ACQUISITIONS, DEVELOPMENT PROJECTS PLACED IN SERVICE AND DISPOSITIONS, PROPERTY DISPOSITIONS (Details) $ in Thousands		12 Months Ended
	Jan. 29, 2016 USD ($) property	Apr. 30, 2017 USD ($) property	Apr. 30, 2016 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain/loss on extinguishment of debt		$ (3,099)	$ (106)
Disposed of by Sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale price		286,926	536,728
Book value and sales cost		211,977	466,835
Gain/(Loss)		74,949	$ 69,893
Sale price, net of properties transferred		$ 286,900
Multi-Family Residential [Member] | Disposed of by Sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties sold | property		1
Multi-Family Residential [Member] | Disposed of by Sale [Member] | Pinecone Villas - Sartell, MN [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date disposed		Apr. 20, 2017
Sale price		$ 3,540
Book value and sales cost		2,732
Gain/(Loss)		$ 808
Multi-Family Residential [Member] | Disposed of by Sale [Member] | 391 unit - St. Cloud Student Housing Portfolio - St. Cloud, MN [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date disposed			Mar. 24, 2016
Sale price			$ 5,615
Book value and sales cost			5,647
Gain/(Loss)			$ (32)
Senior Housing properties [Member] | Disposed of by Sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties sold | property		32
Healthcare [Member] | Disposed of by Sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale price		$ 265,736
Book value and sales cost		202,990
Gain/(Loss)		$ 62,746
Number of properties sold | property		2
Healthcare [Member] | Disposed of by Sale [Member] | Idaho Spring Creek Senior Housing Properties [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date disposed		Oct. 31, 2016
Sale price		$ 43,900
Book value and sales cost		37,397
Gain/(Loss)		$ 6,503
Healthcare [Member] | Disposed of by Sale [Member] | 5 Edgewood Vista Senior Housing Properties
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date disposed		Jan. 18, 2017
Sale price		$ 69,928
Book value and sales cost		50,393
Gain/(Loss)		$ 19,535
Healthcare [Member] | Disposed of by Sale [Member] | Wyoming Senior Housing Portfolio [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date disposed		Feb. 01, 2017
Sale price		$ 49,600
Book value and sales cost		45,469
Gain/(Loss)		$ 4,131
Healthcare [Member] | Disposed of by Sale [Member] | 9 Edgewood Vista Senior Housing Properties [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date disposed		Feb. 15, 2017
Sale price		$ 30,700
Book value and sales cost		24,081
Gain/(Loss)		$ 6,619
Healthcare [Member] | Disposed of by Sale [Member] | 4 Edgewood Vista Senior Housing Properties [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date disposed		Mar. 01, 2017
Sale price		$ 35,348
Book value and sales cost		14,511
Gain/(Loss)		$ 20,837
Healthcare [Member] | Disposed of by Sale [Member] | Healtheast St John & Woodwinds - Maplewood & Woodbury, MN [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date disposed		Mar. 06, 2017
Sale price		$ 20,700
Book value and sales cost		13,777
Gain/(Loss)		$ 6,923
Healthcare [Member] | Disposed of by Sale [Member] | Sartell 2000 23rd Street South - Sartell, MN [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date disposed		Mar. 31, 2017
Sale price		$ 5,600
Book value and sales cost		5,923
Gain/(Loss)		$ (323)
Healthcare [Member] | Disposed of by Sale [Member] | Legends at Heritage Place - Sartell, MN [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date disposed		Apr. 20, 2017
Sale price		$ 9,960
Book value and sales cost		11,439
Gain/(Loss)		$ (1,479)
Healthcare [Member] | Disposed of by Sale [Member] | 61,758 sq ft Nebraska Orthopedic Hospital - Omaha, NE
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date disposed			Apr. 01, 2016
Sale price			$ 24,494
Book value and sales cost			16,512
Gain/(Loss)			7,982
Retail [Member] | Disposed of by Sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties sold | property		1
