Consolidated Statements of Cash Flows (UNITED DOMINION REALTY, L.P) (Unaudited) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Casualty-related (recoveries)/charges noncash income	$ (541)	$ 270	$ (8,495)
Document Period End Date	Dec. 31, 2014
Operating Activities
Net income/(loss)	159,842	46,282	220,303
Adjustments to reconcile net income/(loss) to net cash provided by operating activities:
Other	26,517	24,826	26,009
Changes in operating assets and liabilities:
Increase/(decrease) in operating assets	(1,074)	(15,135)	12,647
Increase/(decrease) in operating liabilites	(5,618)	(16,699)	(21,515)
Net cash provided by operating activities	392,360	339,902	327,187
Gain/(loss) on sales of real estate owned	143,572	0	0
Investing Activities
Development of real estate assets	(251,493)	(280,603)	(246,923)
Payments for Capital Improvements	96,679	153,676	144,877
Net cash provided by/(used in) investing activities	(293,660)	(123,209)	(211,582)
Financing Activities
Proceeds from the issuance of secured debt	5,502	0	250
Payments on secured debt	(80,961)	(46,564)	(491,885)
Net cash (used in)/provided by financing activities	(113,725)	(198,559)	(115,993)
Net increase in cash and cash equivalents	(15,025)	18,134	(388)
Cash and cash equivalents, beginning of period	30,249	12,115	12,503
Cash and cash equivalents, end of period	15,224	30,249	12,115
Supplemental Information:
Interest paid during the period, net of amounts capitalized	131,815	127,877	133,133
Properties acquired, including intangibles in asset exchange	0	129,437	0
Properties disposed in asset exchange, net of accumulated depreciation	54,938	175,951
Secured debt assumed in the acquisitions of properties, including asset exchange	0	63,595	34,412
Reallocation of Credit Facilities Debt from General Partner	0	13,682	0
United Dominion Reality L.P.
Casualty-related (recoveries)/charges noncash income	(541)	270
Document Period End Date	Dec. 31, 2014
Operating Activities
Net income/(loss)	97,179	77,942	44,334
Adjustments to reconcile net income/(loss) to net cash provided by operating activities:
Depreciation and amortization	179,176	181,302	195,051
Hurricane-related recovery noncash income			5,518
Other	1,956	2,097	3,624
Changes in operating assets and liabilities:
Increase/(decrease) in operating assets	(1,756)	(11,685)	(1,543)
Increase/(decrease) in operating liabilites	(5,429)	478	5,205
Net cash provided by operating activities	208,032	208,346	201,095
Gain/(loss) on sales of real estate owned	63,635	0	0
Investing Activities
Development of real estate assets	(47,220)	(66,407)	(36,804)
Payments for Capital Improvements	47,352	76,984
Proceeds from sales of real estate investments, net	47,922	79,437	113,175
Capital expenditures and other major improvements — real estate assets, net of escrow reimbursement			(72,098)
Net cash provided by/(used in) investing activities	(46,650)	(63,954)	4,273
Financing Activities
Advances from General Partner, net	(153,751)	(92,537)	29,391
Proceeds from the issuance of secured debt	5,909	0	26,054
Payments on secured debt	(4,995)	(42,237)	(249,680)
Distributions paid to partnership unitholders	(9,929)	(9,348)	(9,033)
Payment of financing costs	(11)	(1,177)	0
Net cash (used in)/provided by financing activities	(162,777)	(145,299)	(203,268)
Net increase in cash and cash equivalents	(1,395)	(907)	2,100
Cash and cash equivalents, beginning of period	1,897	2,804
Cash and cash equivalents, end of period	502	1,897	2,804
Supplemental Information:
Interest paid during the period, net of amounts capitalized	44,629	42,506	48,545
Noncash Or Part Noncash Distribution, Issued Value		(23,329)	(77,041)
OP Units issued in partial consideration for property acquisition	77,041		0
Capital Expenditures Incurred but Not yet Paid	7,254	6,371	7,440
UDR Pacific Los Alisos, LP [Member] | United Dominion Reality L.P.
Supplemental Information:
Properties disposed in asset exchange, net of accumulated depreciation	0	74,586	0
Partnership Capital [Member] | United Dominion Reality L.P.
Supplemental Information:
Noncash Or Part Noncash Distribution, Issued Value	0	(23,329)	0
OP Units issued in partial consideration for property acquisition		23,329	0
All [Member] | United Dominion Reality L.P.
Changes in operating assets and liabilities:
Gain/(loss) on sales of real estate owned		$ (41,518)	$ 51,094