NET INCOME (LOSS) PER SHARE ATTRIBUTABLE TO THE STOCKHOLDERS OF ARGAN, INC. (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2020	Jul. 31, 2019
NET INCOME (LOSS) PER SHARE ATTRIBUTABLE TO THE STOCKHOLDERS OF ARGAN, INC.
Net income (loss) attributable to the stockholders of Argan, Inc.	$ 5,609	$ 1,154	$ 4,846	$ (28,646)
Weighted average number of shares outstanding - basic	15,653	15,633	15,648	15,608
Effects of stock awards	135	124	119
Weighted average number of shares outstanding - diluted	15,788	15,757	15,767	15,608
Basic (in Dollars per share)	$ 0.36	$ 0.07	$ 0.31	$ (1.84)
Diluted (in Dollars per share)	$ 0.36	$ 0.07	$ 0.31	$ (1.84)