UDR (UDR) 10-Q 27 Oct 15 2015 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2015	Oct. 26, 2015
Entity Registrant Name	UDR, Inc.
Entity Central Index Key	74,208
Document Type	10-Q
Document Period End Date	Sep. 30, 2015
Amendment Flag	false
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		262,015,237
United Dominion Reality L.P. [Member]
Entity Registrant Name	United Dominion Realty L.P.
Entity Central Index Key	1,018,254
Document Type	10-Q
Document Period End Date	Sep. 30, 2015
Amendment Flag	false
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		0

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Real estate owned:
Real estate held for investment	$ 8,162,463	$ 8,205,627
Less: accumulated depreciation	(2,557,490)	(2,434,772)
Real estate held for investment, net	5,604,973	5,770,855
Real estate under development (net of accumulated depreciation of $0)	104,080	177,632
Real estate held for disposition (net of accumulated depreciation of $90,014 and $0)	116,420	0
Total real estate owned, net of accumulated depreciation	5,825,473	5,948,487
Cash and cash equivalents	1,321	15,224
Restricted cash	23,722	22,340
Deferred financing costs, net	20,206	22,686
Notes receivable, net	15,494	14,369
Investment in and advances to unconsolidated joint ventures, net	921,925	718,226
Other assets	114,589	105,202
Total assets	6,922,730	6,846,534
Liabilities:
Secured debt	1,346,992	1,361,529
Unsecured debt	2,166,242	2,221,576
Real estate taxes payable	32,326	15,978
Accrued interest payable	23,577	34,215
Security deposits and prepaid rent	33,879	34,064
Distributions payable	75,937	69,460
Accounts payable, accrued expenses, and other liabilities	56,401	91,282
Total liabilities	3,735,354	3,828,104
Redeemable noncontrolling interests in the Operating Partnership	312,158	282,480
Equity:
8.00% Series E Cumulative Convertible; 2,796,903 and 2,803,812 shares issued and outstanding at September 30, 2015 and December 31, 2014, respectively	46,457	46,571
Common stock, $0.01 par value; 350,000,000 shares authorized; 262,015,237 and 255,114,603 shares issued and outstanding at September 30, 2015 and December 31, 2014, respectively	2,620	2,551
Additional Paid in Capital	4,449,555	4,223,747
Distributions in excess of net income	(1,610,086)	(1,528,917)
Accumulated other comprehensive income/(loss), net	(14,187)	(8,855)
Total stockholders' equity	2,874,359	2,735,097
Noncontrolling interests	859	853
Total equity	2,875,218	2,735,950
Total liabilities and equity	$ 6,922,730	$ 6,846,534

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Real estate owned:
Real estate under development accumulated depreciation	$ 0	$ 0
Real estate held for disposition accumulated depreciation	$ 90,014	$ 0
Equity:
Preferred stock, par or stated value per share	$ 0	$ 0
Preferred stock, shares authorized	50,000,000	50,000,000
Preferred stock, shares outstanding	2,796,903	2,803,812
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	350,000,000	350,000,000
Common stock, shares outstanding	262,015,237	255,114,603

Consolidated Statements of Oper

Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
REVENUES
Rental Income	$ 217,765	$ 203,587	$ 637,576	$ 598,898
Joint venture management and other fees	3,653	3,165	19,457	9,599
Total revenues	221,418	206,752	657,033	608,497
OPERATING EXPENSES
Property operating and maintenance	39,478	39,086	113,922	112,646
Real estate taxes and insurance	24,722	24,697	76,082	73,844
Property management	5,988	5,598	17,533	16,470
Other operating expenses	2,639	2,009	6,174	6,097
Real estate depreciation and amortization	90,568	89,339	269,689	266,748
General and administrative	15,824	11,554	41,697	36,078
Casualty-related (recoveries)/charges, net	541	0	2,380	500
Other depreciation and amortization	1,457	1,385	4,780	3,658
Total operating expenses	181,217	173,668	532,257	516,041
Operating income	40,201	33,084	124,776	92,456
Income/(loss) from unconsolidated entities	2,691	(939)	61,277	(4,932)
Interest expense	(30,232)	(33,087)	(88,705)	(97,662)
Interest and other income/(expense), net	402	9,061	1,144	11,902
Income/(loss) before income taxes, discountinued operations, and gain/(loss) on sale of real estate owned	13,062	8,119	98,492	1,764
Tax benefit/(expense), net	633	2,492	2,462	8,011
Income/(loss) from continuing operations	13,695	10,611	100,954	9,775
Income/(loss) from discontinued operations, net of tax	0	79	0	10
Income/(loss) before gain/(loss) of real estate owned	13,695	10,690	100,954	9,785
Gains/(loss) on sales of real estate owned, net of tax	0	31,302	79,042	82,305
Net income/(loss)	13,695	41,992	179,996	92,090
Net (income)/loss attributable to redeemable noncontrolling interests in the Operating Partnership	(405)	(1,447)	(6,022)	(3,171)
Net (income)/loss attributable to noncontrolling interests	1	4	(6)	(2)
Net income/(loss) attributable to UDR, Inc.	13,291	40,549	173,968	88,917
Distributions to preferred stockholders - Series E (Convertible)	(930)	(931)	(2,792)	(2,793)
Net (loss)/income attributable to common stockholders	$ 12,361	$ 39,618	$ 171,176	$ 86,124
Income/(loss) per weighted average common share - basic and diluted:
Income/(loss) from continuing operations attributable to common stockholders	$ 0.05	$ 0.16	$ 0.66	$ 0.34
Income/(loss) from discontinued operations attributable to common stockholders,	0	0	0	0
Net income/(loss) attributable to common stockholders	$ 0.05	$ 0.16	$ 0.66	$ 0.34
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	2,093	2,077	2,080	1,974
Income/(loss) from continuing operations attributable to common stockholders,	$ 0.05	$ 0.16	$ 0.66	$ 0.34
Income from discontinued operations attributable to common stockholders	0	0	0	0
Net income/(loss) attributable to common stockholders	0.05	0.16	0.66	0.34
Common distributions declared per share	$ 0.2775	$ 0.2600	$ 0.8325	$ 0.7800
Weighted average number of common shares outstanding — basic	259,114	251,655	257,940	250,701
Weighted average number of common shares outstanding — diluted	261,207	253,732	260,020	252,675

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income / (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Net income/(loss)	$ 13,695	$ 41,992	$ 179,996	$ 92,090
Other comprehensive income/(loss), including portion attributable to noncontrolling interests:
Unrealized holding gain/(loss)	(5,707)	362	(7,072)	611
(Gain)/loss reclassified into earnings from other comprehensive income/(loss)	536	1,130	1,565	3,809
Other comprehensive income/(loss), including portion attributable to noncontrolling interests	(5,171)	1,492	(5,507)	4,420
Comprehensive income/(loss)	8,524	43,484	174,489	96,510
Comprehensive (income)/loss attributable to noncontrolling interests	(230)	(1,500)	(5,853)	(3,336)
Comprehensive income/(loss) attributable to UDR, Inc.	$ 8,294	$ 41,984	$ 168,636	$ 93,174

Consolidated Statements of Chan

Consolidated Statements of Changes in Equity (Unaudited) - 9 months ended Sep. 30, 2015 - USD ($) $ in Thousands	Total	Preferred Stock [Member]	Common Stock [Member]	Paid - in Capital	Distributions in Excess of Net Income	Accumulated Other Comprehensive Income/(Loss)	Noncontrolling Interest [Member]	Series E Preferred Stock [Member]	Series E Preferred Stock [Member]Preferred Stock [Member]	Series E Preferred Stock [Member]Common Stock [Member]	Series E Preferred Stock [Member]Paid - in Capital
Beginning Balance, Shares at Dec. 31, 2014		2,803,812	255,114,603
Beginning Balance at Dec. 31, 2014	$ 2,735,950	$ 46,571	$ 2,551	$ 4,223,747	$ (1,528,917)	$ (8,855)	$ 853
Consolidted Statements of Changes in Equity
Net income/(loss) attributable to UDR, Inc.	173,968				173,968
Net income/(loss) attributable to noncontrolling interests	6						6
Other comprehensive income/(loss)	(5,332)					(5,332)
Issuance/(forfeiture) of common and restricted shares, net Shares			(441,344)
Issuance/(forfeitures) of common and restricted shares, net	11,814		$ 4	11,810
Issuance of common shares through public offering	(210,131)		$ 63	210,068				$ 0			$ 114
Conversion of Series E Cumulative Convertible shares, Shares		0							(6,909)
Conversion of Series E Cumulative Convertible shares		$ 0			0				$ (114)
Stock Issued During Period, Shares, New Issues			6,339,636							7,480
Adjustment for conversion of noncontrolling interest of unitholders in the Operating Partnership, Shares			112,174
Adjustment for conversion of noncontrolling interest of unitholders in Operating Partnership	(3,818)		$ (2)	(3,816)
Common stock distributions declared ($0.8325 per share)	(216,837)				216,837
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests							0
Preferred stock distributions declared-Series E ($0.9966 per share)	(2,792)				2,792
Adjustment to reflect redemption value of redeemable noncontrolling interests	(35,508)				(35,508)
Ending Balance at Sep. 30, 2015	$ 2,875,218	$ 46,457	$ 2,620	$ 4,449,555	$ (1,610,086)	$ (14,187)	$ 859
Ending Balance, Shares at Sep. 30, 2015		2,796,903	262,015,237

Consolidated Statements of Cha7

Consolidated Statements of Changes in Equity (Unaudited) (Parenthetical)	9 Months Ended
	Sep. 30, 2015$ / shares
Common distributions declared per share	$ 0.8325
Series E Preferred Stock [Member]
Preferred stock distributions declared	$ 0.9966

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Statement of Cash Flows [Abstract]
Stock Issued During Period, Value, Conversion of Units	$ 3,818	$ 4,318
Operating Activities
Net income/(loss)	179,996	92,090
Adjustments to reconcile net income/(loss) to net cash provided by operating activities:
Depreciation and amortization	274,469	270,405
Gain on sale of real estate owned, net of tax	(79,042)	(82,380)
Tax (benefit)/provision, net	(2,462)	(8,049)
Income/(loss) from unconsolidated entities	(61,277)	4,932
Casualty-related (recoveries)/charges, net	2,380	500
Other	17,839	19,952
Changes in operating assets and liabilities:
(Increase)/decrease in operating assets	(10,026)	(5,870)
Increase/(decrease) in operating liabilities	(16,075)	(9,602)
Net cash provided by/(used in) operating activities	305,802	281,978
Investing Activities
Acquisition of real estate assets	0	(199,012)
Proceeds from sales of real estate investments, net	90,543	233,913
Development of real estate assets	(91,385)	(160,643)
Capital expenditures and other major improvements - real estate assets, net of escrow reimbursement	(80,119)	(82,332)
Capital expenditures - non-real estate assets	(2,684)	(4,277)
Investment in unconsolidated joint ventures	(195,607)	(167,160)
Distributions received from unconsolidated joint venture	53,185	17,884
Purchase deposits on pending acquisitions	(1,000)	(4,000)
(Issuance)/repayment of notes receivable	(1,125)	64,715
Net cash provided by/(used in) investing activities	(228,192)	(300,912)
Financing Activities
Payments on secured debt	(6,861)	(44,390)
Proceeds from the issuance of secured debt	0	5,502
Payments on unsecured debt	(325,429)	(312,500)
Proceeds from Issuance of Unsecured Debt	299,310	298,956
Net proceeds/(repayment) of revolving bank debt	(42,500)	160,000
Proceeds from the issuance of common shares through public offering, net	210,131	99,991
Distributions paid to redeemable noncontrolling interests	(7,761)	(7,419)
Distributions paid to preferred stockholders	(2,792)	(2,793)
Distributions paid to common stockholders	(210,458)	(189,742)
Other	(5,153)	(4,315)
Net cash provided by/(used in) financing activities	(91,513)	3,290
Net increase/(decrease) in cash and cash equivalents	(13,903)	(15,644)
Cash and cash equivalents, beginning of period	15,224	30,249
Cash and cash equivalents, end of period	1,321	14,605
Supplemental Information:
Interest paid during the period, net of amounts capitalized	101,618	105,232
Non-cash transactions:
Acquisition of real estate	24,067	0
Fair value adjustment of debt acquired as part of acquisition of real estate	$ 1,363	$ 0

Consolidated Balance Sheets (UN

Consolidated Balance Sheets (UNITED DOMINION REALTY, L.P) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Real estate owned:
Real estate held for investment	$ 8,162,463	$ 8,205,627
Less: accumulated depreciation	(2,557,490)	(2,434,772)
Real estate held for investment, net	5,604,973	5,770,855
Real estate held for disposition (net of accumulated depreciation of $50,610 and $0)	116,420	0
Real estate under development (net of accumulated depreciation of $0 and $0, respectively)	104,080	177,632
Total real estate owned, net of accumulated depreciation	5,825,473	5,948,487
Cash and cash equivalents	1,321	15,224
Deferred financing costs, net	20,206	22,686
Other assets	114,589	105,202
Total assets	6,922,730	6,846,534
LIABILITIES AND CAPITAL
Secured debt	1,346,992	1,361,529
Real estate taxes payable	32,326	15,978
Accrued interest payable	23,577	34,215
Distributions payable	75,937	69,460
Deferred gains on the sale of depreciable property	9,300	28,500
Accounts payable, accrued expenses, and other liabilities	56,401	91,282
Total liabilities	3,735,354	3,828,104
Partners' Capital:
Accumulated other comprehensive income/(loss), net	(14,187)	(8,855)
Total liabilities and equity	6,922,730	6,846,534
United Dominion Reality L.P. [Member]
Real estate owned:
Real estate held for investment	4,107,120	4,238,770
Less: accumulated depreciation	(1,467,948)	(1,403,303)
Real estate held for investment, net	2,639,172	2,835,467
Real estate held for disposition (net of accumulated depreciation of $50,610 and $0)	100,848	0
Total real estate owned, net of accumulated depreciation	2,740,020	2,835,467
Cash and cash equivalents	131	502
Restricted Cash	14,710	13,811
Deferred financing costs, net	3,355	4,475
Other assets	24,740	24,029
Total assets	2,782,956	2,878,284
LIABILITIES AND CAPITAL
Secured debt	910,309	931,959
Notes payable due to General Partner	88,696	88,696
Real estate taxes payable	15,131	7,061
Accrued interest payable	3,161	3,284
Security deposits and prepaid rent	18,073	18,387
Distributions payable	50,962	47,788
Deferred gains on the sale of depreciable property	0	24,622
Accounts payable, accrued expenses, and other liabilities	18,759	22,436
Total liabilities	$ 1,105,091	$ 1,144,233
Commitments and contingencies (Note 9)
Partners' Capital:
General partner: 110,883 OP Units outstanding at September 30, 2015 and December 31, 2014	$ 1,071	$ 1,105
Limited partners: 183,167,815 OP Units outstanding at September 30, 2015 and December 31, 2014	1,648,460	1,702,971
Accumulated other comprehensive income/(loss), net	(329)	(1,075)
Total partners' capital	1,649,202	1,703,001
Advances (to)/from General Partner	10,162	13,624
Noncontrolling interests	18,501	17,426
Total capital	1,677,865	1,734,051
Total liabilities and equity	$ 2,782,956	$ 2,878,284

Consolidated Balance Sheets (10

Consolidated Balance Sheets (UNITED DOMINION REALTY, L.P) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Real estate under development accumulated depreciation	$ 0	$ 0
Partners' Capital:
Real estate held for disposition accumulated depreciation	90,014	0
United Dominion Reality L.P. [Member]
Real estate under development accumulated depreciation	$ 0	$ 0
Partners' Capital:
OP units outstanding related to general partner	110,883	110,883
OP units outstanding related to limited partner	183,167,815	183,167,815
Real estate held for disposition accumulated depreciation	$ 50,610	$ 0

Consolidated Statements of Op11

Consolidated Statements of Operations (Unaudited) (UNITED DOMINION REALTY, L.P) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
OPERATING EXPENSES
Property operating and maintenance	$ 39,478	$ 39,086	$ 113,922	$ 112,646
Real estate taxes and insurance	24,722	24,697	76,082	73,844
Property management	5,988	5,598	17,533	16,470
Other operating expenses	2,639	2,009	6,174	6,097
General and administrative	15,824	11,554	41,697	36,078
Casualty-related (recoveries)/charges, net	541	0	2,380	500
Total operating expenses	181,217	173,668	532,257	516,041
Operating income	40,201	33,084	124,776	92,456
Interest and other income/(expense), net	402	9,061	1,144	11,902
Income/(loss) from continuing operations	13,695	10,611	100,954	9,775
Income/(loss) from discontinued operations, net of tax	0	79	0	10
Gains/(loss) on sales of real estate owned	0	31,302	79,042	82,305
Net income/(loss)	13,695	41,992	179,996	92,090
Net (income)/loss attributable to noncontrolling interests	(230)	(1,500)	(5,853)	(3,336)
Net (income)/loss attributable to noncontrolling interests			(6)
Net income/(loss) attributable to OP unitholders	13,291	40,549	173,968	88,917
United Dominion Reality L.P. [Member]
REVENUES
Rental income	115,173	107,444	338,426	314,656
OPERATING EXPENSES
Property operating and maintenance	20,393	19,906	58,572	56,468
Real estate taxes and insurance	12,490	11,785	37,166	35,050
Property management	3,167	2,955	9,307	8,653
Other operating expenses	1,482	1,484	4,468	4,371
Real estate depreciation and amortization	43,829	45,043	132,411	134,011
General and administrative	7,935	6,939	20,606	21,368
Casualty-related (recoveries)/charges, net	16	0	888	500
Total operating expenses	89,312	88,112	263,418	260,421
Operating income	25,861	19,332	75,008	54,235
Interest expense	(9,758)	(9,306)	(29,135)	(27,176)
Interest expense on note payable due to General Partner	(1,151)	(1,151)	(3,452)	(3,453)
Income/(loss) before gain/(loss) of real estate owned	14,952	8,875	42,421	23,606
Gains/(loss) on sales of real estate owned	0	0	56,998	40,687
Net income/(loss)	14,952	8,875	99,419	64,293
Net (income)/loss attributable to noncontrolling interests	(335)	(238)	(1,075)	(697)
Net income/(loss) attributable to OP unitholders	$ 14,617	$ 8,637	$ 98,344	$ 63,596
Income/(loss) per OP unit- basic and diluted:
Income/(loss) per weighted average OP Unit - basic and diluted:	$ 0.08	$ 0.05	$ 0.54	$ 0.35
Weighted average OP units outstanding - basic and diluted	183,279	183,279	183,279	183,279

Consolidated Statements of Co12

Consolidated Statements of Comprehensive Income / (Loss) (UNITED DOMINION REALTY, L.P.) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Net income/(loss)	$ 13,695	$ 41,992	$ 179,996	$ 92,090
Other comprehensive income/(loss) - derivative instruments:
Unrealized holding gain/(loss)	(5,707)	362	(7,072)	611
Other comprehensive income/(loss), including portion attributable to noncontrolling interests	(5,171)	1,492	(5,507)	4,420
Comprehensive income/(loss)	8,524	43,484	174,489	96,510
Comprehensive (income)/loss attributable to noncontrolling interests	(230)	(1,500)	(5,853)	(3,336)
Comprehensive income/(loss) attributable to OP unitholders	8,294	41,984	168,636	93,174
United Dominion Reality L.P. [Member]
Net income/(loss)	14,952	8,875	99,419	64,293
Other comprehensive income/(loss) - derivative instruments:
Unrealized holding gain/(loss)	(8)	(3)	(85)	(194)
(Gain)/loss reclassifed into earnings from other comprehensive income/(loss)	278	588	831	1,784
Other comprehensive income/(loss), including portion attributable to noncontrolling interests	270	585	746	1,590
Comprehensive income/(loss)	15,222	9,460	100,165	65,883
Comprehensive (income)/loss attributable to noncontrolling interests	(335)	(238)	(1,075)	(697)
Comprehensive income/(loss) attributable to OP unitholders	$ 14,887	$ 9,222	$ 99,090	$ 65,186

Consolidated Statements of Ch13

Consolidated Statements of Changes in Capital (UNITED DOMINION REALTY, L.P) (Unaudited) - United Dominion Reality L.P. [Member] $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2015USD ($)	Sep. 30, 2015USD ($)
Balance, December 31, 2014		$ 1,734,051
Advances (to)/from General Partner	$ (10,162)	(10,162)
Net income/(loss)		99,419
Distributions		152,889
OP Unit Redemptions for common shares of UDR	0
Adjustment to reflect limited partners' capital at redemption value	0
Unrealized gain on derivative financial investments		746
Net change in amount due to/(from) General Partner		(3,462)
Balance, September 30, 2015	1,677,865	1,677,865
Payable/(Receivable) due to/(from) General Partner [Member] [Member]
Net change in amount due to/(from) General Partner		(3,462)
Accumulated Other Comprehensive Income (Loss) [Member]
Balance, December 31, 2014		(1,075)
Unrealized gain on derivative financial investments		746
Balance, September 30, 2015	(329)	(329)
Partnership Capital [Member]
Balance, December 31, 2014		1,703,001
Net income/(loss)		98,344
Distributions		152,889
Adjustment to reflect limited partners' capital at redemption value	0
Balance, September 30, 2015	1,649,202	1,649,202
Noncontrolling Interest [Member]
Balance, December 31, 2014		17,426
Net income/(loss)		1,075
Balance, September 30, 2015	18,501	18,501
Partnership Capital [Member]
OP Unit Redemptions for common shares of UDR	0
Unrealized gain on derivative financial investments		746
Class A Limited Partner [Member]
Balance, December 31, 2014		53,987
Net income/(loss)		1,008
Distributions		(1,746)
Adjustment to reflect limited partners' capital at redemption value		7,149
Balance, September 30, 2015	60,398	60,398
Limited Partners [Member]
Balance, December 31, 2014		228,493
Net income/(loss)		3,940
Distributions		(6,112)
OP Unit Redemptions for common shares of UDR		(3,816)
Adjustment to reflect limited partners' capital at redemption value		29,255
Balance, September 30, 2015	251,760	251,760
Limited Partner [Member]
Balance, December 31, 2014		1,420,491
Net income/(loss)		93,337
Distributions		(144,938)
OP Unit Redemptions for common shares of UDR		3,816
Adjustment to reflect limited partners' capital at redemption value		(36,404)
Balance, September 30, 2015	1,336,302	1,336,302
General Partner [Member]
Balance, December 31, 2014		1,105
Net income/(loss)		59
Distributions		(93)
Balance, September 30, 2015	$ 1,071	$ 1,071

