Document and Entity Information	3 Months Ended
	Apr. 30, 2015	Jun. 04, 2015
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Apr. 30, 2015
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	Q1
Trading Symbol	AGX
Entity Registrant Name	ARGAN INC
Entity Central Index Key	0000100591
Current Fiscal Year End Date	--01-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		14,767,769