Derivatives and Hedging Activity (UNITED DOMINION REALTY, L.P.) (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended	12 Months Ended
Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	$ 1,130	$ 1,635	$ 3,809	$ 5,180
Amount of Gain or (Loss) Recognized in Income on Derivative	0	280	0		275
Interest Rate Products [Member] \| Interest Expense [Member] \| Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in OCI on Derivative (Effective Portion)	362	(386)	611		(334)
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	(1,130)	(1,635)	(3,809)		(5,180)
United Dominion Reality L.P. [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	588	590	1,784	2,041
Amount of Gain or (Loss) Recognized in Income on Derivative	0	0	0	(5)	(5)
United Dominion Reality L.P. [Member] \| Interest Rate Products [Member] \| Interest Expense [Member] \| Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in OCI on Derivative (Effective Portion)	(3)	(201)	(194)		(284)
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	$ (588)	$ (590)	$ (1,784)		$ (2,041)

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The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4C

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624171-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4D

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624177-113959

+ Details

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- Definition

The effective portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments that was recognized in other comprehensive income during the current period.

+ References

+ Details

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- Definition

Amount of realized and unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments.

+ References

+ Details

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