Consolidated Statements of Ca14

Consolidated Statements of Cash Flows (UNITED DOMINION REALTY, L.P) (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Operating Activities
Net income/(loss)	$ 179,996	$ 92,090
Adjustments to reconcile net income/(loss) to net cash provided by operating activities:
Depreciation and amortization	274,469	270,405
Gain/(loss) on sale of real estate owned	(79,042)	(82,305)
Casualty-related (recoveries)/charges, net	2,380	500
Other	17,839	19,952
Changes in operating assets and liabilities:
(Increase)/decrease in operating assets	(10,026)	(5,870)
Increase/(decrease) in operating liabilities	(16,075)	(9,602)
Net cash provided by/(used in) operating activities	305,802	281,978
Investing Activities
Development of real estate assets	(91,385)	(160,643)
Capital expenditures and other major improvements - real estate assets, net of escrow reimbursement	(80,119)	(82,332)
Net cash provided by/(used in) investing activities	(228,192)	(300,912)
Financing Activities
Proceeds from the issuance of secured debt	0	5,502
Payments on secured debt	(6,861)	(44,390)
Net cash provided by/(used in) financing activities	(91,513)	3,290
Net increase/(decrease) in cash and cash equivalents	(13,903)	(15,644)
Cash and cash equivalents, beginning of period	15,224	30,249
Cash and cash equivalents, end of period	1,321	14,605
Supplemental Information:
Interest paid during the period, net of amounts capitalized	101,618	105,232
United Dominion Reality L.P. [Member]
Operating Activities
Net income/(loss)	99,419	64,293
Adjustments to reconcile net income/(loss) to net cash provided by operating activities:
Depreciation and amortization	132,411	134,011
Gain/(loss) on sale of real estate owned	(56,998)	(40,687)
Casualty-related (recoveries)/charges, net	888	500
Other	(888)	187
Changes in operating assets and liabilities:
(Increase)/decrease in operating assets	(2,174)	(2,540)
Increase/(decrease) in operating liabilities	6,278	2,077
Net cash provided by/(used in) operating activities	178,936	157,841
Investing Activities
Proceeds from sale of real estate investments, net	27,718	47,922
Development of real estate assets	(7,423)	(41,701)
Capital expenditures and other major improvements - real estate assets, net of escrow reimbursement	(44,463)	(32,631)
Net cash provided by/(used in) investing activities	(24,168)	(26,410)
Financing Activities
Distributions and advances from/(to) UDR, Inc.	(143,495)	(120,698)
Payments on secured debt	(3,891)	(3,727)
Distributions paid to partnership unitholders	(7,759)	(7,419)
Payments of financing costs	(6)	0
Net cash provided by/(used in) financing activities	(155,139)	(131,844)
Net increase/(decrease) in cash and cash equivalents	(371)	(413)
Cash and cash equivalents, beginning of period	502	1,897
Cash and cash equivalents, end of period	131	1,484
Supplemental Information:
Interest paid during the period, net of amounts capitalized	$ 34,978	$ 32,792

Consolidation and Basis of Pres

Consolidation and Basis of Presentation	9 Months Ended
	Sep. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
CONSOLIDATION AND BASIS OF PRESENTATION	CONSOLIDATION AND BASIS OF PRESENTATION Consolidation and Basis of Presentation UDR, Inc., collectively with our consolidated subsidiaries (“UDR,” the “Company,” “we,” “our,” or “us”), is a self-administered real estate investment trust, or REIT, that owns, operates, acquires, renovates, develops, redevelops, and manages apartment communities. The accompanying consolidated financial statements include the accounts of UDR and its subsidiaries, including United Dominion Realty, L.P. (the “Operating Partnership” or the “OP”). As of September 30, 2015 , there were 183,278,698 units in the Operating Partnership outstanding, of which 174,225,399 units, or 95.1% , were owned by UDR and 9,053,299 units, or 4.9% , were owned by limited partners. The consolidated financial statements of UDR include the noncontrolling interests of the unitholders in the Operating Partnership. The accompanying interim unaudited consolidated financial statements have been prepared according to the rules and regulations of the Securities and Exchange Commission. Certain information and note disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States have been condensed or omitted according to such rules and regulations, although management believes that the disclosures are adequate to make the information presented not misleading. In the opinion of management, all adjustments and eliminations necessary for the fair presentation of our financial position as of September 30, 2015 , and results of operations for the three and nine months ended September 30, 2015 and 2014 have been included. Such adjustments are normal and recurring in nature. The interim results presented are not necessarily indicative of results that can be expected for a full year. The accompanying interim unaudited consolidated financial statements should be read in conjunction with the audited consolidated financial statements and related notes for the year ended December 31, 2014 appearing in UDR’s Annual Report on Form 10-K, filed with the Securities and Exchange Commission on February 24, 2015 . The accompanying interim unaudited consolidated financial statements are presented in accordance with U.S. generally accepted accounting principles (“GAAP”). GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent liabilities at the dates of the interim unaudited consolidated financial statements and the amounts of revenues and expenses during the reporting periods. Actual amounts realized or paid could differ from those estimates. All significant intercompany accounts and transactions have been eliminated in consolidation.

Consolidation and Basis of Pr16

Consolidation and Basis of Presentation (UNITED DOMINION REALTY, L.P.)	9 Months Ended
	Sep. 30, 2015
Entity Information [Line Items]
CONSOLIDATION AND BASIS OF PRESENTATION	CONSOLIDATION AND BASIS OF PRESENTATION Consolidation and Basis of Presentation UDR, Inc., collectively with our consolidated subsidiaries (“UDR,” the “Company,” “we,” “our,” or “us”), is a self-administered real estate investment trust, or REIT, that owns, operates, acquires, renovates, develops, redevelops, and manages apartment communities. The accompanying consolidated financial statements include the accounts of UDR and its subsidiaries, including United Dominion Realty, L.P. (the “Operating Partnership” or the “OP”). As of September 30, 2015 , there were 183,278,698 units in the Operating Partnership outstanding, of which 174,225,399 units, or 95.1% , were owned by UDR and 9,053,299 units, or 4.9% , were owned by limited partners. The consolidated financial statements of UDR include the noncontrolling interests of the unitholders in the Operating Partnership. The accompanying interim unaudited consolidated financial statements have been prepared according to the rules and regulations of the Securities and Exchange Commission. Certain information and note disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States have been condensed or omitted according to such rules and regulations, although management believes that the disclosures are adequate to make the information presented not misleading. In the opinion of management, all adjustments and eliminations necessary for the fair presentation of our financial position as of September 30, 2015 , and results of operations for the three and nine months ended September 30, 2015 and 2014 have been included. Such adjustments are normal and recurring in nature. The interim results presented are not necessarily indicative of results that can be expected for a full year. The accompanying interim unaudited consolidated financial statements should be read in conjunction with the audited consolidated financial statements and related notes for the year ended December 31, 2014 appearing in UDR’s Annual Report on Form 10-K, filed with the Securities and Exchange Commission on February 24, 2015 . The accompanying interim unaudited consolidated financial statements are presented in accordance with U.S. generally accepted accounting principles (“GAAP”). GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent liabilities at the dates of the interim unaudited consolidated financial statements and the amounts of revenues and expenses during the reporting periods. Actual amounts realized or paid could differ from those estimates. All significant intercompany accounts and transactions have been eliminated in consolidation.
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
CONSOLIDATION AND BASIS OF PRESENTATION	CONSOLIDATION AND BASIS OF PRESENTATION Consolidation and Basis of Presentation United Dominion Realty, L.P. (“UDR, L.P.,” the “Operating Partnership,” “we” or “our”) is a Delaware limited partnership, that owns, acquires, renovates, redevelops, manages, and disposes of multifamily apartment communities generally located in high barrier to entry markets located in the United States. The high barrier to entry markets are characterized by limited land for new construction, difficult and lengthy entitlement process, expensive single-family home prices and significant employment growth potential. UDR, L.P. is a subsidiary of UDR, Inc. (“UDR” or the “General Partner”), a self-administered real estate investment trust, or REIT, through which UDR conducts a significant portion of its business. Rental revenues of the Operating Partnership represented 53% of the General Partner’s consolidated rental revenues for the three and nine months ended September 30, 2015 and 2014 . As of September 30, 2015 , the Operating Partnership’s apartment portfolio consisted of 67 communities located in 17 markets consisting of 20,569 apartment homes. Interests in UDR, L.P. are represented by operating partnership units (“OP Units”). The Operating Partnership’s net income is allocated to the partners, which is initially based on their respective distributions made during the year and secondly, their percentage interests. Distributions are made in accordance with the terms of the Amended and Restated Agreement of Limited Partnership of United Dominion Realty, L.P. (the “Operating Partnership Agreement”), on a per unit basis that is generally equal to the dividend per share on UDR’s common stock, which is publicly traded on the New York Stock Exchange (“NYSE”) under the ticker symbol “UDR.” As of September 30, 2015 , there were 183,278,698 OP Units outstanding, of which 174,225,399 or 95.1% were owned by UDR and affiliated entities and 9,053,299 or 4.9% were owned by non-affiliated limited partners. See Note 8, Capital Structure . The accompanying interim unaudited consolidated financial statements have been prepared according to the rules and regulations of the Securities and Exchange Commission (“SEC”). Certain information and note disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States have been condensed or omitted according to such rules and regulations, although management believes that the disclosures are adequate to make the information presented not misleading. In the opinion of management, all adjustments and eliminations necessary for the fair presentation of our financial position as of September 30, 2015 , and results of operations for the three and nine months ended September 30, 2015 and 2014 have been included. Such adjustments are normal and recurring in nature. The interim results presented are not necessarily indicative of results that can be expected for a full year. The accompanying interim unaudited consolidated financial statements should be read in conjunction with the audited consolidated financial statements and related notes for the year ended September 30, 2015 included in the Annual Report on Form 10-K filed by UDR and the Operating Partnership with the SEC on February 24, 2015 . The accompanying interim unaudited consolidated statements are presented in accordance with U.S. generally accepted accounting principles (“GAAP”). GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent liabilities at the dates of the interim unaudited consolidated financial statements and the amounts of revenues and expenses during the reporting periods. Actual amounts realized or paid could differ from those estimates. All intercompany accounts and transactions have been eliminated in consolidation.

Significant Accounting Policies

Significant Accounting Policies	9 Months Ended
	Sep. 30, 2015
Accounting Policies [Abstract]
SIGNIFICANT ACCOUNTING POLICIES	SIGNIFICANT ACCOUNTING POLICIES Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2014-09, Revenue from Contracts with Customers . The standard provides companies with a single model for use in accounting for revenue arising from contracts with customers and supersedes current revenue recognition guidance, including industry-specific revenue guidance. The updated standard will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. The standard specifically excludes lease contracts. The ASU allows for the use of either the full or modified retrospective transition method, and the standard will be effective for the Company on January 1, 2018; early adoption is permitted on January 1, 2017. The Company has not yet selected a transition method and we are currently evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures. In April 2015, the FASB issued ASU 2015-03, Simplifying the Presentation of Debt Issuance Costs, to revise the presentation of debt issuance costs. Under ASU 2015-03, entities will present debt issuance costs in their balance sheet as a direct deduction from the related debt liability rather than as an asset. Amortization of the deferred costs will continue to be included in interest expense. ASU 2015-03 does not directly address presentation or subsequent measurement of issuance costs related to line-of-credit arrangements. In August 2015, the FASB issued ASU 2015-15, Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements , which clarifies that such costs may be presented as an asset and subsequently amortized over the term of the line-of-credit arrangement. The cumulative guidance, which is to be applied retrospectively to all prior periods, is effective for fiscal years beginning after December 15, 2015, with early adoption permitted for financial statements that have not been previously issued. The Company does not expect ASU 2015-03 or ASU 2015-15 to have a significant effect on its consolidated financial statements. In February 2015, the FASB issued ASU 2015-02, Amendments to the Consolidation Analysis, which makes changes to both the variable interest model and the voting model. Among other changes, the new standard specifically eliminates the presumption in the current voting model that a general partner controls a limited partnership or similar entity unless that presumption can be overcome. The new standard will be effective for the Company beginning on January 1, 2016 and early adoption is permitted, including adoption in an interim period. The new standard must be applied using a modified retrospective approach by recording a cumulative-effect adjustment to equity/capital as of the beginning of the period of adoption or retrospectively to each period presented. The Company is currently evaluating the impact of adopting the new standard on its consolidated financial statements. Discontinued Operations In accordance with GAAP, a discontinued operation represents (1) a component of an entity or group of components that has been disposed of or is classified as held for sale in a single transaction and represents a strategic shift that has or will have a major effect on an entity’s financial results, or (2) an acquired business that is classified as held for sale on the date of acquisition. A strategic shift could include a disposal of (1) a separate major line of business, (2) a separate major geographic area of operations, (3) a major equity method investment, or (4) other major parts of an entity. We record sales of real estate that do not meet the definition of a discontinued operation in Gain/(loss) on sale of real estate owned, net of tax on the Consolidated Statements of Operations. Revenue and Real Estate Sales Gain Recognition Rental income related to leases is recognized on an accrual basis when due from residents and tenants in accordance with GAAP. Rental payments are generally due on a monthly basis and recognized when earned. The Company recognizes interest income, management and other fees and incentives when earned, and the amounts are fixed and determinable. For sale transactions meeting the requirements for full accrual profit recognition, we remove the related assets and liabilities from our Consolidated Balance Sheets and record the gain or loss in the period the transaction closes. For sale transactions that do not meet the full accrual sale criteria due to our continuing involvement, we evaluate the nature of the continuing involvement and account for the transaction under an alternate method of accounting. Unless certain limited criteria are met, non-monetary transactions, including property exchanges, are accounted for at fair value. Sales to entities in which we retain or otherwise own an interest are accounted for as partial sales. If all other requirements for recognizing profit under the full accrual method have been satisfied and no other forms of continuing involvement are present, we recognize profit proportionate to the outside interest in the buyer and defer the gain on the interest we retain. The Company recognizes any deferred gain when the property is sold to a third party. In transactions accounted for by us as partial sales, we determine if the buyer of the majority equity interest in the venture was provided a preference as to cash flows in either an operating or a capital waterfall. If a cash flow preference has been provided, we recognize profit only to the extent that proceeds from the sale of the majority equity interest exceed costs related to the entire property. Notes Receivable The following table summarizes our notes receivable, net as of September 30, 2015 and December 31, 2014 ( dollars in thousands): Interest rate at Balance outstanding September 30, September 30, December 31, 2014 Note due February 2017 (a) 10.00 % $ 12,994 $ 11,869 Note due July 2017 (b) 8.00 % 2,500 2,500 Total notes receivable, net $ 15,494 $ 14,369 (a) The Company has a secured note receivable with an unaffiliated third party with an aggregate commitment of $13.0 million . During the nine months ended September 30, 2015 , the Company loaned an additional $1.1 million . Interest payments are due monthly. The note matures at the earliest of the following: (a) the closing of any private or public capital raising in the amount of $5.0 million or greater; (b) an acquisition; (c) acceleration in the event of default; or (d) the fifth anniversary of the date of the note (February 2017). (b) The Company has a secured note receivable with an unaffiliated third party with an aggregate commitment of $2.5 million . Interest payments are due monthly. The note matures at the earliest of the following: (a) the closing of any private or public capital raising in the amount of $5.0 million or greater; (b) an acquisition; (c) acceleration in the event of default; or (d) the fifth anniversary of the date of the note (July 2017). The Company recognized $0.4 million of interest income from notes receivable during the three months ended September 30, 2015 and 2014 and $1.1 million and $3.0 million during the nine months ended September 30, 2015 and 2014 , respectively, none of which was related party interest income. Interest income is included in Interest income and other income/(expense), net on the Consolidated Statements of Operations. Comprehensive Income/(Loss) Comprehensive income/(loss), which is defined as the change in equity during each period from transactions and other events and circumstances from nonowner sources, including all changes in equity during a period except for those resulting from investments by or distributions to stockholders, is displayed in the accompanying Consolidated Statements of Comprehensive Income/(Loss). For the three and nine months ended September 30, 2015 and 2014 , the Company’s other comprehensive income/(loss) consisted of the gain/(loss) (effective portion) on derivative instruments that are designated as and qualify as cash flow hedges, (gain)/loss on derivative instruments reclassified from other comprehensive income/(loss) into earnings, and the allocation of other comprehensive income/(loss) to redeemable noncontrolling interests. The (gain)/loss on derivative instruments reclassified from other comprehensive income/(loss) is included in Interest expense on the Consolidated Statements of Operations. See Note 10, Derivatives and Hedging Activity, for further discussion. The allocation of other comprehensive income/(loss) to redeemable noncontrolling interests was $(0.2) million and $0.1 million during the three months ended September 30, 2015 and 2014 , respectively, and $(0.2) million and $0.2 million during the nine months ended September 30, 2015 and 2014 , respectively. Income Taxes Due to the structure of the Company as a REIT and the nature of the operations for the operating properties, no provision for federal income taxes has been provided for at UDR. Historically, the Company has generally incurred only state and local excise and franchise taxes. UDR has elected for certain consolidated subsidiaries to be treated as taxable REIT subsidiaries (“TRS”). Income taxes for our TRS are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities from a change in tax rate is recognized in earnings in the period of the enactment date. The Company’s deferred tax assets are generally the result of differing depreciable lives on capitalized assets and timing of expense recognition for certain accrued liabilities. As of September 30, 2015 , UDR’s net deferred tax asset was $10.5 million (net of a valuation allowance of less than $0.1 million ), which is included in Other assets on the Consolidated Balance Sheets. GAAP defines a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. GAAP also provides guidance on derecognition, classification, interest and penalties, accounting for interim periods, disclosure and transition. The Company recognizes its tax positions and evaluates them using a two-step process. First, UDR determines whether a tax position is more likely than not (greater than 50 percent probability) to be sustained upon examination, including resolution of any related appeals or litigation processes, based on the technical merits of the position. Second, the Company will determine the amount of benefit to recognize and record the amount that is more likely than not to be realized upon ultimate settlement. UDR had no material unrecognized tax benefit, accrued interest or penalties at September 30, 2015 . UDR and its subsidiaries are subject to federal income tax as well as income tax of various state and local jurisdictions. The tax years 2011 through 2014 remain open to examination by tax jurisdictions to which we are subject. When applicable, UDR recognizes interest and/or penalties related to uncertain tax positions in Tax benefit/(expense), net on the Consolidated Statements of Operations.

