XML 117 R92.htm IDEA: XBRL DOCUMENT
v3.3.1.900

Secured Debt and Unsecured Debt (Details Textual) |  |  | 1 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | --- | --- | ---
Jun. 27, 2014 | Sep. 26, 2013 | Oct. 20, 2015 | Sep. 30, 2015 USD ($) | Dec. 31, 2015 USD ($) | Dec. 31, 2014 USD ($) | Dec. 31, 2013 USD ($)
Debt Instrument [Line Items] |  |  |  |  |  |  |
Amortization of Financing Costs |  |  |  |  | $ 7,000,000 | $ 7,200,000 |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Secured debt amount which encumbers real estate owned based upon book value |  |  |  |  | $ 2,400,000,000 |  |
Percentage of secured debt which encumbers real estate owned based upon book value |  |  |  |  | 25.90% |  |
Secured debt amount of real estate owned which is unencumbered |  |  |  |  | $ 6,800,000,000 |  |
Percentage of secured debt of real estate owned which is unencumbered |  |  |  |  | 74.10% |  |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt |  |  |  |  | $ 96,486,000 |  |
Unamortized fair market adjustment |  |  |  |  | $ 10,000,000 | 6,700,000 |
Weighted Average Interest Rate |  |  |  |  | 3.74% |  |
Long-term Line of Credit |  |  |  |  | $ 2,300,000 | 1,900,000 |
Number of extension options on loan |  |  | 2 |  |  |  |
Extension period of option on loan |  |  | 6 months |  |  |  |
Fixed Rate Debt |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Secured Debt Including Debt on Real Estate Held for Sale |  |  |  |  | $ 952,801,000 | 963,713,000 |
Weighted Average Interest Rate |  |  |  |  | 4.93% |  |
Variable Rate Debt |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Secured Debt Including Debt on Real Estate Held for Sale |  |  |  |  | $ 424,144,000 | 390,608,000 |
Weighted Average Interest Rate |  |  |  |  | 1.53% |  |
Five Point Two Five Percent, Medium Term Notes, Due January 2015 [Member] |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Unamortized fair market adjustment |  |  |  |  | $ 0 | 6,000 |
Weighted Average Interest Rate |  |  |  |  | 0.00% |  |
Senior Notes |  |  |  |  | $ 0 | 325,169,000 |
3.75 MTN Due July 2024 [Member] |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Unamortized fair market adjustment |  |  |  |  | $ 938,000 | 990,000 |
Weighted Average Interest Rate |  |  |  |  | 3.75% |  |
Debt Instrument, Maturity Date | Jul. 31, 2024 |  |  |  |  |  |
Senior Notes |  |  |  |  | $ 299,114,000 | 299,010,000 |
Mortgages [Member] | Fixed Rate Debt |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Debt instrument, maturity date range, start |  |  |  |  | Jun. 01, 2016 |  |
Debt instrument, maturity date range, end |  |  |  |  | Nov. 01, 2025 |  |
Notes payable minimum interest rates range |  |  |  |  | 3.43% |  |
Notes payable maximum interest rates range |  |  |  |  | 6.16% |  |
Weighted Average Interest Rate |  |  |  |  | 4.57% |  |
Mortgages [Member] | Variable Rate Debt |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Weighted Average Interest Rate |  |  |  |  | 2.19% |  |
Debt Assumed As Part of Acquisition [Member] |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Amortization of Debt Discount (Premium) |  |  |  |  | $ 5,300,000 | 5,100,000 | $ 5,100,000
Fannie Mae credit facilities | Fixed Rate Debt |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Debt instrument, maturity date range, start |  |  |  |  | May 01, 2017 |  |
Debt instrument, maturity date range, end |  |  |  |  | Jul. 01, 2023 |  |
Debt, Weighted Average Interest Rate |  |  |  |  | 5.23% |  |
Fannie Mae credit facilities | Variable Rate Debt |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Interest rate at the end of the period |  |  |  |  | 1.71% |  |
Tax-exempt secured notes payable | Variable Rate Debt |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Debt instrument, maturity date range, start |  |  |  |  | Aug. 01, 2019 |  |
Debt instrument, maturity date range, end |  |  |  |  | Mar. 20, 2032 |  |
Notes payable minimum interest rates range |  |  |  |  | 0.75% |  |
Notes payable maximum interest rates range |  |  |  |  | 0.76% |  |
Unsecured Revolving Credit Facility due October 2015 |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Weighted Average Interest Rate |  |  |  |  | 1.19% |  |
Long-term Line of Credit |  |  |  |  | $ 150,000,000 | 152,500,000 |
4.63% Medium-Term Notes due January 2022 |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Unamortized fair market adjustment |  |  |  |  | $ 2,164,000 | 2,523,000 |
Weighted Average Interest Rate |  |  |  |  | 4.63% |  |
Senior Notes |  |  |  |  | $ 397,836,000 | 397,477,000 |
ThreePointSevenTermNotesDueOctober2020 [Member] |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Debt Instrument, Maturity Date |  | Oct. 01, 2020 |  |  |  |  |
Senior Notes |  |  |  |  | 299,962,000 | 299,954,000 |
Fannie Mae |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Long-term Line of Credit |  |  |  |  | $ 813,840,000 | $ 834,282,000 |
Interest rate at the end of the period |  |  |  |  | 3.93% | 4.00% |
Unsecured Debt [Member] |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Weighted Average Interest Rate |  |  |  |  | 3.64% |  |
Line of Credit Facility, Interest Rate Description |  |  |  |  | 95 |  |
