2.4.0.82401401 - Disclosure - Consolidation and Basis of Presentation (Details)truefalsefalse1false falsefalseI2013Q2http://www.sec.gov/CIK0000074208instant2013-06-30T00:00:000001-01-01T00:00:00numberStandardhttp://www.xbrl.org/2003/instancepurexbrli0sharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli01true 2udr_ConsolidationAndBasisOfPresentationTextualAbstractudr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Consolidation And Basis Of Presentation (Textual) [Abstract]2false 3us-gaap_PartnersCapitalAccountUnitsus-gaap_truenainstantfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1truefalsefalse184281253184281253falsefalsefalsexbrli:sharesItemTypesharesThe number of each class of partnership units outstanding at the balance sheet date. Units represent shares of ownership of the general, limited, and preferred partners.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 946 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.6-04.16(a)) -URI http://asc.fasb.org/extlink&oid=6488278&loc=d3e603758-122996 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 5 -Subparagraph (SAB TOPIC 4.F) -URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187171-122770 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 87-21 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Practice Bulletin (PB) -Number 14 -Paragraph 15 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 16 -Subparagraph a, b -Article 6 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 946 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.6-04.16(b)) -URI http://asc.fasb.org/extlink&oid=6488278&loc=d3e603758-122996 false1Operating Partnership outstanding units3false 3us-gaap_GeneralPartnersCapitalAccountUnitsOutstandingus-gaap_truenainstantfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1truefalsefalse174957876174957876falsefalsefalsexbrli:sharesItemTypesharesThe number of general partner units outstanding.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 5 -Subparagraph (SAB TOPIC 4.F) -URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187171-122770 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 4 -Section F Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 87-21 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Practice Bulletin (PB) -Number 14 -Paragraph 10 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false1OP units outstanding related to general partner4false 3udr_GeneralPartnersCapitalAccountUnitsOwnedPercentageudr_falsenainstantfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1truetruefalse0.9490.949falsefalsefalsenum:percentItemTypepureGeneral Partners Capital Account Units Owned Percentage.No definition available.false0Percentage of units owned by UDRfalseConsolidation and Basis of Presentation (Details)UnKnownNoRoundingUnKnownUnKnowntruefalsefalseSheethttp://www.udr.com/role/ConsolidationAndBasisOfPresentationDetails14