Significant Accounting Polici18

Significant Accounting Policies (UNITED DOMINION REALTY, L.P.)	9 Months Ended
	Sep. 30, 2015
Entity Information [Line Items]
SIGNIFICANT ACCOUNTING POLICIES	SIGNIFICANT ACCOUNTING POLICIES Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2014-09, Revenue from Contracts with Customers . The standard provides companies with a single model for use in accounting for revenue arising from contracts with customers and supersedes current revenue recognition guidance, including industry-specific revenue guidance. The updated standard will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. The standard specifically excludes lease contracts. The ASU allows for the use of either the full or modified retrospective transition method, and the standard will be effective for the Company on January 1, 2018; early adoption is permitted on January 1, 2017. The Company has not yet selected a transition method and we are currently evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures. In April 2015, the FASB issued ASU 2015-03, Simplifying the Presentation of Debt Issuance Costs, to revise the presentation of debt issuance costs. Under ASU 2015-03, entities will present debt issuance costs in their balance sheet as a direct deduction from the related debt liability rather than as an asset. Amortization of the deferred costs will continue to be included in interest expense. ASU 2015-03 does not directly address presentation or subsequent measurement of issuance costs related to line-of-credit arrangements. In August 2015, the FASB issued ASU 2015-15, Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements , which clarifies that such costs may be presented as an asset and subsequently amortized over the term of the line-of-credit arrangement. The cumulative guidance, which is to be applied retrospectively to all prior periods, is effective for fiscal years beginning after December 15, 2015, with early adoption permitted for financial statements that have not been previously issued. The Company does not expect ASU 2015-03 or ASU 2015-15 to have a significant effect on its consolidated financial statements. In February 2015, the FASB issued ASU 2015-02, Amendments to the Consolidation Analysis, which makes changes to both the variable interest model and the voting model. Among other changes, the new standard specifically eliminates the presumption in the current voting model that a general partner controls a limited partnership or similar entity unless that presumption can be overcome. The new standard will be effective for the Company beginning on January 1, 2016 and early adoption is permitted, including adoption in an interim period. The new standard must be applied using a modified retrospective approach by recording a cumulative-effect adjustment to equity/capital as of the beginning of the period of adoption or retrospectively to each period presented. The Company is currently evaluating the impact of adopting the new standard on its consolidated financial statements. Discontinued Operations In accordance with GAAP, a discontinued operation represents (1) a component of an entity or group of components that has been disposed of or is classified as held for sale in a single transaction and represents a strategic shift that has or will have a major effect on an entity’s financial results, or (2) an acquired business that is classified as held for sale on the date of acquisition. A strategic shift could include a disposal of (1) a separate major line of business, (2) a separate major geographic area of operations, (3) a major equity method investment, or (4) other major parts of an entity. We record sales of real estate that do not meet the definition of a discontinued operation in Gain/(loss) on sale of real estate owned, net of tax on the Consolidated Statements of Operations. Revenue and Real Estate Sales Gain Recognition Rental income related to leases is recognized on an accrual basis when due from residents and tenants in accordance with GAAP. Rental payments are generally due on a monthly basis and recognized when earned. The Company recognizes interest income, management and other fees and incentives when earned, and the amounts are fixed and determinable. For sale transactions meeting the requirements for full accrual profit recognition, we remove the related assets and liabilities from our Consolidated Balance Sheets and record the gain or loss in the period the transaction closes. For sale transactions that do not meet the full accrual sale criteria due to our continuing involvement, we evaluate the nature of the continuing involvement and account for the transaction under an alternate method of accounting. Unless certain limited criteria are met, non-monetary transactions, including property exchanges, are accounted for at fair value. Sales to entities in which we retain or otherwise own an interest are accounted for as partial sales. If all other requirements for recognizing profit under the full accrual method have been satisfied and no other forms of continuing involvement are present, we recognize profit proportionate to the outside interest in the buyer and defer the gain on the interest we retain. The Company recognizes any deferred gain when the property is sold to a third party. In transactions accounted for by us as partial sales, we determine if the buyer of the majority equity interest in the venture was provided a preference as to cash flows in either an operating or a capital waterfall. If a cash flow preference has been provided, we recognize profit only to the extent that proceeds from the sale of the majority equity interest exceed costs related to the entire property. Notes Receivable The following table summarizes our notes receivable, net as of September 30, 2015 and December 31, 2014 ( dollars in thousands): Interest rate at Balance outstanding September 30, September 30, December 31, 2014 Note due February 2017 (a) 10.00 % $ 12,994 $ 11,869 Note due July 2017 (b) 8.00 % 2,500 2,500 Total notes receivable, net $ 15,494 $ 14,369 (a) The Company has a secured note receivable with an unaffiliated third party with an aggregate commitment of $13.0 million . During the nine months ended September 30, 2015 , the Company loaned an additional $1.1 million . Interest payments are due monthly. The note matures at the earliest of the following: (a) the closing of any private or public capital raising in the amount of $5.0 million or greater; (b) an acquisition; (c) acceleration in the event of default; or (d) the fifth anniversary of the date of the note (February 2017). (b) The Company has a secured note receivable with an unaffiliated third party with an aggregate commitment of $2.5 million . Interest payments are due monthly. The note matures at the earliest of the following: (a) the closing of any private or public capital raising in the amount of $5.0 million or greater; (b) an acquisition; (c) acceleration in the event of default; or (d) the fifth anniversary of the date of the note (July 2017). The Company recognized $0.4 million of interest income from notes receivable during the three months ended September 30, 2015 and 2014 and $1.1 million and $3.0 million during the nine months ended September 30, 2015 and 2014 , respectively, none of which was related party interest income. Interest income is included in Interest income and other income/(expense), net on the Consolidated Statements of Operations. Comprehensive Income/(Loss) Comprehensive income/(loss), which is defined as the change in equity during each period from transactions and other events and circumstances from nonowner sources, including all changes in equity during a period except for those resulting from investments by or distributions to stockholders, is displayed in the accompanying Consolidated Statements of Comprehensive Income/(Loss). For the three and nine months ended September 30, 2015 and 2014 , the Company’s other comprehensive income/(loss) consisted of the gain/(loss) (effective portion) on derivative instruments that are designated as and qualify as cash flow hedges, (gain)/loss on derivative instruments reclassified from other comprehensive income/(loss) into earnings, and the allocation of other comprehensive income/(loss) to redeemable noncontrolling interests. The (gain)/loss on derivative instruments reclassified from other comprehensive income/(loss) is included in Interest expense on the Consolidated Statements of Operations. See Note 10, Derivatives and Hedging Activity, for further discussion. The allocation of other comprehensive income/(loss) to redeemable noncontrolling interests was $(0.2) million and $0.1 million during the three months ended September 30, 2015 and 2014 , respectively, and $(0.2) million and $0.2 million during the nine months ended September 30, 2015 and 2014 , respectively. Income Taxes Due to the structure of the Company as a REIT and the nature of the operations for the operating properties, no provision for federal income taxes has been provided for at UDR. Historically, the Company has generally incurred only state and local excise and franchise taxes. UDR has elected for certain consolidated subsidiaries to be treated as taxable REIT subsidiaries (“TRS”). Income taxes for our TRS are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities from a change in tax rate is recognized in earnings in the period of the enactment date. The Company’s deferred tax assets are generally the result of differing depreciable lives on capitalized assets and timing of expense recognition for certain accrued liabilities. As of September 30, 2015 , UDR’s net deferred tax asset was $10.5 million (net of a valuation allowance of less than $0.1 million ), which is included in Other assets on the Consolidated Balance Sheets. GAAP defines a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. GAAP also provides guidance on derecognition, classification, interest and penalties, accounting for interim periods, disclosure and transition. The Company recognizes its tax positions and evaluates them using a two-step process. First, UDR determines whether a tax position is more likely than not (greater than 50 percent probability) to be sustained upon examination, including resolution of any related appeals or litigation processes, based on the technical merits of the position. Second, the Company will determine the amount of benefit to recognize and record the amount that is more likely than not to be realized upon ultimate settlement. UDR had no material unrecognized tax benefit, accrued interest or penalties at September 30, 2015 . UDR and its subsidiaries are subject to federal income tax as well as income tax of various state and local jurisdictions. The tax years 2011 through 2014 remain open to examination by tax jurisdictions to which we are subject. When applicable, UDR recognizes interest and/or penalties related to uncertain tax positions in Tax benefit/(expense), net on the Consolidated Statements of Operations.
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
SIGNIFICANT ACCOUNTING POLICIES	SIGNIFICANT ACCOUNTING POLICIES Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2014-09, Revenue from Contracts with Customers . The standard provides companies with a single model for use in accounting for revenue arising from contracts with customers and supersedes current revenue recognition guidance, including industry-specific revenue guidance. The updated standard will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. The standard specifically excludes lease contracts. The ASU allows for the use of either the full or modified retrospective transition method, and the standard will be effective for the Operating Partnership on January 1, 2018; early adoption is permitted on January 1, 2017. The Operating Partnership has not yet selected a transition method and we are currently evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures. In April 2015, the FASB issued ASU 2015-03, Simplifying the Presentation of Debt Issuance Costs, to revise the presentation of debt issuance costs. Under ASU 2015-03, entities will present debt issuance costs in their balance sheet as a direct deduction from the related debt liability rather than as an asset. Amortization of the deferred costs will continue to be included in interest expense. ASU 2015-03 does not directly address presentation or subsequent measurement of issuance costs related to line-of-credit arrangements. In August 2015, the FASB issued ASU 2015-15, Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements , which clarifies that such costs may be presented as an asset and subsequently amortized over the term of the line-of-credit arrangement. The cumulative guidance, which is to be applied retrospectively to all prior periods, is effective for fiscal years beginning after December 15, 2015, with early adoption permitted for financial statements that have not been previously issued. The Operating Partnership does not expect ASU 2015-03 or ASU 2015-15 to have a significant effect on its consolidated financial statements. In February 2015, the FASB issued ASU 2015-02, Amendments to the Consolidation Analysis, which makes changes to both the variable interest model and the voting model. Among other changes, the new standard specifically eliminates the presumption in the current voting model that a general partner controls a limited partnership or similar entity unless that presumption can be overcome. The new standard will be effective for the Operating Partnership beginning on January 1, 2016 and early adoption is permitted, including adoption in an interim period. The new standard must be applied using a modified retrospective approach by recording a cumulative-effect adjustment to equity/capital as of the beginning of the period of adoption or retrospectively to each period presented. The Operating Partnership is currently evaluating the impact of adopting the new standard on its consolidated financial statements. Discontinued Operations In accordance with GAAP, a discontinued operation represents (1) a component of an entity or group of components that has been disposed of or is classified as held for sale in a single transaction and represents a strategic shift that has or will have a major effect on an entity’s financial results, or (2) an acquired business that is classified as held for sale on the date of acquisition. A strategic shift could include a disposal of (1) a separate major line of business, (2) a separate major geographic area of operations, (3) a major equity method investment, or (4) other major parts of an entity. We record sales of real estate that do not meet the definition of a discontinued operation in Gain/(loss) on sale of real estate owned, net of tax on the Consolidated Statements of Operations. Income/(Loss) Per Operating Partnership Unit Basic income/(loss) per OP Unit is computed by dividing net income/(loss) attributable to general and limited partner unitholders by the weighted average number of general and limited partner units outstanding during the year. Diluted income/(loss) per OP Unit reflects the potential dilution that could occur if securities or other contracts to issue OP Units were exercised or converted into OP Units or resulted in the issuance of OP Units and then shared in the income/(loss) of the Operating Partnership. Revenue and Real Estate Sales Gain Recognition Rental income related to leases is recognized on an accrual basis when due from residents and tenants in accordance with GAAP. Rental payments are generally due on a monthly basis and recognized when earned. The Operating Partnership recognizes interest income, fees and incentives when earned, fixed and determinable. For sale transactions meeting the requirements for full accrual profit recognition, we remove the related assets and liabilities from our Consolidated Balance Sheets and record the gain or loss in the period the transaction closes. For sale transactions that do not meet the full accrual sale criteria due to our continuing involvement, we evaluate the nature of the continuing involvement and account for the transaction under an alternate method of accounting. Unless certain limited criteria are met, non-monetary transactions, including property exchanges, are accounted for at fair value. Sales to entities in which we or our General Partner retain or otherwise own an interest are accounted for as partial sales. If all other requirements for recognizing profit under the full accrual method have been satisfied and no other forms of continuing involvement are present, we recognize profit proportionate to the outside interest in the buyer and defer the gain on the interest we or our General Partner retain. The Operating Partnership recognizes any deferred gain when the property is sold to a third party. In transactions accounted by us as partial sales, we determine if the buyer of the majority equity interest in the venture was provided a preference as to cash flows in either an operating or a capital waterfall. If a cash flow preference has been provided, we recognize profit only to the extent that proceeds from the sale of the majority equity interest exceed costs related to the entire property. Comprehensive Income/(Loss) Comprehensive income/(loss), which is defined as the change in equity during each period from transactions and other events and circumstances from nonowner sources, including all changes in equity during a period except for those resulting from investments by or distributions to unitholders, is displayed in the accompanying Consolidated Statements of Comprehensive Income/(Loss). For the three and nine months ended September 30, 2015 and 2014 , the Operating Partnership’s other comprehensive income/(loss) consisted of the gain/(loss) (effective portion) on derivative instruments that are designated as and qualify as cash flow hedges and (gain)/loss reclassified from other comprehensive income/(loss) into earnings. The (gain)/loss reclassified from other comprehensive income/(loss) is included in Interest expense on the Consolidated Statements of Operations. See Note 7, Derivatives and Hedging Activity, for further discussion. Income Taxes The taxable income or loss of the Operating Partnership is reported on the tax returns of the partners. Accordingly, no provision has been made in the accompanying financial statements for federal or state income taxes on income that is passed through to the partners. However, any state or local revenue, excise or franchise taxes that result from the operating activities of the Operating Partnership are recorded at the entity level. The Operating Partnership’s tax returns are subject to examination by federal and state taxing authorities. Net income for financial reporting purposes differs from the net income for income tax reporting purposes primarily due to temporary differences, principally real estate depreciation and the tax deferral of certain gains on property sales. The differences in depreciation result from differences in the book and tax basis of certain real estate assets and the differences in the methods of depreciation and lives of the real estate assets. The Operating Partnership evaluates the accounting and disclosure of tax positions taken or expected to be taken in the course of preparing the Operating Partnership’s tax returns to determine whether the tax positions are “more-likely-than-not” of being sustained by the applicable tax authority. Tax positions not deemed to meet the more-likely-than-not threshold would be recorded as a tax benefit or expense in the current year. Management of the Operating Partnership is required to analyze all open tax years, as defined by the statute of limitations, for all major jurisdictions, which include federal and certain states. The Operating Partnership has no examinations in progress and none are expected at this time. Management of the Operating Partnership has reviewed all open tax years ( 2011 through 2014 ) of tax jurisdictions and concluded there is no tax liability resulting from unrecognized tax benefits relating to uncertain income tax positions taken or expected to be taken in future tax returns.

Real Estate Owned

Real Estate Owned	9 Months Ended
	Sep. 30, 2015
Real Estate [Abstract]
REAL ESTATE OWNED	REAL ESTATE OWNED Real estate assets owned by the Company consist of income producing operating properties, properties under development, land held for future development, and sold or held for disposition properties. The Company had eight communities with a total of 1,755 apartment homes that met the criteria to be classified as held for disposition at September 30, 2015 . The communities are located in Virginia Beach, Hampton and Yorktown, VA, Columbia, MD, Pinellas Park, FL, Orange County, CA, and Oxnard, CA. As of September 30, 2015 , the Company owned and consolidated 136 communities in 10 states plus the District of Columbia totaling 39,405 apartment homes. The following table summarizes the carrying amounts for our real estate owned (at cost) as of September 30, 2015 and December 31, 2014 (dollars in thousands): September 30, December 31, 2014 Land and land improvements $ 1,840,823 $ 1,980,221 Depreciable property — held and used: Building, improvements, and furniture, fixtures and equipment 6,321,640 6,225,406 Under development: Land and land improvements 78,085 24,584 Building, improvements, and furniture, fixtures and equipment 25,995 153,048 Real estate held for disposition: Land and land improvements 81,080 — Building, improvements, and furniture, fixtures and equipment 125,354 — Real estate owned 8,472,977 8,383,259 Accumulated depreciation (2,647,504 ) (2,434,772 ) Real estate owned, net $ 5,825,473 $ 5,948,487 In February 2015, the Company acquired an office building in Highlands Ranch, Colorado, for total consideration of approximately $24.0 million , which was comprised of assumed debt. The Company's corporate offices, as well as other leased office space, are located in the acquired building. The building consists of approximately 120,000 square feet. All existing leases were assumed by the Company at the time of acquisition. During the nine months ended September 30, 2015 , the Company sold three communities with a total of 812 apartment homes for gross proceeds of $109.9 million , resulting in net proceeds of $90.5 million and a total gain, net of tax, of $79.0 million . A portion of the sale proceeds were designated as a tax-deferred exchange related to a 2014 acquisition under Section 1031 of the Internal Revenue Code. Predevelopment, development, and redevelopment projects and related costs are capitalized and reported on the Consolidated Balance Sheets as Total real estate owned, net of accumulated depreciation . The Company capitalizes costs directly related to the predevelopment, development, and redevelopment of a capital project, which include, but are not limited to, interest, real estate taxes, insurance, and allocated development and redevelopment overhead related to support costs for personnel working on the capital projects. We use our professional judgment in determining whether such costs meet the criteria for capitalization or must be expensed as incurred. These costs are capitalized only during the period in which activities necessary to ready an asset for its intended use are in progress and such costs are incremental and identifiable to a specific activity to get the asset ready for its intended use. These costs, excluding the direct costs of development and redevelopment and capitalized interest, were $1.7 million and $1.7 million for the three months ended September 30, 2015 and 2014 , respectively, and $5.5 million and $7.2 million for the nine months ended September 30, 2015 and 2014 , respectively. Total interest capitalized was $3.6 million and $5.2 million for the three months ended September 30, 2015 and 2014 , respectively, and $12.2 million and $15.4 million for the nine months ended September 30, 2015 and 2014 , respectively. As each home in a capital project is completed and becomes available for lease-up, the Company ceases capitalization on the related portion and depreciation commences over the estimated useful life.

Real Estate Owned (UNITED DOMIN

Real Estate Owned (UNITED DOMINION REALTY, L.P.)	9 Months Ended
	Sep. 30, 2015
Entity Information [Line Items]
REAL ESTATE OWNED	REAL ESTATE OWNED Real estate assets owned by the Company consist of income producing operating properties, properties under development, land held for future development, and sold or held for disposition properties. The Company had eight communities with a total of 1,755 apartment homes that met the criteria to be classified as held for disposition at September 30, 2015 . The communities are located in Virginia Beach, Hampton and Yorktown, VA, Columbia, MD, Pinellas Park, FL, Orange County, CA, and Oxnard, CA. As of September 30, 2015 , the Company owned and consolidated 136 communities in 10 states plus the District of Columbia totaling 39,405 apartment homes. The following table summarizes the carrying amounts for our real estate owned (at cost) as of September 30, 2015 and December 31, 2014 (dollars in thousands): September 30, December 31, 2014 Land and land improvements $ 1,840,823 $ 1,980,221 Depreciable property — held and used: Building, improvements, and furniture, fixtures and equipment 6,321,640 6,225,406 Under development: Land and land improvements 78,085 24,584 Building, improvements, and furniture, fixtures and equipment 25,995 153,048 Real estate held for disposition: Land and land improvements 81,080 — Building, improvements, and furniture, fixtures and equipment 125,354 — Real estate owned 8,472,977 8,383,259 Accumulated depreciation (2,647,504 ) (2,434,772 ) Real estate owned, net $ 5,825,473 $ 5,948,487 In February 2015, the Company acquired an office building in Highlands Ranch, Colorado, for total consideration of approximately $24.0 million , which was comprised of assumed debt. The Company's corporate offices, as well as other leased office space, are located in the acquired building. The building consists of approximately 120,000 square feet. All existing leases were assumed by the Company at the time of acquisition. During the nine months ended September 30, 2015 , the Company sold three communities with a total of 812 apartment homes for gross proceeds of $109.9 million , resulting in net proceeds of $90.5 million and a total gain, net of tax, of $79.0 million . A portion of the sale proceeds were designated as a tax-deferred exchange related to a 2014 acquisition under Section 1031 of the Internal Revenue Code. Predevelopment, development, and redevelopment projects and related costs are capitalized and reported on the Consolidated Balance Sheets as Total real estate owned, net of accumulated depreciation . The Company capitalizes costs directly related to the predevelopment, development, and redevelopment of a capital project, which include, but are not limited to, interest, real estate taxes, insurance, and allocated development and redevelopment overhead related to support costs for personnel working on the capital projects. We use our professional judgment in determining whether such costs meet the criteria for capitalization or must be expensed as incurred. These costs are capitalized only during the period in which activities necessary to ready an asset for its intended use are in progress and such costs are incremental and identifiable to a specific activity to get the asset ready for its intended use. These costs, excluding the direct costs of development and redevelopment and capitalized interest, were $1.7 million and $1.7 million for the three months ended September 30, 2015 and 2014 , respectively, and $5.5 million and $7.2 million for the nine months ended September 30, 2015 and 2014 , respectively. Total interest capitalized was $3.6 million and $5.2 million for the three months ended September 30, 2015 and 2014 , respectively, and $12.2 million and $15.4 million for the nine months ended September 30, 2015 and 2014 , respectively. As each home in a capital project is completed and becomes available for lease-up, the Company ceases capitalization on the related portion and depreciation commences over the estimated useful life.
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
REAL ESTATE OWNED	REAL ESTATE OWNED Real estate assets owned by the Operating Partnership consists of income producing operating properties, properties under development, land held for future development, and sold or held for disposition properties. The Operating Partnership had four communities with a total of 909 apartment homes that met the criteria to be classified as held for sale at September 30, 2015 . The communities are located in Columbia, MD, Pinellas Park, FL, Orange County, CA and Oxnard, CA. As of September 30, 2015 , the Operating Partnership owned and consolidated 67 communities in nine states plus the District of Columbia totaling 20,569 apartment homes. The following table summarizes the carrying amounts for our real estate owned (at cost) as of September 30, 2015 and December 31, 2014 (dollars in thousands) : September 30, December 31, 2014 Land $ 932,717 $ 1,008,014 Depreciable property — held and used: Buildings, improvements, and furniture, fixture and equipment 3,174,403 3,230,756 Real estate held for disposition: Land 75,160 — Buildings, improvements, and furniture, fixture and equipment 76,298 — Real estate owned 4,258,578 4,238,770 Accumulated depreciation (1,518,558 ) (1,403,303 ) Real estate owned, net $ 2,740,020 $ 2,835,467 The Operating Partnership did not have any acquisitions or dispositions during the three months ended September 30, 2015 . During the nine months ended September 30, 2015 , the Operating Partnership sold one community with a total of 240 apartment homes for gross proceeds of $45.3 million , resulting in net proceeds of $27.7 million and a total gain, net of tax, of $32.4 million . Additionally, the Operating Partnership recognized a gain of $24.6 million , which was previously deferred, in connection with the sale of the communities held by the Texas Joint Venture. Predevelopment, development, and redevelopment projects and related costs are capitalized and reported on the Consolidated Balance Sheets as Total real estate owned, net of accumulated depreciation . The Operating Partnership capitalizes costs directly related to the predevelopment, development, and redevelopment of a capital project, which include, but are not limited to, interest, real estate taxes, insurance, and allocated development and redevelopment overhead related to support costs for personnel working on the capital projects. We use our professional judgment in determining whether such costs meet the criteria for capitalization or must be expensed as incurred. These costs are capitalized only during the period in which activities necessary to ready an asset for its intended use are in progress and such costs are incremental and identifiable to a specific activity to get the asset ready for its intended use. These costs, excluding the direct costs of development and redevelopment and capitalized interest, were $0.2 million and $0.5 million for the three months ended September 30, 2015 and 2014 , respectively, and $0.5 million and $1.8 million for the nine months ended September 30, 2015 and 2014 , respectively. Total interest capitalized was $0.1 million and $0.8 million during the three months ended September 30, 2015 and 2014 , respectively, and $0.1 million and $2.8 million during the nine months ended September 30, 2015 and 2014 , respectively. As each home in a capital project is completed and becomes available for lease-up, the Operating Partnership ceases capitalization on the related portion and depreciation commences over the estimated useful life.

Discontinued Operations

Discontinued Operations	9 Months Ended
	Sep. 30, 2015
Discontinued Operations and Disposal Groups [Abstract]
DISCONTINUED OPERATIONS	DISCONTINUED OPERATIONS Effective January 1, 2014, UDR prospectively adopted ASU No. 2014-08, Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity , for all communities not previously sold or classified as held for sale. The standard had a material impact on the Company’s consolidated financial statements. As a result of adopting the ASU, during the three and nine months ended September 30, 2014 , gains (net of tax) of $31.3 million and $81.2 million , respectively, from disposition of real estate, excluding a $1.1 million gain related to the sale of land, are included in Gain/(loss) on sale of real estate owned, net of tax on the Consolidated Statements of Operations rather than in Income/(loss) from discontinued operations, net of tax on the Consolidated Statements of Operations. In July 2014, the Company sold one operating property that was classified as held for sale prior to the adoption of ASU 2014-08 and, therefore, met the requirements to be reported as a discontinued operation. The sale of this property resulted in an immaterial gain (net of tax) of less than $0.1 million . The gain (net of tax) and operating results of the property for the three and nine months ended September 30, 2014 are included in Income/(loss) from discontinued operations, net of tax on the Consolidated Statements of Operations. The following is a summary of income/(loss) from discontinued operations, net of tax for the three and nine months ended September 30, 2015 and 2014 ( dollars in thousands ): Three Months Ended Nine Months Ended September 30, September 30, 2015 2014 2015 2014 Rental income $ — $ 21 $ — $ 147 Rental expenses — 11 — 225 Property management — 1 — 4 Interest income and other (income)/expense, net — 3 — 21 Income/(loss) attributable to disposed properties and assets held for sale — 6 — (103 ) Net gain/(loss) on the sale of depreciable properties — 75 — 75 Income tax benefit/(expense) — (2 ) — 38 Income/(loss) from discontinued operations, net of tax $ — $ 79 $ — $ 10 Income/(loss) from discontinued operations attributable to UDR, Inc. $ — $ 73 $ — $ 6

