REPORTABLE SEGMENTS (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022 USD ($) home	Jun. 30, 2021 USD ($)	Jun. 30, 2022 USD ($) home segment	Jun. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Segments
Same store communities | home	47,734		47,434
Reportable Segments
Number of reportable segments | segment			2
Condition for Community considered to have stabilized occupancy			90%
Time to maintain percent occupancy to be considered a community			3 months
Practical expedient, single lease component			true
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Rental income	$ 367,748	$ 309,116	$ 723,929	$ 608,942
Reconciling items:
Joint venture management and other fees	$ 1,419	$ 2,232	$ 2,504	$ 3,847
Type of revenue	udr:ManagementAndOtherFeesMember	udr:ManagementAndOtherFeesMember	udr:ManagementAndOtherFeesMember	udr:ManagementAndOtherFeesMember
Property management	$ (11,952)	$ (9,273)	$ (23,528)	$ (18,268)
Other operating expenses	(5,027)	(4,373)	(9,739)	(8,808)
Real estate depreciation and amortization	(167,584)	(146,169)	(331,206)	(290,257)
General and administrative	(16,585)	(15,127)	(31,493)	(27,863)
Casualty-related (charges)/recoveries, net	(1,074)	2,463	(309)	(3,114)
Other depreciation and amortization	(3,016)	(2,602)	(6,091)	(5,203)
Gain/(loss) on sale of real estate owned	0	0	0	50,829
Income/(loss) from unconsolidated entities	(11,229)	9,751	(5,817)	14,673
Interest expense	(36,832)	(35,404)	(72,748)	(113,560)
Interest income and other income/(expense), net	3,001	2,536	561	4,593
Tax (provision)/benefit, net	(312)	(135)	(655)	(754)
Net (income)/loss attributable to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership	(272)	(807)	(1,151)	(961)
Net (income)/loss attributable to noncontrolling interests	(8)	(8)	(27)	(24)
Net income/(loss) attributable to UDR, Inc.	5,084	11,720	18,789	14,824
Reportable apartment home segment assets:
Total segment assets	15,273,460		15,273,460		$ 14,740,803
Accumulated depreciation	(5,445,095)		(5,445,095)		(5,137,096)
Total real estate owned, net of accumulated depreciation	9,828,365		9,828,365		9,603,707
Reconciling items:
Cash and cash equivalents	921	3,370	921	3,370	967	$ 1,409
Restricted cash	27,768	32,700	27,768	32,700	27,451	$ 22,762
Notes receivable, net	37,548		37,548		26,860
Investment in and advances to unconsolidated joint ventures, net	691,864		691,864		702,461
Operating lease right-of-use assets	195,755		195,755		197,463
Other assets	214,765		214,765		216,311
Total consolidated assets	10,996,986		10,996,986		10,775,220
Same Store Communities Western Region
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Lease revenue	113,871	101,219	225,520	200,985
Other revenue	3,007	2,599	5,965	5,306
Rental income	116,878	103,818	231,485	206,291
Reportable apartment home segment NOI	88,301	75,789	173,938	150,380
Reportable apartment home segment assets:
Total segment assets	4,317,878		4,317,878		4,288,116
Same Store Communities Mid-Atlantic Region
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Lease revenue	66,629	63,239	132,322	124,933
Other revenue	2,877	2,147	5,239	4,041
Rental income	69,506	65,386	137,561	128,974
Reportable apartment home segment NOI	48,283	44,997	95,244	88,540
Reportable apartment home segment assets:
Total segment assets	2,854,671		2,854,671		2,856,144
Same Store Communities Northeast Region
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Lease revenue	66,544	59,853	129,249	116,582
Other revenue	1,548	1,132	2,755	2,210
Rental income	68,092	60,985	132,004	118,792
Reportable apartment home segment NOI	44,769	38,456	85,611	73,665
Reportable apartment home segment assets:
Total segment assets	3,435,760		3,435,760		3,422,846
Same Store Communities Southeastern Region
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Lease revenue	46,185	39,873	90,505	78,639
Other revenue	2,121	1,965	3,914	3,601
Rental income	48,306	41,838	94,419	82,240
Reportable apartment home segment NOI	33,135	27,897	64,595	54,543
Reportable apartment home segment assets:
Total segment assets	1,219,002		1,219,002		1,208,183
Same Store Communities Southwestern Region
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Lease revenue	26,708	23,765	52,755	46,976
Other revenue	1,052	1,055	1,946	1,930
Rental income	27,760	24,820	54,701	48,906
Reportable apartment home segment NOI	17,689	15,315	35,029	30,150
Reportable apartment home segment assets:
Total segment assets	908,531		908,531		900,931
Non-Mature communities/Other
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Lease revenue	35,869	11,861	71,162	23,141
Other revenue	1,337	408	2,597	598
Rental income	37,206	12,269	73,759	23,739
Reportable apartment home segment NOI	22,378	6,182	44,071	12,416
Reportable apartment home segment assets:
Total segment assets	2,537,618		2,537,618		$ 2,064,583
Total Communities
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Lease revenue	355,806	299,810	701,513	591,256
Other revenue	11,942	9,306	22,416	17,686
Rental income	367,748	309,116	723,929	608,942
Reportable apartment home segment NOI	$ 254,555	$ 208,636	$ 498,488	$ 409,694
Taxable REIT Subsidiaries
Reportable Segments
Management fee (as a percent)			3.25%