EARNINGS PER SHARE ATTRIBUTABLE TO THE STOCKHOLDERS OF ARGAN, INC. (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Apr. 30, 2017	Apr. 30, 2016
EARNINGS PER SHARE ATTRIBUTABLE TO THE STOCKHOLDERS OF ARGAN, INC.
Net income attributable to the stockholders of Argan, Inc.	$ 20,625	$ 12,230
Weighted average number of shares outstanding - basic	15,467	14,842
Effect of stock options	304	213
Weighted average number of shares outstanding - diluted	15,771	15,055
Basic (in dollars per share)	$ 1.33	$ 0.82
Diluted (in dollars per share)	$ 1.31	$ 0.81