Casualty (Recoveries)/Charges

No definition available.

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Namespace Prefix:	udr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	udr_HurricaneRelatedChargesLineItems
Namespace Prefix:	udr_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of Apartments Owned

+ References

No definition available.

+ Details

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Namespace Prefix:	udr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of Communities Owned

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Total Estimated Insurance Recovery

+ References

No definition available.

+ Details

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Namespace Prefix:	udr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The aggregate amount of write-downs for impairments recognized during the period for long lived assets held for use (including those held for disposal by means other than sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 45

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=8077374&loc=d3e2420-110228

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6391110&loc=d3e2921-110230

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 958

-SubTopic 225

-Section 45

-Paragraph 11

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=28367520&loc=d3e92212-112881

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Impairment

-URI http://asc.fasb.org/extlink&oid=6515133

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount recovered from insurance. These recoveries reduce costs and losses that are reported as a separate line item under operating expenses.

+ References

+ Details

Name:	us-gaap_InsuranceRecoveries
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The total amount of other operating cost and expense items that are associated with the entity's normal revenue producing operation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.3)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 3

-Article 5

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of other expense that is infrequent in occurrence or unusual in nature.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 20

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6365513&loc=d3e15122-107781

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash inflow from the amounts received by the insured under the terms of an insurance contract settlement. This element pertains only to insurance proceeds related to operating activities. It excludes insurance settlements classified as investing cash flows, for example, insurance settlements related to fixed assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 16

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3337-108585

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

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- Details

Name:	udr_InsuranceClaimsAxis=udr_HurricaneSandyMember
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- Details

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- Details

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- Details

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Hurricane Related Charges (Details) (USD $)	12 Months Ended			4 Months Ended
Hurricane Related Charges (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Apr. 30, 2013
Hurricane Related Charges [Line Items]
Casualty-related (recoveries)/charges, net	$ (541,000)udr_CasualtyRecoveriesCharges	$ 12,253,000udr_CasualtyRecoveriesCharges	$ (8,495,000)udr_CasualtyRecoveriesCharges
Other Cost and Expense, Operating	8,271,000us-gaap_OtherCostAndExpenseOperating	7,136,000us-gaap_OtherCostAndExpenseOperating	5,718,000us-gaap_OtherCostAndExpenseOperating
Proceeds from Insurance Settlement, Investing Activities		2,600,000	4,200,000
Casualty-related (recoveries)/charges, net	(541,000)us-gaap_InsuranceRecoveries	12,253,000us-gaap_InsuranceRecoveries	(8,495,000)us-gaap_InsuranceRecoveries
New York Properties [Member]
Hurricane Related Charges [Line Items]
Number of Communities Owned			3
Number of Apartments Owned			1,706
Impairment of Long-Lived Assets Held-for-use		0	9,000,000
Other Cost and Expense, Operating			10,400,000
Hurricane Sandy [Member]
Hurricane Related Charges [Line Items]
Total Estimated Insurance Recovery			14,500,000
Casualty-related (recoveries)/charges, net		4,800,000
Other Nonrecurring Expense		3,400,000	4,400,000
Hurricane Sandy [Member] \| Casualty Gain [Member]
Hurricane Related Charges [Line Items]
Casualty-related (recoveries)/charges, net		654,000
Hurricane Sandy [Member] \| Rent concessions
Hurricane Related Charges [Line Items]
Other Nonrecurring Expense			3,600,000
Hurricane Sandy [Member] \| Rent not contractually receivable
Hurricane Related Charges [Line Items]
Other Nonrecurring Expense			767,000
United Dominion Reality L.P.
Hurricane Related Charges [Line Items]
Other Cost and Expense, Operating	5,172,000	5,728,000	5,272,000
Casualty-related (recoveries)/charges, net	(541,000)	8,083,000	(5,518,000)
United Dominion Reality L.P. \| New York Properties [Member]
Hurricane Related Charges [Line Items]
Number of Communities Owned			2
Number of Apartments Owned			1,001
United Dominion Reality L.P. \| Hurricane Sandy [Member]
Hurricane Related Charges [Line Items]
Impairment of Long-Lived Assets Held-for-use		0	7,100,000
Other Cost and Expense, Operating			7,000,000
Total Estimated Insurance Recovery		10,800,000	10,800,000
Casualty-related (recoveries)/charges, net		3,300,000
Other Nonrecurring Expense		2,100,000	2,200,000
United Dominion Reality L.P. \| Hurricane Sandy [Member] \| Casualty Gain [Member]
Hurricane Related Charges [Line Items]
Casualty-related (recoveries)/charges, net		582,000
United Dominion Reality L.P. \| Hurricane Sandy [Member] \| Rent concessions
Hurricane Related Charges [Line Items]
Other Nonrecurring Expense			1,800,000
United Dominion Reality L.P. \| Hurricane Sandy [Member] \| Rent not contractually receivable
Hurricane Related Charges [Line Items]
Other Nonrecurring Expense			400,000
Business Interruption [Member] \| Hurricane Sandy [Member]
Hurricane Related Charges [Line Items]
Proceeds from Insurance Settlement, Investing Activities		6,800,000
Business Interruption [Member] \| United Dominion Reality L.P. \| Hurricane Sandy [Member]
Hurricane Related Charges [Line Items]
Proceeds from Insurance Settlement, Investing Activities		4,200,000
FY 2012 [Member] \| Business Interruption [Member] \| Hurricane Sandy [Member]
Hurricane Related Charges [Line Items]
Proceeds from Insurance Settlement, Investing Activities		4,200,000
FY 2012 [Member] \| Business Interruption [Member] \| United Dominion Reality L.P. \| Hurricane Sandy [Member]
Hurricane Related Charges [Line Items]
Proceeds from Insurance Settlement, Investing Activities		2,100,000
FY 2013 [Member] \| Business Interruption [Member] \| Hurricane Sandy [Member]
Hurricane Related Charges [Line Items]
Proceeds from Insurance Settlement, Investing Activities		2,600,000
FY 2013 [Member] \| Business Interruption [Member] \| United Dominion Reality L.P. \| Hurricane Sandy [Member]
Hurricane Related Charges [Line Items]
Proceeds from Insurance Settlement, Investing Activities				$ 2,100,000