ACQUISITIONS AND DISPOSITIONS (Details) (USD $)	9 Months Ended
	Jan. 31, 2013		Jan. 31, 2012
Significant Acquisitions and Disposals [Line Items]
Project costs incurred to date	$ 125,000		$ 466,000
Acquisitions and development projects placed in service [Abstract]
Land	20,284,000		6,289,000
Buildings	51,892,000		46,063,000
Intangible assets	813,000		3,744,000
Acquisition costs	72,989,000		56,096,000
Results of operations from acquired properties [Abstract]
Total revenue	4,669,000		2,383,000
Net income	(116,000)		454,000
Project costs incurred to date	125,000		466,000
Dispositions [Abstract]
Sales price	10,173,000		2,175,000
Book value and sales cost	6,721,000		1,586,000
Gain/(Loss)	3,452,000		589,000
Multi-Family Residential [Member]
Acquisitions and development projects placed in service [Abstract]
Land	4,715,000		2,720,000
Buildings	51,892,000		18,655,000
Intangible assets	813,000		0
Acquisition costs	57,420,000		21,375,000
Dispositions [Abstract]
Sales price	8,850,000
Book value and sales cost	5,272,000
Gain/(Loss)	3,578,000
Commercial Medical [Member]
Acquisitions and development projects placed in service [Abstract]
Land			3,153,000
Buildings			27,408,000
Intangible assets			3,744,000
Acquisition costs			34,305,000
Unimproved Land [Member]
Acquisitions and development projects placed in service [Abstract]
Land	15,569,000
Buildings	0
Intangible assets	0
Acquisition costs	15,569,000
Other Disposition [Member]
Dispositions [Abstract]
Sales price	698,000
Book value and sales cost	757,000
Gain/(Loss)	(59,000)
Badger Hills - Rochester, MN [Member] | Unimproved Land [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition	Dec. 14, 2012	[1]
Land	1,050,000	[1]
Buildings	0	[1]
Intangible assets	0	[1]
Acquisition costs	1,050,000	[1]
Candlelight - Fargo, ND [Member] | Multi-Family Residential [Member]
Dispositions [Abstract]
Number of apartment units	66
Date Disposal	Nov. 27, 2012
Sales price	1,950,000
Book value and sales cost	1,178,000
Gain/(Loss)	772,000
Colony - Lincoln, NE [Member] | Multi-Family Residential [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition	Jun. 04, 2012
Land	1,515,000
Buildings	15,731,000
Intangible assets	254,000
Acquisition costs	17,500,000
Number of apartment units	232
Commons at Southgate - Minot, ND [Member] | Unimproved Land [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition	Jan. 22, 2013	[2]
Land	3,691,000	[2]
Buildings	0	[2]
Intangible assets	0	[2]
Acquisition costs	3,691,000	[2]
Cottage West Twin Homes - Sioux Falls, SD [Member] | Multi-Family Residential [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition			Oct. 12, 2011
Land			968,000
Buildings			3,762,000
Intangible assets			0
Acquisition costs			4,730,000
Number of apartment units			50
Cypress Court - St. Cloud, MN [Member] | Unimproved Land [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition	Aug. 10, 2012
Land	447,000
Buildings	0
Intangible assets	0
Acquisition costs	447,000
Cypress Court Apartment Development - St. Cloud, MN [Member] | Unimproved Land [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition	Aug. 10, 2012	[3]
Land	1,136,000	[3]
Buildings	0	[3]
Intangible assets	0	[3]
Acquisition costs	1,136,000	[3]
Edina 6525 Drew Ave S - Edina, MN [Member] | Commercial Medical [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition			Oct. 13, 2011
Land			388,000
Buildings			117,000
Intangible assets			0
Acquisition costs			505,000
Area of a real estate property (in square feet)			3,431
Evergreen II - Isanti, MN [Member] | Multi-Family Residential [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition			Nov. 01, 2011
Land			701,000
Buildings			2,774,000
Intangible assets			0
Acquisition costs			3,475,000
Number of apartment units			36
Gables Townhomes - Sioux Falls, SD [Member] | Multi-Family Residential [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition			Nov. 12, 2012
Land			349,000
Buildings			1,921,000
Intangible assets			0
Acquisition costs			2,270,000
Number of apartment units			24
Georgetown Square Condominiums 5 and 6 [Member] | Other Disposition [Member]
Dispositions [Abstract]
Date Disposal	Jun. 21, 2012
Sales price	330,000
Book value and sales cost	336,000
Gain/(Loss)	(6,000)
Georgetown Square Condominiums 3 and 4 [Member] | Other Disposition [Member]
Dispositions [Abstract]
Date Disposal	Aug. 02, 2012
Sales price	368,000
Book value and sales cost	421,000
Gain/(Loss)	(53,000)
