REPORTABLE SEGMENTS (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($) segment home	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Segments
Same store communities | home	51,802
Reportable Segments
Management fee (as a percent)	3.25%
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	$ 411,669	$ 398,307
Reconciling items:
Joint venture management and other fees	$ 1,965	$ 1,242
Type of revenue	udr:ManagementAndOtherFeesMember	udr:ManagementAndOtherFeesMember
Property management	$ (13,379)	$ (12,945)
Other operating expenses	(6,828)	(3,032)
Real estate depreciation and amortization	(169,858)	(169,300)
General and administrative	(17,810)	(17,480)
Casualty-related (charges)/recoveries, net	(6,278)	(4,156)
Other depreciation and amortization	(4,316)	(3,649)
Gain/(loss) on sale of real estate owned	16,867	1
Income/(loss) from unconsolidated entities	9,085	9,707
Interest expense	(48,062)	(43,742)
Interest income and other income/(expense), net	5,865	1,010
Tax (provision)/benefit, net	(337)	(234)
Net (income)/loss attributable to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership	(3,149)	(1,953)
Net (income)/loss attributable to noncontrolling interests	(12)	(8)
Net income/(loss) attributable to UDR, Inc.	43,149	30,964
Reportable apartment home segment assets:
Total segment assets	15,991,196		$ 16,023,859
Accumulated depreciation	(6,407,111)		(6,267,830)
Total real estate owned, net of accumulated depreciation	9,584,085		9,756,029
Reconciling items:
Cash and cash equivalents	2,116	1,172	2,922	$ 1,193
Restricted cash	29,850	28,038	31,944	$ 29,001
Notes receivable, net	235,382		228,825
Investment in and advances to unconsolidated joint ventures, net	954,301		952,934
Operating lease right-of-use assets	189,729		190,619
Other assets	195,025		209,969
Total consolidated assets	11,190,488		11,373,242
Total Communities
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Lease revenue	399,179	387,017
Other revenue	12,490	11,290
Rental income	411,669	398,307
Reportable apartment home segment NOI	279,396	275,503
Same Communities | 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	117,899	114,289
Other revenue	2,974	2,783
Rental income	120,873	117,072
Reportable apartment home segment NOI	89,413	88,369
Reportable apartment home segment assets:
Total segment assets	4,376,985		4,366,038
Same Communities | 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	76,811	74,122
Other revenue	3,124	2,472
Rental income	79,935	76,594
Reportable apartment home segment NOI	54,705	53,441
Reportable apartment home segment assets:
Total segment assets	3,214,861		3,205,036
Same Communities | 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	80,330	77,342
Other revenue	1,735	1,742
Rental income	82,065	79,084
Reportable apartment home segment NOI	52,634	52,398
Reportable apartment home segment assets:
Total segment assets	3,899,854		3,890,762
Same Communities | 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	56,784	55,799
Other revenue	2,414	2,133
Rental income	59,198	57,932
Reportable apartment home segment NOI	40,275	39,785
Reportable apartment home segment assets:
Total segment assets	1,599,068		1,589,605
Same Communities | 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	37,615	37,678
Other revenue	1,566	1,379
Rental income	39,181	39,057
Reportable apartment home segment NOI	24,791	24,600
Reportable apartment home segment assets:
Total segment assets	1,334,198		1,330,063
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	29,740	27,787
Other revenue	677	781
Rental income	30,417	28,568
Reportable apartment home segment NOI	17,578	$ 16,910
Reportable apartment home segment assets:
Total segment assets	$ 1,566,230		$ 1,642,355