NET INCOME PER SHARE ATTRIBUTABLE TO THE STOCKHOLDERS OF ARGAN (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2021	Jul. 31, 2020	Jul. 31, 2021	Jul. 31, 2020
NET INCOME PER SHARE ATTRIBUTABLE TO THE STOCKHOLDERS OF ARGAN
Net income attributable to the stockholders of Argan, Inc.	$ 12,870	$ 5,609	$ 23,636	$ 4,846
Weighted average number of shares outstanding - basic	15,769	15,653	15,748	15,648
Effects of stock awards	213	135	230	119
Weighted average number of shares outstanding - diluted	15,982	15,788	15,978	15,767
Basic	$ 0.82	$ 0.36	$ 1.50	$ 0.31
Diluted	$ 0.81	$ 0.36	$ 1.48	$ 0.31