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The amount due to UDR by an equity method investment of the entity.

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Equity method investment summarized financial information balance sheets.

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Equity Method Investment Summarized Financial Information Cash and cash equivalents

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The amount of depreciation and amortization reported by an equity method investment of the entity.

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Equity Method Investment Summarized Financial Information Income/(loss) from discontinued operations

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Equity Method Investment Summarized Financial Information Interest expense

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Equity Method Investment Summarized Financial Information Other assets

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Equity Method Investment Summarized Financial Information Other income/(expense)

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Equity Method Investment Summarized Financial Information Property Operating Expense

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The amount of net real estate assets reported by an equity method investment of the entity.

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Equity Method of Investment Summarized Financial Information, Assets Sold or Held For Sale

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Equity Method of Investment Summarized Financial Information, Liabilities Sold or Held For Sale

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Equity Method of Investment Summarized Financial Information Operating income/(loss)

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Income from Participating Loan

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Participating Loan, Interest Rate, Stated Percentage

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Participating Loan Years to Maturity

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Amount of gain on the sale of property that does not qualify for gain recognition as of the balance sheet date.

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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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The amount of assets reported by an equity method investment of the entity.

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Amount of equity, including noncontrolling interest, reported by an equity method investment of the entity.

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The amount of liabilities reported by an equity method investment of the entity.

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The amount of liabilities and equity reported by an equity method investment of the entity.

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The amount of net income (loss) reported by an equity method investment of the entity.

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The amount of noncurrent liabilities reported by an equity method investment of the entity.

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The amount of revenue from sale of goods and services reduced by sales returns, allowances, and discounts reported by an equity method investment of the entity.

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No definition available.

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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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This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. This item includes income or expense related to stock-based compensation based on the investor's grant of stock to employees of an equity method investee.

