COMMITMENTS AND CONTINGENCIES (Details) $ in Thousands	Sep. 30, 2020 USD ($) community
Real estate properties
Number of communities owned (in communities) | community	148
Costs Incurred to Date	$ 253,736
UDR's Remaining Commitment	$ 262,053
Wholly owned - under development
Real estate properties
Number of communities owned (in communities) | community	4
Costs Incurred to Date	$ 197,823
UDR's Remaining Commitment	$ 225,677
Wholly owned - redevelopment
Real estate properties
Number of communities owned (in communities) | community	2
Costs Incurred to Date	$ 20,825
UDR's Remaining Commitment	$ 8,425
Preferred Equity Investments
Real estate properties
Number of communities owned (in communities) | community	1
Costs Incurred to Date	$ 13,693
UDR's Remaining Commitment	6,801
Other investments
Real estate properties
Costs Incurred to Date	21,395
UDR's Remaining Commitment	$ 21,150