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Derivatives and Hedging Activity (UNITED DOMINION REALTY, L.P.) (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Entity Information [Line Items]
Derivative, Collateral, Obligation to Return Cash	$ 0	$ 0
Losses in the fair value of derivatives not designated in hedging relationships	23,000	4,000	$ (271,000)
Payment required to pay for contract termination	2,200,000
United Dominion Reality L.P.
Entity Information [Line Items]
Derivative, Collateral, Obligation to Return Cash	0	0
Fair value of derivatives in a net liability position	0.0
Interest rate contracts | Other Income Expense [Member] | United Dominion Reality L.P.
Entity Information [Line Items]
Losses in the fair value of derivatives not designated in hedging relationships	23,000	3,000	9,000
Cash Flow Hedging | Interest rate contracts | Interest expense
Entity Information [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net, Total	(11,000)	3,000	0
Cash Flow Hedging | Interest rate contracts | Interest expense | United Dominion Reality L.P.
Entity Information [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net, Total	$ (11,000)	$ 0	$ 0

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The aggregate fair value of assets needed to immediately settle the derivative instruments with credit-risk-related contingent features if the credit-risk-related contingent features were triggered at the end of the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4H
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624258-113959

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Amount of obligation to return cash collateral under master netting arrangements that have not been offset against derivative assets.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=35706170&loc=d3e41678-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (d)(2)
-URI http://asc.fasb.org/extlink&oid=34720828&loc=SL20225862-175312

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-Publisher FASB
-Name Accounting Standards Codification
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The portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments representing (a) the amount of the hedge ineffectiveness and (b) the amount, if any, excluded from the assessment of hedge effectiveness.

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

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-Publisher FASB
-Name Accounting Standards Codification
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Amount of realized and unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (e)
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The aggregate fair value amounts of derivative instruments that contain credit-risk-related contingent features that are in a net liability position at the end of the reporting period. For nonderivative instruments that are designated and qualify as hedging instruments, the fair value amounts are the carrying value of the nonderivative hedging instrument, including the adjustment for the foreign currency transaction gain (loss) on that instrument.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4H
-Subparagraph (c)
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