EARNINGS PER SHARE ATTRIBUTABLE TO THE STOCKHOLDERS OF ARGAN, INC. - Additional Information (Details) - shares	3 Months Ended		9 Months Ended
	Oct. 31, 2015	Oct. 31, 2014	Oct. 31, 2015	Oct. 31, 2014
EARNINGS PER SHARE ATTRIBUTABLE TO THE STOCKHOLDERS OF ARGAN, INC.
Additional shares included in the calculation of diluted EPS	257,000	325,000	271,000	371,000
Shares covered by antidilutive stock options	105,000	40,000	180,000	40,000