ACQUISITIONS AND DISPOSITIONS - Acquisitions (Details) $ in Thousands		12 Months Ended
	Sep. 01, 2021 USD ($)	Dec. 31, 2021 USD ($) apartmentUnit	Dec. 31, 2020 USD ($) apartmentUnit
Investment Allocation
Preferred shares, liquidation preference		$ 97,036	$ 97,036
Series E Preferred Stock
Investment Allocation
Preferred shares, liquidation preference	$ 181,400
2021 Acquisitions
Acquisitions and development projects placed in service [Abstract]
Total acquisition costs		499,816
Form of Consideration
Form of consideration, cash		155,599
Form of consideration, units		217,513
Form of consideration, other		126,704
Investment Allocation
Investment allocation, land		51,746
Investment allocation, building		431,189
Investment allocation, intangible assets		19,234
Other, Liabilities		$ (2,353)
2021 Acquisitions | Series E Preferred Stock
Acquisitions and development projects placed in service [Abstract]
Total acquisition costs	$ 36,100
Union Pointe Apartment Homes - Longmont, CO
Acquisitions and development projects placed in service [Abstract]
Number of apartment homes | apartmentUnit		256
Total acquisition costs		$ 76,900
Form of Consideration
Form of consideration, cash		76,900
Form of consideration, units		0
Form of consideration, other		0
Investment Allocation
Investment allocation, land		5,727
Investment allocation, building		69,966
Investment allocation, intangible assets		1,207
Other, Liabilities		$ 0
Bayberry Place - Minneapolis, MN
Acquisitions and development projects placed in service [Abstract]
Number of apartment homes | apartmentUnit		120
Total acquisition costs		$ 16,673
Form of Consideration
Form of consideration, cash		898
Form of consideration, units		9,855
Form of consideration, other		5,920
Investment Allocation
Investment allocation, land		1,807
Investment allocation, building		14,113
Investment allocation, intangible assets		753
Other, Liabilities		$ 0
Burgandy & Hillsboro Court - Minneapolis, MN
Acquisitions and development projects placed in service [Abstract]
Number of apartment homes | apartmentUnit		251
Total acquisition costs		$ 35,569
Form of Consideration
Form of consideration, cash		2,092
Form of consideration, units		22,542
Form of consideration, other		10,935
Investment Allocation
Investment allocation, land		2,834
Investment allocation, building		31,148
Investment allocation, intangible assets		1,587
Other, Liabilities		$ 0
Venue on Knox - Minneapolis, MN
Acquisitions and development projects placed in service [Abstract]
Number of apartment homes | apartmentUnit		97
Total acquisition costs		$ 18,896
Form of Consideration
Form of consideration, cash		500
Form of consideration, units		11,375
Form of consideration, other		7,021
Investment Allocation
Investment allocation, land		3,438
Investment allocation, building		14,743
Investment allocation, intangible assets		715
Other, Liabilities		$ 0
Gatewood - St. Cloud, MN
Acquisitions and development projects placed in service [Abstract]
Number of apartment homes | apartmentUnit		120
Total acquisition costs		$ 7,781
Form of Consideration
Form of consideration, cash		378
Form of consideration, units		3,388
Form of consideration, other		4,015
Investment Allocation
Investment allocation, land		327
Investment allocation, building		6,858
Investment allocation, intangible assets		596
Other, Liabilities		$ 0
Grove Ridge - Minneapolis, MN
Acquisitions and development projects placed in service [Abstract]
Number of apartment homes | apartmentUnit		84
Total acquisition costs		$ 12,060
Form of Consideration
Form of consideration, cash		121
Form of consideration, units		8,579
Form of consideration, other		3,360
Investment Allocation
Investment allocation, land		1,250
Investment allocation, building		10,271
Investment allocation, intangible assets		539
Other, Liabilities		$ 0
The Legacy - St. Cloud, MN
Acquisitions and development projects placed in service [Abstract]
Number of apartment homes | apartmentUnit		119
Total acquisition costs		$ 10,560
Form of Consideration
Form of consideration, cash		229
Form of consideration, units		5,714
Form of consideration, other		4,617
Investment Allocation
Investment allocation, land		412
Investment allocation, building		9,556
Investment allocation, intangible assets		592
Other, Liabilities		$ 0
New Hope Garden & Village - Minneapolis, MN
Acquisitions and development projects placed in service [Abstract]
Number of apartment homes | apartmentUnit		151
Total acquisition costs		$ 15,006
Form of Consideration
Form of consideration, cash		1,435
Form of consideration, units		10,812
Form of consideration, other		2,759
Investment Allocation
Investment allocation, land		1,603
Investment allocation, building		12,578
Investment allocation, intangible assets		825
Other, Liabilities		$ 0
Palisades - Minneapolis, MN
Acquisitions and development projects placed in service [Abstract]
Number of apartment homes | apartmentUnit		330
Total acquisition costs		$ 53,354
Form of Consideration
Form of consideration, cash		2,884
Form of consideration, units		30,470
Form of consideration, other		20,000
Investment Allocation
Investment allocation, land		6,919
Investment allocation, building		46,577
Investment allocation, intangible assets		2,211
Other, Liabilities		$ (2,353)
Plymouth Pointe - Minneapolis, MN
Acquisitions and development projects placed in service [Abstract]
Number of apartment homes | apartmentUnit		96
Total acquisition costs		$ 14,450
Form of Consideration
Form of consideration, cash		370
Form of consideration, units		9,061
Form of consideration, other		5,019
Investment Allocation
Investment allocation, land		1,042
Investment allocation, building		12,809
