NET INCOME PER SHARE ATTRIBUTABLE TO THE STOCKHOLDERS OF ARGAN (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2021	Oct. 31, 2020	Oct. 31, 2021	Oct. 31, 2020
NET INCOME PER SHARE ATTRIBUTABLE TO THE STOCKHOLDERS OF ARGAN
Net income attributable to the stockholders of Argan, Inc.	$ 12,393	$ 9,454	$ 36,029	$ 14,300
Weighted average number of shares outstanding - basic	15,774	15,680	15,757	15,659
Effects of stock awards	189	153	223	136
Weighted average number of shares outstanding - diluted	15,963	15,833	15,980	15,795
Basic	$ 0.79	$ 0.60	$ 2.29	$ 0.91
Diluted	$ 0.78	$ 0.60	$ 2.25	$ 0.91