Other Comprehensive Loss (Details) (USD $) In Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Other comprehensive Loss:
Net loss attributable to UDR, Inc.	$ (13,251)	$ (23,766)	$ (26,475)	$ (74,443)
Net income attributable to non-controlling interest	46	31	134	111
Unrealized gains reclassified out of accumulated other comprehensive income/(loss) into earnings			(3,492)
Change in marketable securities		3,055		2,151
Change in unrealized gain on derivative financial instruments	(5,342)	(3,192)	(8,895)	(6,030)
Allocation to redeemable non-controlling interests	200	1	429	136
Comprehensive income/(loss)	$ (18,347)	$ (23,871)	$ (38,299)	$ (78,075)