Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended
Apr. 30, 2018	Apr. 30, 2017
Disaggregation of Revenue [Line Items]
Sales by product	$ 28,889	$ 23,501
Sales by product (percent of total)	100.00%	100.00%
Revenue recognized that was included in contract liabilities	$ 1,800
Contract liabilities expected to be recognized in revenue in the next year	600
Products [Member]
Disaggregation of Revenue [Line Items]
Sales by product	$ 2,429	$ 1,331
Sales by product (percent of total)	8.00%	6.00%
Specialty Piping Systems And Coating [Member] \| Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Sales by product	$ 11,102	$ 9,117
Sales by product (percent of total)	38.00%	39.00%
Specialty Piping Systems And Coating [Member] \| Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Sales by product	$ 15,358	$ 13,053
Sales by product (percent of total)	54.00%	55.00%

Percent Of Revenue From Contract With Customer, Excluding Assessed Tax

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- Definition

Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable, classified as current.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
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-URI http://asc.fasb.org/extlink&oid=82913847&loc=SL49130549-203045

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-Publisher FASB
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Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=82913847&loc=SL49130549-203045

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-Publisher FASB
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+ References

No definition available.

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Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
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-URI http://asc.fasb.org/extlink&oid=82859839&loc=SL82860478-203043

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