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

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

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Joint Ventures (Details)	3 Months Ended		6 Months Ended
Joint Ventures (Details)	Jun. 30, 2015 USD ($) Communities	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($) Communities	Jun. 30, 2014 USD ($)	Jun. 30, 2013 USD ($)	Dec. 31, 2014 USD ($)
Financial information relating to unconsolidated joint ventures operations
UDR income/(loss) from unconsolidated entities	$ (573,000)	$ (428,000)	$ 58,586,000	$ (3,993,000)
Combined summary of balance sheets relating to unconsolidated joint ventures
Investment in and advances to unconsolidated joint ventures, net	914,815,000		914,815,000			$ 718,226,000
Deferred gains on the sale of depreciable property	$ 6,800,000		$ 6,800,000			28,500,000
Number of Real Estate Properties \| Communities	136		136
Unconsolidated Joint Ventures [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment Summarized Financial Information Income/(loss) from discontinued operations	$ 0	(4,705,000)	$ 182,488,000	(31,688,000)
Financial information relating to unconsolidated joint ventures operations
Total revenues	55,450,000	48,379,000	109,996,000		$ 87,334,000
Equity Method Investment Summarized Financial Information Property Operating Expense	(21,557,000)	(18,001,000)	(41,724,000)	(32,360,000)
Real estate depreciation and amortization	(19,402,000)	(16,808,000)	(38,754,000)		(31,496,000)
Net income /(loss)	(1,685,000)	(6,063,000)	179,769,000		$ (35,289,000)
Combined summary of balance sheets relating to unconsolidated joint ventures
Total real estate, net	3,004,723,000		3,004,723,000			2,941,803,000
Equity Method of Investment Summarized Financial Information, Assets Sold or Held For Sale	0		0			216,196,000
Equity Method Investment Summarized Financial Information Cash and cash equivalents	36,820,000		36,820,000			32,544,000
Equity Method Investment Summarized Financial Information Other assets	32,869,000		32,869,000			28,707,000
Total assets	3,074,412,000		3,074,412,000			3,219,250,000
Amount due to UDR	6,434,000		6,434,000			2,997,000
Third party debt	1,529,724,000		1,529,724,000			1,504,477,000
Equity Method of Investment Summarized Financial Information, Liabilities Sold or Held For Sale	0		0			229,706,000
Equity Method Investment Summarized Financial Information Accounts payable and accrued liabilities	63,521,000		63,521,000			44,335,000
Total liabilities	1,599,679,000		1,599,679,000			1,781,515,000
Total equity	1,474,733,000		1,474,733,000			1,437,735,000
Equity Method Investment, Summarized Financial Information, Liabilities and Equity	3,074,412,000		3,074,412,000			3,219,250,000
Investment in and advances to unconsolidated joint ventures, net	695,980,000		695,980,000			655,519,000
Equity Method of Investment Summarized Financial Information Operating income/(loss)	14,491,000	13,570,000	29,518,000	23,478,000
Equity Method Investment Summarized Financial Information Interest expense	(16,169,000)	(14,928,000)	(32,230,000)	(27,079,000)
Equity Method Investment Summarized Financial Information Other income/(expense)	(7,000)	0	(7,000)	0
Unconsolidated Joint Venture Four Texas [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Deferred gains on the sale of depreciable property	24,200,000		24,200,000
Operating Community [Member] \| Unconsolidated Joint Venture UDR Met Life I Partnership [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Investment in and advances to unconsolidated joint ventures, net	$ 14,181,000		$ 14,181,000			$ 13,306,000
Equity Method Investment, Ownership Percentage	16.10%		16.10%			15.70%
Number of apartment homes	0		0
Number of Real Estate Properties	4		4
Operating Community [Member] \| Unconsolidated Joint Venture UDR MetLife II Partnership [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Investment in and advances to unconsolidated joint ventures, net	$ 428,321,000		$ 428,321,000			$ 431,277,000
Equity Method Investment, Ownership Percentage	50.00%		50.00%			50.00%
Number of apartment homes	4,642		4,642
Number of Real Estate Properties	21		21
Operating Community [Member] \| Unconsolidated Joint Venture Vitruvian Park [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Investment in and advances to unconsolidated joint ventures, net	$ 75,531,000		$ 75,531,000			$ 80,302,000
Equity Method Investment, Ownership Percentage	50.00%		50.00%			50.00%
Number of apartment homes	1,130		1,130
Number of Real Estate Properties	3		3
Operating Community [Member] \| Unconsolidated Joint Venture Three [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Investment in and advances to unconsolidated joint ventures, net	$ 19,775,000		$ 19,775,000			$ 21,596,000
Equity Method Investment, Ownership Percentage	30.00%		30.00%			30.00%
Number of apartment homes	660		660
Number of Real Estate Properties	3		3
Operating Community [Member] \| Unconsolidated Joint Venture Four Texas [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Equity Method Investment, Ownership Percentage	0.00%		0.00%			20.00%
Number of Real Estate Properties \| Communities	8		8
Operating Community [Member] \| Unconsolidated Joint Venture Other MetLife [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Investment in and advances to unconsolidated joint ventures, net	$ 158,172,000		$ 158,172,000			$ 134,939,000
Equity Method Investment, Ownership Percentage	50.60%		50.60%			50.60%
Number of apartment homes	1,437		1,437
Number of Real Estate Properties	1		1
Land Parcel [Member] \| Unconsolidated Joint Venture Vitruvian Park [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Number of Real Estate Properties	6		6
Development Community [Member] \| Unconsolidated Joint Venture Four Texas [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Investment in and advances to unconsolidated joint ventures, net	$ 0		$ 0			$ (25,901,000)
Number of apartment homes	0		0
Number of Real Estate Properties	0		0
Development Community [Member] \| Unconsolidated Joint Venture Other MetLife [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Number of Real Estate Properties	4		4
Development Community [Member] \| Participating Loan Investment Steele Creek Denver Colorado [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Investment in and advances to unconsolidated joint ventures, net	$ 85,208,000		$ 85,208,000			62,707,000
Income from Participating Loan	$ 1,352,000	456,000	$ 2,506,000	777,000
Participating Loan, Interest Rate, Stated Percentage	6.50%		6.50%
Participating Loan Years to Maturity			2 years 1 month 6 days
Development Community [Member] \| Preferred Equity Investment West Coast Development JV [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Investment in and advances to unconsolidated joint ventures, net	$ 133,627,000		$ 133,627,000			$ 0
Income from Participating Loan	$ (548)	$ 0	$ (548)	$ 0
Participating Loan, Interest Rate, Stated Percentage	6.50%		6.50%
Land [Member] \| Unconsolidated Joint Venture Other MetLife [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Number of Real Estate Properties	1		1