Joint Ventures (Details) (USD $) In Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
Financial information relating to unconsolidated joint ventures operations
UDR recorded loss from unconsolidated entities	$ (1,348)	$ (1,185)	$ (2,680)	$ (1,922)
Unconsolidated Joint Ventures [Member]
Financial information relating to unconsolidated joint ventures operations
Revenues	48,414	10,629	95,005	10,629
Real estate depreciation and amortization	16,737	5,526	33,338	5,526
Net loss	3,142	5,051	8,731	5,051
UDR recorded loss from unconsolidated entities	1,348	1,185	2,680	1,185
Combined Summary of Balance Sheets Relating to Unconsolidated Joint Ventures
Real estate, net	2,682,663		2,682,663		2,692,167
Total assets	2,845,697		2,845,697		2,807,886
Amount due to UDR	3,177		3,177		672
Third party debt	1,493,145		1,493,145		1,524,872
Total liabilities	1,519,299		1,519,299		1,580,733
Non-controlling interest	14,572		14,572		14,537
Equity	$ 1,311,826		$ 1,311,826		$ 1,212,616

The amount due to UDR by an equity method investment of the entity.

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The amount of equity (capital), including the noncontrolling interest (if any), reported by an equity method investment of the entity.

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