Joint Ventures

Joint Ventures	9 Months Ended
	Sep. 30, 2015
Schedule of Equity Method Investments [Line Items]
Equity Method Investments and Joint Ventures Disclosure [Text Block]	JOINT VENTURES AND PARTNERSHIPS UDR has entered into joint ventures and partnerships with unrelated third parties to acquire real estate assets that are either consolidated and included in Real estate owned on the Consolidated Balance Sheets or are accounted for under the equity method of accounting, and are included in Investment in and advances to unconsolidated joint ventures, net on the Consolidated Balance Sheets. The Company consolidates the entities that we control as well as any variable interest entity where we are the primary beneficiary. In addition, the Company consolidates any joint venture or partnership in which we are the general partner or managing member and the third party does not have the ability to substantively participate in the decision-making process nor the ability to remove us as general partner or managing member without cause. UDR’s joint ventures and partnerships are funded with a combination of debt and equity. Our losses are limited to our investment and except as noted below, the Company does not guarantee any debt, capital payout or other obligations associated with our joint ventures and partnerships. Unconsolidated Joint Ventures and Partnerships The Company recognizes income or losses from our investments in unconsolidated joint ventures and partnerships consisting of our proportionate share of the net income or losses of the joint ventures and partnerships. In addition, we may earn fees for providing management services to the unconsolidated joint ventures and partnerships. The following table summarizes the Company’s investment in and advances to unconsolidated joint ventures and partnerships, net, which are accounted for under the equity method of accounting as of September 30, 2015 and December 31, 2014 (dollars in thousands) : Joint Venture Location of Properties Number of Properties Number of Apartment Homes Investment at UDR’s Ownership Interest September 30, September 30, September 30, December 31, September 30, December 31, Operating and development: UDR/MetLife I Various 4 land parcels — $ 14,804 $ 13,306 16.4 % 15.7 % UDR/MetLife II Various 21 operating communities 4,642 425,963 431,277 50.0 % 50.0 % Other UDR/MetLife Development Joint Ventures 1 operating community; 4 development communities (a); Various 1 land parcel 1,437 163,961 134,939 50.6 % 50.6 % UDR/MetLife Vitruvian Park ® Addison, TX 3 operating communities 6 land parcels 1,130 73,618 80,302 50.0 % 50.0 % UDR/KFH Washington, D.C. 3 operating communities 660 18,308 21,596 30.0 % 30.0 % Texas (b) Texas — — — (25,901 ) — % 20.0 % Investment in and advances to unconsolidated joint ventures, net, before participating loan investment and preferred equity investment 695,980,000 696,654 655,519 Income from Investment Investment at Three Months Ended September 30, Nine Months Ended September 30, Location Rate Years To Maturity September 30, December 31, 2015 2014 2015 2014 Participating loan investment: Steele Creek Denver, CO 6.5% 1.8 89,498 62,707 $1,458 $ 642 $3,964 $ 1,419 Preferred equity investment: West Coast Development Joint Venture (c) Various 6.5% — 135,773 — $2,086 $ — $1,578 $ — Total investment in and advances to unconsolidated joint ventures, net $ 921,925 $ 718,226 (a) The number of apartment homes for the communities under development presented in the table above is based on the projected number of total homes. As of September 30, 2015 , no apartment homes had been completed in Other UDR/MetLife Development Joint Ventures. (b) In January 2015, the eight communities held by the Texas Joint Venture were sold, generating net proceeds to UDR of $43.5 million . The Company recorded promote and disposition fee income of $9.6 million and a gain of $59.1 million (including $24.2 million of previously deferred gains) in connection with the sale. (c) In May 2015, the Company entered into a joint venture agreement with real estate private equity firm, The Wolff Company (“Wolff”), and agreed to pay $136.3 million for a 48 percent interest in a portfolio of five communities that are currently under construction (the "West Coast Development Joint Venture"). As of September 30, 2015 , the Company had funded $129.6 million of its investment and had a remaining commitment of $6.7 million . The communities are located in three of the Company’s core, coastal markets: Metro Seattle, Los Angeles and Orange County, CA. UDR earns a 6.5 percent preferred return on its investment through each individual community’s date of stabilization, defined as when a community reaches 80 percent occupancy for ninety consecutive days, while Wolff is allocated all operating income and expense during the pre-stabilization period. Upon stabilization, income and expense will be shared based on each partner’s ownership percentage. The Company will serve as property manager and be paid a management fee during the lease-up phase and subsequent operation of each of the communities. Wolff is the general partner of the joint venture and the developer of the communities. The Company has a fixed price option to acquire Wolff’s remaining interest in each community beginning one year after completion. If the options are exercised for all five communities, the Company’s total price will be $597.4 million . In the event the Company does not exercise its options to purchase at least two communities, Wolff will be entitled to earn a contingent disposition fee equal to 6.5 percent return on its implied equity in the communities not acquired. Wolff is providing certain guaranties and there are construction loans on all five communities. Once completed, the five communities will contain 1,533 homes. The Company has concluded it does not control the joint venture and accounts for it under the equity method of accounting. The Company's recorded equity investment in the West Coast Development Joint Venture at September 30, 2015 of $135.8 million is inclusive of outside basis costs and our accrued but unpaid preferred return. During the three months ended September 30, 2015 , the Company earned a preferred return of $2.1 million . During the nine months ended September 30, 2015 , the Company earned a preferred return of $3.1 million , offset by its share of the West Coast Development Joint Venture transaction expenses of $1.5 million . As of September 30, 2015 and December 31, 2014 , the Company had deferred fees and deferred profit from the sale of properties to joint ventures or partnerships of $9.3 million and $28.5 million , respectively, which will be recognized through income over the weighted average life of the related properties, upon the disposition of the properties to a third party, or upon completion of certain development obligations. The Company recognized management fees for our management of the joint ventures and partnerships of $3.3 million and $2.7 million for the three months ended September 30, 2015 and 2014 , respectively, and $8.5 million and $8.3 million for the nine months ended September 30, 2015 and 2014 , respectively. The management fees are included in Joint venture management and other fees on the Consolidated Statements of Operations. The Company may, in the future, make additional capital contributions to certain of our joint ventures and partnerships should additional capital contributions be necessary to fund acquisitions or operations. We evaluate our investments in unconsolidated joint ventures and partnerships when events or changes in circumstances indicate that there may be an other-than-temporary decline in value. We consider various factors to determine if a decrease in the value of the investment is other-than-temporary. The Company did not recognize any other-than-temporary decreases in the value of its investments in unconsolidated joint ventures or partnerships during the three and nine months ended September 30, 2015 and 2014 . Combined summary balance sheets relating to all of the unconsolidated joint ventures and partnerships (not just our proportionate share) are presented below as of September 30, 2015 and December 31, 2014 ( dollars in thousands ): September 30, December 31, 2014 Total real estate, net $ 3,074,723 $ 2,941,803 Assets held for sale — 216,196 Cash and cash equivalents 37,768 32,544 Other assets 44,259 28,707 Total assets $ 3,156,750 $ 3,219,250 Amount due to UDR $ 7,465 $ 2,997 Third party debt 1,586,380 1,504,477 Liabilities held for sale — 229,706 Accounts payable and accrued liabilities 87,730 44,335 Total liabilities 1,681,575 1,781,515 Total equity 1,475,175 1,437,735 Total liabilities and equity $ 3,156,750 $ 3,219,250 UDR’s investment in unconsolidated joint ventures $ 921,925 $ 718,226 Combined summary financial information relating to all of the unconsolidated joint ventures’ and partnerships’ operations (not just our proportionate share), is presented below for the three and nine months ended September 30, 2015 and 2014 ( dollars in thousands ) : Three Months Ended Nine Months Ended September 30, September 30, 2015 2014 2015 2014 Total revenues $ 55,948 $ 52,804 $ 165,944 $ 140,138 Property operating expenses (21,981 ) (19,837 ) (63,692 ) (52,197 ) Real estate depreciation and amortization (18,272 ) (19,158 ) (57,026 ) (50,654 ) Operating income/(loss) 15,695 13,809 45,226 37,287 Interest expense (16,310 ) (15,755 ) (48,540 ) (42,833 ) Other income/(expense) (182 ) — (190 ) — Income/(loss) from discontinued operations (37 ) (2,891 ) 182,452 (37,579 ) Net income/(loss) $ (834 ) $ (4,837 ) $ 178,948 $ (43,125 ) UDR income/(loss) from unconsolidated entities $ 2,691 $ (939 ) $ 61,277 $ (4,932 )

Secured and Unsecured Debt

Secured and Unsecured Debt	9 Months Ended
	Sep. 30, 2015
Debt Disclosure [Abstract]
Debt Disclosure [Text Block]	SECURED AND UNSECURED DEBT The following is a summary of our secured and unsecured debt at September 30, 2015 and December 31, 2014 ( dollars in thousands ): Nine Months Ended Principal Outstanding September 30, 2015 September 30, December 31, 2014 Weighted Average Interest Rate Weighted Average Years to Maturity Number of Communities Encumbered Secured Debt: Fixed Rate Debt Mortgage notes payable (a) $ 406,183 $ 401,210 5.51 % 0.9 7 Fannie Mae credit facilities (b) 565,394 568,086 5.12 % 3.3 21 Total fixed rate secured debt 971,577 969,296 5.28 % 2.3 28 Variable Rate Debt Mortgage notes payable 31,337 31,337 2.00 % 1.3 1 Tax-exempt secured notes payable (c) 94,700 94,700 0.75 % 7.4 2 Fannie Mae credit facilities (b) 249,378 266,196 1.65 % 4.5 7 Total variable rate secured debt 375,415 392,233 1.45 % 5.0 10 Total Secured Debt 1,346,992 1,361,529 4.21 % 3.0 38 Unsecured Debt: Commercial Banks Borrowings outstanding under an unsecured credit facility due December 2017 (d) (g) 110,000 152,500 1.19 % 2.2 Senior Unsecured Notes 5.25% Medium-Term Notes due January 2015 (net of discounts of $0 and $6, respectively) (e) — 325,169 — % — 5.25% Medium-Term Notes due January 2016 83,260 83,260 5.25 % 0.3 6.21% Term Notes due July 2016 12,351 — 6.21 % 0.8 4.25% Medium-Term Notes due June 2018 (net of discounts of $1,144 and $1,465, respectively) (g) 298,856 298,535 4.25 % 2.7 1.70% Term Notes due June 2018 (g) 215,000 215,000 1.70 % 2.7 1.53% Term Notes due June 2018 (g) 100,000 100,000 1.53 % 2.7 1.35% Term Notes due June 2018 (g) 35,000 35,000 1.35 % 2.7 3.70% Medium-Term Notes due October 2020 (net of discounts of $40 and $46, respectively) (g) 299,960 299,954 3.70 % 5.0 4.63% Medium-Term Notes due January 2022 (net of discounts of $2,254 and $2,523, respectively) (g) 397,746 397,477 4.63 % 6.3 3.75% Medium-Term Notes due July 2024 (net of discount of $912 and $990, respectively) (g) 299,088 299,010 3.75 % 8.8 8.50% Debentures due September 2024 15,644 15,644 8.50 % 9.0 4.00% Medium-Term Notes due October 2025 (net of discount of $688 and $0, respectively) (f) (g) 299,312 — 4.00 % 10.0 Other 25 27 N/A N/A Total Unsecured Debt 2,166,242 2,221,576 3.72 % 5.5 Total Debt $ 3,513,234 $ 3,583,105 3.91 % 4.5 Our secured debt instruments generally feature either monthly interest and principal or monthly interest-only payments with balloon payments due at maturity. For purposes of classification of the above table, variable rate debt with a derivative financial instrument designated as a cash flow hedge is deemed as fixed rate debt due to the Company having effectively established a fixed interest rate for the underlying debt instrument. As of September 30, 2015 , secured debt encumbered $2.3 billion or 26.6% of UDR’s total real estate owned based upon gross book value ( $6.2 billion or 73.4% of UDR’s real estate owned based on gross book value is unencumbered). (a) At September 30, 2015 , fixed rate mortgage notes payable are generally due in monthly installments of principal and interest and mature at various dates from December 2015 through May 2019 and carry interest rates ranging from 3.43% to 6.16% . The Company will from time to time acquire properties subject to fixed rate debt instruments. In those situations, the Company records the debt at its estimated fair value and amortizes any difference between the fair value and par to interest expense over the life of the underlying debt instrument. The Company had a reduction to interest expense based on the amortization of the fair market adjustment of debt assumed in the acquisition of properties of $1.3 million and $1.3 million during the three months ended September 30, 2015 and 2014 , respectively, and $3.7 million and $3.8 million during the nine months ended September 30, 2015 and 2014 , respectively. The unamortized fair market adjustment was a net premium of $4.4 million and $6.7 million at September 30, 2015 and December 31, 2014 , respectively. (b) UDR has three secured credit facilities with Fannie Mae with an aggregate commitment of $814.8 million at September 30, 2015 . The Fannie Mae credit facilities mature at various dates from May 2017 through July 2023 and bear interest at floating and fixed rates. At September 30, 2015 , $565.4 million of the outstanding balance was fixed and had a weighted average interest rate of 5.12% and the remaining balance of $249.4 million had a weighted average variable interest rate of 1.65% . Further information related to these credit facilities is as follows (dollars in thousands) : September 30, December 31, 2014 Borrowings outstanding $ 814,772 $ 834,282 Weighted average borrowings during the period ended 825,311 835,873 Maximum daily borrowings during the period ended 834,003 837,564 Weighted average interest rate during the period ended 4.0 % 4.1 % Weighted average interest rate at the end of the period 4.1 % 4.0 % (c) The variable rate mortgage notes payable that secure tax-exempt housing bond issues mature in August 2019 and March 2032 . Interest on these notes is payable in monthly installments. The variable rate mortgage notes have interest rates of 0.75% and 0.76% as of September 30, 2015 . (d) As of September 30, 2015 , the Company has a $900 million unsecured revolving credit facility that matures in December 2017 . The credit facility has a six month extension option and contains an accordion feature that allows us to increase the facility to $1.45 billion . Based on the Company’s current credit rating, the credit facility carries an interest rate equal to LIBOR plus a spread of 100 basis points and a facility fee of 15 basis points. The following is a summary of short-term bank borrowings under UDR’s revolving credit facility at September 30, 2015 and December 31, 2014 (dollars in thousands): September 30, December 31, 2014 Total revolving credit facility $ 900,000 $ 900,000 Borrowings outstanding at end of period (1) 110,000 152,500 Weighted average daily borrowings during the period ended 409,215 291,761 Maximum daily borrowings during the period ended 541,500 625,000 Weighted average interest rate during the period ended 1.2 % 1.2 % Interest rate at end of the period 1.2 % 1.1 % (1) Excludes $2.3 million and $1.9 million of letters of credit at September 30, 2015 and December 31, 2014 , respectively. (e) Paid off at maturity with borrowings under the Company's $900 million unsecured revolving credit facility. (f) On September 22, 2015, the Company issued $300 million of 4.00% senior unsecured medium-term notes due October 1, 2025. Interest is payable semi-annually beginning on April 1, 2016. The notes were priced at 99.770% of the principal amount at issuance and had a discount of $0.7 million at September 30, 2015 . The Company used the net proceeds to pay down a portion of the borrowings outstanding on its $900 million unsecured credit facility and for general corporate purposes. The Company previously entered into forward starting interest rate swaps to hedge against interest rate risk on $200 million of this debt issuance. The all-in weighted average interest rate, inclusive of the impact of these interest rate swaps, was 4.55% . (g) The Operating Partnership is a guarantor of this debt. The aggregate maturities, including amortizing principal payments of unsecured and secured debt, of total debt for the next five calendar years subsequent to September 30, 2015 are as follows (dollars in thousands): Year Total Fixed Secured Debt Total Variable Secured Debt Total Secured Debt Total Unsecured Debt (a) Total Debt 2015 $ 187,916 $ — $ 187,916 $ 25 $ 187,941 2016 148,223 — 148,223 94,402 242,625 2017 177,882 96,337 274,219 110,000 384,219 2018 121,685 87,969 209,654 648,311 857,965 2019 245,871 67,700 313,571 — 313,571 Thereafter 90,000 123,409 213,409 1,313,504 1,526,913 Total $ 971,577 $ 375,415 $ 1,346,992 $ 2,166,242 $ 3,513,234 (a) With the exception of the 1.35% Term Notes due June 2018 and the revolving credit facility which carry a variable interest rate, all unsecured debt carries fixed interest rates. We were in compliance with the covenants of our debt instruments at September 30, 2015 .

Debt (UNITED DOMINION REALTY, L

Debt (UNITED DOMINION REALTY, L.P.)	9 Months Ended
	Sep. 30, 2015
Entity Information [Line Items]
DEBT	SECURED AND UNSECURED DEBT The following is a summary of our secured and unsecured debt at September 30, 2015 and December 31, 2014 ( dollars in thousands ): Nine Months Ended Principal Outstanding September 30, 2015 September 30, December 31, 2014 Weighted Average Interest Rate Weighted Average Years to Maturity Number of Communities Encumbered Secured Debt: Fixed Rate Debt Mortgage notes payable (a) $ 406,183 $ 401,210 5.51 % 0.9 7 Fannie Mae credit facilities (b) 565,394 568,086 5.12 % 3.3 21 Total fixed rate secured debt 971,577 969,296 5.28 % 2.3 28 Variable Rate Debt Mortgage notes payable 31,337 31,337 2.00 % 1.3 1 Tax-exempt secured notes payable (c) 94,700 94,700 0.75 % 7.4 2 Fannie Mae credit facilities (b) 249,378 266,196 1.65 % 4.5 7 Total variable rate secured debt 375,415 392,233 1.45 % 5.0 10 Total Secured Debt 1,346,992 1,361,529 4.21 % 3.0 38 Unsecured Debt: Commercial Banks Borrowings outstanding under an unsecured credit facility due December 2017 (d) (g) 110,000 152,500 1.19 % 2.2 Senior Unsecured Notes 5.25% Medium-Term Notes due January 2015 (net of discounts of $0 and $6, respectively) (e) — 325,169 — % — 5.25% Medium-Term Notes due January 2016 83,260 83,260 5.25 % 0.3 6.21% Term Notes due July 2016 12,351 — 6.21 % 0.8 4.25% Medium-Term Notes due June 2018 (net of discounts of $1,144 and $1,465, respectively) (g) 298,856 298,535 4.25 % 2.7 1.70% Term Notes due June 2018 (g) 215,000 215,000 1.70 % 2.7 1.53% Term Notes due June 2018 (g) 100,000 100,000 1.53 % 2.7 1.35% Term Notes due June 2018 (g) 35,000 35,000 1.35 % 2.7 3.70% Medium-Term Notes due October 2020 (net of discounts of $40 and $46, respectively) (g) 299,960 299,954 3.70 % 5.0 4.63% Medium-Term Notes due January 2022 (net of discounts of $2,254 and $2,523, respectively) (g) 397,746 397,477 4.63 % 6.3 3.75% Medium-Term Notes due July 2024 (net of discount of $912 and $990, respectively) (g) 299,088 299,010 3.75 % 8.8 8.50% Debentures due September 2024 15,644 15,644 8.50 % 9.0 4.00% Medium-Term Notes due October 2025 (net of discount of $688 and $0, respectively) (f) (g) 299,312 — 4.00 % 10.0 Other 25 27 N/A N/A Total Unsecured Debt 2,166,242 2,221,576 3.72 % 5.5 Total Debt $ 3,513,234 $ 3,583,105 3.91 % 4.5 Our secured debt instruments generally feature either monthly interest and principal or monthly interest-only payments with balloon payments due at maturity. For purposes of classification of the above table, variable rate debt with a derivative financial instrument designated as a cash flow hedge is deemed as fixed rate debt due to the Company having effectively established a fixed interest rate for the underlying debt instrument. As of September 30, 2015 , secured debt encumbered $2.3 billion or 26.6% of UDR’s total real estate owned based upon gross book value ( $6.2 billion or 73.4% of UDR’s real estate owned based on gross book value is unencumbered). (a) At September 30, 2015 , fixed rate mortgage notes payable are generally due in monthly installments of principal and interest and mature at various dates from December 2015 through May 2019 and carry interest rates ranging from 3.43% to 6.16% . The Company will from time to time acquire properties subject to fixed rate debt instruments. In those situations, the Company records the debt at its estimated fair value and amortizes any difference between the fair value and par to interest expense over the life of the underlying debt instrument. The Company had a reduction to interest expense based on the amortization of the fair market adjustment of debt assumed in the acquisition of properties of $1.3 million and $1.3 million during the three months ended September 30, 2015 and 2014 , respectively, and $3.7 million and $3.8 million during the nine months ended September 30, 2015 and 2014 , respectively. The unamortized fair market adjustment was a net premium of $4.4 million and $6.7 million at September 30, 2015 and December 31, 2014 , respectively. (b) UDR has three secured credit facilities with Fannie Mae with an aggregate commitment of $814.8 million at September 30, 2015 . The Fannie Mae credit facilities mature at various dates from May 2017 through July 2023 and bear interest at floating and fixed rates. At September 30, 2015 , $565.4 million of the outstanding balance was fixed and had a weighted average interest rate of 5.12% and the remaining balance of $249.4 million had a weighted average variable interest rate of 1.65% . Further information related to these credit facilities is as follows (dollars in thousands) : September 30, December 31, 2014 Borrowings outstanding $ 814,772 $ 834,282 Weighted average borrowings during the period ended 825,311 835,873 Maximum daily borrowings during the period ended 834,003 837,564 Weighted average interest rate during the period ended 4.0 % 4.1 % Weighted average interest rate at the end of the period 4.1 % 4.0 % (c) The variable rate mortgage notes payable that secure tax-exempt housing bond issues mature in August 2019 and March 2032 . Interest on these notes is payable in monthly installments. The variable rate mortgage notes have interest rates of 0.75% and 0.76% as of September 30, 2015 . (d) As of September 30, 2015 , the Company has a $900 million unsecured revolving credit facility that matures in December 2017 . The credit facility has a six month extension option and contains an accordion feature that allows us to increase the facility to $1.45 billion . Based on the Company’s current credit rating, the credit facility carries an interest rate equal to LIBOR plus a spread of 100 basis points and a facility fee of 15 basis points. The following is a summary of short-term bank borrowings under UDR’s revolving credit facility at September 30, 2015 and December 31, 2014 (dollars in thousands): September 30, December 31, 2014 Total revolving credit facility $ 900,000 $ 900,000 Borrowings outstanding at end of period (1) 110,000 152,500 Weighted average daily borrowings during the period ended 409,215 291,761 Maximum daily borrowings during the period ended 541,500 625,000 Weighted average interest rate during the period ended 1.2 % 1.2 % Interest rate at end of the period 1.2 % 1.1 % (1) Excludes $2.3 million and $1.9 million of letters of credit at September 30, 2015 and December 31, 2014 , respectively. (e) Paid off at maturity with borrowings under the Company's $900 million unsecured revolving credit facility. (f) On September 22, 2015, the Company issued $300 million of 4.00% senior unsecured medium-term notes due October 1, 2025. Interest is payable semi-annually beginning on April 1, 2016. The notes were priced at 99.770% of the principal amount at issuance and had a discount of $0.7 million at September 30, 2015 . The Company used the net proceeds to pay down a portion of the borrowings outstanding on its $900 million unsecured credit facility and for general corporate purposes. The Company previously entered into forward starting interest rate swaps to hedge against interest rate risk on $200 million of this debt issuance. The all-in weighted average interest rate, inclusive of the impact of these interest rate swaps, was 4.55% . (g) The Operating Partnership is a guarantor of this debt. The aggregate maturities, including amortizing principal payments of unsecured and secured debt, of total debt for the next five calendar years subsequent to September 30, 2015 are as follows (dollars in thousands): Year Total Fixed Secured Debt Total Variable Secured Debt Total Secured Debt Total Unsecured Debt (a) Total Debt 2015 $ 187,916 $ — $ 187,916 $ 25 $ 187,941 2016 148,223 — 148,223 94,402 242,625 2017 177,882 96,337 274,219 110,000 384,219 2018 121,685 87,969 209,654 648,311 857,965 2019 245,871 67,700 313,571 — 313,571 Thereafter 90,000 123,409 213,409 1,313,504 1,526,913 Total $ 971,577 $ 375,415 $ 1,346,992 $ 2,166,242 $ 3,513,234 (a) With the exception of the 1.35% Term Notes due June 2018 and the revolving credit facility which carry a variable interest rate, all unsecured debt carries fixed interest rates. We were in compliance with the covenants of our debt instruments at September 30, 2015 .
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
DEBT	DEBT Our secured debt instruments generally feature either monthly interest and principal or monthly interest-only payments with balloon payments due at maturity. For purposes of classification in the following table, variable rate debt with a derivative financial instrument designated as a cash flow hedge is deemed as fixed rate debt due to the Operating Partnership having effectively established the fixed interest rate for the underlying debt instrument. Secured debt consists of the following as of September 30, 2015 and December 31, 2014 ( dollars in thousands ): Nine Months Ended Principal Outstanding September 30, 2015 September 30, December 31, 2014 Weighted Average Interest Rate Weighted Average Years to Maturity Number of Communities Encumbered Fixed Rate Debt Mortgage notes payable $ 371,888 $ 378,371 5.50 % 0.9 5 Fannie Mae credit facilities 333,912 333,828 4.90 % 3.8 9 Total fixed rate secured debt 705,800 712,199 5.22 % 2.3 14 Variable Rate Debt Tax-exempt secured note payable 27,000 27,000 0.76 % 16.5 1 Fannie Mae credit facilities 177,509 192,760 1.89 % 5.4 5 Total variable rate secured debt 204,509 219,760 1.74 % 6.9 6 Total Secured Debt $ 910,309 $ 931,959 4.44 % 3.3 20 As of September 30, 2015 , an aggregate commitment of $511.4 million of the General Partner's secured credit facilities with Fannie Mae was allocated to the Operating Partnership based on the ownership of the assets securing the debt. The entire commitment was outstanding at September 30, 2015 . The Fannie Mae credit facilities mature at various dates from May 2017 through July 2023 and bear interest at floating and fixed rates. At September 30, 2015 , $333.9 million of the outstanding balance was fixed and had a weighted average interest rate of 4.90% and the remaining balance of $177.5 million on these facilities had a weighted average variable interest rate of 1.89% . The following information relates to the credit facilities allocated to the Operating Partnership (dollars in thousands) : September 30, December 31, 2014 Borrowings outstanding $ 511,421 $ 526,588 Weighted average borrowings during the period ended 518,036 527,592 Maximum daily borrowings during the period 523,492 528,659 Weighted average interest rate during the period ended 3.8 % 4.1 % Interest rate at the end of the period 3.9 % 4.0 % The Operating Partnership may from time to time acquire properties subject to fixed rate debt instruments. In those situations, management will record the secured debt at its estimated fair value and amortize any difference between the fair value and par to interest expense over the life of the underlying debt instrument. The unamortized fair value adjustment of the fixed rate debt instruments on the Operating Partnership’s properties was a net premium of $3.3 million and $6.2 million at September 30, 2015 and December 31, 2014 , respectively. Fixed Rate Debt Mortgage notes payable. Fixed rate mortgage notes payable are generally due in monthly installments of principal and interest and mature at various dates from December 2015 through May 2019 and carry interest rates ranging from 3.43% to 5.94% . Secured credit facilities. At September 30, 2015 , the General Partner had borrowings against its fixed rate facilities of $565.4 million , of which $333.9 million was allocated to the Operating Partnership based on the ownership of the assets securing the debt. As of September 30, 2015 , the fixed rate Fannie Mae credit facilities allocated to the Operating Partnership had a weighted average fixed interest rate of 4.90% . Variable Rate Debt Tax-exempt secured note payable. The variable rate mortgage note payable that secures tax-exempt housing bond issues matures March 2032 . Interest on this note is payable in monthly installments. The mortgage note payable has an interest rate of 0.76% as of September 30, 2015 . Secured credit facilities. At September 30, 2015 , the General Partner had borrowings against its variable rate facilities of $249.4 million , of which $177.5 million was allocated to the Operating Partnership based on the ownership of the assets securing the debt. As of September 30, 2015 , the variable rate borrowings under the Fannie Mae credit facilities allocated to the Operating Partnership had a weighted average floating interest rate of 1.89% . The aggregate maturities of the Operating Partnership’s secured debt due during each of the next five calendar years subsequent to September 30, 2015 are as follows (dollars in thousands): Fixed Variable Year Mortgage Notes Payable Secured Credit Facilities Tax-Exempt Secured Notes Payable Secured Credit Facilities Total 2015 $ 186,592 $ 94 $ — $ — $ 186,686 2016 131,946 385 — — 132,331 2017 1,629 15,640 — 6,566 23,835 2018 1,685 111,256 — 81,559 194,500 2019 50,036 123,095 — — 173,131 Thereafter — 83,442 27,000 89,384 199,826 Total $ 371,888 $ 333,912 $ 27,000 $ 177,509 $ 910,309 Guarantor on Unsecured Debt The Operating Partnership is a guarantor on the General Partner’s unsecured revolving credit facility with an aggregate borrowing capacity of $900 million , $250 million of term notes due June 2018 , $100 million of term notes due June 2018 , $300 million of medium-term notes due June 2018 , $300 million of medium-term notes due October 2020 , $400 million of medium-term notes due January 2022 , $300 million of medium-term notes due July 2024 , and $300 million of medium-term notes due October 2025 . As of September 30, 2015 and December 31, 2014 , the outstanding balance under the unsecured revolving credit facility was $110.0 million and $152.5 million , respectively.

