| Document and Entity Information | Feb. 11, 2021 |
| Entity information | |
| Document Type | 8-K |
| Document Period End Date | Feb. 11, 2021 |
| Entity Registrant Name | UDR, Inc. |
| Entity Incorporation, State or Country Code | MD |
| Entity File Number | 1-10524 |
| Entity Tax Identification Number | 54-0857512 |
| Entity Address, Address Line One | 1745 Shea Center Drive, Suite 200 |
| Entity Address, City or Town | Highlands Ranch |
| Entity Address, State or Province | CO |
| Entity Address, Postal Zip Code | 80129 |
| City Area Code | 720 |
| Local Phone Number | 283-6120 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock |
| Trading Symbol | UDR |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0000074208 |
| Amendment Flag | false |
| United Dominion Realty L.P. | |
| Entity information | |
| Document Type | 8-K |
| Document Period End Date | Feb. 11, 2021 |
| Entity Registrant Name | United Dominion Realty, L.P. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 333-156002-01 |
| Entity Tax Identification Number | 54-1776887 |
| Entity Address, Address Line One | 1745 Shea Center Drive, Suite 200 |
| Entity Address, City or Town | Highlands Ranch |
| Entity Address, State or Province | CO |
| Entity Address, Postal Zip Code | 80129 |
| City Area Code | 720 |
| Local Phone Number | 283-6120 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001018254 |
| Amendment Flag | false |
