ACQUISITIONS, DEVELOPMENTS PLACED IN SERVICE AND DISPOSITIONS, DEVELOPMENT PROJECTS PLACED IN SERVICE (Details) (Development Projects Placed in Service [Member], USD $) In Thousands, unless otherwise specified					6 Months Ended						6 Months Ended
	Oct. 31, 2014		Oct. 31, 2013		Oct. 31, 2014 Multi-Family Residential [Member] Dakota Commons, Williston, North Dakota [Member] Unit		Apr. 30, 2015 Multi-Family Residential [Member] Dakota Commons, Williston, North Dakota [Member]		Apr. 30, 2014 Multi-Family Residential [Member] Dakota Commons, Williston, North Dakota [Member]		Oct. 31, 2014 Multi-Family Residential [Member] Landing at Southgate - Minot, ND [Member]		Oct. 31, 2013 Multi-Family Residential [Member] Landing at Southgate - Minot, ND [Member] Unit
Significant Development Projects Placed in Service [Line Items]
Date placed in service					Jul. 15, 2014	[1],[2]					Sep. 04, 2013	[3],[4]
Land	$ 823	[1]	$ 2,262	[3]	$ 823	[1],[2]							$ 2,262	[3],[4]
Building	9,452	[1]	12,864	[3]	9,452	[1],[2]							12,864	[3],[4]
Development costs of projects placed in service	$ 10,275	[1]	$ 15,126	[3]	$ 10,275	[1],[2]	$ 2,200	[1],[2]	$ 8,100	[1],[2]			$ 15,126	[3],[4]
Number of units					44	[1],[2]							108	[3],[4]

[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 three months ended July 31, 2014.

[2] Development property placed in service July 15, 2014. Costs paid in fiscal year 2014 totaled $8.1 million, including the land acquired in fiscal year 2013. Additional costs paid in fiscal year 2015 totaled $2.2 million, for a total project cost at July 31, 2014 of $10.3 million.

[3] 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 River Ridge and Cypress Court projects, which were partially placed in service during the three months ended October 31, 2013.

[4] Development property placed in service September 4, 2013. Costs paid in fiscal year 2013 totaled $6.3 million. Costs paid in fiscal year 2014 totaled $8.8 million for a total project cost at October 31, 2013 of $15.1 million. The project is owned by a joint venture entity in which the Company has an approximately 52.9% interest.