Income_(Loss) Per Share

Income/(Loss) Per Share	9 Months Ended
	Sep. 30, 2015
Earnings Per Share [Abstract]
EARNINGS/(LOSS) PER SHARE	/(LOSS) PER SHARE The following table sets forth the computation of basic and diluted income/(loss) per share for the periods presented (dollars and shares in thousands, except per share data): Three Months Ended Nine Months Ended September 30, September 30, 2015 2014 2015 2014 Numerator for income/(loss) per share: Income/(loss) from continuing operations $ 13,695 $ 10,611 $ 100,954 $ 9,775 Gain/(loss) on sale of real estate owned, net of tax — 31,302 79,042 82,305 (Income)/loss from continuing operations attributable to redeemable noncontrolling interests in the Operating Partnership (405 ) (1,441 ) (6,022 ) (3,167 ) (Income)/loss from continuing operations attributable to noncontrolling interests 1 4 (6 ) (2 ) Income/(loss) from continuing operations attributable to UDR, Inc. 13,291 40,476 173,968 88,911 Distributions to preferred stockholders - Series E (Convertible) (930 ) (931 ) (2,792 ) (2,793 ) Income/(loss) from continuing operations attributable to common stockholders $ 12,361 $ 39,545 $ 171,176 $ 86,118 Income/(loss) from discontinued operations, net of tax $ — $ 79 $ — $ 10 (Income)/loss from discontinued operations attributable to redeemable noncontrolling interests in the Operating Partnership — (6 ) — (4 ) Income/(loss) from discontinued operations attributable to common stockholders $ — $ 73 $ — $ 6 Net income/(loss) attributable to common stockholders $ 12,361 $ 39,618 $ 171,176 $ 86,124 Denominator for income/(loss) per share: Weighted average common shares outstanding 260,302 252,891 259,151 251,860 Non-vested restricted stock awards (1,188 ) (1,236 ) (1,211 ) (1,159 ) Denominator for basic income/(loss) per share 259,114 251,655 257,940 250,701 Incremental shares issuable from assumed conversion of preferred stock, stock options, and unvested restricted stock 2,093 2,077 2,080 1,974 Denominator for diluted income/(loss) per share 261,207 253,732 260,020 252,675 Income/(loss) per weighted average common share-basic: Income/(loss) from continuing operations attributable to common stockholders $ 0.05 $ 0.16 $ 0.66 $ 0.34 Income/(loss) from discontinued operations attributable to common stockholders — — — — Net income/(loss) attributable to common stockholders $ 0.05 $ 0.16 $ 0.66 $ 0.34 Income/(loss) per weighted average common share-diluted: Income/(loss) from continuing operations attributable to common stockholders $ 0.05 $ 0.16 $ 0.66 $ 0.34 Income/(loss) from discontinued operations attributable to common stockholders — — — — Net income/(loss) attributable to common stockholders $ 0.05 $ 0.16 $ 0.66 $ 0.34 Basic income/(loss) per common share is computed based upon the weighted average number of common shares outstanding. Diluted income/(loss) per share is computed based upon the weighted average number of common shares outstanding plus the common shares issuable from the assumed conversion of the OP Units, convertible preferred stock, stock options, and restricted stock. Only those instruments having a dilutive impact on our basic income/(loss) per share are included in diluted income/(loss) per share during the periods. The following table sets forth the additional shares of common stock outstanding by equity instrument if converted to common stock for each of the three and nine months ended September 30, 2015 and 2014 (shares in thousands) : Three Months Ended Nine Months Ended September 30, September 30, 2015 2014 2015 2014 OP Units 9,061 9,189 9,117 9,274 Preferred stock 3,029 3,036 3,033 3,036 Stock options and unvested restricted stock 2,093 2,077 2,080 1,974

Noncontrolling Interests

Noncontrolling Interests	9 Months Ended
	Sep. 30, 2015
Noncontrolling Interest [Abstract]
NONCONTROLLING INTERESTS	NONCONTROLLING INTERESTS Redeemable Noncontrolling Interests in the Operating Partnership Interests in the Operating Partnership held by limited partners are represented by OP Units. The income is allocated to holders of OP Units based upon net income attributable to common stockholders and the weighted average number of OP Units outstanding to total common shares plus OP Units outstanding during the period. Capital contributions, distributions, and profits and losses are allocated to noncontrolling interests in accordance with the terms of the individual partnership agreements. Limited partners have the right to require the Operating Partnership to redeem all or a portion of the OP Units held by the limited partners at a redemption price equal to and in the form of the Cash Amount as defined in the Amended and Restated Agreement of Limited Partnership of the Operating Partnership (the “Operating Partnership Agreement”), provided that such OP Units have been outstanding for at least one year. UDR, as the general partner of the Operating Partnership may, in its sole discretion, purchase the OP Units by paying to the limited partner either the Cash Amount or the REIT Share Amount (generally one share of common stock of the Company for each OP Unit), as defined in the Operating Partnership Agreement. Accordingly, the Company records the OP Units outside of permanent equity and reports the OP Units at their redemption value using the Company’s stock price at each balance sheet date. The following table sets forth redeemable noncontrolling interests in the Operating Partnership for the following period ( dollars in thousands ): Redeemable noncontrolling interests in the Operating Partnership, December 31, 2014 $ 282,480 Mark-to-market adjustment to redeemable noncontrolling interests in the Operating Partnership 35,508 Conversion of OP Units to Common Stock (3,818 ) Net income/(loss) attributable to redeemable noncontrolling interests in the Operating Partnership 6,022 Distributions to redeemable noncontrolling interests in the Operating Partnership (7,859 ) Allocation of other comprehensive income/(loss) (175 ) Redeemable noncontrolling interests in the Operating Partnership, September 30, 2015 $ 312,158 The following sets forth net income/(loss) attributable to common stockholders and transfers from redeemable noncontrolling interests in the Operating Partnership for the following periods (dollars in thousands) : Three Months Ended Nine Months Ended September 30, September 30, 2015 2014 2015 2014 Net income/(loss) attributable to common stockholders $ 12,361 $ 39,618 $ 171,176 $ 86,124 Conversion of OP Units to UDR Common stock 320 4,127 3,818 4,318 Change in equity from net income/(loss) attributable to common stockholders and conversion of OP Units to UDR Common Stock $ 12,681 $ 43,745 $ 174,994 $ 90,442 Noncontrolling Interests Noncontrolling interests represent interests of unrelated partners in certain consolidated affiliates, and are presented as part of equity in the Consolidated Balance Sheets since these interests are not redeemable. Net (income)/loss attributable to noncontrolling interests was $1,000 and $4,000 during the three months ended September 30, 2015 and 2014 , respectively, and $(6,000) and $(2,000) during the nine months ended September 30, 2015 and 2014 , respectively

Related Party Transactions (UNI

Related Party Transactions (UNITED DOMINION REALTY, L.P.)	9 Months Ended
	Sep. 30, 2015
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
RELATED PARTY TRANSACTIONS	RELATED PARTY TRANSACTIONS Advances (To)/From the General Partner The Operating Partnership participates in the General Partner’s central cash management program, wherein all the Operating Partnership’s cash receipts are remitted to the General Partner and all cash disbursements are funded by the General Partner. In addition, other miscellaneous costs such as administrative expenses are incurred by the General Partner on behalf of the Operating Partnership. As a result of these various transactions between the Operating Partnership and the General Partner, the Operating Partnership had net Advances (to)/from General Partner of $10.2 million and $13.6 million at September 30, 2015 and December 31, 2014 , respectively, which are reflected as increases of capital on the Consolidated Balance Sheets. Allocation of General and Administrative Expenses The General Partner provides various general and administrative and other overhead services for the Operating Partnership including legal assistance, acquisitions analysis, marketing and advertising, and allocates these expenses to the Operating Partnership first on the basis of direct usage when identifiable, with the remainder allocated based on its pro-rata portion of UDR’s total apartment homes. The general and administrative expenses allocated to the Operating Partnership by UDR were $6.5 million and $6.6 million during the three months ended September 30, 2015 and 2014 , respectively, and $16.3 million and $20.5 million during the nine months ended September 30, 2015 and 2014 , respectively, and are included in General and administrative on the Consolidated Statements of Operations. In the opinion of management, this method of allocation reflects the level of services received by the Operating Partnership from the General Partner. During the three months ended September 30, 2015 and 2014 , the Operating Partnership incurred $4.7 million and $3.2 million , respectively, and during the nine months ended September 30, 2015 and 2014 incurred $13.3 million and $9.4 million , respectively, of related party management fees related to a management agreement entered into in 2011 with wholly-owned subsidiaries of UDR's taxable REIT subsidiaries ("TRS"). (See further discussion in paragraph below.) These related party management fees are initially recorded in General and administrative on the Consolidated Statements of Operations, and a portion related to management fees charged by UDR's TRS is reclassified to Property management on the Consolidated Statements of Operations. (See further discussion below.) Management Fee In 2011, the Operating Partnership entered into a management agreement with wholly owned subsidiaries of UDR's TRSs. Under the management agreement, the Operating Partnership is charged a management fee equal to 2.75% of gross rental revenues, which is classified in Property management on the Consolidated Statements of Operations. Notes Payable to General Partner As of September 30, 2015 and December 31, 2014 , the Operating Partnership had $88.7 million of unsecured notes payable to the General Partner at annual interest rates between 5.18% and 5.34% . Certain limited partners of the Operating Partnership have provided guarantees related to these notes payable. The guarantees were provided by the limited partners in conjunction with their contribution of properties to the Operating Partnership. The notes mature on August 31, 2021 and December 31, 2023 and interest payments are made monthly. The Operating Partnership recognized interest expense on the notes payable of $1.2 million during the three months ended September 30, 2015 and 2014 and $3.5 million during the nine months ended September 30, 2015 and 2014 .

Fair Value of Derivatives and F

Fair Value of Derivatives and Financial Instruments	9 Months Ended
	Sep. 30, 2015
Fair Value Disclosures [Abstract]
FAIR VALUE OF DERIVATIVES AND FINANCIAL INSTRUMENTS	FAIR VALUE OF DERIVATIVES AND FINANCIAL INSTRUMENTS Fair value is based on the price that would be received to sell an asset or the exit price that would be paid to transfer a liability in an orderly transaction between market participants at the measurement date. A three-level valuation hierarchy prioritizes observable and unobservable inputs used to measure fair value. The fair value hierarchy consists of three broad levels, which are described below: • Level 1 — Quoted prices in active markets for identical assets or liabilities that the entity has the ability to access. • Level 2 — Observable inputs other than prices included in Level 1, such as quoted prices for similar assets and liabilities in active markets; quoted prices for identical or similar assets and liabilities in markets that are not active; or other inputs that are observable or can be corroborated with observable market data. • Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets and liabilities. This includes certain pricing models, discounted cash flow methodologies and similar techniques that use significant unobservable inputs. The estimated fair values of the Company’s financial instruments either recorded or disclosed on a recurring basis as of September 30, 2015 and December 31, 2014 are summarized as follows (dollars in thousands) : Fair Value at September 30, 2015, Using Total Carrying Amount in Statement of Financial Position at September 30, 2015 Fair Value Estimate at September 30, 2015 Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Description: Notes receivable (a) $ 15,494 $ 15,795 $ — $ — $ 15,795 Derivatives - Interest rate contracts (b) 6 6 — 6 — Total assets $ 15,500 $ 15,801 $ — $ 6 $ 15,795 Derivatives - Interest rate contracts (b) $ 3,205 $ 3,205 $ — $ 3,205 $ — Secured debt instruments - fixed rate: (c) Mortgage notes payable 406,183 416,287 — — 416,287 Fannie Mae credit facilities 565,394 595,907 — — 595,907 Secured debt instruments - variable rate: (c) Mortgage notes payable 31,337 31,337 — — 31,337 Tax-exempt secured notes payable 94,700 94,700 — — 94,700 Fannie Mae credit facilities 249,378 249,378 — — 249,378 Unsecured debt instruments: (c) Commercial bank 110,000 110,000 — — 110,000 Senior unsecured notes 2,056,242 2,128,901 — — 2,128,901 Total liabilities $ 3,516,439 $ 3,629,715 $ — $ 3,205 $ 3,626,510 Redeemable noncontrolling interests in the Operating Partnership (d) $ 312,158 $ 312,158 $ — $ 312,158 $ — Fair Value at December 31, 2014, Using Total Carrying Amount in Statement of Financial Position at December 31, 2014 Fair Value Estimate at December 31, 2014 Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Description: Notes receivable (a) $ 14,369 $ 14,808 $ — $ — $ 14,808 Derivatives - Interest rate contracts (b) 88 88 — 88 — Total assets $ 14,457 $ 14,896 $ — $ 88 $ 14,808 Derivatives- Interest rate contracts (b) $ 10,368 $ 10,368 $ — $ 10,368 $ — Secured debt instruments - fixed rate: (c) Mortgage notes payable 401,210 415,663 — — 415,663 Fannie Mae credit facilities 568,086 606,623 — — 606,623 Secured debt instruments - variable rate: (c) Mortgage notes payable 31,337 31,337 — — 31,337 Tax-exempt secured notes payable 94,700 94,700 — — 94,700 Fannie Mae credit facilities 266,196 266,196 — — 266,196 Unsecured debt instruments: (c) Commercial bank 152,500 152,500 — — 152,500 Senior unsecured notes 2,069,076 2,144,125 — — 2,144,125 Total liabilities $ 3,593,473 $ 3,721,512 $ — $ 10,368 $ 3,711,144 Redeemable noncontrolling interests in the Operating Partnership (d) $ 282,480 $ 282,480 $ — $ 282,480 $ — (a) See Note 2, Significant Accounting Policies. (b) See Note 10, Derivatives and Hedging Activity. (c) See Note 6, Secured and Unsecured Debt. (d) See Note 8, Noncontrolling Interests. There were no transfers into or out of each of the levels of the fair value hierarchy. Financial Instruments Carried at Fair Value The fair values of interest rate swaps are determined using the market standard methodology of netting the discounted future fixed cash receipts (or payments) and the discounted expected variable cash payments (or receipts). The variable cash payments (or receipts) are based on an expectation of future interest rates (forward curves) derived from observable market interest rate curves. The fair values of interest rate options are determined using the market standard methodology of discounting the future expected cash receipts that would occur if variable interest rates rise above the strike rate of the caps. The variable interest rates used in the calculation of projected receipts on the cap are based on an expectation of future interest rates derived from observable market interest rate curves and volatilities. The Company incorporates credit valuation adjustments to appropriately reflect both its own nonperformance risk and the respective counterparty’s nonperformance risk in the fair value measurements. In adjusting the fair value of its derivative contracts for the effect of nonperformance risk, the Company has considered the impact of netting and any applicable credit enhancements, such as collateral postings, thresholds, mutual puts, and guarantees. Although the Company has determined that the majority of the inputs used to value its derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with its derivatives utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by itself and its counterparties. However, as of September 30, 2015 and December 31, 2014 , the Company has assessed the significance of the impact of the credit valuation adjustments on the overall valuation of its derivative positions and has determined that the credit valuation adjustments are not significant to the overall valuation of its derivatives. As a result, the Company has determined that its derivative valuations in their entirety are classified in Level 2 of the fair value hierarchy. In conjunction with the FASB’s fair value measurement guidance, the Company made an accounting policy election to measure the credit risk of its derivative financial instruments that are subject to master netting agreements on a net basis by counterparty portfolio. Redeemable noncontrolling interests in the Operating Partnership have a redemption feature and are marked to their redemption value. The redemption value is based on the fair value of the Company’s common stock at the redemption date, and therefore, is calculated based on the fair value of the Company’s common stock at the balance sheet date. Since the valuation is based on observable inputs such as quoted prices for similar instruments in active markets, redeemable noncontrolling interests in the Operating Partnership are classified as Level 2. Financial Instruments Not Carried at Fair Value At September 30, 2015 , the fair values of cash and cash equivalents, restricted cash, accounts receivable, prepaids, real estate taxes payable, accrued interest payable, security deposits and prepaid rent, distributions payable and accounts payable approximated their carrying values because of the short term nature of these instruments. The estimated fair values of other financial instruments were determined by the Company using available market information and appropriate valuation methodologies. Considerable judgment is necessary to interpret market data and develop estimated fair values. Accordingly, the estimates presented herein are not necessarily indicative of the amounts the Company would realize on the disposition of the financial instruments. The use of different market assumptions or estimation methodologies may have a material effect on the estimated fair value amounts. We estimate the fair value of our notes receivable and debt instruments by discounting the remaining cash flows of the debt instrument at a discount rate equal to the replacement market credit spread plus the corresponding treasury yields. Factors considered in determining a replacement market credit spread include general market conditions, borrower specific credit spreads, time remaining to maturity, loan-to-value ratios and collateral quality, where applicable (Level 3). We record impairment losses on long-lived assets used in operations when events and circumstances indicate that the assets might be impaired and the undiscounted cash flows estimated to be generated by the future operation and disposition of those assets are less than the net book value of those assets. Our cash flow estimates are based upon historical results adjusted to reflect our best estimate of future market and operating conditions and our estimated holding periods. The net book value of impaired assets is reduced to fair value. Our estimates of fair value represent our best estimate based upon Level 3 inputs such as industry trends and reference to market rates and transactions. We consider various factors to determine if a decrease in the value of our investment in and advances to unconsolidated joint ventures, net is other-than-temporary. These factors include, but are not limited to, age of the venture, our intent and ability to retain our investment in the entity, the financial condition and long-term prospects of the entity, and the relationships with the other joint venture partners and its lenders. Based on the significance of the unobservable inputs, we classify these fair value measurements within Level 3 of the valuation hierarchy. The Company did not incur any other-than-temporary decrease in the value of its investments in unconsolidated joint ventures during the three and nine months ended September 30, 2015 and 2014 . After determining an other-than-temporary decrease in the value of an equity method investment has occurred, we estimate the fair value of our investment by estimating the proceeds we would receive upon a hypothetical liquidation of the investment at the date of measurement. Inputs reflect management’s best estimate of what market participants would use in pricing the investment giving consideration to the terms of the joint venture agreement and the estimated discounted future cash flows to be generated from the underlying joint venture assets. The inputs and assumptions utilized to estimate the future cash flows of the underlying assets are based upon the Company’s evaluation of the economy, market trends, operating results, and other factors, including judgments regarding costs to complete any construction activities, lease up and occupancy rates, rental rates, inflation rates, capitalization rates utilized to estimate the projected cash flows at the disposition, and discount rates.

