QUARTERLY RESULTS OF CONSOLIDATED OPERATIONS (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Apr. 30, 2016	Jan. 31, 2016	Oct. 31, 2015	Jul. 31, 2015	Apr. 30, 2015	Jan. 31, 2015	Oct. 31, 2014	Jul. 31, 2014	Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2014
QUARTERLY RESULTS OF CONSOLIDATED OPERATIONS (unaudited) [Abstract]
Revenues	$ 48,523	$ 48,406	$ 46,346	$ 45,045	$ 45,141	$ 45,630	$ 45,236	$ 43,314	$ 188,320	$ 179,321	$ 164,590
Net income (loss) attributable to Investors Real Estate Trust	11,003	39,797	16,666	4,540	10,753	8,371	5,114	(151)	72,006	24,087	(13,174)
Net income (loss) available to common shareholders	$ 8,125	$ 36,918	$ 13,788	$ 1,661	$ 7,875	$ 5,492	$ 2,236	$ (3,030)	$ 60,492	$ 12,573	$ (24,688)
Net income (loss) per common share - basic & diluted (in dollars per share)	$ 0.07	$ 0.30	$ 0.11	$ 0.01	$ 0.07	$ 0.05	$ 0.02	$ (0.03)	$ 0.49	$ 0.11	$ (0.23)