Investment allocation, intangible assets		599
Other, Liabilities		$ 0
Pointe West - St. Cloud, MN
Acquisitions and development projects placed in service [Abstract]
Number of apartment homes | apartmentUnit		93
Total acquisition costs		$ 7,558
Form of Consideration
Form of consideration, cash		91
Form of consideration, units		3,605
Form of consideration, other		3,862
Investment Allocation
Investment allocation, land		246
Investment allocation, building		6,849
Investment allocation, intangible assets		463
Other, Liabilities		$ 0
River Pointe - Minneapolis, MN
Acquisitions and development projects placed in service [Abstract]
Number of apartment homes | apartmentUnit		301
Total acquisition costs		$ 38,348
Form of Consideration
Form of consideration, cash		2,249
Form of consideration, units		21,653
Form of consideration, other		14,446
Investment Allocation
Investment allocation, land		3,346
Investment allocation, building		33,117
Investment allocation, intangible assets		1,885
Other, Liabilities		$ 0
Southdale Parc - Minneapolis, MN
Acquisitions and development projects placed in service [Abstract]
Number of apartment homes | apartmentUnit		70
Total acquisition costs		$ 9,670
Form of Consideration
Form of consideration, cash		165
Form of consideration, units		7,907
Form of consideration, other		1,598
Investment Allocation
Investment allocation, land		1,569
Investment allocation, building		7,740
Investment allocation, intangible assets		361
Other, Liabilities		$ 0
Portage - Minneapolis, MN
Acquisitions and development projects placed in service [Abstract]
Number of apartment homes | apartmentUnit		62
Total acquisition costs		$ 9,171
Form of Consideration
Form of consideration, cash		323
Form of consideration, units		5,588
Form of consideration, other		3,260
Investment Allocation
Investment allocation, land		2,133
Investment allocation, building		6,685
Investment allocation, intangible assets		353
Other, Liabilities		$ 0
Windsor Gates - Minneapolis, MN
Acquisitions and development projects placed in service [Abstract]
Number of apartment homes | apartmentUnit		200
Total acquisition costs		$ 22,231
Form of Consideration
Form of consideration, cash		1,122
Form of consideration, units		12,080
Form of consideration, other		9,029
Investment Allocation
Investment allocation, land		2,140
Investment allocation, building		18,943
Investment allocation, intangible assets		1,148
Other, Liabilities		$ 0
Wingate - Minneapolis, MN
Acquisitions and development projects placed in service [Abstract]
Number of apartment homes | apartmentUnit		136
Total acquisition costs		$ 15,784
Form of Consideration
Form of consideration, cash		723
Form of consideration, units		10,246
Form of consideration, other		4,815
Investment Allocation
Investment allocation, land		1,480
Investment allocation, building		13,530
Investment allocation, intangible assets		774
Other, Liabilities		$ 0
Woodhaven - Minneapolis, MN
Acquisitions and development projects placed in service [Abstract]
Number of apartment homes | apartmentUnit		178
Total acquisition costs		$ 25,009
Form of Consideration
Form of consideration, cash		1,682
Form of consideration, units		15,200
Form of consideration, other		8,127
Investment Allocation
Investment allocation, land		3,940
Investment allocation, building		20,080
Investment allocation, intangible assets		989
Other, Liabilities		$ 0
Woodland Pointe - Minneapolis, MN
Acquisitions and development projects placed in service [Abstract]
Number of apartment homes | apartmentUnit		288
Total acquisition costs		$ 47,796
Form of Consideration
Form of consideration, cash		437
Form of consideration, units		29,438
Form of consideration, other		17,921
Investment Allocation
Investment allocation, land		5,367
Investment allocation, building		40,422
Investment allocation, intangible assets		2,007
Other, Liabilities		$ 0
Civic Lofts - Denver, CO
Acquisitions and development projects placed in service [Abstract]
Number of apartment homes | apartmentUnit		176
Total acquisition costs		$ 63,000
Form of Consideration
Form of consideration, cash		63,000
Form of consideration, units		0
Form of consideration, other		0
Investment Allocation
Investment allocation, land		6,166
Investment allocation, building		55,204
Investment allocation, intangible assets		1,630
Other, Liabilities		$ 0
2020 Acquisitions
Acquisitions and development projects placed in service [Abstract]
Total acquisition costs			191,013
Form of Consideration
Form of consideration, cash			173,350
Form of consideration, other			17,663
Investment Allocation
Investment allocation, land			12,639
Investment allocation, building			168,974
Investment allocation, intangible assets			2,995
Other, Assets			$ 6,405
Ironwood Apartments - New Hope, MN
Acquisitions and development projects placed in service [Abstract]
Number of apartment homes | apartmentUnit			182
Total acquisition costs			$ 46,263
Form of Consideration
Form of consideration, cash			28,600
Form of consideration, other			17,663
Investment Allocation
Investment allocation, land			2,165
Investment allocation, building			36,869
Investment allocation, intangible assets			824
Other, Assets			$ 6,405
Parkhouse Apartment Homes - Thornton, CO
Acquisitions and development projects placed in service [Abstract]
Number of apartment homes | apartmentUnit			465
Total acquisition costs			$ 144,750
Form of Consideration
Form of consideration, cash			144,750
Form of consideration, other			0
Investment Allocation
Investment allocation, land			10,474
Investment allocation, building			132,105
Investment allocation, intangible assets			2,171
Other, Assets			$ 0