Fair Value of Derivatives and29

Fair Value of Derivatives and Financial Instruments (UNITED DOMINION REALTY, L.P.)	9 Months Ended
	Sep. 30, 2015
Entity Information [Line Items]
FAIR VALUE OF DERIVATIVES AND FINANCIAL INSTRUMENTS	FAIR VALUE OF DERIVATIVES AND FINANCIAL INSTRUMENTS Fair value is based on the price that would be received to sell an asset or the exit price that would be paid to transfer a liability in an orderly transaction between market participants at the measurement date. A three-level valuation hierarchy prioritizes observable and unobservable inputs used to measure fair value. The fair value hierarchy consists of three broad levels, which are described below: • Level 1 — Quoted prices in active markets for identical assets or liabilities that the entity has the ability to access. • Level 2 — Observable inputs other than prices included in Level 1, such as quoted prices for similar assets and liabilities in active markets; quoted prices for identical or similar assets and liabilities in markets that are not active; or other inputs that are observable or can be corroborated with observable market data. • Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets and liabilities. This includes certain pricing models, discounted cash flow methodologies and similar techniques that use significant unobservable inputs. The estimated fair values of the Company’s financial instruments either recorded or disclosed on a recurring basis as of September 30, 2015 and December 31, 2014 are summarized as follows (dollars in thousands) : Fair Value at September 30, 2015, Using Total Carrying Amount in Statement of Financial Position at September 30, 2015 Fair Value Estimate at September 30, 2015 Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Description: Notes receivable (a) $ 15,494 $ 15,795 $ — $ — $ 15,795 Derivatives - Interest rate contracts (b) 6 6 — 6 — Total assets $ 15,500 $ 15,801 $ — $ 6 $ 15,795 Derivatives - Interest rate contracts (b) $ 3,205 $ 3,205 $ — $ 3,205 $ — Secured debt instruments - fixed rate: (c) Mortgage notes payable 406,183 416,287 — — 416,287 Fannie Mae credit facilities 565,394 595,907 — — 595,907 Secured debt instruments - variable rate: (c) Mortgage notes payable 31,337 31,337 — — 31,337 Tax-exempt secured notes payable 94,700 94,700 — — 94,700 Fannie Mae credit facilities 249,378 249,378 — — 249,378 Unsecured debt instruments: (c) Commercial bank 110,000 110,000 — — 110,000 Senior unsecured notes 2,056,242 2,128,901 — — 2,128,901 Total liabilities $ 3,516,439 $ 3,629,715 $ — $ 3,205 $ 3,626,510 Redeemable noncontrolling interests in the Operating Partnership (d) $ 312,158 $ 312,158 $ — $ 312,158 $ — Fair Value at December 31, 2014, Using Total Carrying Amount in Statement of Financial Position at December 31, 2014 Fair Value Estimate at December 31, 2014 Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Description: Notes receivable (a) $ 14,369 $ 14,808 $ — $ — $ 14,808 Derivatives - Interest rate contracts (b) 88 88 — 88 — Total assets $ 14,457 $ 14,896 $ — $ 88 $ 14,808 Derivatives- Interest rate contracts (b) $ 10,368 $ 10,368 $ — $ 10,368 $ — Secured debt instruments - fixed rate: (c) Mortgage notes payable 401,210 415,663 — — 415,663 Fannie Mae credit facilities 568,086 606,623 — — 606,623 Secured debt instruments - variable rate: (c) Mortgage notes payable 31,337 31,337 — — 31,337 Tax-exempt secured notes payable 94,700 94,700 — — 94,700 Fannie Mae credit facilities 266,196 266,196 — — 266,196 Unsecured debt instruments: (c) Commercial bank 152,500 152,500 — — 152,500 Senior unsecured notes 2,069,076 2,144,125 — — 2,144,125 Total liabilities $ 3,593,473 $ 3,721,512 $ — $ 10,368 $ 3,711,144 Redeemable noncontrolling interests in the Operating Partnership (d) $ 282,480 $ 282,480 $ — $ 282,480 $ — (a) See Note 2, Significant Accounting Policies. (b) See Note 10, Derivatives and Hedging Activity. (c) See Note 6, Secured and Unsecured Debt. (d) See Note 8, Noncontrolling Interests. There were no transfers into or out of each of the levels of the fair value hierarchy. Financial Instruments Carried at Fair Value The fair values of interest rate swaps are determined using the market standard methodology of netting the discounted future fixed cash receipts (or payments) and the discounted expected variable cash payments (or receipts). The variable cash payments (or receipts) are based on an expectation of future interest rates (forward curves) derived from observable market interest rate curves. The fair values of interest rate options are determined using the market standard methodology of discounting the future expected cash receipts that would occur if variable interest rates rise above the strike rate of the caps. The variable interest rates used in the calculation of projected receipts on the cap are based on an expectation of future interest rates derived from observable market interest rate curves and volatilities. The Company incorporates credit valuation adjustments to appropriately reflect both its own nonperformance risk and the respective counterparty’s nonperformance risk in the fair value measurements. In adjusting the fair value of its derivative contracts for the effect of nonperformance risk, the Company has considered the impact of netting and any applicable credit enhancements, such as collateral postings, thresholds, mutual puts, and guarantees. Although the Company has determined that the majority of the inputs used to value its derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with its derivatives utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by itself and its counterparties. However, as of September 30, 2015 and December 31, 2014 , the Company has assessed the significance of the impact of the credit valuation adjustments on the overall valuation of its derivative positions and has determined that the credit valuation adjustments are not significant to the overall valuation of its derivatives. As a result, the Company has determined that its derivative valuations in their entirety are classified in Level 2 of the fair value hierarchy. In conjunction with the FASB’s fair value measurement guidance, the Company made an accounting policy election to measure the credit risk of its derivative financial instruments that are subject to master netting agreements on a net basis by counterparty portfolio. Redeemable noncontrolling interests in the Operating Partnership have a redemption feature and are marked to their redemption value. The redemption value is based on the fair value of the Company’s common stock at the redemption date, and therefore, is calculated based on the fair value of the Company’s common stock at the balance sheet date. Since the valuation is based on observable inputs such as quoted prices for similar instruments in active markets, redeemable noncontrolling interests in the Operating Partnership are classified as Level 2. Financial Instruments Not Carried at Fair Value At September 30, 2015 , the fair values of cash and cash equivalents, restricted cash, accounts receivable, prepaids, real estate taxes payable, accrued interest payable, security deposits and prepaid rent, distributions payable and accounts payable approximated their carrying values because of the short term nature of these instruments. The estimated fair values of other financial instruments were determined by the Company using available market information and appropriate valuation methodologies. Considerable judgment is necessary to interpret market data and develop estimated fair values. Accordingly, the estimates presented herein are not necessarily indicative of the amounts the Company would realize on the disposition of the financial instruments. The use of different market assumptions or estimation methodologies may have a material effect on the estimated fair value amounts. We estimate the fair value of our notes receivable and debt instruments by discounting the remaining cash flows of the debt instrument at a discount rate equal to the replacement market credit spread plus the corresponding treasury yields. Factors considered in determining a replacement market credit spread include general market conditions, borrower specific credit spreads, time remaining to maturity, loan-to-value ratios and collateral quality, where applicable (Level 3). We record impairment losses on long-lived assets used in operations when events and circumstances indicate that the assets might be impaired and the undiscounted cash flows estimated to be generated by the future operation and disposition of those assets are less than the net book value of those assets. Our cash flow estimates are based upon historical results adjusted to reflect our best estimate of future market and operating conditions and our estimated holding periods. The net book value of impaired assets is reduced to fair value. Our estimates of fair value represent our best estimate based upon Level 3 inputs such as industry trends and reference to market rates and transactions. We consider various factors to determine if a decrease in the value of our investment in and advances to unconsolidated joint ventures, net is other-than-temporary. These factors include, but are not limited to, age of the venture, our intent and ability to retain our investment in the entity, the financial condition and long-term prospects of the entity, and the relationships with the other joint venture partners and its lenders. Based on the significance of the unobservable inputs, we classify these fair value measurements within Level 3 of the valuation hierarchy. The Company did not incur any other-than-temporary decrease in the value of its investments in unconsolidated joint ventures during the three and nine months ended September 30, 2015 and 2014 . After determining an other-than-temporary decrease in the value of an equity method investment has occurred, we estimate the fair value of our investment by estimating the proceeds we would receive upon a hypothetical liquidation of the investment at the date of measurement. Inputs reflect management’s best estimate of what market participants would use in pricing the investment giving consideration to the terms of the joint venture agreement and the estimated discounted future cash flows to be generated from the underlying joint venture assets. The inputs and assumptions utilized to estimate the future cash flows of the underlying assets are based upon the Company’s evaluation of the economy, market trends, operating results, and other factors, including judgments regarding costs to complete any construction activities, lease up and occupancy rates, rental rates, inflation rates, capitalization rates utilized to estimate the projected cash flows at the disposition, and discount rates.
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
FAIR VALUE OF DERIVATIVES AND FINANCIAL INSTRUMENTS	FAIR VALUE OF DERIVATIVES AND FINANCIAL INSTRUMENTS Fair value is based on the price that would be received to sell an asset or the exit price that would be paid to transfer a liability in an orderly transaction between market participants at the measurement date. A three-level valuation hierarchy prioritizes observable and unobservable inputs used to measure fair value. The fair value hierarchy consists of three broad levels, which are described below: • Level 1 — Quoted prices in active markets for identical assets or liabilities that the entity has the ability to access. • Level 2 — Observable inputs other than prices included in Level 1, such as quoted prices for similar assets and liabilities in active markets; quoted prices for identical or similar assets and liabilities in markets that are not active; or other inputs that are observable or can be corroborated with observable market data. • Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets and liabilities. This includes certain pricing models, discounted cash flow methodologies and similar techniques that use significant unobservable inputs. The estimated fair values of the Operating Partnership’s financial instruments either recorded or disclosed on a recurring basis as of September 30, 2015 and December 31, 2014 are summarized as follows (dollars in thousands) : Fair Value at September 30, 2015, Using Total Carrying Amount in Statement of Financial Position at September 30, 2015 Fair Value Estimate at September 30, 2015 Quoted Prices in Significant Significant Description: Derivatives - Interest rate contracts (a) $ 4 $ 4 $ — $ 4 $ — Total assets $ 4 $ 4 $ — $ 4 $ — Derivatives - Interest rate contracts (a) $ 175 $ 175 $ — $ 175 $ — Secured debt instruments - fixed rate: (b) Mortgage notes payable 371,888 380,820 — — 380,820 Fannie Mae credit facilities 333,912 352,452 — — 352,452 Secured debt instruments - variable rate: (b) Tax-exempt secured notes payable 27,000 27,000 — — 27,000 Fannie Mae credit facilities 177,509 177,509 — — 177,509 Total liabilities $ 910,484 $ 937,956 $ — $ 175 $ 937,781 Fair Value at December 31, 2014, Using Total Carrying Amount in Statement of Financial Position at December 31, 2014 Fair Value Estimate at December 31, 2014 Quoted Prices in Significant Significant Description: Derivatives - Interest rate contracts (a) $ 39 $ 39 $ — $ 39 $ — Total assets $ 39 $ 39 $ — $ 39 $ — Derivatives - Interest rate contracts (a) $ 918 $ 918 $ — $ 918 $ — Secured debt instruments - fixed rate: (b) Mortgage notes payable 378,371 391,835 — — 391,835 Fannie Mae credit facilities 333,828 355,470 — — 355,470 Secured debt instruments - variable rate: (b) Tax-exempt secured notes payable 27,000 27,000 — — 27,000 Fannie Mae credit facilities 192,760 192,760 — — 192,760 Total liabilities $ 932,877 $ 967,983 $ — $ 918 $ 967,065 (a) See Note 7, Derivatives and Hedging Activity. (b) See Note 4, Debt. Financial Instruments Carried at Fair Value The fair values of interest rate swaps are determined using the market standard methodology of netting the discounted future fixed cash receipts (or payments) and the discounted expected variable cash payments (or receipts). The variable cash payments (or receipts) are based on an expectation of future interest rates (forward curves) derived from observable market interest rate curves. The fair values of interest rate options are determined using the market standard methodology of discounting the future expected cash receipts that would occur if variable interest rates rise above the strike rate of the caps. The variable interest rates used in the calculation of projected receipts on the cap are based on an expectation of future interest rates derived from observable market interest rate curves and volatilities. The General Partner, on behalf of the Operating Partnership, incorporates credit valuation adjustments to appropriately reflect both its own nonperformance risk and the respective counterparty’s nonperformance risk in the fair value measurements. In adjusting the fair value of its derivative contracts for the effect of nonperformance risk, the Operating Partnership has considered the impact of netting and any applicable credit enhancements, such as collateral postings, thresholds, mutual puts, and guarantees. Although the General Partner, on behalf of the Operating Partnership, has determined that the majority of the inputs used to value its derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with its derivatives utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by itself and its counterparties. However, as of September 30, 2015 and December 31, 2014 , the Operating Partnership has assessed the significance of the impact of the credit valuation adjustments on the overall valuation of its derivative positions and has determined that the credit valuation adjustments are not significant to the overall valuation of its derivatives. As a result, the Operating Partnership has determined that its derivative valuations in their entirety are classified in Level 2 of the fair value hierarchy. In conjunction with the FASB’s fair value measurement guidance, the Operating Partnership made an accounting policy election to measure the credit risk of its derivative financial instruments that are subject to master netting agreements on a net basis by counterparty portfolio. Financial Instruments Not Carried at Fair Value As of September 30, 2015 , the fair values of cash and cash equivalents, restricted cash, accounts receivable, prepaids, real estate taxes payable, accrued interest payable, security deposits and prepaid rent, distributions payable and accounts payable approximated their carrying values because of the short term nature of these instruments. The estimated fair values of other financial instruments were determined by the Operating Partnership using available market information and appropriate valuation methodologies. Considerable judgment is necessary to interpret market data and develop estimated fair values. Accordingly, the estimates presented herein are not necessarily indicative of the amounts the Operating Partnership would realize on the disposition of the financial instruments. The use of different market assumptions or estimation methodologies may have a material effect on the estimated fair value amounts. Fair value of our debt instruments is estimated by discounting the remaining cash flows of the debt instrument at a discount rate equal to the replacement market credit spread plus the corresponding treasury yields. Factors considered in determining a replacement market credit spread include general market conditions, borrower specific credit spreads, time remaining to maturity, loan-to-value ratios and collateral quality (Level 3). The Operating Partnership records impairment losses on long-lived assets used in operations when events and circumstances indicate that the assets might be impaired and the undiscounted cash flows estimated to be generated by the future operation and disposition of those assets are less than the net book value of those assets. Cash flow estimates are based upon historical results adjusted to reflect management’s best estimate of future market and operating conditions and our estimated holding periods. The net book value of impaired assets is reduced to fair value. The General Partner’s estimates of fair value represent management’s estimates based upon Level 3 inputs such as industry trends and reference to market rates and transactions.

Derivatives and Hedging Activit

Derivatives and Hedging Activity	9 Months Ended
	Sep. 30, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities Disclosure [Text Block]	DERIVATIVES AND HEDGING ACTIVITY Risk Management Objective of Using Derivatives The Company is exposed to certain risks arising from both its business operations and economic conditions. The Company principally manages its exposures to a wide variety of business and operational risks through management of its core business activities. The Company manages economic risks, including interest rate, liquidity, and credit risk primarily by managing the amount, sources, and duration of its debt funding and through the use of derivative financial instruments. Specifically, the Company may enter into derivative financial instruments to manage exposures that arise from business activities that result in the receipt or payment of future known and uncertain cash amounts, the value of which are determined by interest rates. The Company’s derivative financial instruments are used to manage differences in the amount, timing, and duration of the Company’s known or expected cash receipts and its known or expected cash payments principally related to the Company’s investments and borrowings. Cash Flow Hedges of Interest Rate Risk The Company’s objectives in using interest rate derivatives are to add stability to interest expense and to manage its exposure to interest rate movements. To accomplish this objective, the Company primarily uses interest rate swaps and caps as part of its interest rate risk management strategy. Interest rate swaps designated as cash flow hedges involve the receipt of variable-rate amounts from a counterparty in exchange for the Company making fixed-rate payments over the life of the agreements without exchange of the underlying notional amount. Interest rate caps designated as cash flow hedges involve the receipt of variable-rate amounts from a counterparty if interest rates rise above the strike rate on the contract in exchange for an up front premium. The effective portion of changes in the fair value of derivatives designated and that qualify as cash flow hedges is recorded in Accumulated other comprehensive income/(loss), net in the Consolidated Balance Sheets and is subsequently reclassified into earnings in the period that the hedged forecasted transaction affects earnings. During the three and nine months ended September 30, 2015 and 2014 , such derivatives were used to hedge the variable cash flows associated with existing variable-rate debt and forecasted issuances of fixed-rate debt. The ineffective portion of the change in fair value of the derivatives is recognized directly in earnings. During the three and nine months ended September 30, 2015 , the Company recognized an $11,000 loss reclassified from Accumulated OCI to Interest expense due to the de-designation of a cash flow hedge and recorded no other ineffectiveness to earnings. During the three and nine months ended September 30, 2014 , the Company recorded a gain of approximately $0 and $3,000 , respectively, related to the ineffective portion of the derivative, which was caused by a timing difference between the derivative and the hedge item. Amounts reported in Accumulated other comprehensive income/(loss), net in the Consolidated Balance Sheets related to derivatives will be reclassified to interest expense as interest payments are made on the Company’s hedged debt. Through September 30, 2016 , the Company estimates that an additional $3.5 million will be reclassified as an increase to interest expense. As of September 30, 2015 , the Company had the following outstanding interest rate derivatives that were designated as cash flow hedges of interest rate risk ( dollars in thousands ): Product Number of Instruments Notional Interest rate swaps 6 $ 365,000 Interest rate caps 2 $ 203,166 Derivatives not designated as hedges are not speculative and are used to manage the Company’s exposure to interest rate movements and other identified risks but do not meet the strict hedge accounting requirements of GAAP or the Company has elected to not apply hedge accounting. Changes in the fair value of derivatives not designated in hedging relationships are recorded directly in earnings and resulted in gain/(loss) of $(1,000) and $(25,000) for the three and nine months ended September 30, 2015 , respectively, and no adjustment to earnings for for the three and nine months ended September 30, 2014 . As of September 30, 2015 , the Company had the following outstanding derivatives that were not designated as hedges in qualifying hedging relationships ( dollars in thousands ): Product Number of Instruments Notional Interest rate caps 3 $ 133,107 Tabular Disclosure of Fair Values of Derivative Instruments on the Consolidated Balance Sheets The tables below present the fair value of the Company’s derivative financial instruments as well as their classification on the Consolidated Balance Sheets as of September 30, 2015 and December 31, 2014 ( dollars in thousands ): Asset Derivatives (included in Other assets ) Liability Derivatives (included in Other liabilities ) Fair Value at: Fair Value at: September 30, December 31, September 30, December 31, Derivatives designated as hedging instruments: Interest rate products $ 4 86 $ 3,205 $ 10,368 Derivatives not designated as hedging instruments: Interest rate products $ 2 $ 2 $ — $ — Tabular Disclosure of the Effect of Derivative Instruments on the Consolidated Statements of Operations The tables below present the effect of the Company’s derivative financial instruments on the Consolidated Statements of Operations for the three and nine months ended September 30, 2015 and 2014 ( dollars in thousands ): Derivatives in Cash Flow Hedging Relationships Unrealized holding gain/(loss) Recognized in OCI (Effective Portion) Gain/(Loss) Reclassified from Accumulated OCI into Interest expense (Effective Portion) Gain/(Loss) Recognized in Interest expense (Ineffective Portion and Amount Excluded from Effectiveness Testing) 2015 2014 2015 2014 2015 2014 Three Months Ended September 30, Interest rate products $ (5,707 ) $ 362 $ (525 ) $ (1,130 ) $ (11 ) $ — Nine Months Ended September 30, Interest rate products $ (7,072 ) $ 611 $ (1,554 ) $ (3,809 ) $ (11 ) $ 3 Gain/(Loss) Recognized in Interest income and other income/(expense), net Derivatives Not Designated as Hedging Instruments 2015 2014 Three Months Ended September 30, Interest rate products $ (1 ) $ — Nine Months Ended September 30, Interest rate products $ (25 ) $ — Credit-risk-related Contingent Features The Company has agreements with some of its derivative counterparties that contain a provision where (1) if the Company defaults on any of its indebtedness, including default where repayment of the indebtedness has not been accelerated by the lender, then the Company could also be declared in default on its derivative obligations; or (2) the Company could be declared in default on its derivative obligations if repayment of the underlying indebtedness is accelerated by the lender due to the Company’s default on the indebtedness. Certain of the Company’s agreements with its derivative counterparties contain provisions where, if there is a change in the Company’s financial condition that materially changes the Company’s creditworthiness in an adverse manner, the Company may be required to fully collateralize its obligations under the derivative instrument. The Company also has an agreement with a derivative counterparty that incorporates the loan and financial covenant provisions of the Company’s indebtedness with a lender affiliate of the derivative counterparty. Failure to comply with these covenant provisions would result in the Company being in default on any derivative instrument obligations covered by the agreement. As of September 30, 2015 , the fair value of derivatives in a net liability position, which includes accrued interest but excludes any adjustment for nonperformance risk, related to these agreements was $3.4 million . As of September 30, 2015 , the Company has not posted any collateral related to these agreements. If the Company had breached any of these provisions at September 30, 2015 , it may have been required to settle its obligations under the agreements at their termination value of $3.4 million . Tabular Disclosure of Offsetting Derivatives Company has elected not to offset derivative positions in the consolidated financial statements. The tables below present the effect on its financial position had the Company made the election to offset its derivative positions as of September 30, 2015 and December 31, 2014 (dollars in thousands): Offsetting of Derivative Assets Gross Amounts of Recognized Assets Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts of Assets Presented in the Consolidated Balance Sheets (a) Gross Amounts Not Offset in the Consolidated Balance Sheets Financial Instruments Cash Collateral Received Net Amount September 30, 2015 $ 6 $ — $ 6 $ — $ — $ 6 December 31, 2014 $ 88 $ — $ 88 $ (27 ) $ — $ 61 (a) Amounts reconcile to the aggregate fair value of derivative assets in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Balance Sheet” located in this footnote. Offsetting of Derivative Liabilities Gross Amounts of Recognized Liabilities Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts of Liabilities Presented in the Consolidated Balance Sheets (b) Gross Amounts Not Offset in the Consolidated Balance Sheets Financial Instruments Cash Collateral Posted Net Amount September 30, 2015 $ 3,205 $ — $ 3,205 $ — $ — $ 3,205 December 31, 2014 $ 10,368 $ — $ 10,368 $ (27 ) $ — $ 10,341 (b) Amounts reconcile to the aggregate fair value of derivative liabilities in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Balance Sheet” located in this footnote.