Line of Credit Facility, Description Range Low |  |  |  |  | 90 |  |
Line of Credit Facility, Description Range High |  |  |  |  | 175 |  |
Unsecured Working Capital Credit Facility due January 2019 [Member] |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Weighted Average Interest Rate |  |  |  |  | 0.00% |  |
Long-term Line of Credit |  |  |  |  | $ 0 | $ 0 |
Line of Credit Facility, Interest Rate Description |  |  |  |  | 90 |  |
Line of Credit Facility, Description Range Low |  |  |  |  | 85 |  |
Line of Credit Facility, Description Range High |  |  |  |  | 155 |  |
Revolving Credit Facility [Member] |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Line of Credit Facility, Interest Rate Description |  |  |  |  | 90 |  |
Line of Credit Facility, Commitment Fee Description |  |  |  |  | 15 |  |
Line of Credit Facility, Description Range Low |  |  |  |  | 85 |  |
Line of Credit Facility, Description Range High |  |  |  |  | 155 |  |
Line of Credit Facility, Commitment Fee Description Range Low |  |  |  |  | 12.5 |  |
Line of Credit Facility, Commitment Fee Description Range High |  |  |  |  | 30 |  |
4.00% MTN Due October 2025 [Member] |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Unamortized fair market adjustment |  |  |  |  | $ 671,000 | 0 |
Portion of Medium Term Note subject to Interest Rate Swaps |  |  |  |  | 200,000,000 |  |
Medium-term Notes |  |  |  |  | $ 300,000,000 |  |
Weighted Average Interest Rate |  |  |  |  | 4.00% |  |
Fixed interest rate |  |  |  |  | 4.00% |  |
Debt Instrument, Maturity Date |  |  |  | Oct. 01, 2025 |  |  |
Percentage of Debt Instrument Price |  |  |  |  | 99.77% |  |
Long-term Debt, Weighted Average Interest Rate |  |  |  |  | 4.55% |  |
Senior Notes |  |  |  |  | $ 299,329,000 | 0 |
Five Point Two Five Percent, Medium Term Notes, Due January 2016 [Member] |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Weighted Average Interest Rate |  |  |  |  | 5.25% |  |
Senior Notes |  |  |  |  | $ 83,260,000 | 83,260,000 |
6.21 Medium Term Note, Due January 2016 [Member] |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Weighted Average Interest Rate |  |  |  |  | 6.21% |  |
Senior Notes |  |  |  |  | $ 12,091,000 | 0 |
UDR Bank Credit Facility |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Credit facilities with aggregate commitment |  |  |  |  | $ 2,000,000,000 | $ 900,000,000 |
Interest rate at the end of the period |  |  |  |  | 1.20% | 1.10% |
UDR Bank Credit Facility | Unsecured Debt [Member] |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Credit facilities with aggregate commitment |  |  |  |  | $ 350,000,000 |  |
UDR Bank Credit Facility | Revolving Credit Facility [Member] |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Credit facilities with aggregate commitment |  |  |  |  | 1,100,000,000 |  |
Unsecured Working Capital Credit Facility due January 2019 [Member] |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Credit facilities with aggregate commitment |  |  |  |  | $ 30,000,000 |  |
Beginning of range of initial term of debt [Member] | Fannie Mae credit facilities |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Debt Instrument, Term |  |  |  |  | 7 years |  |
End of range of inital term of debt [Member] | Fannie Mae credit facilities |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Debt Instrument, Term |  |  |  |  | 10 years |  |
Fair Value, Measurements, Recurring [Member] | Fannie Mae credit facilities | Reported Value Measurement [Member] | Fannie Mae credit facilities | Fixed Rate Debt |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Secured Debt Including Debt on Real Estate Held for Sale |  |  |  |  | $ 514,462,000 | $ 568,086,000 |
Fair Value, Measurements, Recurring [Member] | Fannie Mae credit facilities | Reported Value Measurement [Member] | Fannie Mae credit facilities | Variable Rate Debt |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Secured Debt Including Debt on Real Estate Held for Sale |  |  |  |  | 299,378,000 | 266,196,000 |
Fair Value, Measurements, Recurring [Member] | Mortgages [Member] | Reported Value Measurement [Member] | Mortgages [Member] | Fixed Rate Debt |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Secured Debt Including Debt on Real Estate Held for Sale |  |  |  |  | 442,617,000 | 401,210,000 |
Fair Value, Measurements, Recurring [Member] | Mortgages [Member] | Reported Value Measurement [Member] | Mortgages [Member] | Variable Rate Debt |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Secured Debt Including Debt on Real Estate Held for Sale |  |  |  |  | 31,337,000 | 31,337,000 |
United Dominion Reality L.P. |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Amortization of Financing Costs |  |  |  |  | 1,300,000 | 1,400,000 |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Secured Debt Including Debt on Real Estate Held for Sale |  |  |  |  | $ 475,964,000 | 927,484,000 |
Weighted Average Interest Rate |  |  |  |  | 3.76% |  |
United Dominion Reality L.P. | Fixed Rate Debt |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Secured Debt Including Debt on Real Estate Held for Sale |  |  |  |  | $ 279,333,000 | 708,534,000 |
