Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

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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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The estimated net amount of unrealized gains or losses on interest rate cash flow hedges as of the balance sheet date expected to be reclassified to earnings within the next twelve months.

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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
	Mar. 31, 2020 USD ($) instrument	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($)
Derivatives
Estimated additional accumulated other comprehensive Income/(Loss) transferred to interest expense	$ 4,600
Interest rate caps \| Not Designated as Hedging Instrument
Outstanding interest rate derivatives not designated as hedging instrument
Number instruments \| instrument	1
Notional	$ 19,880
United Dominion Realty L.P.
Derivatives
Derivatives	0		$ 0
United Dominion Realty L.P. \| Interest rate contracts
Derivatives
Gain/(Loss) recognized in Interest Income and Other Income/(Expense), net	$ 0	$ 0
United Dominion Realty L.P. \| Interest rate caps \| Not Designated as Hedging Instrument
Outstanding interest rate derivatives not designated as hedging instrument
Number instruments \| instrument	1
Notional	$ 19,880
Other income/(expense) \| Interest rate contracts
Derivatives
Gain/(Loss) recognized in Interest Income and Other Income/(Expense), net	0	0
Other income/(expense) \| United Dominion Realty L.P. \| Interest rate contracts
Derivatives
Gain/(Loss) recognized in Interest Income and Other Income/(Expense), net	$ 0	$ 0