Consolidated Statements of Changes in Capital (UNITED DOMINION REALTY, L.P) (Unaudited) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Increase (Decrease) in Partners' Capital [Roll Forward]
Other comprehensive income (loss)	$ (4,131)	$ (3,861)	$ 6,382
United Dominion Reality L.P.
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance	1,734,051	1,803,097	1,918,756
Net income (loss)	215,063	97,179	77,942
Distributions	(203,852)	(191,150)	(173,716)
OP Unit Redemptions for common shares of UDR	0
Distribution of community to UDR			(77,041)
Adjustment to reflect limited partners' capital at redemption value	0
Unrealized gain on derivative financial investments	962
Other comprehensive income (loss)	962	1,990	2,304
Net change in receivable due from General Partner	(24,894)	22,935	54,852
Balance	1,721,330	1,734,051	1,803,097
United Dominion Reality L.P. \| Payable/(Receivable) due to/(from) General Partner [Member] [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance	13,624	(9,916)	(11,056)
Distribution of community to UDR			(53,712)
Net change in receivable due from General Partner	(24,894)	23,540	54,852
Balance	(11,270)	13,624	(9,916)
United Dominion Reality L.P. \| Accumulated Other Comprehensive Income/(Loss)
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance	(1,075)	(3,065)	(5,369)
Unrealized gain on derivative financial investments	962
Other comprehensive income (loss)		1,990	2,304
Balance	(113)	(1,075)	(3,065)
United Dominion Reality L.P. \| Total Partner's Capital
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance	1,703,001	1,795,934	1,917,299
Net income (loss)	213,301	96,227	73,376
Distributions	(203,852)	(191,150)	(173,716)
OP Unit Redemptions for common shares of UDR	0
Distribution of community to UDR	0	0	(23,329)
Adjustment to reflect limited partners' capital at redemption value	0
Unrealized gain on derivative financial investments	962
Other comprehensive income (loss)		1,990	2,304
Balance	1,713,412	1,703,001	1,795,934
United Dominion Reality L.P. \| Noncontrolling Interest
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance	17,426	17,079	12,513
Net income (loss)	1,762	952	4,566
Adjustment to reflect limited partners' capital at redemption value	0
Balance	19,188	17,426	17,079
United Dominion Reality L.P. \| Class A Limited Partner
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance	53,987	40,902	41,656
Net income (loss)	2,201	920	868
Distributions	(2,328)	(2,328)	(2,324)
OP Unit Redemptions for common shares of UDR	0
Adjustment to reflect limited partners' capital at redemption value	10,549	14,493	702
Balance	64,409	53,987	40,902
United Dominion Reality L.P. \| Limited Partners
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance	228,493	176,695	181,762
Net income (loss)	8,515	3,938	3,016
Distributions	(8,138)	(7,789)	(7,118)
OP Unit Redemptions for common shares of UDR	(3,816)	(4,371)	(1,817)
Adjustment to reflect limited partners' capital at redemption value	43,427	60,020	852
Balance	268,481	228,493	176,695
United Dominion Reality L.P. \| Limited Partner [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance	1,420,491	1,580,239	1,698,027
Net income (loss)	202,456	91,311	69,448
Distributions	(193,262)	(180,917)	(164,170)
OP Unit Redemptions for common shares of UDR	3,816	4,371	1,817
Distribution of community to UDR			(23,329)
Adjustment to reflect limited partners' capital at redemption value	(53,976)	(74,513)	(1,554)
Balance	1,379,525	1,420,491	1,580,239
United Dominion Reality L.P. \| General Partner [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance	1,105	1,163	1,223
Net income (loss)	129	58	44
Distributions	(124)	(116)	(104)
Adjustment to reflect limited partners' capital at redemption value	0
Balance	$ 1,110	$ 1,105	$ 1,163

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