ACQUISITIONS, DEVELOPMENTS PLACED IN SERVICE AND DISPOSITIONS, Development Projects Placed in Service (Details)		9 Months Ended				12 Months Ended
		Jan. 31, 2016 USD ($) ft² Unit		Jan. 31, 2015 USD ($) ft² Unit		Apr. 30, 2015 USD ($)	Apr. 30, 2014 USD ($)
Business Acquisition [Line Items]
Land		$ 6,819,000	[1]	$ 9,941,000
Building		129,979,000	[1]	103,627,000
Development Cost		136,798,000	[1],[2],[3],[4],[5],[6]	113,568,000	[7],[8],[9],[10],[11],[12]
Multifamily [Member]
Business Acquisition [Line Items]
Land		3,320,000	[1]	8,949,000
Building		73,772,000	[1]	101,434,000
Development Cost		$ 77,092,000	[1],[2],[6]	$ 110,383,000	[8],[9],[10],[11],[12]
Multifamily [Member] | 72 unit - Chateau II - Minot, ND [Member]
Business Acquisition [Line Items]
Date Placed in Service	[1],[2]	Jun. 01, 2015
Land	[1],[2]	$ 240,000
Building	[1],[2]	14,401,000
Development Cost	[1],[2]	14,641,000
Development cost paid		$ 2,300,000				$ 12,300,000
Number of apartment units owned | Unit	[1],[2]	72
Multifamily [Member] | 288 unit - Renaissance Heights - Williston, ND [Member]
Business Acquisition [Line Items]
Date Placed in Service	[1],[2],[6]	Jul. 27, 2015
Land	[1],[6]	$ 3,080,000
Building	[1],[6]	59,371,000
Development Cost	[1],[6]	62,451,000
Development cost paid		$ 4,800,000				57,700,000
Interest in joint venture		70.00%
Number of apartment units owned | Unit	[1],[2],[6]	288
Multifamily [Member] | 44 unit - Dakota Commons - Williston, ND [Member]
Business Acquisition [Line Items]
Date Placed in Service	[12]			Jul. 15, 2014
Land	[12]			$ 823,000
Building	[12]			9,596,000
Development Cost	[12]			10,419,000
Development cost paid				$ 2,300,000			$ 8,100,000
Number of apartment units owned | Unit	[12]			44
Multifamily [Member] | 130 unit - Red 20 - Minneapolis, MN [Member]
Business Acquisition [Line Items]
Date Placed in Service	[10]			Nov. 21, 2014
Land	[10]			$ 1,900,000
Building	[10]			26,430,000
Development Cost	[10]			28,330,000
Development cost paid				$ 16,100,000			12,200,000
Interest in joint venture				58.60%
Number of apartment units owned | Unit	[10]			130
Multifamily [Member] | 233 unit - Commons at Southgate - Minot, ND [Member]
Business Acquisition [Line Items]
Date Placed in Service	[11]			Dec. 09, 2014
Land	[11]			$ 3,691,000
Building	[11]			30,921,000
Development Cost	[11]			34,612,000
Development cost paid				$ 8,100,000			26,500,000
Interest in joint venture				52.90%
Number of apartment units owned | Unit	[11]			233
Multifamily [Member] | 64 unit - Cypress Court II - St. Cloud, MN [Member]
Business Acquisition [Line Items]
Date Placed in Service	[8]			Jan. 01, 2015
Land	[8]			$ 447,000
Building	[8]			6,191,000
Development Cost	[8]			6,638,000
Development cost paid				$ 5,500,000			1,200,000
Interest in joint venture				86.10%
Number of apartment units owned | Unit	[8]			64
Multifamily [Member] | 165 unit - Arcata - Golden Valley, MN [Member]
Business Acquisition [Line Items]
Date Placed in Service	[8],[9],[10],[11],[12]			Jan. 01, 2015
Land	[9]			$ 2,088,000
Building	[9]			28,296,000
Development Cost	[9]			30,384,000
Development cost paid				$ 19,100,000			11,300,000
Number of apartment units owned | Unit	[8],[9],[10],[11],[12]			165
Healthcare [Member]
Business Acquisition [Line Items]
Land	[1],[3],[5]	$ 2,610,000
Building	[1],[3],[5]	54,473,000
Development Cost	[1],[3],[5]	$ 57,083,000
Healthcare [Member] | 57,624 sq ft Edina 6565 France SMC III - Edina, MN [Member]
Business Acquisition [Line Items]
Date Placed in Service	[1],[5]	Jun. 01, 2015
Land	[1],[5]	$ 0
Building	[1],[5]	32,725,000
Development Cost	[1],[5]	32,725,000
Development cost paid		$ 11,900,000				20,800,000
Area of real estate property | ft²	[1],[5]	57,624
Healthcare [Member] | 70,756 sq ft PrairieCare Medical - Brooklyn Park, MN [Member]
Business Acquisition [Line Items]
Date Placed in Service	[1],[3],[5]	Sep. 08, 2015
Land	[1],[3]	$ 2,610,000
Building	[1],[3]	21,748,000
Development Cost	[1],[3]	24,358,000
Development cost paid		$ 7,100,000				17,300,000
Area of real estate property | ft²	[1],[3],[5]	70,756
Other [Member] | 7,963 sq ft Minot Southgate Retail - Minot, ND [Member]
Business Acquisition [Line Items]
Date Placed in Service	[1],[2],[3],[4],[5],[6]	Oct. 01, 2015
Land	[1],[4]	$ 889,000
Building	[1],[4]	1,734,000
Development Cost	[1],[4]	2,623,000
Development cost paid		$ 500,000				$ 2,100,000
Area of real estate property | ft²	[1],[3],[4],[5]	7,963
Other [Member] | 4,998 Sq Ft Minot Wells Fargo Bank - Minot, ND [Member]
Business Acquisition [Line Items]
Date Placed in Service	[7],[8],[9],[10],[11],[12]			Nov. 10, 2014
Land	[7]			$ 992,000
Building	[7]			2,193,000
Development Cost	[7]			3,185,000
Development cost paid				$ 2,200,000			$ 1,000,000
Area of real estate property | ft²	[7]			4,998

