Retirement plans Plan assets (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Jan. 31, 2015 Rate	Jan. 31, 2014 Rate	Jan. 31, 2013
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Prohibited Investments	The plans hold no securities of MFRI, Inc.
Defined Benefit Plan, Actual Plan Asset Allocations	100.00%
Available-for-sale Securities	$ 5,828us-gaap_AvailableForSaleSecurities	$ 5,942us-gaap_AvailableForSaleSecurities
Defined Benefit Plan, Fair Value of Plan Assets	6,168	6,351	6,065
Defined Benefit Plan, Target Allocation Percentage	target asset allocations of 55% equities (with a range of 40% - 65%), 25% fixed income (with a range of 20% - 35%) and 20% Alternative Investments (with a range of 15% - 25%)
Defined benefit -plan, actual gain on plan assets	63	531
Net periodic benefit cost, expected long-term return on assets	8.00%	8.00%
Equity Securities [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Actual Plan Asset Allocations	62.00%
Available-for-sale Securities, Equity Securities	3,795	3,340
Bonds [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Actual Plan Asset Allocations	33.00%
Available-for-sale Securities	2,033	2,453
Money Market Funds [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Actual Plan Asset Allocations	5.00%
Money Market Funds, at Carrying Value	340	409
Real Estate Funds [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Available-for-sale Securities	$ 0	$ 149

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Amount of equity securities categorized neither as held-to-maturity nor as trading.

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The difference between fair value of plan assets at the end of the period and the fair value at the beginning of the period, adjusted for contributions and payments of benefits during the period, and after adjusting for taxes and other expenses, as applicable.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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-Glossary Actual Return on Plan Assets (Component of Net Periodic Postretirement Benefit Cost)

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-Glossary Actual Return on Plan Assets (Component of Net Periodic Pension Cost)

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An assumption as to the rate of return on plan assets reflecting the average rate of earnings expected on the funds invested or to be invested to provide for the benefits included in the benefit obligation.

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Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets.

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Description of prohibited investments that are pertinent to an understanding of the plan investment policies and strategies.

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Description of target allocation percentages, or range of percentages, considering the major categories of plan assets as of the latest statement of financial position presented (on a weighted-average basis for employers with more than one plan) that are pertinent to an understanding of the plan investment policies and strategies.

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Percentage of fair value of investments (categorized by debt securities, equity securities, real estate and other plan assets) to the fair value of plan assets held.

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Investment in short-term money-market instruments (such as commercial paper, banker's acceptances, repurchase agreements, government securities, certificates of deposit, and so forth) which are highly liquid (that is, readily convertible to known amounts of cash) and so near their maturity that they present an insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify as cash equivalents by definition. Original maturity means an original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

+ References

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