Derivatives and Hedging Activ31

Derivatives and Hedging Activity (UNITED DOMINION REALTY, L.P.)	9 Months Ended
	Sep. 30, 2015
Entity Information [Line Items]
DERIVATIVES AND HEDGING ACTIVITY	DERIVATIVES AND HEDGING ACTIVITY Risk Management Objective of Using Derivatives The Company is exposed to certain risks arising from both its business operations and economic conditions. The Company principally manages its exposures to a wide variety of business and operational risks through management of its core business activities. The Company manages economic risks, including interest rate, liquidity, and credit risk primarily by managing the amount, sources, and duration of its debt funding and through the use of derivative financial instruments. Specifically, the Company may enter into derivative financial instruments to manage exposures that arise from business activities that result in the receipt or payment of future known and uncertain cash amounts, the value of which are determined by interest rates. The Company’s derivative financial instruments are used to manage differences in the amount, timing, and duration of the Company’s known or expected cash receipts and its known or expected cash payments principally related to the Company’s investments and borrowings. Cash Flow Hedges of Interest Rate Risk The Company’s objectives in using interest rate derivatives are to add stability to interest expense and to manage its exposure to interest rate movements. To accomplish this objective, the Company primarily uses interest rate swaps and caps as part of its interest rate risk management strategy. Interest rate swaps designated as cash flow hedges involve the receipt of variable-rate amounts from a counterparty in exchange for the Company making fixed-rate payments over the life of the agreements without exchange of the underlying notional amount. Interest rate caps designated as cash flow hedges involve the receipt of variable-rate amounts from a counterparty if interest rates rise above the strike rate on the contract in exchange for an up front premium. The effective portion of changes in the fair value of derivatives designated and that qualify as cash flow hedges is recorded in Accumulated other comprehensive income/(loss), net in the Consolidated Balance Sheets and is subsequently reclassified into earnings in the period that the hedged forecasted transaction affects earnings. During the three and nine months ended September 30, 2015 and 2014 , such derivatives were used to hedge the variable cash flows associated with existing variable-rate debt and forecasted issuances of fixed-rate debt. The ineffective portion of the change in fair value of the derivatives is recognized directly in earnings. During the three and nine months ended September 30, 2015 , the Company recognized an $11,000 loss reclassified from Accumulated OCI to Interest expense due to the de-designation of a cash flow hedge and recorded no other ineffectiveness to earnings. During the three and nine months ended September 30, 2014 , the Company recorded a gain of approximately $0 and $3,000 , respectively, related to the ineffective portion of the derivative, which was caused by a timing difference between the derivative and the hedge item. Amounts reported in Accumulated other comprehensive income/(loss), net in the Consolidated Balance Sheets related to derivatives will be reclassified to interest expense as interest payments are made on the Company’s hedged debt. Through September 30, 2016 , the Company estimates that an additional $3.5 million will be reclassified as an increase to interest expense. As of September 30, 2015 , the Company had the following outstanding interest rate derivatives that were designated as cash flow hedges of interest rate risk ( dollars in thousands ): Product Number of Instruments Notional Interest rate swaps 6 $ 365,000 Interest rate caps 2 $ 203,166 Derivatives not designated as hedges are not speculative and are used to manage the Company’s exposure to interest rate movements and other identified risks but do not meet the strict hedge accounting requirements of GAAP or the Company has elected to not apply hedge accounting. Changes in the fair value of derivatives not designated in hedging relationships are recorded directly in earnings and resulted in gain/(loss) of $(1,000) and $(25,000) for the three and nine months ended September 30, 2015 , respectively, and no adjustment to earnings for for the three and nine months ended September 30, 2014 . As of September 30, 2015 , the Company had the following outstanding derivatives that were not designated as hedges in qualifying hedging relationships ( dollars in thousands ): Product Number of Instruments Notional Interest rate caps 3 $ 133,107 Tabular Disclosure of Fair Values of Derivative Instruments on the Consolidated Balance Sheets The tables below present the fair value of the Company’s derivative financial instruments as well as their classification on the Consolidated Balance Sheets as of September 30, 2015 and December 31, 2014 ( dollars in thousands ): Asset Derivatives (included in Other assets ) Liability Derivatives (included in Other liabilities ) Fair Value at: Fair Value at: September 30, December 31, September 30, December 31, Derivatives designated as hedging instruments: Interest rate products $ 4 86 $ 3,205 $ 10,368 Derivatives not designated as hedging instruments: Interest rate products $ 2 $ 2 $ — $ — Tabular Disclosure of the Effect of Derivative Instruments on the Consolidated Statements of Operations The tables below present the effect of the Company’s derivative financial instruments on the Consolidated Statements of Operations for the three and nine months ended September 30, 2015 and 2014 ( dollars in thousands ): Derivatives in Cash Flow Hedging Relationships Unrealized holding gain/(loss) Recognized in OCI (Effective Portion) Gain/(Loss) Reclassified from Accumulated OCI into Interest expense (Effective Portion) Gain/(Loss) Recognized in Interest expense (Ineffective Portion and Amount Excluded from Effectiveness Testing) 2015 2014 2015 2014 2015 2014 Three Months Ended September 30, Interest rate products $ (5,707 ) $ 362 $ (525 ) $ (1,130 ) $ (11 ) $ — Nine Months Ended September 30, Interest rate products $ (7,072 ) $ 611 $ (1,554 ) $ (3,809 ) $ (11 ) $ 3 Gain/(Loss) Recognized in Interest income and other income/(expense), net Derivatives Not Designated as Hedging Instruments 2015 2014 Three Months Ended September 30, Interest rate products $ (1 ) $ — Nine Months Ended September 30, Interest rate products $ (25 ) $ — Credit-risk-related Contingent Features The Company has agreements with some of its derivative counterparties that contain a provision where (1) if the Company defaults on any of its indebtedness, including default where repayment of the indebtedness has not been accelerated by the lender, then the Company could also be declared in default on its derivative obligations; or (2) the Company could be declared in default on its derivative obligations if repayment of the underlying indebtedness is accelerated by the lender due to the Company’s default on the indebtedness. Certain of the Company’s agreements with its derivative counterparties contain provisions where, if there is a change in the Company’s financial condition that materially changes the Company’s creditworthiness in an adverse manner, the Company may be required to fully collateralize its obligations under the derivative instrument. The Company also has an agreement with a derivative counterparty that incorporates the loan and financial covenant provisions of the Company’s indebtedness with a lender affiliate of the derivative counterparty. Failure to comply with these covenant provisions would result in the Company being in default on any derivative instrument obligations covered by the agreement. As of September 30, 2015 , the fair value of derivatives in a net liability position, which includes accrued interest but excludes any adjustment for nonperformance risk, related to these agreements was $3.4 million . As of September 30, 2015 , the Company has not posted any collateral related to these agreements. If the Company had breached any of these provisions at September 30, 2015 , it may have been required to settle its obligations under the agreements at their termination value of $3.4 million . Tabular Disclosure of Offsetting Derivatives Company has elected not to offset derivative positions in the consolidated financial statements. The tables below present the effect on its financial position had the Company made the election to offset its derivative positions as of September 30, 2015 and December 31, 2014 (dollars in thousands): Offsetting of Derivative Assets Gross Amounts of Recognized Assets Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts of Assets Presented in the Consolidated Balance Sheets (a) Gross Amounts Not Offset in the Consolidated Balance Sheets Financial Instruments Cash Collateral Received Net Amount September 30, 2015 $ 6 $ — $ 6 $ — $ — $ 6 December 31, 2014 $ 88 $ — $ 88 $ (27 ) $ — $ 61 (a) Amounts reconcile to the aggregate fair value of derivative assets in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Balance Sheet” located in this footnote. Offsetting of Derivative Liabilities Gross Amounts of Recognized Liabilities Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts of Liabilities Presented in the Consolidated Balance Sheets (b) Gross Amounts Not Offset in the Consolidated Balance Sheets Financial Instruments Cash Collateral Posted Net Amount September 30, 2015 $ 3,205 $ — $ 3,205 $ — $ — $ 3,205 December 31, 2014 $ 10,368 $ — $ 10,368 $ (27 ) $ — $ 10,341 (b) Amounts reconcile to the aggregate fair value of derivative liabilities in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Balance Sheet” located in this footnote.
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
DERIVATIVES AND HEDGING ACTIVITY	DERIVATIVES AND HEDGING ACTIVITY Risk Management Objective of Using Derivatives The Operating Partnership is exposed to certain risks arising from both its business operations and economic conditions. The General Partner principally manages its exposures to a wide variety of business and operational risks through management of its core business activities. The General Partner manages economic risks, including interest rate, liquidity, and credit risk primarily by managing the amount, sources, and duration of its debt funding and through the use of derivative financial instruments. Specifically, the General Partner enters into derivative financial instruments to manage exposures that arise from business activities that result in the receipt or payment of future known and uncertain cash amounts, the value of which are determined by interest rates. The General Partner’s and the Operating Partnership’s derivative financial instruments are used to manage differences in the amount, timing, and duration of the General Partner’s known or expected cash payments principally related to the General Partner’s borrowings. Cash Flow Hedges of Interest Rate Risk The General Partner’s objectives in using interest rate derivatives are to add stability to interest expense and to manage its exposure to interest rate movements. To accomplish this objective, the General Partner primarily uses interest rate swaps and caps as part of its interest rate risk management strategy. Interest rate swaps designated as cash flow hedges involve the receipt of variable-rate amounts from a counterparty in exchange for the General Partner making fixed-rate payments over the life of the agreements without exchange of the underlying notional amount. Interest rate caps designated as cash flow hedges involve the receipt of variable-rate amounts from a counterparty if interest rates rise above the strike rate on the contract in exchange for an up front premium. A portion of the General Partner’s interest rate derivatives have been allocated to the Operating Partnership based on the General Partner’s underlying debt instruments allocated to the Operating Partnership. (See Note 4, Debt. ) The effective portion of changes in the fair value of derivatives designated and that qualify as cash flow hedges is recorded in Accumulated other comprehensive income/(loss), net in the Consolidated Balance Sheets and is subsequently reclassified into earnings in the period that the hedged forecasted transaction affects earnings. During the three and nine months ended September 30, 2015 and 2014 , such derivatives were used to hedge the variable cash flows associated with existing variable-rate debt and forecasted issuances of fixed-rate debt. The ineffective portion of the change in fair value of the derivatives is recognized directly in earnings. During the three and nine months ended September 30, 2015 , the Company recognized an $11,000 loss reclassified from Accumulated OCI to Interest expense due to the de-designation of a cash flow hedge and recorded no other ineffectiveness to earnings. The Operating Partnership recorded no gain or loss from ineffectiveness during the three and nine months ended September 30, 2015 , and 2014 . Amounts reported in Accumulated other comprehensive income/(loss), net related to derivatives will be reclassified to interest expense as interest payments are made on the General Partner’s variable-rate debt that is allocated to the Operating Partnership. Through September 30, 2016 , we estimate that an additional $0.2 million will be reclassified as an increase to interest expense. As of September 30, 2015 , the Operating Partnership had the following outstanding interest rate derivatives designated as cash flow hedges of interest rate risk ( dollars in thousands ): Product Number of Instruments Notional Interest rate swaps 1 $ 46,357 Interest rate caps 1 $ 127,916 Derivatives not designated as hedges are not speculative and are used to manage the Operating Partnership’s exposure to interest rate movements and other identified risks but do not meet the strict hedge accounting requirements of GAAP or the Operating Partnership has elected to not apply hedge accounting. Changes in the fair value of derivatives not designated in hedging relationships are recorded directly in earnings and resulted in gain/(loss) of $(1,000) and $(24,000) for the three and nine months ended September 30, 2015 , respectively, and no adjustment to earnings for for the three and nine months ended September 30, 2014 . As of September 30, 2015 , we had the following outstanding derivatives that were not designated as a hedges in a qualifying hedging relationships ( dollars in thousands ): Product Number of Instruments Notional Interest rate caps 3 $ 124,856 Tabular Disclosure of Fair Values of Derivative Instruments on the Balance Sheet The table below presents the fair value of the Operating Partnership’s derivative financial instruments as well as their classification on the Consolidated Balance Sheets as of September 30, 2015 and December 31, 2014 ( dollars in thousands ): Asset Derivatives (included in Other assets ) Liability Derivatives (included in Other liabilities ) Fair Value at: Fair Value at: September 30, December 31, September 30, December 31, Derivatives designated as hedging instruments: Interest rate products $ 2 $ 37 $ 175 $ 918 Derivatives not designated as hedging instruments: Interest rate products $ 2 $ 2 $ — $ — Tabular Disclosure of the Effect of Derivative Instruments on the Consolidated Statements of Operations The tables below present the effect of the derivative financial instruments on the Consolidated Statements of Operations for the three and nine months ended September 30, 2015 and 2014 ( dollars in thousands ): Unrealized holding gain/(loss) Recognized in OCI (Effective Portion) Gain/(Loss) Reclassified from Accumulated OCI into Interest expense (Effective Portion) Gain/(Loss) Recognized in Interest expense (Ineffective Portion and Amount Excluded from Effectiveness Testing) Derivatives in Cash Flow Hedging Relationships 2015 2014 2015 2014 2015 2014 Three Months Ended September 30, Interest rate products $ (8 ) $ (3 ) $ (267 ) $ (588 ) $ (11 ) $ — Nine Months Ended September 30, Interest rate products $ (85 ) $ (194 ) $ (820 ) $ (1,784 ) $ (11 ) $ — Gain/(Loss) Recognized in Interest income and other income/(expense), net Derivatives Not Designated as Hedging Instruments 2015 2014 Three Months Ended September 30, Interest rate products $ (1 ) $ — Nine Months Ended September 30, Interest rate products $ (24 ) $ — Credit-risk-related Contingent Features The General Partner has agreements with some of its derivative counterparties that contain a provision where (1) if the General Partner defaults on any of its indebtedness, including default where repayment of the indebtedness has not been accelerated by the lender, then the General Partner could also be declared in default on its derivative obligations; or (2) the General Partner could be declared in default on its derivative obligations if repayment of the underlying indebtedness is accelerated by the lender due to the General Partner’s default on the indebtedness. Certain of the General Partner’s agreements with its derivative counterparties contain provisions where if there is a change in the General Partner’s financial condition that materially changes the General Partner’s creditworthiness in an adverse manner, the General Partner may be required to fully collateralize its obligations under the derivative instrument. At September 30, 2015 and December 31, 2014 , no cash collateral was posted or required to be posted by the General Partner or by a counterparty. The General Partner also has an agreement with a derivative counterparty that incorporates the loan and financial covenant provisions of the General Partner’s indebtedness with a lender affiliate of the derivative counterparty. Failure to comply with these covenant provisions would result in the General Partner being in default on any derivative instrument obligations covered by the agreement. The General Partner has certain agreements with some of its derivative counterparties that contain a provision where in the event of default by the General Partner or the counterparty, the right of setoff may be exercised. Any amount payable to one party by the other party may be reduced by its setoff against any amounts payable by the other party. Events that give rise to default by either party may include, but are not limited to, the failure to pay or deliver payment under the derivative contract, the failure to comply with or perform under the derivative agreement, bankruptcy, a merger without assumption of the derivative agreement, or in a merger, a surviving entity’s creditworthiness is materially weaker than the original party to the derivative agreement. As of September 30, 2015 , the fair value of derivatives in a net liability position that were allocated to the Operating Partnership, which includes accrued interest but excludes any adjustment for nonperformance risk, related to these agreements was $0.2 million . As of September 30, 2015 , the General Partner has not posted any collateral related to these agreements. If the General Partner had breached any of these provisions at September 30, 2015 , it would have been required to settle its obligations under the agreements at their termination value of $0.2 million . The General Partner has elected not to offset derivative positions in the consolidated financial statements. The table below presents the effect on the Operating Partnership’s financial position had the General Partner made the election to offset its derivative positions as of September 30, 2015 and December 31, 2014 : Offsetting of Derivative Assets Gross Amounts of Recognized Assets Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts of Assets Presented in the Consolidated Balance Sheets (a) Gross Amounts Not Offset in the Consolidated Balance Sheets Financial Instruments Cash Collateral Received Net Amount September 30, 2015 $ 4 $ — $ 4 $ — $ — $ 4 December 31, 2014 $ 39 $ — $ 39 $ — $ — $ 39 (a) Amounts reconcile to the aggregate fair value of derivative assets in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Balance Sheet” located in this footnote. Offsetting of Derivative Liabilities Gross Amounts of Recognized Liabilities Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts of Liabilities Presented in the Consolidated Balance Sheets (b) Gross Amounts Not Offset in the Consolidated Balance Sheets Financial Instruments Cash Collateral Posted Net Amount September 30, 2015 $ 175 $ — $ 175 $ — $ — $ 175 December 31, 2014 $ 918 $ — $ 918 $ — $ — $ 918 (b) Amounts reconcile to the aggregate fair value of derivative liabilities in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Balance Sheet” located in this footnote.

Stock Based Compensation

Stock Based Compensation	9 Months Ended
	Sep. 30, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
STOCK BASED COMPENSATION	STOCK BASED COMPENSATION The Company recognized stock based compensation expense, inclusive of awards granted to our independent directors, net of capitalization, of $4.4 million and $3.3 million during the three months ended September 30, 2015 and 2014 , respectively, and $13.5 million and $10.2 million during the nine months ended September 30, 2015 and 2014 , respectively.

Capital Structure (UNITED DOMIN

Capital Structure (UNITED DOMINION REALTY, L.P.)	9 Months Ended
	Sep. 30, 2015
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
CAPITAL STRUCTURE	CAPITAL STRUCTURE General Partnership Units The General Partner has complete discretion to manage and control the operations and business of the Operating Partnership, which includes but is not limited to the acquisition and disposition of real property, construction of buildings and making capital improvements, and the borrowing of funds from outside lenders or UDR and its subsidiaries to finance such activities. The General Partner can generally authorize, issue, sell, redeem or purchase any OP Unit or securities of the Operating Partnership without the approval of the limited partners. The General Partner can also approve, with regard to the issuances of OP Units, the class or one or more series of classes, with designations, preferences, participating, optional or other special rights, powers and duties including rights, powers and duties senior to limited partnership interests without approval of any limited partners except holders of Class A Limited Partnership Units. There were 110,883 General Partnership units outstanding at September 30, 2015 and December 31, 2014 , all of which were held by UDR. Limited Partnership Units As of September 30, 2015 and December 31, 2014 , there were 183,167,815 limited partnership units outstanding, of which 1,873,332 were Class A Limited Partnership Units. UDR owned 174,114,516 , or 95.1% of, and 174,002,342 , or 95.0% of, OP Units outstanding at September 30, 2015 and December 31, 2014 , respectively, of which 121,661 were Class A Limited Partnership Units. The remaining 9,053,299 , or 4.9% of, and 9,165,473 , or 5.0% of, OP Units outstanding, were held by non-affiliated partners at September 30, 2015 and December 31, 2014 , respectively, of which 1,751,671 were Class A Limited Partnership Units. Subject to the terms of the Operating Partnership Agreement, the limited partners have the right to require the Operating Partnership to redeem all or a portion of the OP Units held by the limited partner at a redemption price equal to and in the form of the Cash Amount (as defined in the Operating Partnership Agreement), provided that such OP Units have been outstanding for at least one year. UDR, as general partner of the Operating Partnership may, in its sole discretion, purchase the OP Units by paying to the limited partner either the Cash Amount or the REIT Share Amount (generally one share of common stock of UDR for each OP Unit), as defined in the Operating Partnership Agreement. The non-affiliated limited partners’ capital is adjusted to redemption value at the end of each reporting period with the corresponding offset against UDR’s limited partner capital account based on the redemption rights noted above. The aggregate value upon redemption of the then-outstanding OP Units held by limited partners was $312.2 million and $282.5 million as of September 30, 2015 and December 31, 2014 , respectively, based on the value of UDR’s common stock at each period end. A limited partner has no right to receive any distributions from the Operating Partnership on or after the date of redemption of its OP Units. Class A Limited Partnership Units Class A Limited Partnership Units have a cumulative, annual, non-compounded preferred return, which is equal to 8% based on a value of $16.61 per Class A Limited Partnership Unit. Holders of the Class A Limited Partnership Units exclusively possess certain voting rights. The Operating Partnership may not do the following without approval of the holders of the Class A Limited Partnership Units: (i) increase the authorized or issued amount of Class A Limited Partnership Units, (ii) reclassify any other partnership interest into Class A Limited Partnership Units, (iii) create, authorize or issue any obligations or security convertible into or the right to purchase any Class A Limited Partnership units, (iv) enter into a merger or acquisition, or (v) amend or modify the Agreement of Limited Partnership of the Operating Partnership in a manner that adversely affects the relative rights, preferences or privileges of the Class A Limited Partnership Units. Allocation of Profits and Losses Profit of the Operating Partnership is allocated in the following order: (i) to the General Partner and the Limited Partners in proportion to and up to the amount of cash distributions made during the year, and (ii) to the General Partner and Limited Partners in accordance with their percentage interests. Losses and depreciation and amortization expenses, non-recourse liabilities are allocated to the General Partner and Limited Partners in accordance with their percentage interests. Losses allocated to the Limited Partners are capped to the extent that such an allocation would not cause a deficit in the Limited Partners’ capital account. Such losses are, therefore, allocated to the General Partner. If any Partner’s capital balance were to fall into a deficit, any income and gains are allocated to each Partner sufficient to eliminate its negative capital balance.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2015
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Commitments Real Estate Under Development The following summarizes the Company’s real estate commitments at September 30, 2015 ( dollars in thousands ): Number of Properties Costs Incurred as of September 30, 2015 (a) Expected Costs to Complete Average Ownership Stake Wholly-owned — under development 1 $ 104,080 (b) $ 237,920 100 % Wholly-owned — redevelopment 1 7,383 (b) 7,617 100 % Joint ventures: Unconsolidated joint ventures 4 427,545 117,195 (c) Various Participating loan investments 1 89,498 (d) 3,960 (e) 0 % Preferred equity investments 5 129,592 (f) 6,735 (g) 48 % $ 758,098 $ 373,427 (a) Represents 100% of project costs incurred as of September 30, 2015 . (b) Costs incurred to date include $2.8 million and $1.2 million of accrued fixed assets for development and redevelopment, respectively. (c) Represents UDR’s proportionate share of expected remaining costs to complete. (d) Represents the participating loan balance funded as of September 30, 2015 . (e) Represents UDR’s remaining participating loan commitment for Steele Creek. (f) Represents UDR's share of capital contributed to the West Coast Development Joint Venture as of September 30, 2015 . (g) Represents UDR's remaining funding commitment on Katella Grand II. Contingencies Litigation and Legal Matters The Company is subject to various legal proceedings and claims arising in the ordinary course of business. The Company cannot determine the ultimate liability with respect to such legal proceedings and claims at this time. The Company believes that such liability, to the extent not provided for through insurance or otherwise, will not have a material adverse effect on our financial condition, results of operations or cash flow.

Commitments and Contingencies (

Commitments and Contingencies (UNITED DOMINION REALTY, L.P.) Commitments and Contingencies (UNITED DOMINION REALTY, L.P.)	9 Months Ended
	Sep. 30, 2015
Entity Information [Line Items]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Commitments Real Estate Under Development The following summarizes the Company’s real estate commitments at September 30, 2015 ( dollars in thousands ): Number of Properties Costs Incurred as of September 30, 2015 (a) Expected Costs to Complete Average Ownership Stake Wholly-owned — under development 1 $ 104,080 (b) $ 237,920 100 % Wholly-owned — redevelopment 1 7,383 (b) 7,617 100 % Joint ventures: Unconsolidated joint ventures 4 427,545 117,195 (c) Various Participating loan investments 1 89,498 (d) 3,960 (e) 0 % Preferred equity investments 5 129,592 (f) 6,735 (g) 48 % $ 758,098 $ 373,427 (a) Represents 100% of project costs incurred as of September 30, 2015 . (b) Costs incurred to date include $2.8 million and $1.2 million of accrued fixed assets for development and redevelopment, respectively. (c) Represents UDR’s proportionate share of expected remaining costs to complete. (d) Represents the participating loan balance funded as of September 30, 2015 . (e) Represents UDR’s remaining participating loan commitment for Steele Creek. (f) Represents UDR's share of capital contributed to the West Coast Development Joint Venture as of September 30, 2015 . (g) Represents UDR's remaining funding commitment on Katella Grand II. Contingencies Litigation and Legal Matters The Company is subject to various legal proceedings and claims arising in the ordinary course of business. The Company cannot determine the ultimate liability with respect to such legal proceedings and claims at this time. The Company believes that such liability, to the extent not provided for through insurance or otherwise, will not have a material adverse effect on our financial condition, results of operations or cash flow.
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Commitments Real Estate Under Development The following summarizes the Operating Partnership’s real estate commitments at September 30, 2015 ( dollars in thousands ): Number of Properties Costs Incurred to Date (a) Expected Costs to Complete (unaudited) Real estate communities — redevelopment 1 7,383 7,617 (a) Costs incurred to date include $1.2 million of accrued fixed assets for redevelopment. Contingencies Litigation and Legal Matters The Operating Partnership is subject to various legal proceedings and claims arising in the ordinary course of business. The Operating Partnership cannot determine the ultimate liability with respect to such legal proceedings and claims at this time. The General Partner believes that such liability, to the extent not provided for through insurance or otherwise, will not have a material adverse effect on the Operating Partnership’s financial condition, results of operations or cash flow.

