SUBSEQUENT EVENTS (Details) (USD $)	3 Months Ended		6 Months Ended			0 Months Ended	6 Months Ended					6 Months Ended									6 Months Ended
	Oct. 31, 2013	Oct. 31, 2012	Oct. 31, 2013	Oct. 31, 2012	Nov. 30, 2013	Nov. 30, 2013 Subsequent Event [Member]	Oct. 31, 2013 Subsequent Event [Member]	Dec. 05, 2013 Subsequent Event [Member] Chateau Apartments Fire [Member] Building	Dec. 05, 2013 Subsequent Event [Member] Chateau Apartments Fire, Building 1 [Member] Unit	Dec. 05, 2013 Subsequent Event [Member] Chateau Apartments Fire, Building 2 [Member] Unit	Dec. 05, 2013 Subsequent Event [Member] Chateau Apartments Fire, Building 3 [Member] Unit	Oct. 31, 2013 Subsequent Event [Member] Minnetonka, Minnesota [Member]	Oct. 31, 2013 Subsequent Event [Member] Bismarck, North Dakota [Member] acre	Oct. 31, 2013 Subsequent Event [Member] Fruitland, Idaho [Member] sqft	Oct. 31, 2013 Subsequent Event [Member] Isanti, Minnesota [Member] acre	Oct. 31, 2013 Subsequent Event [Member] Rapid City, South Dakota 1 [Member] Building Unit acre	Oct. 31, 2013 Subsequent Event [Member] Brooklyn Park, Minnesota [Member] Minimum [Member] acre	Oct. 31, 2013 Subsequent Event [Member] Brooklyn Park, Minnesota [Member] Maximum [Member] acre	Oct. 31, 2013 Subsequent Event [Member] Rapid City, South Dakota 2 [Member] acre Unit Building	Oct. 31, 2013 Subsequent Event [Member] vacant land in Fruitland, Idaho [Member]	Oct. 31, 2013 Subsequent Event [Member] Series A Preferred Stock [Member]	Oct. 31, 2013 Subsequent Event [Member] Series A Preferred Stock [Member] Dividend Declared [Member]	Oct. 31, 2013 Subsequent Event [Member] Series B Preferred Stock [Member]	Oct. 31, 2013 Subsequent Event [Member] Series B Preferred Stock [Member] Dividend Declared [Member]
Subsequent Event [Line Items]
Distributions, common shares and units (in dollars per share)	$ 0.1300	$ 0.1300	$ 0.2600	$ 0.2600			$ 0.1300
Distributions, Redeemable Preferred Shares (in dollars per share)																						$ 0.5156		$ 0.4968
Dividends date declared							Dec. 05, 2013														Dec. 05, 2013		Dec. 05, 2013
Dividends date of record																					Dec. 16, 2013		Dec. 16, 2013
Dividends date to be paid																					Dec. 31, 2013		Dec. 31, 2013
Area of land (in acres)													35.0		4.7	10.0	10	12	2.0
Area of property (square feet)														39,222
Sales price of property												$ 3,800,000
Cash paid for acquisition of property													4,300,000	7,100,000	50,000	5,000,000			997,000	335,000
Number of units									15	57	32					152			52
Number of buildings								2								11			4
Purchase price of acquired property																15,000,000			3,300,000
Assumed debt																10,000,000			2,300,000
Revolving credit facility, amended					72,000,000	72,000,000
Revolving credit facility, maximum capacity	60,000,000		60,000,000			75,000,000
Number of properties securing line of credit	23		23			14
Line of credit facility, basis for variable interest rate						Prime Rate
Line of credit facility, basis spread on variable rate (in hundredths)						1.25%
Line of credit facility, interest rate range, minimum (in hundredths)						4.75%
Line of credit facility, interest rate range, maximum (in hundredths)						8.65%
Line of credit facility, covenant terms						Advances under the facility may not exceed 60% of the value of the properties provided as security.
Revolving credit facility covenant terms, deposit requirement						6,000,000
Revolving credit facility covenant terms, non-interest bearing deposit requirement						$ 1,500,000