Weighted Average Interest Rate |  |  |  |  | 4.90% |  |
United Dominion Reality L.P. | Variable Rate Debt |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Secured Debt Including Debt on Real Estate Held for Sale |  |  |  |  | $ 196,631,000 | 218,950,000 |
Weighted Average Interest Rate |  |  |  |  | 1.74% |  |
United Dominion Reality L.P. | Mortgages [Member] | Fixed Rate Debt |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Notes payable minimum interest rates range |  |  |  |  | 3.43% |  |
Secured Debt Including Debt on Real Estate Held for Sale |  |  |  |  | $ 30,132,000 | 378,371,000 |
Weighted Average Interest Rate |  |  |  |  | 3.43% |  |
United Dominion Reality L.P. | Fannie Mae credit facilities | Fixed Rate Debt |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Weighted Average Interest Rate |  |  |  |  | 5.08% |  |
United Dominion Reality L.P. | Fannie Mae credit facilities | Variable Rate Debt |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Weighted Average Interest Rate |  |  |  |  | 1.90% |  |
United Dominion Reality L.P. | 4.63% Medium-Term Notes due January 2022 |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Debt instrument, maturity date range, end |  |  |  | Jan. 01, 2022 |  |  |
United Dominion Reality L.P. | Fannie Mae |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Long-term Line of Credit |  |  |  |  | $ 421,031,000 | $ 526,588,000 |
Interest rate at the end of the period |  |  |  |  | 3.80% | 4.00% |
United Dominion Reality L.P. | Fair Value, Measurements, Recurring [Member] | Fannie Mae credit facilities | Reported Value Measurement [Member] | Fannie Mae credit facilities | Fixed Rate Debt |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Secured Debt Including Debt on Real Estate Held for Sale |  |  |  |  | $ 250,828,000 | $ 333,828,000 |
United Dominion Reality L.P. | Fair Value, Measurements, Recurring [Member] | Fannie Mae credit facilities | Reported Value Measurement [Member] | Fannie Mae credit facilities | Variable Rate Debt |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Secured Debt Including Debt on Real Estate Held for Sale |  |  |  |  | 170,203,000 | $ 192,760,000 |
Financial Guarantee | United Dominion Reality L.P. | 3.75 MTN Due July 2024 [Member] |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Guarantor borrowing capacity |  |  |  | $ 300,000,000 |  |  |
Financial Guarantee | United Dominion Reality L.P. | 4.63% Medium-Term Notes due January 2022 |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Guarantor borrowing capacity |  |  |  | 400,000,000 |  |  |
Financial Guarantee | United Dominion Reality L.P. | 2.90% Term Notes due January 2016 |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Guarantor borrowing capacity |  |  |  |  | 250,000,000 |  |
Financial Guarantee | United Dominion Reality L.P. | 1.68% Term Notes due December 2016 |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Guarantor borrowing capacity |  |  |  |  | $ 100,000,000 |  |
Financial Guarantee | United Dominion Reality L.P. | 4.00% MTN Due October 2025 [Member] |  |  |  |  |  |  |
Secured Debt (Textual) [Abstract] |  |  |  |  |  |  |
Guarantor borrowing capacity |  |  |  | $ 300,000,000 |  |  |

X
- Definition Extension period of option on loan + References No definition available. + Details
Name: | udr_Extensionperiodofoptiononloan
Namespace Prefix: | udr_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line of Credit Facility, Commitment Fee Description Range High + References No definition available. + Details
Name: | udr_LineofCreditFacilityCommitmentFeeDescriptionRangeHigh
Namespace Prefix: | udr_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line of Credit Facility, Commitment Fee Description Range Low + References No definition available. + Details
Name: | udr_LineofCreditFacilityCommitmentFeeDescriptionRangeLow
Namespace Prefix: | udr_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line of Credit Facility, Description Range High + References No definition available. + Details
Name: | udr_LineofCreditFacilityDescriptionRangeHigh
Namespace Prefix: | udr_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line of Credit Facility, Description Range Low + References No definition available. + Details
Name: | udr_LineofCreditFacilityDescriptionRangeLow
Namespace Prefix: | udr_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of extension options on loan + References No definition available. + Details
Name: | udr_Numberofextensionoptionsonloan
Namespace Prefix: | udr_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of Debt Instrument Price + References No definition available. + Details
Name: | udr_PercentageofDebtInstrumentPrice
Namespace Prefix: | udr_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Portion of Medium Term Note subject to Interest Rate Swaps + References No definition available. + Details
Name: | udr_PortionofMediumTermNotesubjecttoInterestRateSwaps
Namespace Prefix: | udr_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Secured Debt, Encumbers Real Estate Owned, Amount. + References No definition available. + Details
Name: | udr_SecuredDebtEncumbersRealEstateOwnedAmount
