QUARTERLY UNAUDITED INFORMATION (Details) - Schedule of Quarterly Financial Information - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Jan. 31, 2019	Oct. 31, 2018	Jul. 31, 2018	Apr. 30, 2018	Jan. 31, 2018	Oct. 31, 2017	Jul. 31, 2017	Apr. 30, 2017	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2017
Schedule of Quarterly Financial Information [Abstract]
Net sales and revenue	$ 113,344	$ 123,750	$ 128,757	$ 120,820	$ 109,535	$ 121,164	$ 108,744	$ 113,143	$ 486,671	$ 452,586	$ 453,799
Gross profit	2,218	7,747	9,399	10,851	6,024	14,867	10,781	12,489	30,215	44,161	71,039
Net income	2,899	13,769	10,490	10,352	20,135	14,994	4,171	5,612	37,510	44,912	39,518
Net income attributable to REX common shareholders	$ 1,057	$ 11,875	$ 9,217	$ 9,496	$ 19,053	$ 13,168	$ 2,941	$ 4,544	$ 31,645	$ 39,706	$ 32,333
Basic and diluted net income per share attributable to REX common shareholders (in Dollars per share)	$ 170	$ 1,860	$ 1,430	$ 1,450	$ 2,890	$ 2,000	$ 450	$ 690	$ 4.91	$ 6.02	$ 4.91