COMMITMENTS AND CONTINGENCIES (Details) (USD $)	12 Months Ended
	Apr. 30, 2014 sqft Property Unit		Apr. 30, 2013
Real Estate Properties [Line Items]
Number of properties under operating ground and air rights lease	12
Rent payable per year under ground lease	$ 500,000
Operating Leases, Future Minimum Payments [Abstract]
2015	506,000
2016	475,000
2017	449,000
2018	449,000
2019	449,000
Thereafter	21,213,000
Total	23,541,000
Tenant improvements	9,700,000
Commitment period for tenant improvements (in months)	12 months
Number of Properties subject to purchase options.	15
Total property cost subject to purchase options	120,500,000
Total gross rental revenue from properties subject to purchase options	9,800,000
Property Cost and Gross Rental Revenue [Abstract]
Total property cost subject to purchase options	120,500,000
Total gross rental revenue from properties subject to purchase options	9,800,000
Number of properties subject to restrictions on taxable dispositions	110
Area of a real estate property (in square feet)	5,500,000
Number of apartment units subject to restrictions on taxable dispositions	4,953
Real estate investment amount of properties (net of accumulated depreciation)	814,500,000
Redemption basis	1:1
Minimum redemption holding period (in years)	1 year
Number of consecutive trading days for valuation (in days)	10 days
Aggregate redemption value of UPREIT Units of operating partnership owned by limited partners	185,700,000		209,700,000
Area of property (square feet)	5,500,000
Anticipated Total Cost	234,990,000
Project costs incurred to date	116,096,000	[1]
Loans Closed or Committed	142,828,000
Minimum [Member]
Real Estate Properties [Line Items]
Lease term of property (in years)	1 year 6 months
Lease expiration date	Oct. 31, 2015
Number of renewal options (in leases)	6
Maximum [Member]
Real Estate Properties [Line Items]
Lease term of property (in years)	87 years
Lease expiration date	Oct. 31, 2100
Number of renewal options (in leases)	12
Multi Family Residential [Member] | Arcata Apartments, Golden Valley, MN [Member]
Property Cost and Gross Rental Revenue [Abstract]
Number of apartment units	165
Anticipated Total Cost	33,448,000
Project costs incurred to date	13,018,000	[1]
Loans Closed or Committed	24,250,000
Estimated quarter for completion	3
Estimated year for completion	2015
Multi Family Residential [Member] | Cardinal Point Grand Forks Nd [Member]
Property Cost and Gross Rental Revenue [Abstract]
Number of apartment units	251
Anticipated Total Cost	40,042,000
Project costs incurred to date	6,829,000	[1]
Loans Closed or Committed	24,500,000
Estimated quarter for completion	1
Estimated year for completion	2016
Multi Family Residential [Member] | Chateau II - Minot, ND [Member]
Property Cost and Gross Rental Revenue [Abstract]
Number of apartment units	72	[2]
Anticipated Total Cost	14,711,000	[2]
Project costs incurred to date	2,098,000	[1],[2]
Loans Closed or Committed	0	[2]
Estimated quarter for completion	4	[2]
Estimated year for completion	2015	[2]
Multi Family Residential [Member] | Commons at Southgate - Minot, ND [Member]
Property Cost and Gross Rental Revenue [Abstract]
Number of apartment units	233	[3]
Anticipated Total Cost	37,201,000	[3]
Project costs incurred to date	28,065,000	[1],[3]
Loans Closed or Committed	24,480,000	[3]
Estimated quarter for completion	2	[3]
Estimated year for completion	2015	[3]
Interest in joint venture (in hundredths)	51.00%	[3]
Multi Family Residential [Member] | Cypress Court II - St. Cloud, MN [Member]
Property Cost and Gross Rental Revenue [Abstract]
Number of apartment units	66	[4]
Anticipated Total Cost	7,028,000	[4]
Project costs incurred to date	1,580,000	[1],[4]
Loans Closed or Committed	4,200,000	[4]
Estimated quarter for completion	3	[4]
Estimated year for completion	2015	[4]
Interest in joint venture (in hundredths)	86.00%	[4]
Multi Family Residential [Member] | Dakota Commons - Williston, ND [Member]
Property Cost and Gross Rental Revenue [Abstract]
Number of apartment units	44
Anticipated Total Cost	10,736,000
Project costs incurred to date	9,013,000	[1]
Loans Closed or Committed	0
Estimated quarter for completion	1
Estimated year for completion	2015
Multi Family Residential [Member] | Other [Member]
Property Cost and Gross Rental Revenue [Abstract]
Number of apartment units
Anticipated Total Cost
Project costs incurred to date	2,496,000	[1]
Loans Closed or Committed
Estimated quarter for completion
Estimated year for completion
Multi Family Residential [Member] | RED 20 - Minneapolis, MN [Member]
Property Cost and Gross Rental Revenue [Abstract]
Area of a real estate property (in square feet)	10,625	[5]
Area of property (square feet)	10,625	[5]
Number of apartment units	130	[5]
Anticipated Total Cost	29,462,000	[5]
Project costs incurred to date	13,980,000	[1],[5]
Loans Closed or Committed	21,726,000	[5]
Estimated quarter for completion	3	[5]
Estimated year for completion	2015	[5]
Interest in joint venture (in hundredths)	58.60%	[5]
Multi Family Residential [Member] | Renaissance Heights I Apartments, Williston, ND [Member]
Property Cost and Gross Rental Revenue [Abstract]
Number of apartment units	288	[6]
Anticipated Total Cost	62,362,000	[6]
Project costs incurred to date	39,017,000	[1],[6]
Loans Closed or Committed	43,672,000	[6]
Estimated quarter for completion	4	[6]
Estimated year for completion	2015	[6]
Interest in joint venture (in hundredths)	70.00%	[6]
Costs related to development projects placed in service in phases.	$ 11,500,000	[6]

[1] Includes costs related to development projects that are placed in service in phases (Renaissance Heights I - $11.5 million).

[2] On December 5, 2013, this development project was destroyed by fire. As of April 30, 2014, $6.1 million of expected insurance proceeds were included in accounts receivable on the Company’s consolidated balance sheet. See Note 2 for additional information.

[3] The Company is an approximately 51% partner in the joint venture entity constructing this project; the anticipated total cost amount given is the total cost to the joint venture entity.

[4] The Company is an approximately 86.1% partner in the joint venture entity constructing this project; the anticipated total cost amount given is the total cost to the joint venture entity.

[5] The Company is an approximately 58.6% partner in the joint venture entity constructing this project; the anticipated total cost amount given is the total cost to the joint venture entity.

[6] The Company is an approximately 70% partner in the joint venture entity constructing this project; the anticipated total cost amount given is the total cost to the joint venture entity.