Document and Entity Information	9 Months Ended
	Oct. 31, 2012	Dec. 04, 2012
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, 2012
Amendment Flag	false
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--01-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		12,837,859