Document and Entity Information (USD $)	3 Months Ended
	Apr. 30, 2012	Jun. 06, 2012	Jul. 31, 2011
Entity Information [Line Items]
Entity Registrant Name	MFRI INC.
Entity Central Index Key	0000914122
Current Fiscal Year End Date	--01-31
Entity Filer Category	Smaller Reporting Company
Document Type	10-Q
Document Period End Date	Apr. 30, 2012
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		6,923,396
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 53,878,437