CONSOLIDATED STATEMENTS OF EQUITY - USD ($) shares in Thousands, $ in Thousands	Preferred Class A [Member] ACCUMULATED DISTRIBUTIONS IN EXCESS OF NET INCOME [Member]	Preferred Class A [Member]	Preferred Class B [Member] ACCUMULATED DISTRIBUTIONS IN EXCESS OF NET INCOME [Member]	Preferred Class B [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, 2013					$ 138,674	$ 784,454	$ (310,341)	$ 142,657	$ 755,444
Balance (in shares) at Apr. 30, 2013					5,750	101,488
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to Investors Real Estate Trust and noncontrolling interests							(13,174)	(4,033)	(17,207)
Distributions - common shares and units							(54,729)	(11,283)	(66,012)
Distributions - preferred shares	$ (2,372)	$ (2,372)	$ (9,142)	$ (9,142)					(11,514)
Distribution reinvestment and share purchase plan						$ 55,793			55,793
Distribution reinvestment and share purchase plan (in shares)						6,615
Shares issued and share-based compensation						$ 112			112
Shares issued and share-based compensation (in shares)						13
Partnership units issued								3,480	3,480
Redemption of units for common shares						$ 4,353		(4,353)
Redemption of units for common shares (in shares)						903
Contributions from nonredeemable noncontrolling interests consolidated real estate entities								3,895	3,895
Other						$ (1,444)		(2,001)	(3,445)
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