[1] Development projects that are placed in service in phases are excluded from this table until the entire project has been placed in service. See Note 6 for additional information on the Deer Ridge, 71 France, and Cardinal Point projects, which were partially placed in service during the nine months ended January 31, 2016.

[2] Costs paid in prior fiscal years totaled $12.3 million. Additional costs incurred in fiscal year 2016 totaled $2.3 million, for a total project cost at January 31, 2016 of $14.6 million.

[3] Costs paid in prior fiscal years totaled $17.3 million. Additional costs incurred in fiscal year 2016 totaled $7.1 million, for a total project cost at January 31, 2016 of $24.4 million.

[4] Costs paid in prior fiscal years totaled $2.1 million. Additional costs incurred in fiscal year 2016 totaled approximately $500,000, for a total project cost at January 31, 2016 of $2.6 million.

[5] Costs paid in prior fiscal years totaled $20.8 million. Additional costs incurred in fiscal year 2016 totaled $11.9 million, for a total project cost at January 31, 2016 of $32.7 million.

[6] Costs paid in prior fiscal years totaled $57.7 million. Additional costs incurred in fiscal year 2016 totaled $4.8 million, for a total project cost at January 31, 2016 of $62.5 million. The project is owned by a joint venture entity in which we currently have an approximately 70.0% interest. The joint venture is consolidated in our financial statements.

[7] Costs paid in prior fiscal years totaled $1.0 million. Additional cost paid in fiscal year 2015 totaled $2.2 million, for a total project cost at January 31, 2015 of $3.2 million.

[8] Costs paid in prior fiscal years totaled $1.2 million. Additional costs paid in fiscal year 2015 totaled $5.5 million, for a total project cost at January 31, 2015 of $6.6 million. The project is owned by a joint venture entity in which we currently have an approximately 86.1% interest. The joint venture is consolidated in our financial statements.

[9] Costs paid in prior fiscal years totaled $11.3 million. Additional costs paid in fiscal year 2015 totaled $19.1 million, for a total project cost at January 31, 2015 of $30.4 million.

[10] Costs paid in prior fiscal years totaled $12.2 million. Additional costs paid in fiscal year 2015 totaled $16.1 million, for a total project cost at January 31, 2015 of $28.3 million. The project is owned by a joint venture entity in which we currently have an approximately 58.6% interest. The joint venture is consolidated in our financial statements.

[11] Costs paid in prior fiscal years totaled $26.5 million. Additional costs paid in fiscal year 2015 totaled $8.1 million, for a total project cost at January 31, 2015 of $34.6 million. The project is owned by a joint venture entity in which we have an approximately 52.9% interest. The joint venture is consolidated in our financial statements.

[12] Costs paid in prior fiscal years totaled $8.1 million. Additional costs paid in fiscal year 2015 totaled $2.3 million, for a total project cost at January 31, 2015 of $10.4 million.