UNCONSOLIDATED ENTITIES (UNITED DOMINION REALTY, L.P.) (Details) $ in Thousands	12 Months Ended
Dec. 31, 2018 USD ($) home	Dec. 31, 2019 USD ($) community
Properties
Number of real estate properties \| community		148
Investment in unconsolidated entities	$ 585,490
United Dominion Realty L.P.
Properties
Number of real estate properties \| community		52
Investment in unconsolidated entities	$ 103,026	$ 76,222
UDR Lighthouse DownREIT L.P. \| United Dominion Realty L.P.
Properties
Number of real estate properties \| community		12
Number of apartment homes	604	5,657
Proceeds from sale of real estate	$ 150,700
Gain on sale of property	51,100
Investment in unconsolidated entities	$ 103,000	$ 76,200

This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

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- Definition

The difference between the carrying value and the sale price of real estate or properties that were intended to be sold or held for capital appreciation or rental income. This element refers to the gain (loss) included in earnings and not to the cash proceeds of the sale. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (c)
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Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

The number of real estate properties owned as of the balance sheet date.

+ References

No definition available.

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- Definition

The number of units in a real estate property owned as of the balance sheet date.

+ References

No definition available.

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- Definition

Cash received for the sale of real estate that is not part of an investing activity during the current period.

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-Name Accounting Standards Codification
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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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