ACQUISITIONS, DEVELOPMENT PROJECTS PLACED IN SERVICE AND DISPOSITIONS, DEVELOPMENT PROJECTS PLACED IN SERVICE (Details)	3 Months Ended		12 Months Ended
	Jul. 31, 2016 USD ($) item	Jul. 31, 2015 USD ($) ft² item	Apr. 30, 2016 USD ($)	Apr. 30, 2015 USD ($)
Business Acquisition [Line Items]
Project costs incurred to date	$ 99,633,000
Impairment of real estate continuing and discontinued operations	54,153,000	$ 1,725,000
Acquisitions Member
Acquisitions and development projects placed in service [Abstract]
Total acquisition costs	0	0
Development Projects Placed in Service [Member]
Business Acquisition [Line Items]
Land	4,721,000	3,320,000
Building	67,509,000	102,435,000
Development cost	$ 72,230,000	105,755,000
Development Projects Placed in Service [Member] | Multi-Family Residential [Member]
Business Acquisition [Line Items]
Land		3,320,000
Building		73,619,000
Development cost		$ 76,939,000
Development Projects Placed in Service [Member] | Multi-Family Residential [Member] | 71 France - Edina, MN [Member]
Business Acquisition [Line Items]
Date placed in service	May 01, 2016
Land	$ 4,721,000
Building	67,509,000
Development cost	$ 72,230,000
Number of apartment units | item	241
Development costs paid	$ 1,300,000		$ 70,900,000
Interest in joint venture (in hundredths)	52.60%
Development Projects Placed in Service [Member] | Multi-Family Residential [Member] | 72 unit - Chateau II - Minot, ND [Member]
Business Acquisition [Line Items]
Date placed in service		Jun. 01, 2015
Land		$ 240,000
Building		14,360,000
Development cost		$ 14,600,000
Number of apartment units | item		72
Development costs paid		$ 2,300,000		$ 12,300,000
Development Projects Placed in Service [Member] | Multi-Family Residential [Member] | 288 unit - Renaissance Heights - Williston, ND [Member]
Business Acquisition [Line Items]
Date placed in service		Jul. 27, 2015
Land		$ 3,080,000
Building		59,259,000
Development cost		$ 62,339,000
Number of apartment units | item		288
Development costs paid		$ 4,600,000		57,700,000
Interest in joint venture (in hundredths)		70.00%
Impairment of real estate continuing and discontinued operations	$ 36,700,000
Development Projects Placed in Service [Member] | Healthcare [Member] | 57,624 sq ft Edina 6565 France SMC III - Edina, MN [Member]
Business Acquisition [Line Items]
Date placed in service		Jun. 01, 2015
Building		$ 28,816,000
Development cost		$ 28,816,000
Area of real estate property | ft²		57,624
Development costs paid		$ 8,000,000		$ 20,800,000