Fair value of financial instruments	3 Months Ended
Fair value of financial instruments	Apr. 30, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Disclosures [Text Block]	Fair Value. In relation to the acquisition of Perma-Pipe Canada, Ltd. ("PPC"), the Company estimated the fair value of the assets acquired and liabilities assumed at acquisition date. See "Notes to Consolidated Financial Statements Note 13 Acquisition", for a further discussion of this purchase. The carrying values of cash and cash equivalents, accounts receivable and accounts payable are reasonable estimates of their fair value due to their short-term nature. The carrying amount of the Company's short-term debt, revolving line of credit and long-term debt approximate fair value, because the majority of the amounts outstanding accrue interest at variable rates. The Company held a marketable equity security of approximately $0.1 million at April 30, 2017, which it classified as available-for-sale and recorded in other non-current assets on the consolidated balance sheets. This security is carried at estimated fair value with unrealized gains and losses reflected in Accumulated Other Comprehensive Income and classified as Level 1 in the fair value hierarchy. The assessment for impairment of marketable equity securities as available-for-sale is based on established financial methodologies, including quoted market prices for publicly traded securities. If the Company determines that a loss in the value of the investment is other than temporary, any such losses are recorded in other expense (income), net.

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.