Retirement plans Assumptions (Details)	12 Months Ended
	Jan. 31, 2016 Rate	Jan. 31, 2015 Rate
Compensation and Retirement Disclosure [Abstract]
Defined Benefit Plan, Prohibited Investments	The plans hold no securities of MFRI, Inc.
Discount rate	4.05%	3.35%
Net periodic benefit cost, discount rate	4.50%	4.50%
Net periodic benefit cost, expected long-term return on assets	8.00%	8.00%