Industrial [Member] | Disposed of by Sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties sold | property		1
Other [Member] | Disposed of by Sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale price		$ 17,400	506,599
Book value and sales cost		5,981	444,655
Gain/(Loss)		$ 11,419	$ 61,944
Other [Member] | Disposed of by Sale [Member] | Stone Container - Fargo, ND [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date disposed		Jul. 25, 2016
Sale price		$ 13,400
Book value and sales cost		4,418
Gain/(Loss)		$ 8,982
Other [Member] | Disposed of by Sale [Member] | Grand Forks Carmike - Grand Forks, ND [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date disposed		Dec. 29, 2016
Sale price		$ 4,000
Book value and sales cost		1,563
Gain/(Loss)		$ 2,437
Other [Member] | Disposed of by Sale [Member] | 117,144 sq ft Thresher Square - Minneapolis, MN [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date disposed			May 18, 2015
Sale price			$ 7,000
Book value and sales cost			7,175
Gain/(Loss)			$ (175)
Other [Member] | Disposed of by Sale [Member] | 2,549,222 sq ft Office Sale Portfolio [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date disposed			Aug. 03, 2015
Sale price			$ 250,000
Book value and sales cost			231,908
Gain/(Loss)			$ 18,092
Other [Member] | Disposed of by Sale [Member] | 420,216 sq ft Mendota Office Center Portfolio - Mendota Heights, MN [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date disposed			Aug. 12, 2015
Sale price			$ 40,000
Book value and sales cost			41,574
Gain/(Loss)			$ (1,574)
Other [Member] | Disposed of by Sale [Member] | 1,027,208 sq ft Retail Sale Portfolio [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date disposed			Sep. 30, 2015
Sale price			$ 78,960
Book value and sales cost			72,000
Gain/(Loss)			$ 6,960
Other [Member] | Disposed of by Sale [Member] | 48,700 sq ft Eden Prairie 6101 Blue Circle Drive - Eden Prairie, MN [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date disposed			Oct. 19, 2015
Sale price			$ 2,900
Book value and sales cost			2,928
Gain/(Loss)			$ (28)
Other [Member] | Disposed of by Sale [Member] | Burnsville 1 Strip Center - Burnsville, MN [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date disposed			Dec. 23, 2015
Sale price			$ 1,300
Book value and sales cost			913
Gain/(Loss)			$ 387
Other [Member] | Disposed of by Sale [Member] | Pine City C-Store - Pine City, MN [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date disposed			Jan. 08, 2016
Sale price			$ 300
Book value and sales cost			355
Gain/(Loss)			$ (55)
Other [Member] | Disposed of by Sale [Member] | Minot Plaza - Minot, ND [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date disposed			Jan. 19, 2016
Sale price			$ 1,854
Book value and sales cost			393
Gain/(Loss)			$ 1,461
Other [Member] | Disposed of by Sale [Member] | 937,518 sq ft 9-Building Office Portfolio [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date disposed			Jan. 29, 2016
Sale price			$ 122,610
Book value and sales cost			86,154
Gain/(Loss)			$ 36,456
Number of properties transferred | property	9
Non-recourse loan	$ 122,600
Estimated fair value of properties transferred	$ 89,300
Other [Member] | Disposed of by Sale [Member] | 3,702 sq ft Arrowhead First International Bank - Minot, ND
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date disposed			Apr. 06, 2016
Sale price			$ 1,675
Book value and sales cost			1,255
Gain/(Loss)			$ 420
Unimproved Land [Member] | Disposed of by Sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties sold | property		2
Unimproved Land [Member] | Disposed of by Sale [Member] | Georgetown Square - Grand Chute, WI [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date disposed		May 06, 2016
Sale price		$ 250
Book value and sales cost		274
Gain/(Loss)		$ (24)
Unimproved Land [Member] | Disposed of by Sale [Member] | River Falls - River Falls, WI [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date disposed			Apr. 06, 2016
Sale price			$ 20
Book value and sales cost			21
Gain/(Loss)			$ (1)