Namespace Prefix: | udr_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Secured Debt, Encumbers Real Estate Owned, Percent. + References No definition available. + Details
Name: | udr_SecuredDebtEncumbersRealEstateOwnedPercent
Namespace Prefix: | udr_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Secured debt including debt on real estate held for sale. + References No definition available. + Details
Name: | udr_SecuredDebtIncludingDebtOnRealEstateHeldForSale
Namespace Prefix: | udr_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Secured debt. + References No definition available. + Details
Name: | udr_SecuredDebtTextualAbstract
Namespace Prefix: | udr_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Secured Debt, Unencumbered Real Estate Owned, Amount. + References No definition available. + Details
Name: | udr_SecuredDebtUnencumberedRealEstateOwnedAmount
Namespace Prefix: | udr_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Secured Debt, Unencumbered Real Estate Owned, Percent. + References No definition available. + Details
Name: | udr_SecuredDebtUnencumberedRealEstateOwnedPercent
Namespace Prefix: | udr_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of noncash expense included in interest expense to amortize debt discount and premium associated with the related debt instruments. Excludes amortization of financing costs. Alternate captions include noncash interest expense. + 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 835 -SubTopic 30 -Section 45 -Paragraph 1A -URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28541-108399 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.8) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 8 -Article 5 + Details
Name: | us-gaap_AmortizationOfDebtDiscountPremium
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of noncash expense included in interest expense to issue debt and obtain financing associated with the related debt instruments. Alternate captions include noncash interest expense. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -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 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.8) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 8 -Article 5 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 8 -Article 9 + Details
Name: | us-gaap_AmortizationOfFinancingCosts
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of long-term debt due after one year or the normal operating cycle, if longer, assumed at the acquisition date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=39739317&loc=d3e4845-128472 + Details
Name: | us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesLongTermDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The average effective interest rate during the reporting period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 + Details
Name: | us-gaap_DebtInstrumentInterestRateDuringPeriod
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 + Details
Name: | us-gaap_DebtInstrumentInterestRateEffectivePercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition When presenting a range of interest rates, the highest effective rate for funds borrowed under the debt agreement as of the balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 + Details
Name: | us-gaap_DebtInstrumentInterestRateEffectivePercentageRateRangeMaximum
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition When presenting a range of interest rates, the lowest effective rate for funds borrowed under the debt agreement as of the balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 + Details
Name: | us-gaap_DebtInstrumentInterestRateEffectivePercentageRateRangeMinimum
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 + Details
Name: | us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- 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. + Details
Name: | us-gaap_DebtInstrumentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(2)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 + Details
Name: | us-gaap_DebtInstrumentMaturityDate
Namespace Prefix: | us-gaap_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Latest date the outstanding debt instruments are required to be repaid, in CCYY-MM-DD format. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(2)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 + Details
Name: | us-gaap_DebtInstrumentMaturityDateRangeEnd1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Earliest date the outstanding debt instruments are required to be repaid, in CCYY-MM-DD format. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(2)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 + Details
Name: | us-gaap_DebtInstrumentMaturityDateRangeStart1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentTerm
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of debt discount that was originally recognized at the issuance of the instrument that has yet to be amortized. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 1A -URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28541-108399 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=34725769&loc=d3e28878-108400 + Details
