Document And Entity Information	3 Months Ended
	Mar. 31, 2012	Apr. 30, 2012
Document and Entity Information [Abstract]
Entity Registrant Name	MetroCorp Bancshares, Inc.
Document Type	10-Q
Current Fiscal Year End Date	--12-31
Entity Common Stock, Shares Outstanding		13,333,047
Amendment Flag	false
Entity Central Index Key	0001068300
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Smaller Reporting Company
Entity Well-known Seasoned Issuer	No
Document Period End Date	Mar. 31, 2012
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	Q1