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

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Number of interest rate derivative instruments held by the entity at the reporting date.

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DERIVATIVES AND HEDGING ACTIVITY (UNITED DOMINION REALTY, L.P.) (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($) instrument	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) instrument	Jun. 30, 2019 USD ($)	Dec. 31, 2019 instrument
Derivatives
Estimated additional accumulated other comprehensive Income/(Loss) transferred to interest expense	$ 3,900		$ 3,900
Not Designated as Hedging Instrument
Outstanding interest rate derivatives not designated as hedging instrument
Notional	0		0
United Dominion Realty L.P. \| Maximum
Derivatives
Estimated additional accumulated other comprehensive Income/(Loss) transferred to interest expense	$ 100		$ 100
United Dominion Realty L.P. \| Cash Flow Hedging
Outstanding interest rate derivatives not designated as hedging instrument
Number instruments \| instrument	1		1		0
United Dominion Realty L.P. \| Not Designated as Hedging Instrument
Outstanding interest rate derivatives not designated as hedging instrument
Number instruments \| instrument	0		0
United Dominion Realty L.P. \| Interest rate contracts
Derivatives
Gain/(Loss) recognized in Interest Income and Other Income/(Expense), net	$ 0	$ 0	$ 0	$ 0
United Dominion Realty L.P. \| Interest rate caps \| Cash Flow Hedging
Outstanding interest rate derivatives not designated as hedging instrument
Number instruments \| instrument	1		1
Notional	$ 19,880		$ 19,880
Other income/(expense) \| Interest rate contracts
Derivatives
Gain/(Loss) recognized in Interest Income and Other Income/(Expense), net	$ 0	$ 0	$ 0	$ 0