Grand Forks Unimproved - Grand Forks, ND [Member] | Unimproved Land [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition	Dec. 31, 2012
Land	4,278,000
Buildings	0
Intangible assets	0
Acquisition costs	4,278,000
Kentwood Thomasville - Kentwood, MI [Member] | Commercial Retail [Member]
Dispositions [Abstract]
Date Disposal	Jun. 20, 2012
Sales price	625,000
Book value and sales cost	692,000
Gain/(Loss)	(67,000)
Area of a real estate property (in square feet)	16,080
Lakeside Village - Lincoln, NE [Member] | Multi-Family Residential [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition	Jun. 04, 2012
Land	1,215,000
Buildings	15,837,000
Intangible assets	198,000
Acquisition costs	17,250,000
Number of apartment units	208
Landing at Southgate - Minot, ND [Member] | Unimproved Land [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition	Jan. 22, 2013	[2]
Land	2,262,000	[2]
Buildings	0	[2]
Intangible assets	0	[2]
Acquisition costs	2,262,000	[2]
Livingstone Pamida - Livingston, MT [Member] | Commercial Retail [Member]
Dispositions [Abstract]
Date Disposal			Aug. 01, 2011
Sales price			2,175,000
Book value and sales cost			1,586,000
Gain/(Loss)			589,000
Area of a real estate property (in square feet)			41,200
Meadow Wind Land - Casper, WY [Member] | Commercial Medical [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition			Sep. 01, 2011
Land			50,000
Buildings			0
Intangible assets			0
Acquisition costs			50,000
Minot IPS - Minot, ND [Member] | Unimproved Land [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition			Sep. 07, 2011
Land			416,000
Buildings			0
Intangible assets			0
Acquisition costs			416,000
Minot Unimproved - Minot, ND [Member] | Unimproved Land [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition	Jan. 11, 2013
Land	1,882,000
Buildings	0
Intangible assets	0
Acquisition costs	1,882,000
Prairiewood Meadows - Fargo, ND [Member] | Multi-Family Residential [Member]
Dispositions [Abstract]
Number of apartment units	85
Date Disposal	Sep. 27, 2012
Sales price	3,450,000
Book value and sales cost	2,846,000
Gain/(Loss)	604,000
Regency Park Estates - St. Cloud, MN [Member] | Multi-Family Residential [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition			Aug. 01, 2011
Land			702,000
Buildings			10,198,000
Intangible assets			0
Acquisition costs			10,900,000
Number of apartment units			147
Spring Creek American Falls - American Falls, ID [Member] | Commercial Medical [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition			Sep. 01, 2011
Land			137,000
Buildings			3,409,000
Intangible assets			524,000
Acquisition costs			4,070,000
Area of a real estate property (in square feet)			17,273
Spring Creek Soda Springs - Soda Springs, ID [Member] | Commercial Medical [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition			Sep. 01, 2011
Land			66,000
Buildings			2,122,000
Intangible assets			42,000
Acquisition costs			2,230,000
Area of a real estate property (in square feet)			15,571
Spring Creek Eagle - Eagle, ID [Member] | Commercial Medical [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition			Sep. 01, 2011
Land			250,000
Buildings			3,191,000
Intangible assets			659,000
Acquisition costs			4,100,000
Area of a real estate property (in square feet)			15,559
Spring Creek Meridian - Meridian, ID [Member] | Commercial Medical [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition			Sep. 01, 2011
Land			428,000
Buildings			5,499,000
Intangible assets			1,323,000
Acquisition costs			7,250,000
Area of a real estate property (in square feet)			31,820
Spring Creek Overland - Boise, ID [Member] | Commercial Medical [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition			Sep. 01, 2011
Land			656,000
Buildings			5,001,000
Intangible assets			1,068,000
Acquisition costs			6,725,000
Area of a real estate property (in square feet)			26,605
Spring Creek Boise - Boise, ID [Member] | Commercial Medical [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition			Sep. 01, 2011
Land			711,000
Buildings			4,236,000
Intangible assets			128,000
Acquisition costs			5,075,000
Area of a real estate property (in square feet)			16,311
Spring Creek Ustick - Meridian, ID [Member] | Commercial Medical [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition			Sep. 01, 2011
Land			467,000
Buildings			3,833,000
Intangible assets			0
Acquisition costs			4,300,000
Area of a real estate property (in square feet)			26,605