Name: | us-gaap_DebtInstrumentUnamortizedDiscount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Weighted average interest rate of debt outstanding. + References No definition available. + Details
Name: | us-gaap_DebtWeightedAverageInterestRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 460 -SubTopic 10 -Section 50 -Paragraph 4 -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=6851643&loc=d3e12069-110248 + Details
Name: | us-gaap_GuaranteeObligationsMaximumExposure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 20, 22 -Article 5 + Details
Name: | us-gaap_LineOfCredit
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Description of the fees for amounts available, but unused under the credit facility. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 + Details
Name: | us-gaap_LineOfCreditFacilityCommitmentFeeDescription
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The effective interest rate at the end of the reporting period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 + Details
Name: | us-gaap_LineOfCreditFacilityInterestRateAtPeriodEnd
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Description of the interest rate for the amounts borrowed under the credit facility, including the terms and the method for determining the interest rate (for example, fixed or variable, LIBOR plus a percentage, increasing rate, timing of interest rate resets, remarketing provisions). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 + Details
Name: | us-gaap_LineOfCreditFacilityInterestRateDescription
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 + Details
Name: | us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Weighted average interest rate of long-term debt outstanding. + References No definition available. + Details
Name: | us-gaap_LongtermDebtWeightedAverageInterestRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Including the current and noncurrent portions, carrying value at the balance sheet date of a financial instrument used to receive debt funding on a regular basis with original maturities ranging from 5-10 years. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16(a)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 16 -Article 9 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 20, 22 -Article 5 + Details
Name: | us-gaap_MediumTermNotes
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16(a)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 16 -Article 9 + Details
Name: | us-gaap_SeniorNotes
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_DebtInstrumentAxis=udr_FixedRateDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=udr_VariableRateDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=udr_FivePointTwoFivePercentMediumTermNotesDueJanuary2015Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=udr_A3.75MTNDueJuly2024Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=us-gaap_MortgagesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=udr_DebtAssumedAsPartOfAcquisitionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=udr_TaxExemptSecuredNotesPayableMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=udr_UnsecuredRevolvingCreditFacilityDueOctoberTwoThousandFifteenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=udr_FourPointSixThreePercentTermMediumNotesDueJanuaryTwoThousandTwentyTwoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=udr_ThreePointSevenTermNotesDueOctober2020Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=udr_FannieMaeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=us-gaap_UnsecuredDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=udr_UnsecuredWorkingCapitalCreditFacilitydueJanuary2019Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=udr_A4.00MTNDueOctober2025Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=udr_FivePointTwoFivePercentMediumTermNotesDueJanuary2016Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=udr_A6.21MediumTermNoteDueJanuary2016Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LineOfCreditFacilityAxis=udr_UdrBankCreditFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LineOfCreditFacilityAxis=udr_UnsecuredWorkingCapitalCreditFacilitydueJanuary2019Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | udr_RangeofinitaltermofdebtAxis=udr_BeginningofrangeofinitialtermofdebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | udr_RangeofinitaltermofdebtAxis=udr_EndofrangeofinitaltermofdebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_LineOfCreditMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByMeasurementBasisAxis=us-gaap_CarryingReportedAmountFairValueDisclosureMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_MortgagesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=udr_UnitedDominionRealityLPMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_GuaranteeObligationsByNatureAxis=us-gaap_FinancialGuaranteeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=udr_TwoPointNineZeroPercentTermNotesDueJanuaryTwoThousandSixteenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=udr_TwoPointSixEightPercentTermNotesDueDecemberTwoThousandSixteenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |