ACQUISITIONS, DEVELOPMENTS PLACED IN SERVICE AND DISPOSITIONS, DEVELOPMENT PROJECTS PLACED IN SERVICE (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Jan. 31, 2015 Unit		Jan. 31, 2014		Apr. 30, 2015		Apr. 30, 2014		Apr. 30, 2013
Multi-Family Residential [Member]
Significant Development Projects Placed in Service [Line Items]
Land	$ 8,949
Building	101,434
Development costs of projects placed in service	110,383
Development Projects Placed in Service [Member]
Significant Development Projects Placed in Service [Line Items]
Land	9,941	[1]	3,987
Building	103,627	[1]	49,540
Development costs of projects placed in service	113,568	[1]	53,527
Development Projects Placed in Service [Member] | Multi-Family Residential [Member] | Dakota Commons, Williston, North Dakota [Member]
Significant Development Projects Placed in Service [Line Items]
Date placed in service	Jul. 15, 2014	[1],[2]
Land	823	[1],[2]
Building	9,596	[1],[2]
Development costs of projects placed in service	10,419	[1],[2]			2,300	[1],[2]	8,100	[1],[2]
Number of units	44	[1],[2]
Development Projects Placed in Service [Member] | Multi-Family Residential [Member] | Landing at Southgate - Minot, ND [Member]
Significant Development Projects Placed in Service [Line Items]
Date placed in service	Sep. 04, 2013	[3]
Land			2,262	[3]
Building			12,864	[3]
Development costs of projects placed in service			15,126	[3]			8,800	[3]	6,300	[3]
Interest in development			52.90%	[3]
Number of units			108	[3]
Development Projects Placed in Service [Member] | Multi-Family Residential [Member] | Cypress Court - St. Cloud, MN [Member]
Significant Development Projects Placed in Service [Line Items]
Date placed in service	Nov. 01, 2013	[4]
Land			1,136	[4]
Building			12,447	[4]
Development costs of projects placed in service			13,583	[4]			7,800	[4]	5,800	[4]
Interest in development			86.10%	[4]
Number of units			132	[4]
Development Projects Placed in Service [Member] | Multi-Family Residential [Member] | Arcata - Golden Valley, MN [Member]
Significant Development Projects Placed in Service [Line Items]
Date placed in service	Jan. 01, 2015	[1],[5]
Land	2,088	[1],[5]
Building	28,296	[1],[5]
Development costs of projects placed in service	30,384	[1],[5]			19,100	[1],[5]	8,600	[1],[5]	2,700	[1],[5]
Number of units	165	[1],[5]
Development Projects Placed in Service [Member] | Multi-Family Residential [Member] | Commons at Southgate - Minot, ND [Member]
Significant Development Projects Placed in Service [Line Items]
Date placed in service	Dec. 09, 2014	[1],[6]
Land	3,691	[1],[6]
Building	30,921	[1],[6]
Development costs of projects placed in service	34,612	[1],[6]			8,100	[1],[6]	20,600	[1],[6]	5,900	[1],[6]
Interest in development	52.90%	[1],[6]
Number of units	233	[1],[6]
Development Projects Placed in Service [Member] | Multi-Family Residential [Member] | Cypress Court II - St. Cloud, MN [Member]
Significant Development Projects Placed in Service [Line Items]
Date placed in service	Jan. 01, 2015	[1],[7]
Land	447	[1],[7]
Building	6,191	[1],[7]
Development costs of projects placed in service	6,638	[1],[7]			5,500	[1],[7]	1,200	[1],[7]
Interest in development	86.10%	[1],[7]
Number of units	64	[1],[7]
Development Projects Placed in Service [Member] | Multi-Family Residential [Member] | RED 20 - Minneapolis, MN [Member]
Significant Development Projects Placed in Service [Line Items]
Date placed in service	Nov. 21, 2014	[1],[8]
Land	1,900	[1],[8]
Building	26,430	[1],[8]
Development costs of projects placed in service	28,330	[1],[8]			16,100	[1],[8]	12,200	[1],[8]
Interest in development	58.60%	[1],[8]
Number of units	130	[1],[8]
Development Projects Placed in Service [Member] | Multi-Family Residential [Member] | River Ridge - Bismarck, ND [Member]
Significant Development Projects Placed in Service [Line Items]
Date placed in service	Dec. 02, 2013	[9]
Land			589	[9]
Building			24,229	[9]
Development costs of projects placed in service			24,818	[9]			14,700	[9]	10,100	[9]
Number of units			146	[9]
Development Projects Placed in Service [Member] | Commercial Retail [Member] | Minot Wells Fargo Bank - Minot, ND [Member]
Significant Development Projects Placed in Service [Line Items]
Land	992	[1],[10]
Building	2,193	[1],[10]
Development costs of projects placed in service	$ 3,185	[1],[10]
Number of units	4,998	[1],[10]

[1] Development projects that are placed in service in phases are excluded from this table until the entire project has been placed in service. See Note 6 for additional information on the Renaissance Heights I project, which was partially placed in service during the fiscal year 2014 and the nine months ended January 31, 2015.

[2] Costs paid in prior fiscal years totaled $8.1 million. Additional costs paid in fiscal year 2015 totaled $2.3 million, for a total project cost at January 31, 2015 of $10.4 million.

[3] Costs paid in prior fiscal years totaled $6.3 million. Costs paid in fiscal year 2014 totaled $8.8 million for a total project cost at January 31, 2014 of $15.1 million. The project is owned by a joint venture entity in which the Company has an approximately 52.9% interest.

[4] Costs paid in prior fiscal years totaled $5.8 million. Costs paid in fiscal year 2014 totaled $7.8 million for a total project cost at January 31, 2014 of $13.6 million. The project is owned by a joint venture entity in which the Company has an approximately 86.1% interest.

[5] Costs paid in prior fiscal years totaled $11.3 million, respectively. Additional costs paid in fiscal year 2015 totaled $19.1 million, for a total project cost at January 31, 2015 of $30.4 million.

[6] Costs paid in prior fiscal years totaled $26.5 million, respectively. Additional costs paid in fiscal year 2015 totaled $8.1 million, for a total project cost at January 31, 2015 of $34.6 million. The project is owned by a joint venture entity in which the Company has an approximately 52.9% interest. The joint venture is consolidated in IRETs financial statements.

[7] Costs paid in prior fiscal years totaled $1.2 million. Additional costs paid in fiscal year 2015 totaled $5.5 million, for a total project cost at January 31, 2015 of $6.6 million. The project is owned by a joint venture entity in which the Company has an approximately 86.1% interest. The joint venture is consolidated in IRETs financial statements

[8] Costs paid in prior fiscal years totaled $12.2 million. Additional costs paid in fiscal year 2015 totaled $16.1 million, for a total project cost at January 31, 2015 of $28.3 million. The project is owned by a joint venture entity in which the Company has an approximately 58.6% interest. The joint venture is consolidated in IRETs financial statements.

[9] Costs paid in prior fiscal years totaled $10.1 million. Costs paid in fiscal year 2014 totaled $14.7 million for a total project cost at January 31, 2014 of $24.8 million.

[10] Costs paid in fiscal year 2015 totaled $3.2 million, including land acquired in fiscal year 2013.