Derivatives and Hedging Activity (UNITED DOMINION REALTY, L.P.) (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Entity Information [Line Items]
Derivative, Collateral, Obligation to Return Cash	$ 0	$ 0
Cash flow hedge ineffectiveness in earnings materiality	3000	less than $1,000	less than a  $1,000
Estimated additional accumulated other comprehensive Income/(Loss) transferred to interest expense	5,000,000
Fair value of derivatives in a net liability position	10,600,000
Payment required to pay for contract termination	10,600,000
Maximum
Entity Information [Line Items]
Cash flow hedge ineffectiveness in earnings		1,000	1,000
United Dominion Reality L.P.
Entity Information [Line Items]
Derivative, Collateral, Obligation to Return Cash	0	0
Cash flow hedge ineffectiveness in earnings materiality	less than $1,000
Estimated additional accumulated other comprehensive Income/(Loss) transferred to interest expense	900,000
Fair value of derivatives in a net liability position	1,000,000
Payment required to pay for contract termination	1,000,000
Interest rate contracts | Other Income Expense [Member]
Entity Information [Line Items]
Losses in the fair value of derivatives not designated in hedging relationships	4,000	(271,000)	(290,000)
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	$ 3,000	$ 9,000	9,000