COMMITMENTS AND CONTINGENCIES (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($) community	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($)
Real estate properties
Development costs and capital expenditures incurred but not yet paid	$ 25,568	$ 10,745
Number of communities owned (in communities) | community	150
Costs Incurred to Date	$ 161,997
UDR's Remaining Commitment	$ 229,062
King of Prussia
Real estate properties
Contractual purchase price commitment			$ 14,800
Deposit on purchase			$ 800
Wholly owned - under development
Real estate properties
Number of communities owned (in communities) | community	3
Costs Incurred to Date	$ 95,326
UDR's Remaining Commitment	$ 183,174
Wholly owned - redevelopment
Real estate properties
Number of communities owned (in communities) | community	2
Costs Incurred to Date	$ 17,660
UDR's Remaining Commitment	$ 7,840
Preferred Equity Investments
Real estate properties
Number of communities owned (in communities) | community	2
Costs Incurred to Date	$ 34,647
UDR's Remaining Commitment	14,348
Other investments
Real estate properties
Costs Incurred to Date	14,364
UDR's Remaining Commitment	$ 23,700