BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES - Involuntary Conversion of Assets(Details) $ / shares in Units, $ in Thousands, shares in Millions		1 Months Ended	12 Months Ended
	Mar. 22, 2016 USD ($) $ / shares shares	Dec. 31, 2013 item	Apr. 30, 2016 USD ($)	Apr. 30, 2015 USD ($)	Apr. 30, 2014 USD ($)	Feb. 29, 2012 property
Unusual or Infrequent Item [Line Items]
Total gain on involuntary conversion					$ 2,480
GAIN ON BARGAIN PURCHASE [Abstract]
Gain on bargain purchase			$ 3,424
187 unit - Avalon Cove - Rochester, MN [Member]
GAIN ON BARGAIN PURCHASE [Abstract]
Fair value at acquisition	$ 36,000
Cash consideration	$ 15,000
Units issued, acquisitions | shares	2.5
Value of units issued, acquisitions	$ 17,800
Share price on acquisition date | $ / shares	$ 7.09
Gain on bargain purchase	$ 3,000
2012 Fire [Member]
Unusual or Infrequent Item [Line Items]
Number of buildings destroyed | property						1
Proceeds from final settlement					5,100
Total gain on involuntary conversion					2,500
2013 Fire [Member]
Unusual or Infrequent Item [Line Items]
Total gain on involuntary conversion				$ 0
Insurance proceeds received for flood clean up costs and redevelopment				$ 6,000	$ 1,000
2013 Fire [Member] | Building One [Member]
Unusual or Infrequent Item [Line Items]
Number of units in building | item		15
2013 Fire [Member] | Building Two [Member]
Unusual or Infrequent Item [Line Items]
Number of units in building | item		57