CONDENSED CONSOLIDATED STATEMENTS OF EQUITY (unaudited) - USD ($) shares in Thousands, $ in Thousands	Series A Preferred Stock [Member] ACCUMULATED DISTRIBUTIONS IN EXCESS OF NET INCOME [Member]	Series A Preferred Stock [Member]	Series B Preferred Stock [Member] ACCUMULATED DISTRIBUTIONS IN EXCESS OF NET INCOME [Member]	Series B Preferred Stock [Member]	PREFERRED SHARES [Member]	Common Shares and Limited Partnership Units [Member]	ACCUMULATED DISTRIBUTIONS IN EXCESS OF NET INCOME [Member]	NONREDEEMABLE NONCONTROLLING INTERESTS [Member]	Total
Balance at Apr. 30, 2014					$ 138,674	$ 843,268	$ (389,758)	$ 128,362	$ 720,546
Balance (in shares) at Apr. 30, 2014					5,750	109,019
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to Investors Real Estate Trust and noncontrolling interests							24,087	4,432	28,519
Distributions - common shares and units							(61,247)	(8,607)	(69,854)
Distributions - preferred shares	$ (2,372)	$ (2,372)	$ (9,142)	$ (9,142)					(11,514)
Distribution reinvestment and share purchase plan						$ 64,856			64,856
Distribution reinvestment and share purchase plan (in shares)						8,102
Shares issued and share-based compensation						$ 2,626			2,626
Shares issued and share-based compensation (in shares)						151
Partnership units issued								800	800
Redemption of units for common shares						$ 41,264		(41,264)
Redemption of units for common shares (in shares)						7,183
Contributions from nonredeemable noncontrolling interests - consolidated real estate entities								8,909	8,909
Distributions to nonredeemable noncontrolling interests - consolidated real estate entities								(3,926)	(3,926)
Other						$ (146)		138	(8)
Balance at Apr. 30, 2015					$ 138,674	$ 951,868	(438,432)	88,844	740,954
Balance (in shares) at Apr. 30, 2015					5,750	124,455
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to Investors Real Estate Trust and noncontrolling interests							72,006	4,562	76,568
Distributions - common shares and units							(64,060)	(7,230)	(71,290)
Distributions - preferred shares	(2,372)	(2,372)	(9,142)	(9,142)					(11,514)
Distribution reinvestment and share purchase plan						$ 5,619			5,619
Distribution reinvestment and share purchase plan (in shares)						821
Shares issued and share-based compensation						$ 1,728			1,728
Shares issued and share-based compensation (in shares)						185
Partnership units issued								18,226	18,226
Redemption of units for common shares						$ 1,477		(1,477)
Redemption of units for common shares (in shares)						273
Shares repurchased						$ (35,000)			(35,000)
Shares repurchased (in shares)						(4,643)
Distributions to nonredeemable noncontrolling interests - consolidated real estate entities								(7,029)	(7,029)
Adjustments to prior year redemption of units for common shares						$ (3,608)		3,608
Balance at Apr. 30, 2016					$ 138,674	$ 922,084	(442,000)	99,504	718,262
Balance (in shares) at Apr. 30, 2016					5,750	121,091
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to Investors Real Estate Trust and noncontrolling interests							43,347	(12,400)	30,947
Distributions - common shares and units							(55,907)	(7,453)	(63,360)
Distributions - preferred shares	$ (1,403)	$ (1,403)	$ (9,143)	$ (9,143)					(10,546)
Shares issued and share-based compensation						$ 358			358
Shares issued and share-based compensation (in shares)						389
Redemption of units for common shares						$ 875		(875)
Redemption of units for common shares (in shares)						503
Redemption of units for cash								(966)	(966)
Shares repurchased					$ (27,317)	$ (4,501)	(1,435)		(33,253)
Shares repurchased (in shares)					(1,150)	(778)
Contributions from nonredeemable noncontrolling interests - consolidated real estate entities								7,188	7,188
Distributions to nonredeemable noncontrolling interests - consolidated real estate entities								(174)	(174)
Conversion of to equity of notes receivable from nonredeemable noncontrolling interests – consolidated real estate entities								(7,366)	(7,366)
Acquisition of nonredeemable noncontrolling interests – consolidated real estate entities						$ (2,677)		(2,261)	(4,938)
Other						$ (18)		(40)	(58)
Other (in shares)						(6)
Balance at Apr. 30, 2017					$ 111,357	$ 916,121	$ (466,541)	$ 75,157	$ 636,094
Balance (in shares) at Apr. 30, 2017					4,600	121,199