Document and Entity Information (USD $)	9 Months Ended
	Oct. 31, 2011	Dec. 05, 2011	Jul. 31, 2010
Document and Entity Information [Abstract]
Entity Registrant Name	MITCHAM INDUSTRIES INC
Entity Central Index Key	0000926423
Document Type	10-Q
Document Period End Date	Oct. 31, 2011
Amendment Flag	false
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--01-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Smaller Reporting Company
Entity Public Float			$ 68,264,499
Entity Common Stock, Shares Outstanding		12,423,909