Document and Entity Information (USD $)	12 Months Ended
	Jan. 31, 2012	Apr. 05, 2012	Jul. 31, 2011
Document and Entity Information [Abstract]
Entity Registrant Name	ARGAN INC
Entity Central Index Key	0000100591
Document Type	10-K
Document Period End Date	Jan. 31, 2012
Amendment Flag	false
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	FY
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			$ 31,218,000
Entity Common Stock, Shares Outstanding		13,657,865