ACQUISITIONS AND DISPOSITIONS - Dispositions (Details) - Disposed of by Sale $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($) apartmentUnit apartmentProperty	Dec. 31, 2021 USD ($) apartmentUnit commercialProperty	Dec. 31, 2021 USD ($) apartmentUnit	Dec. 31, 2020 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties sold	5	1
Sales Price	$ 62,250	$ 62,250	$ 62,250	$ 44,300
Book Value and Sales Cost	34,733	34,733	34,733	18,828
Gain/(Loss)			27,517	25,472
Multifamily
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales Price	60,000	60,000	60,000	42,500
Book Value and Sales Cost	$ 33,160	$ 33,160	33,160	16,864
Gain/(Loss)			$ 26,840	25,636
Multifamily | Crystal Bay - Rochester, MN
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of apartment units | apartmentUnit	76	76	76
Sales Price	$ 13,650	$ 13,650	$ 13,650
Book Value and Sales Cost	$ 10,255	$ 10,255	10,255
Gain/(Loss)			$ 3,395
Multifamily | French Creek - Rochester, MN
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of apartment units | apartmentUnit	40	40	40
Sales Price	$ 6,700	$ 6,700	$ 6,700
Book Value and Sales Cost	$ 4,474	$ 4,474	4,474
Gain/(Loss)			$ 2,226
Multifamily | Heritage Manor- Rochester, MN
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of apartment units | apartmentUnit	182	182	182
Sales Price	$ 14,125	$ 14,125	$ 14,125
Book Value and Sales Cost	$ 4,892	$ 4,892	4,892
Gain/(Loss)			$ 9,233
Multifamily | Olympik Village - Rochester, MN
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of apartment units | apartmentUnit	140	140	140
Sales Price	$ 10,725	$ 10,725	$ 10,725
Book Value and Sales Cost	$ 6,529	$ 6,529	6,529
Gain/(Loss)			$ 4,196
Multifamily | Winchester/Village Green-Rochester, MN
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of apartment units | apartmentUnit	151	151	151
Sales Price	$ 14,800	$ 14,800	$ 14,800
Book Value and Sales Cost	$ 7,010	$ 7,010	7,010
Gain/(Loss)			$ 7,790
Multifamily | Forest Park - Grand Forks, ND
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of apartment units | apartmentUnit	268	268	268
Sales Price				19,625
Book Value and Sales Cost				6,884
Gain/(Loss)				12,741
Multifamily | Landmark, Grand Forks, ND
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of apartment units | apartmentUnit	90	90	90
Sales Price				3,725
Book Value and Sales Cost				1,348
Gain/(Loss)				2,377
Multifamily | Southwind, Grand Forks, ND
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of apartment units | apartmentUnit	164	164	164
Sales Price				10,850
Book Value and Sales Cost				4,573
Gain/(Loss)				6,277
Multifamily | Valley Park - Grand Forks, ND
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of apartment units | apartmentUnit	168	168	168
Sales Price				8,300
Book Value and Sales Cost				4,059
Gain/(Loss)				4,241
Other | Minot IPS
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales Price	$ 2,250	$ 2,250	$ 2,250
Book Value and Sales Cost	1,573	1,573	1,573
Gain/(Loss)			677
Other | Dakota West
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales Price				500
Book Value and Sales Cost				474
Gain/(Loss)				26
Unimproved Land | Rapid City Land - Rapid City, SD
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales Price	$ 1,300	$ 1,300	$ 1,300
Book Value and Sales Cost				1,490
Gain/(Loss)				$ (190)