COMMITMENTS AND CONTINGENCIES, Development, Expansion and Renovation Projects (Details) - Apr. 30, 2015 $ in Thousands		USD ($) ft² Unit
Real Estate Properties [Line Items]
Anticipated Total Cost		$ 292,765
Project costs incurred to date	[1]	208,982
Other [Member]
Real Estate Properties [Line Items]
Project costs incurred to date	[1]	$ 6,618
Commercial Industrial [Member] | Roseville 3075 Long Lake Rd - Roseville, MN [Member]
Real Estate Properties [Line Items]
Area of real estate property | ft²		202,807
Anticipated Total Cost		$ 13,915
Project costs incurred to date	[1]	$ 9,036
Multi Family Residential [Member] | Chateau II - Minot, ND [Member]
Real Estate Properties [Line Items]
Number of apartment units | Unit		72
Anticipated Total Cost		$ 14,711
Project costs incurred to date	[1]	$ 13,129
Estimated quarter for completion		1
Estimated year for completion		2016
Multi Family Residential [Member] | Renaissance Heights - Williston ND [Member]
Real Estate Properties [Line Items]
Number of apartment units | Unit	[2]	288
Anticipated Total Cost	[2]	$ 62,362
Project costs incurred to date	[1],[2]	$ 59,087
Estimated quarter for completion	[2]	1
Estimated year for completion	[2]	2016
Interest in joint venture (in hundredths)		70.00%
Costs related to development projects placed in service in phases		$ 46,000
Multi Family Residential [Member] | Deer Ridge - Jamestown, ND [Member]
Real Estate Properties [Line Items]
Number of apartment units | Unit		163
Anticipated Total Cost		$ 24,519
Project costs incurred to date	[1]	$ 15,355
Estimated quarter for completion		2
Estimated year for completion		2016
Multi Family Residential [Member] | Cardinal Point - Grand Forks, ND [Member]
Real Estate Properties [Line Items]
Number of apartment units | Unit		251
Anticipated Total Cost		$ 40,042
Project costs incurred to date	[1]	$ 26,450
Estimated quarter for completion		3
Estimated year for completion		2016
Multi Family Residential [Member] | 71 France Phase I, II, III - Edina, MN [Member]
Real Estate Properties [Line Items]
Area of real estate property | ft²		21,772
Number of apartment units | Unit	[3]	241
Anticipated Total Cost	[3]	$ 73,290
Project costs incurred to date	[1],[3]	$ 35,137
Estimated quarter for completion	[3]	3
Estimated year for completion	[3]	2016
Interest in joint venture (in hundredths)		52.60%
Commercial Healthcare [Member] | Edina 6565 France SMC III - Edina, MN [Member]
Real Estate Properties [Line Items]
Area of real estate property | ft²		57,479
Anticipated Total Cost		$ 36,752
Project costs incurred to date	[1]	$ 22,549
Estimated quarter for completion		1
Estimated year for completion		2016
Commercial Healthcare [Member] | PrairieCare Medical - Brooklyn Park, MN [Member]
Real Estate Properties [Line Items]
Area of real estate property | ft²		72,895
Anticipated Total Cost		$ 24,251
Project costs incurred to date	[1]	$ 19,457
Estimated quarter for completion		2
Estimated year for completion		2016
Commercial Retail [Member] | Minot Southgate Retail Minot ND [Member]
Real Estate Properties [Line Items]
Area of real estate property | ft²		7,963
Anticipated Total Cost		$ 2,923
Project costs incurred to date	[1]	$ 2,164
Estimated quarter for completion		1
Estimated year for completion		2016

[1] Includes costs related to development projects that are placed in service in phases (Renaissance Heights - $46.0 million).

[2] 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.

[3] The project will be constructed in three phases by a joint venture entity in which the Company has an approximately 52.6% interest. The anticipated total cost amount given in the table above is the total cost to the joint venture entity. The anticipated total cost includes approximately 21,772 square feet of retail space.