Terrace on the Green - Fargo, ND [Member] | Multi-Family Residential [Member]
Dispositions [Abstract]
Number of apartment units	116
Date Disposal	Sep. 27, 2012
Sales price	3,450,000
Book value and sales cost	1,248,000
Gain/(Loss)	2,202,000
The Ponds at Heritage Place - Sartell, MN [Member] | Multi-Family Residential [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition	Oct. 10, 2012
Land	395,000
Buildings	4,564,000
Intangible assets	61,000
Acquisition costs	5,020,000
Number of apartment units	58
University Commons - Williston, ND [Member] | Unimproved Land [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition	Aug. 01, 2012
Land	823,000
Buildings	0
Intangible assets	0
Acquisition costs	823,000
Villa West - Topeka, KS [Member] | Multi-Family Residential [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition	May 08, 2012
Land	1,590,000
Buildings	15,760,000
Intangible assets	300,000
Acquisition costs	17,650,000
Number of apartment units	308
Development Projects Placed in Service [Member]
Acquisitions and development projects placed in service [Abstract]
Land	0		0
Buildings	22,178,000		10,224,000
Intangible assets	0		0
Acquisition costs	22,178,000		10,224,000
Development Projects Placed in Service [Member] | Multi-Family Residential [Member]
Acquisitions and development projects placed in service [Abstract]
Land	0
Buildings	11,649,000
Intangible assets	0
Acquisition costs	11,649,000
Development Projects Placed in Service [Member] | Commercial Medical [Member]
Acquisitions and development projects placed in service [Abstract]
Land	0		0
Buildings	6,576,000		9,402,000
Intangible assets	0		0
Acquisition costs	6,576,000		9,402,000
Development Projects Placed in Service [Member] | Quarry Ridge II - Rochester, MN [Member] | Multi-Family Residential [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition	Jun. 29, 2012	[4]
Land	0	[4]
Buildings	4,591,000	[4]
Intangible assets	0	[4]
Acquisition costs	4,591,000	[4]
Number of apartment units	159	[4]
Development Projects Placed in Service [Member] | Jamestown Buffalo Mall - Jamestown, ND [Member] | Commercial Retail [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition			Jun. 15, 2011	[5]
Land			0	[5]
Buildings			822,000	[5]
Intangible assets			0	[5]
Acquisition costs			822,000	[5]
Area of a real estate property (in square feet)			19,037	[5]
Development Projects Placed in Service [Member] | Jamestown Medical Office Building - Jamestown, ND [Member] | Commercial Medical [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition	Jan. 01, 2013	[6]
Land	0	[6]
Buildings	4,901,000	[6]
Intangible assets	0	[6]
Acquisition costs	4,901,000	[6]
Area of a real estate property (in square feet)	45,222	[6]
Development Projects Placed in Service [Member] | Meadow Winds Addition - Casper, WY [Member] | Commercial Medical [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition			Dec. 30, 2011	[7]
Land			0	[7]
Buildings			3,840,000	[7]
Intangible assets			0	[7]
Acquisition costs			3,840,000	[7]
Area of a real estate property (in square feet)			22,193	[7]
Development Projects Placed in Service [Member] | Minot IPS - Minot, ND [Member] | Commercial Industrial [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition	Dec. 17, 2012	[8]
Land	0	[8]
Buildings	3,953,000	[8]
Intangible assets	0	[8]
Acquisition costs	3,953,000	[8]
Area of a real estate property (in square feet)	27,567	[8]
Development Projects Placed in Service [Member] | Spring Wind Expansion - Laramie, WY [Member] | Commercial Medical [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition	Nov. 16, 2012	[9]
Land	0	[9]
Buildings	1,675,000	[9]
Intangible assets	0
Acquisition costs	1,675,000	[9]
Area of a real estate property (in square feet)	26,662	[9]
Development Projects Placed in Service [Member] | Trinity at Plaza 16 - Minot, ND( [Member] | Commercial Medical [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition			Sep. 23, 2011	[10]
Land			0	[10]
Buildings			5,562,000	[10]
Intangible assets			0	[10]
Acquisition costs			5,562,000	[10]
Area of a real estate property (in square feet)			24,795	[10]
Development Projects Placed in Service [Member] | Williston Garden Buildings 3 and 4 - Williston, ND [Member] | Multi-Family Residential [Member]
Acquisitions and development projects placed in service [Abstract]
Date Acquisition	Jul. 31, 2013	[11]
Land	0	[11]
Buildings	7,058,000	[11]
Intangible assets	0	[11]
Acquisition costs	$ 7,058,000	[11]
Number of apartment units	73	[11]

