Derivatives and Hedging Activity (UNITED DOMINION REALTY, L.P.) (Details 2) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net, Total	$ 1,608,000	$ 1,897,000	$ 3,545,000	$ 3,752,000
Derivative Instruments, Gain (Loss) Recognized in Income, Net, Total	(3,000)	(7,000)	(5,000)	291,000
Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income, Effective Portion, Net, Total	144,000	(1,533,000)	52,000	(3,492,000)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net, Total	(1,608,000)	(1,897,000)	(3,545,000)	(3,752,000)
Derivative Instruments, Gain (Loss) Recognized in Income, Net, Total	(3,000)	(7,000)	(5,000)	291,000
Interest Rate Products [Member] | Interest Expense [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income, Effective Portion, Net, Total	144,000	(1,533,000)	52,000	(3,492,000)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net, Total	(1,608,000)	(1,897,000)	(3,545,000)	(3,752,000)
United Dominion Reality L.P. [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net, Total	569,000	850,000	1,451,000	1,682,000
Derivative Instruments, Gain (Loss) Recognized in Income, Net, Total	(3,000)	(5,000)	(5,000)	(7,000)
United Dominion Reality L.P. [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income, Effective Portion, Net, Total	(29,000)	(701,000)	(83,000)	(1,370,000)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net, Total	(569,000)	(850,000)	(1,451,000)	(1,682,000)
Derivative Instruments, Gain (Loss) Recognized in Income, Net, Total	(3,000)	(5,000)	(5,000)	(7,000)
United Dominion Reality L.P. [Member] | Interest Rate Products [Member] | Interest Expense [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income, Effective Portion, Net, Total	(29,000)	(701,000)	(83,000)	(1,370,000)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net, Total	$ (569,000)	$ (850,000)	$ (1,451,000)	$ (1,682,000)