CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Thousands	Preferred Stock	Common Stock	Paid-in Capital	Distributions in Excess of Net Income Adjustment	Distributions in Excess of Net Income	Accumulated Other Comprehensive Income/(Loss), net	Noncontrolling Interests	Adjustment	Total
Consolidated Statements of Changes in Equity
Cumulative effect upon adoption of ASC 326	$ 46,201	$ 2,755	$ 4,920,732		$ (2,063,996)	$ (67)	$ 17,152		$ 2,922,777
Beginning Balance at Dec. 31, 2018	46,201	2,755	4,920,732		(2,063,996)	(67)	17,152		2,922,777
Consolidated Statements of Changes in Equity
Net income/(loss) attributable to UDR, Inc.					87,326				87,326
Net income/(loss) attributable to noncontrolling interests							97		97
Contribution of noncontrolling interests in consolidated real estate							125		125
Long Term Incentive Plan Unit grants/(vestings), net							7,839		7,839
Other comprehensive income/(loss)						(8,955)			(8,955)
Issuance/(forfeiture) of common and restricted shares, net			877						877
Issuance of common shares through public offering, net		145	661,864						662,009
Cumulative effect upon adoption of ASC 326	46,201	2,755	4,920,732		(2,063,996)	(67)	17,152		2,922,777
Adjustment for conversion of noncontrolling interest of unitholders in the Operating Partnership and DownREIT Partnership		29	119,309						119,338
Common stock distributions declared					(294,180)				(294,180)
Preferred stock distributions declared-Series E					(3,073)				(3,073)
Adjustment to reflect redemption value of redeemable noncontrolling interests					(222,405)				(222,405)
Ending Balance at Sep. 30, 2019	46,201	2,929	5,702,782		(2,496,328)	(9,022)	25,213		3,271,775
Consolidated Statements of Changes in Equity
Cumulative effect upon adoption of ASC 326	46,201	2,831	5,244,819		(2,336,609)	(7,838)	18,611		2,968,015
Beginning Balance at Jun. 30, 2019	46,201	2,831	5,244,819		(2,336,609)	(7,838)	18,611		2,968,015
Consolidated Statements of Changes in Equity
Net income/(loss) attributable to UDR, Inc.					27,204				27,204
Net income/(loss) attributable to noncontrolling interests							40		40
Long Term Incentive Plan Unit grants/(vestings), net							6,562		6,562
Other comprehensive income/(loss)						(1,184)			(1,184)
Issuance/(forfeiture) of common and restricted shares, net			1,175						1,175
Issuance of common shares through public offering, net		96	449,041						449,137
Cumulative effect upon adoption of ASC 326	46,201	2,929	5,702,782		(2,496,328)	(9,022)	25,213		3,271,775
Adjustment for conversion of noncontrolling interest of unitholders in the Operating Partnership and DownREIT Partnership		2	7,747						7,749
Common stock distributions declared					(100,657)				(100,657)
Preferred stock distributions declared-Series E					(1,031)				(1,031)
Adjustment to reflect redemption value of redeemable noncontrolling interests					(85,235)				(85,235)
Ending Balance at Sep. 30, 2019	46,201	2,929	5,702,782		(2,496,328)	(9,022)	25,213		3,271,775
Consolidated Statements of Changes in Equity
Cumulative effect upon adoption of ASC 326	46,201	2,929	5,702,782		(2,496,328)	(9,022)	25,213		3,271,775
Cumulative effect upon adoption of ASC 326	46,201	2,946	5,781,975		(2,462,132)	(10,448)	30,772		3,389,314
Beginning Balance at Dec. 31, 2019	46,201	2,946	5,781,975		(2,462,132)	(10,448)	30,772		3,389,314
Consolidated Statements of Changes in Equity
Net income/(loss) attributable to UDR, Inc.					37,734				37,734
Net income/(loss) attributable to noncontrolling interests							24		24
Repurchase of common shares		(6)	(19,789)						(19,795)
Long Term Incentive Plan Unit grants/(vestings), net							(10,000)		(10,000)
Other comprehensive income/(loss)						(46)			(46)
Issuance/(forfeiture) of common and restricted shares, net		1	1,026						1,027
Cumulative effect upon adoption of ASC 326	46,201	2,946	5,776,267	$ (2,182)	(2,500,827)	(10,448)	20,796	$ (2,182)	3,389,314
Conversion of Series E Cumulative Convertible Shares	(1,436)	1	1,435
Adjustment for conversion of noncontrolling interest of unitholders in the Operating Partnership and DownREIT Partnership		3	11,620						11,623
Common stock distributions declared					(318,442)				(318,442)
Preferred stock distributions declared-Series E					(3,179)				(3,179)
Adjustment to reflect redemption value of redeemable noncontrolling interests					247,374				247,374
Ending Balance at Sep. 30, 2020	44,765	2,945	5,776,267	(2,182)	(2,500,827)	(10,494)	20,796	(2,182)	3,333,452
Consolidated Statements of Changes in Equity
Cumulative effect upon adoption of ASC 326	44,765	2,951	5,794,428		(2,432,882)	(11,940)	17,623		3,414,945
Beginning Balance at Jun. 30, 2020	44,765	2,951	5,794,428		(2,432,882)	(11,940)	17,623		3,414,945
Consolidated Statements of Changes in Equity
Net income/(loss) attributable to UDR, Inc.					(25,258)				(25,258)
Net income/(loss) attributable to noncontrolling interests							15		15
Repurchase of common shares		(6)	(19,789)						(19,795)
Long Term Incentive Plan Unit grants/(vestings), net							3,158		3,158
Other comprehensive income/(loss)						1,446			1,446
Issuance/(forfeiture) of common and restricted shares, net			1,255						1,255
Cumulative effect upon adoption of ASC 326	44,765	2,945	5,776,267	(2,182)	(2,500,827)	(10,494)	20,796	(2,182)	3,414,945
Adjustment for conversion of noncontrolling interest of unitholders in the Operating Partnership and DownREIT Partnership			373						373
Common stock distributions declared					(106,020)				(106,020)
Preferred stock distributions declared-Series E					(1,051)				(1,051)
Adjustment to reflect redemption value of redeemable noncontrolling interests					64,384				64,384
Ending Balance at Sep. 30, 2020	44,765	2,945	5,776,267	(2,182)	(2,500,827)	(10,494)	20,796	(2,182)	3,333,452
Consolidated Statements of Changes in Equity
Cumulative effect upon adoption of ASC 326	$ 44,765	$ 2,945	$ 5,776,267	$ (2,182)	$ (2,500,827)	$ (10,494)	$ 20,796	$ (2,182)	$ 3,333,452