Consolidated Statements of Changes in Capital (UNITED DOMINION REALTY, L.P) (Unaudited) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2009
Increase (Decrease) in Partners' Capital [Roll Forward]
Other comprehensive income (loss)	$ (3,861)	$ 6,382	$ 2,725
United Dominion Reality L.P.
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance	1,803,097	1,918,756		1,853,369
Distributions	(191,150)	(173,716)	(163,008)
Noncash Or Part Noncash Distribution, Issued Value		(23,329)	(77,041)
OP Units issued for real estate	(77,041)		0
Adjustment to reflect limited partners' capital at redemption value	0
Net income (loss)	97,179	77,942	44,334
Other comprehensive income (loss)	1,990	2,304	1,533
Net change in receivable due from General Partner	22,935	54,852	182,528
Balance	1,734,051	1,803,097	1,918,756	1,853,369
United Dominion Reality L.P. \| Payable/(Receivable) due to/(from) General Partner [Member] [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance	(9,916)
Net change in receivable due from General Partner	23,540
United Dominion Reality L.P. \| Accumulated Other Comprehensive Income/(Loss)
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance	(3,065)	(5,369)		(6,902)
Other comprehensive income (loss)	1,990	2,304	1,533
Balance	(1,075)	(3,065)	(5,369)	(6,902)
United Dominion Reality L.P. \| Total Partner's Capital
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance	1,795,934	1,917,299		2,034,792
Distributions	(191,150)	(173,716)	(163,008)
Noncash Or Part Noncash Distribution, Issued Value	0	(23,329)	0
OP Units issued for real estate		(23,329)	0
Adjustment to reflect limited partners' capital at redemption value	0
Net income (loss)	96,227	73,376	43,982
Other comprehensive income (loss)	1,990	2,304	1,533
Balance	1,703,001	1,795,934	1,917,299	2,034,792
United Dominion Reality L.P. \| Receivable Due From General Partner
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance		(11,056)		(193,584)
Noncash Or Part Noncash Distribution, Issued Value			(53,712)
Net change in receivable due from General Partner		54,852	182,528
Balance	13,624		(11,056)	(193,584)
United Dominion Reality L.P. \| Noncontrolling Interest
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance	17,079	12,513		12,161
Net income (loss)	952	4,566	352
Balance	17,426	17,079	12,513	12,161
United Dominion Reality L.P. \| Class A Limited Partner
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance	40,902	41,656		43,967
Distributions	(2,328)	(2,324)	(2,328)
Adjustment to reflect limited partners' capital at redemption value	14,493	702	(596)
Net income (loss)	920	868	613
Balance	53,987	40,902	41,656	43,967
United Dominion Reality L.P. \| Limited Partners
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance	176,695	181,762		192,508
Distributions	(7,789)	(7,118)	(6,738)
OP Unit Redemptions for common shares of UDR	(4,371)	(1,817)	(529)
OP Units issued for real estate			(133)
Adjustment to reflect limited partners' capital at redemption value	60,020	852	(5,166)
Net income (loss)	3,938	3,016	1,820
Balance	228,493	176,695	181,762	192,508
United Dominion Reality L.P. \| Limited Partner [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance	1,580,239	1,698,027		1,803,926
Distributions	(180,917)	(164,170)	(153,846)
OP Unit Redemptions for common shares of UDR	4,371	1,817	529
Noncash Or Part Noncash Distribution, Issued Value		(23,329)
OP Units issued for real estate			133
Adjustment to reflect limited partners' capital at redemption value	(74,513)	(1,554)	5,762
Net income (loss)	91,311	69,448	41,523
Balance	1,420,491	1,580,239	1,698,027	1,803,926
United Dominion Reality L.P. \| General Partner
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance	1,163	1,223		1,293
Distributions	(116)	(104)	(96)
Net income (loss)	58	44	26
Balance	1,105	1,163	1,223	1,293
Receivable Due From General Partner [Member] \| United Dominion Reality L.P.
Increase (Decrease) in Partners' Capital [Roll Forward]
OP Units issued for real estate	$ (53,712)

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Total distributions to each class of partners (i.e., general, limited and preferred partners).

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