[1] (2) Acquisition of unimproved land consisted of two parcels acquired separately on December 14 and December 20, 2012, respectively.

[2] (3) Land is owned by a joint venture entity in which the Company has an approximately 51% interest.

[3] (1) Land is owned by a joint venture in which the Company has an approximately 79% interest.

[4] (1) Development property placed in service June 29, 2012. Additional costs paid in fiscal years 2012 and 2011, and land acquired in fiscal year 2007, totaled $13.0 million, for a total project cost at January 31, 2013 of $17.6 million.

[5] (3) Construction project placed in service June 15, 2011. Additional costs paid in fiscal year 2011 totaled $1.4 million, for a total project cost at January 31, 2012 of $2.3 million.

[6] (4) Development property placed in service January 1, 2013. Additional costs paid in fiscal year 2012 totaled $1.0 million, for a total project cost at January 31, 2013 of $5.9 million.

[7] (2) Expansion project placed in service December 30, 2011.

[8] (5) Development property placed in service December 17, 2012. Additional costs paid in fiscal year 2012 totaled $1.8 million, for a total project cost at January 31, 2013 of $5.8 million.

[9] (3) Expansion project placed in service November 16, 2012. Additional costs paid in fiscal year 2012 totaled $1.8 million, for a total project cost at January 31, 2013 of $3.5 million.

[10] (1) Development property placed in service September 23, 2011. Additional costs paid in fiscal year 2011 totaled $3.3 million, for a total project cost at January 31, 2012 of $8.8 million.

[11] (2) Development property placed in service July 31, 2012. Buildings 1 and 2 were placed in service in fiscal year 2012. Additional costs paid in fiscal year 2012 totaled $12.0 million, for a total project cost at January 31, 2013 of $19.1 million.