Consolidated Statements of Changes in Capital (UNITED DOMINION REALTY, L.P) (Unaudited) (United Dominion Reality L.P. [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015
Balance, December 31, 2014	$ 1,734,051
Advances (to)/from General Partner	(22,418)us-gaap_DueFromRelatedParties
Net income/(loss)	36,740
Distributions	50,962
OP Unit Redemptions for common shares of UDR	0
Adjustment to reflect limited partners' capital at redemption value	0
Unrealized Gain (Loss) on Derivatives	235us-gaap_UnrealizedGainLossOnDerivatives
Net change in amount due to/(from) General Partner	8,794
Balance, March 31, 2015	1,728,858
Payable/(Receivable) due to/(from) General Partner [Member] [Member]
Net change in amount due to/(from) General Partner	8,794
Accumulated Other Comprehensive Income (Loss) [Member]
Balance, December 31, 2014	(1,075)
Unrealized Gain (Loss) on Derivatives	235
Balance, March 31, 2015	(840)
Total Partner's Capital [Member]
Balance, December 31, 2014	1,703,001
Net income/(loss)	36,346
Distributions	50,962
Adjustment to reflect limited partners' capital at redemption value	0
Balance, March 31, 2015	1,688,620
Noncontrolling Interest [Member]
Balance, December 31, 2014	17,426
Net income/(loss)	394
Balance, March 31, 2015	17,820
Partnership Capital [Member]
OP Unit Redemptions for common shares of UDR	0
Unrealized Gain (Loss) on Derivatives	235
Class A Limited Partner [Member]
Balance, December 31, 2014	53,987
Net income/(loss)	415
Distributions	(582)
Adjustment to reflect limited partners' capital at redemption value	5,789
Balance, March 31, 2015	59,609
Limited Partners [Member]
Balance, December 31, 2014	228,493
Net income/(loss)	1,467
Distributions	(2,057)
OP Unit Redemptions for common shares of UDR	(16)
Adjustment to reflect limited partners' capital at redemption value	24,387
Balance, March 31, 2015	252,274
Limited Partner [Member]
Balance, December 31, 2014	1,420,491
Net income/(loss)	34,442
Distributions	(48,292)
OP Unit Redemptions for common shares of UDR	16
Adjustment to reflect limited partners' capital at redemption value	(30,176)
Balance, March 31, 2015	1,376,481
General Partner [Member]
Balance, December 31, 2014	1,105
Net income/(loss)	22
Distributions	(31)
Balance, March 31, 2015	$ 1,096

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