]
Subsequent event date	Feb. 04, 2016
Subsequent event description	the remaining 51% interest in BPPC was acquired from a subsidiary of Aegion Corporation for consideration of approximately $9.6 million in cash and debt

Describes the event or transaction that occurred between the balance sheet date and the date the financial statements are issued or available to be issued.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 855
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6842918&loc=SL6314017-165662

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- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

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- Definition

Date the event occurred after the balance sheet date but before financial statements are issues or available to be issued, in CCYY-MM-DD format.

+ References

+ Details

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