Reportable Segments

Reportable Segments	9 Months Ended
	Sep. 30, 2015
Segment Reporting [Abstract]
REPORTABLE SEGMENTS	REPORTABLE SEGMENTS GAAP guidance requires that segment disclosures present the measure(s) used by the chief operating decision maker to decide how to allocate resources and for purposes of assessing such segments’ performance. UDR’s chief operating decision maker is comprised of several members of its executive management team who use several generally accepted industry financial measures to assess the performance of the business for our reportable operating segments. UDR owns and operates multifamily apartment communities that generate rental and other property related income through the leasing of apartment homes to a diverse base of tenants. The primary financial measures for UDR’s apartment communities are rental income and net operating income (“NOI”). Rental income represents gross market rent less adjustments for concessions, vacancy loss and bad debt. NOI is defined as rental income less direct property rental expenses. Rental expenses include real estate taxes, insurance, personnel, utilities, repairs and maintenance, administrative and marketing. Excluded from NOI is property management expense, which is calculated as 2.75% of property revenue to cover the regional supervision and accounting costs related to consolidated property operations, and land rent. UDR’s chief operating decision maker utilizes NOI as the key measure of segment profit or loss. UDR’s two reportable segments are Same-Store Communities and Non-Mature Communities/Other : • Same-Store Communities represent those communities acquired, developed, and stabilized prior to July 1, 2014 for quarter-to-date comparison and January 1, 2014 for year-to-date comparison and held as of September 30, 2015 . A comparison of operating results from the prior year is meaningful as these communities were owned and had stabilized occupancy and operating expenses as of the beginning of the prior period, there is no plan to conduct substantial redevelopment activities, and the community is not held for disposition within the current year. A community is considered to have stabilized occupancy once it achieves 90% occupancy for at least three consecutive months. • Non-Mature Communities/Other represent those communities that do not meet the criteria to be included in Same-Store Communities , including, but not limited to, recently acquired, developed and redeveloped properties, and the non-apartment components of mixed use properties. Management evaluates the performance of each of our apartment communities on a Same-Store Community and Non-Mature Community/Other basis, as well as individually and geographically. This is consistent with the aggregation criteria under GAAP as each of our apartment communities generally has similar economic characteristics, facilities, services, and tenants. Therefore, the Company’s reportable segments have been aggregated by geography in a manner identical to that which is provided to the chief operating decision maker. All revenues are from external customers and no single tenant or related group of tenants contributed 10% or more of UDR’s total revenues during the three and nine months ended September 30, 2015 and 2014 . The following table details rental income and NOI from continuing and discontinued operations for UDR’s reportable segments for the three and nine months ended September 30, 2015 and 2014 , and reconciles NOI to Net Income/(Loss) Attributable to UDR, Inc . in the Consolidated Statements of Operations (dollars in thousands) : Three Months Ended Nine Months Ended September 30, (a) September 30, (b) 2015 2014 2015 2014 Reportable apartment home segment rental income Same-Store Communities West Region $ 77,837 $ 72,014 $ 197,831 $ 183,887 Mid-Atlantic Region 40,029 39,351 119,546 117,384 Southeast Region 26,293 24,682 77,420 73,151 Northeast Region 21,914 20,721 64,242 60,817 Southwest Region 14,599 13,859 43,068 40,949 Non-Mature Communities/Other 37,093 32,981 135,469 122,857 Total consolidated rental income $ 217,765 $ 203,608 $ 637,576 $ 599,045 Reportable apartment home segment NOI Same-Store Communities West Region $ 58,071 $ 52,128 $ 147,725 $ 133,037 Mid-Atlantic Region 26,995 27,015 82,046 81,285 Southeast Region 17,562 15,869 51,875 48,494 Northeast Region 16,161 15,571 47,996 45,576 Southwest Region 8,967 8,509 26,500 25,130 Non-Mature Communities/Other 25,809 20,722 91,430 78,808 Total consolidated NOI 153,565 139,814 447,572 412,330 Reconciling items: Joint venture management and other fees 3,653 3,165 19,457 9,599 Property management (5,988 ) (5,599 ) (17,533 ) (16,474 ) Other operating expenses (2,639 ) (2,012 ) (6,174 ) (6,118 ) Real estate depreciation and amortization (90,568 ) (89,339 ) (269,689 ) (266,748 ) General and administrative (15,824 ) (11,554 ) (41,697 ) (36,078 ) Casualty-related recoveries/(charges), net (541 ) — (2,380 ) (500 ) Other depreciation and amortization (1,457 ) (1,385 ) (4,780 ) (3,658 ) Income/(loss) from unconsolidated entities 2,691 (939 ) 61,277 (4,932 ) Interest expense (30,232 ) (33,087 ) (88,705 ) (97,662 ) Interest income and other income/(expense), net 402 9,061 1,144 11,902 Tax benefit/(expense), net 633 2,490 2,462 8,049 Gain/(loss) on sale of real estate owned, net of tax — 31,377 79,042 82,380 Net (income)/loss attributable to redeemable noncontrolling interests in the Operating Partnership (405 ) (1,447 ) (6,022 ) (3,171 ) Net (income)/loss attributable to noncontrolling interests 1 4 (6 ) (2 ) Net income/(loss) attributable to UDR, Inc. $ 13,291 $ 40,549 $ 173,968 $ 88,917 (a) Same-Store Community population consisted of 34,774 apartment homes. (b) Same-Store Community population consisted of 33,495 apartment homes. The following table details the assets of UDR’s reportable segments as of September 30, 2015 and December 31, 2014 (dollars in thousands) : September 30, December 31, Reportable apartment home segment assets: Same-Store Communities: West Region $ 2,963,025 $ 2,935,430 Mid-Atlantic Region 1,464,514 1,453,532 Southeast Region 726,186 716,427 Northeast Region 1,083,935 1,076,656 Southwest Region 446,145 440,721 Non-Mature Communities/Other 1,789,172 1,760,493 Total assets 8,472,977 8,383,259 Accumulated depreciation (2,647,504 ) (2,434,772 ) Total assets — net book value 5,825,473 5,948,487 Reconciling items: Cash and cash equivalents 1,321 15,224 Restricted cash 23,722 22,340 Deferred financing costs, net 20,206 22,686 Notes receivable, net 15,494 14,369 Investment in and advances to unconsolidated joint ventures, net 921,925 718,226 Other assets 114,589 105,202 Total consolidated assets $ 6,922,730 $ 6,846,534 Capital expenditures related to our Same-Store Communities totaled $22.3 million and $14.0 million for the three months ended September 30, 2015 and 2014 , respectively, and $54.5 million and $33.9 million for the nine months ended September 30, 2015 and 2014 , respectively. Capital expenditures related to our Non-Mature Communities/Other totaled $3.1 million and $2.4 million for the three months ended September 30, 2015 and 2014 , respectively, and $8.5 million and $7.6 million for the nine months ended September 30, 2015 and 2014 . Markets included in the above geographic segments are as follows: i. West Region — Orange County, San Francisco, Seattle, Los Angeles, Monterey Peninsula, Other Southern California, and Portland ii. Mid-Atlantic Region — Metropolitan D.C., Baltimore, Richmond, Norfolk, and Other Mid-Atlantic iii. Southeast Region — Tampa, Orlando, Nashville, and Other Florida iv. Northeast Region — New York and Boston v. Southwest Region — Dallas and Austin

Reportable Segments (UNITED DOM

Reportable Segments (UNITED DOMINION REALTY, L.P.)	9 Months Ended
	Sep. 30, 2015
Entity Information [Line Items]
REPORTABLE SEGMENTS	REPORTABLE SEGMENTS GAAP guidance requires that segment disclosures present the measure(s) used by the chief operating decision maker to decide how to allocate resources and for purposes of assessing such segments’ performance. UDR’s chief operating decision maker is comprised of several members of its executive management team who use several generally accepted industry financial measures to assess the performance of the business for our reportable operating segments. UDR owns and operates multifamily apartment communities that generate rental and other property related income through the leasing of apartment homes to a diverse base of tenants. The primary financial measures for UDR’s apartment communities are rental income and net operating income (“NOI”). Rental income represents gross market rent less adjustments for concessions, vacancy loss and bad debt. NOI is defined as rental income less direct property rental expenses. Rental expenses include real estate taxes, insurance, personnel, utilities, repairs and maintenance, administrative and marketing. Excluded from NOI is property management expense, which is calculated as 2.75% of property revenue to cover the regional supervision and accounting costs related to consolidated property operations, and land rent. UDR’s chief operating decision maker utilizes NOI as the key measure of segment profit or loss. UDR’s two reportable segments are Same-Store Communities and Non-Mature Communities/Other : • Same-Store Communities represent those communities acquired, developed, and stabilized prior to July 1, 2014 for quarter-to-date comparison and January 1, 2014 for year-to-date comparison and held as of September 30, 2015 . A comparison of operating results from the prior year is meaningful as these communities were owned and had stabilized occupancy and operating expenses as of the beginning of the prior period, there is no plan to conduct substantial redevelopment activities, and the community is not held for disposition within the current year. A community is considered to have stabilized occupancy once it achieves 90% occupancy for at least three consecutive months. • Non-Mature Communities/Other represent those communities that do not meet the criteria to be included in Same-Store Communities , including, but not limited to, recently acquired, developed and redeveloped properties, and the non-apartment components of mixed use properties. Management evaluates the performance of each of our apartment communities on a Same-Store Community and Non-Mature Community/Other basis, as well as individually and geographically. This is consistent with the aggregation criteria under GAAP as each of our apartment communities generally has similar economic characteristics, facilities, services, and tenants. Therefore, the Company’s reportable segments have been aggregated by geography in a manner identical to that which is provided to the chief operating decision maker. All revenues are from external customers and no single tenant or related group of tenants contributed 10% or more of UDR’s total revenues during the three and nine months ended September 30, 2015 and 2014 . The following table details rental income and NOI from continuing and discontinued operations for UDR’s reportable segments for the three and nine months ended September 30, 2015 and 2014 , and reconciles NOI to Net Income/(Loss) Attributable to UDR, Inc . in the Consolidated Statements of Operations (dollars in thousands) : Three Months Ended Nine Months Ended September 30, (a) September 30, (b) 2015 2014 2015 2014 Reportable apartment home segment rental income Same-Store Communities West Region $ 77,837 $ 72,014 $ 197,831 $ 183,887 Mid-Atlantic Region 40,029 39,351 119,546 117,384 Southeast Region 26,293 24,682 77,420 73,151 Northeast Region 21,914 20,721 64,242 60,817 Southwest Region 14,599 13,859 43,068 40,949 Non-Mature Communities/Other 37,093 32,981 135,469 122,857 Total consolidated rental income $ 217,765 $ 203,608 $ 637,576 $ 599,045 Reportable apartment home segment NOI Same-Store Communities West Region $ 58,071 $ 52,128 $ 147,725 $ 133,037 Mid-Atlantic Region 26,995 27,015 82,046 81,285 Southeast Region 17,562 15,869 51,875 48,494 Northeast Region 16,161 15,571 47,996 45,576 Southwest Region 8,967 8,509 26,500 25,130 Non-Mature Communities/Other 25,809 20,722 91,430 78,808 Total consolidated NOI 153,565 139,814 447,572 412,330 Reconciling items: Joint venture management and other fees 3,653 3,165 19,457 9,599 Property management (5,988 ) (5,599 ) (17,533 ) (16,474 ) Other operating expenses (2,639 ) (2,012 ) (6,174 ) (6,118 ) Real estate depreciation and amortization (90,568 ) (89,339 ) (269,689 ) (266,748 ) General and administrative (15,824 ) (11,554 ) (41,697 ) (36,078 ) Casualty-related recoveries/(charges), net (541 ) — (2,380 ) (500 ) Other depreciation and amortization (1,457 ) (1,385 ) (4,780 ) (3,658 ) Income/(loss) from unconsolidated entities 2,691 (939 ) 61,277 (4,932 ) Interest expense (30,232 ) (33,087 ) (88,705 ) (97,662 ) Interest income and other income/(expense), net 402 9,061 1,144 11,902 Tax benefit/(expense), net 633 2,490 2,462 8,049 Gain/(loss) on sale of real estate owned, net of tax — 31,377 79,042 82,380 Net (income)/loss attributable to redeemable noncontrolling interests in the Operating Partnership (405 ) (1,447 ) (6,022 ) (3,171 ) Net (income)/loss attributable to noncontrolling interests 1 4 (6 ) (2 ) Net income/(loss) attributable to UDR, Inc. $ 13,291 $ 40,549 $ 173,968 $ 88,917 (a) Same-Store Community population consisted of 34,774 apartment homes. (b) Same-Store Community population consisted of 33,495 apartment homes. The following table details the assets of UDR’s reportable segments as of September 30, 2015 and December 31, 2014 (dollars in thousands) : September 30, December 31, Reportable apartment home segment assets: Same-Store Communities: West Region $ 2,963,025 $ 2,935,430 Mid-Atlantic Region 1,464,514 1,453,532 Southeast Region 726,186 716,427 Northeast Region 1,083,935 1,076,656 Southwest Region 446,145 440,721 Non-Mature Communities/Other 1,789,172 1,760,493 Total assets 8,472,977 8,383,259 Accumulated depreciation (2,647,504 ) (2,434,772 ) Total assets — net book value 5,825,473 5,948,487 Reconciling items: Cash and cash equivalents 1,321 15,224 Restricted cash 23,722 22,340 Deferred financing costs, net 20,206 22,686 Notes receivable, net 15,494 14,369 Investment in and advances to unconsolidated joint ventures, net 921,925 718,226 Other assets 114,589 105,202 Total consolidated assets $ 6,922,730 $ 6,846,534 Capital expenditures related to our Same-Store Communities totaled $22.3 million and $14.0 million for the three months ended September 30, 2015 and 2014 , respectively, and $54.5 million and $33.9 million for the nine months ended September 30, 2015 and 2014 , respectively. Capital expenditures related to our Non-Mature Communities/Other totaled $3.1 million and $2.4 million for the three months ended September 30, 2015 and 2014 , respectively, and $8.5 million and $7.6 million for the nine months ended September 30, 2015 and 2014 . Markets included in the above geographic segments are as follows: i. West Region — Orange County, San Francisco, Seattle, Los Angeles, Monterey Peninsula, Other Southern California, and Portland ii. Mid-Atlantic Region — Metropolitan D.C., Baltimore, Richmond, Norfolk, and Other Mid-Atlantic iii. Southeast Region — Tampa, Orlando, Nashville, and Other Florida iv. Northeast Region — New York and Boston v. Southwest Region — Dallas and Austin
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
REPORTABLE SEGMENTS	REPORTABLE SEGMENTS GAAP guidance requires that segment disclosures present the measure(s) used by the chief operating decision maker to decide how to allocate resources and for purposes of assessing such segments’ performance. The Operating Partnership has the same chief operating decision maker as that of its parent, the General Partner. The chief operating decision maker consists of several members of UDR’s executive management team who use several generally accepted industry financial measures to assess the performance of the business for our reportable operating segments. The Operating Partnership owns and operates multifamily apartment communities throughout the United States that generate rental and other property related income through the leasing of apartment homes to a diverse base of tenants. The primary financial measures of the Operating Partnership’s apartment communities are rental income and net operating income (“NOI”), and are included in the chief operating decision maker’s assessment of the Operating Partnership’s performance on a consolidated basis. Rental income represents gross market rent less adjustments for concessions, vacancy loss and bad debt. NOI is defined as total revenues less direct property operating expenses. Rental expenses include real estate taxes, insurance, personnel, utilities, repairs and maintenance, administrative and marketing. Excluded from NOI is property management expense which is calculated as 2.75% of property revenue to cover the regional supervision and accounting costs related to consolidated property operations, and land rent. The chief operating decision maker of the General Partner utilizes NOI as the key measure of segment profit or loss. The Operating Partnership’s two reportable segments are Same-Store Communities and Non-Mature Communities/Other: • Same-Store Communities represent those communities acquired, developed, and stabilized prior to July 1, 2014 for quarter-to-date comparison and January 1, 2014 for year-to-date comparison and held as of September 30, 2015 . A comparison of operating results from the prior year is meaningful as these communities were owned and had stabilized occupancy and operating expenses as of the beginning of the prior period, there is no plan to conduct substantial redevelopment activities, and the community is not held for disposition within the current year. A community is considered to have stabilized occupancy once it achieves 90% occupancy for at least three consecutive months. • Non-Mature Communities/Other represent those communities that do not meet the criteria to be included in Same-Store Communities , including, but not limited to, recently acquired, developed and redeveloped properties, and the non-apartment components of mixed use properties. Management of the General Partner evaluates the performance of each of the Operating Partnership’s apartment communities on a Same-Store Community and Non-Mature Community/Other basis, as well as individually and geographically. This is consistent with the aggregation criteria under GAAP as each of the apartment communities generally has similar economic characteristics, facilities, services, and tenants. Therefore, the Operating Partnership’s reportable segments have been aggregated by geography in a manner identical to that which is provided to the chief operating decision maker. All revenues are from external customers and no single tenant or related group of tenants contributed 10% or more of the Operating Partnership’s total revenues during the three and nine months ended September 30, 2015 and 2014 . The following table details rental income and NOI from continuing and discontinued operations for the Operating Partnership’s reportable segments for the three and nine months ended September 30, 2015 and 2014 , and reconciles NOI to Net income/(loss) attributable to OP unitholders in the Consolidated Statements of Operations (dollars in thousands) : Three Months Ended Nine Months Ended September 30, (a) September 30, (b) 2015 2014 2015 2014 Reportable apartment home segment rental income Same-Store Communities West Region $ 52,731 $ 48,536 $ 136,298 $ 125,653 Mid-Atlantic Region 16,702 16,364 49,907 49,331 Southeast Region 11,363 10,677 33,535 31,757 Northeast Region 15,810 14,968 46,379 43,894 Southwest Region 6,989 6,667 20,594 19,873 Non-Mature Communities/Other 11,578 10,232 51,713 44,148 Total consolidated rental income $ 115,173 $ 107,444 $ 338,426 $ 314,656 Reportable apartment home segment NOI Same-Store Communities West Region $ 39,121 $ 35,066 $ 101,855 $ 91,363 Mid-Atlantic Region 10,639 10,873 32,845 33,185 Southeast Region 7,602 6,882 22,357 20,999 Northeast Region 12,025 11,609 35,672 33,662 Southwest Region 4,383 4,192 12,956 12,578 Non-Mature Communities/Other 8,520 7,131 37,003 31,351 Total consolidated NOI 82,290 75,753 242,688 223,138 Reconciling items: Property management (3,167 ) (2,955 ) (9,307 ) (8,653 ) Other operating expenses (1,482 ) (1,484 ) (4,468 ) (4,371 ) Real estate depreciation and amortization (43,829 ) (45,043 ) (132,411 ) (134,011 ) General and administrative (7,935 ) (6,939 ) (20,606 ) (21,368 ) Casualty-related recoveries/(charges), net (16 ) — (888 ) (500 ) Interest expense (10,909 ) (10,457 ) (32,587 ) (30,629 ) Gain/(loss) on sale of real estate owned — — 56,998 40,687 Net (income)/loss attributable to noncontrolling interests (335 ) (238 ) (1,075 ) (697 ) Net income/(loss) attributable to OP unitholders $ 14,617 $ 8,637 $ 98,344 $ 63,596 (a) Same-Store Community population consisted of 19,024 apartment homes. (b) Same-Store Community population consisted of 18,060 apartment homes The following table details the assets of the Operating Partnership’s reportable segments as of September 30, 2015 and December 31, 2014 (dollars in thousands) : September 30, December 31, 2014 Reportable apartment home segment assets Same-Store Communities West Region $ 1,873,029 $ 1,853,283 Mid-Atlantic Region 691,799 686,708 Southeast Region 320,578 316,788 Northeast Region 782,366 777,376 Southwest Region 231,748 228,997 Non-Mature Communities/Other 359,058 375,618 Total assets 4,258,578 4,238,770 Accumulated depreciation (1,518,558 ) (1,403,303 ) Total assets - net book value 2,740,020 2,835,467 Reconciling items: Cash and cash equivalents 131 502 Restricted cash 14,710 13,811 Deferred financing costs, net 3,355 4,475 Other assets 24,740 24,029 Total consolidated assets $ 2,782,956 $ 2,878,284 Capital expenditures related to the Operating Partnership’s Same-Store Communities totaled $13.6 million and $8.0 million for the three months ended September 30, 2015 and 2014 , respectively, and $32.8 million and $19.1 million for the nine months ended September 30, 2015 and 2014 , respectively. Capital expenditures related to the Operating Partnership’s Non-Mature Communities/Other totaled $0.9 million and $0.7 million for the three months ended September 30, 2015 and 2014 , respectively, and $3.2 million and $1.4 million for the nine months ended September 30, 2015 and 2014 , respectively. Markets included in the above geographic segments are as follows: i. West Region — Orange County, San Francisco, Seattle, Los Angeles, Monterey Peninsula, Other Southern California, and Portland ii. Mid-Atlantic Region — Metropolitan D.C. and Baltimore iii. Southeast Region — Tampa, Nashville, and Other Florida iv. Northeast Region — New York and Boston v. Southwest Region — Dallas

Subsequent Events (Notes)

Subsequent Events (Notes)	9 Months Ended
	Sep. 30, 2015
Subsequent Events [Abstract]
Subsequent Events [Text Block]	SUBSEQUENT EVENTS The Company evaluated subsequent events through the date its financial statements were issued and noted the following: UDR Lighthouse DownREIT L.P. Formation In connection with the acquisitions described below, on October 5, 2015, the Company, as the sole general partner and a limited partner, the Operating Partnership and UDR Texas Properties LLC, a Delaware limited liability company owned 0.5% by the Company and 99.5% by the Operating Partnership ("UDR Texas"), as limited partners, entered into the Agreement of Limited Partnership (the “Partnership Agreement”) of UDR Lighthouse DownREIT L.P. (the “DownREIT Partnership”). As the sole general partner of the DownREIT Partnership, the Company has full, complete and exclusive discretion to manage and control the business of the DownREIT Partnership and to make all decisions affecting the business and assets of the DownREIT Partnership, subject to certain limitations set forth in the Partnership Agreement. As of the closing of the transactions under the Contribution Agreement (as defined below), the Company, the Operating Partnership and UDR Texas owned approximately 8.5% , 32.5% and 9.1% , respectively, of the units of limited partnership interest in the DownREIT Partnership (“DownREIT Units”), which they received in exchange for their contribution of the following properties to the DownREIT Partnership: Property Location Ridge at Blue Hills (1) Braintree, MA Residences at the Domain (1) Austin, TX Inwood West (2) Woburn, MA Thirty377 (2) Dallas, TX Legacy Village (2) Plano, TX Delancey at Shirlington (2) Arlington, VA Circle Towers (2) Fairfax, VA Barton Creek Landing (3) Austin, TX The Whitmore (3) Arlington, VA (1) Contributed by the Company. (2) Contributed by the Operating Partnership. (3) Contributed by UDR Texas. The limited partners have no power to remove the Company as general partner of the DownREIT Partnership. The DownREIT Partnership is structured to make distributions in respect of DownREIT Units that will be equivalent to the distributions made to holders of the Company’s common stock. Subject to certain terms and conditions set forth in the Partnership Agreement, limited partners in the DownREIT Partnership (other than the Company and its affiliates) have the right, commencing one year after the date of issuance, to tender their DownREIT Units for redemption for cash or, at the Company’s election, for shares of its common stock on a one-for-one basis (subject to the anti-dilution adjustments provided in the Partnership Agreement). Property Acquisitions From October 6-8, 2015, the Company completed the acquisition of six Washington, DC area properties from Home Properties, L.P., a New York limited partnership (“Home OP”), for a total purchase price of $901 million , which was comprised of $565 million of newly issued DownREIT Units issued at $35 per unit (a total of 16.1 million units), the assumption of $89 million of debt, $221 million of reverse exchanges pursuant to Section 1031 of the Internal Revenue Code of 1986, as amended, and $26 million of cash. In addition, the Company issued approximately 13.7 million shares of its Series F Preferred Stock to former limited partners of Home OP, which had the right to subscribe for one share of Series F Preferred Stock for each DownREIT Unit issued in connection with the acquisitions. The acquisitions were made pursuant to the previously disclosed Contribution Agreement, dated as of June 22, 2015, as amended, by and among the Company, the Operating Partnership, Home OP and LSREF4 Lighthouse Acquisitions, LLC, a Delaware limited liability company (the “Contribution Agreement”). Of the six properties acquired from Home OP, four properties were acquired through the DownREIT Partnership, one property was acquired by the Operating Partnership through a reverse Section 1031 exchange and one property was acquired by an affiliate of the Company through a reverse Section 1031 exchange, as reflected in the following table: Property Location Eleven55 Ripley (1) Silver Spring, MD Arbor Park of Alexandria (1) Alexandria, VA Newport Village (1) Alexandria, VA The Courts at Dulles (1) Herndon, VA 1200 East West (2) Silver Spring, MD Courts at Huntington Station (3) Alexandria, VA (1) Acquired through the DownREIT Partnership. (2) Acquired by an affiliate of the Company through a reverse Section 1031 exchange. (3) Acquired by the Operating Partnership through a reverse Section 1031 exchange. Revolving Credit Facility On October 20, 2015, the Company, as borrower, entered into a credit agreement (the “Credit Agreement”), which provides for a $1.1 billion senior unsecured revolving credit facility (the “Revolving Credit Facility”) and a $350.0 million senior unsecured term loan facility (the “Term Loan Facility”). The Credit Agreement includes an accordion feature that allows the total commitments under the Revolving Credit Facility and the total borrowings under the Term Loan Facility to be increased to an aggregate maximum amount of up to $2.0 billion , subject to certain conditions, including obtaining commitments from any one or more lenders. The Revolving Credit Facility has a scheduled maturity date of January 31, 2020, with two six -month extension options, subject to certain conditions. The Term Loan Facility has a scheduled maturity date of January 29, 2021. The Credit Agreement replaces (i) the Company’s $900 million revolving credit facility scheduled to mature in December 2017 (the “Prior Credit Agreement”) and (ii) the Company’s $250 million term loan and the Company’s $100 million term loan, both due June 2018 (together, the “Prior Term Loan Agreements”). On October 20, 2015, the Company borrowed $200 million under the Revolving Credit Facility and $350 million under the Term Loan Facility to pay outstanding balances under the Prior Credit Agreement and the Prior Term Loan Agreements, respectively. Based on the Company’s current credit rating, the Revolving Credit Facility has an interest rate equal to LIBOR plus a margin of 90 basis points and a facility fee of 15 basis points, and the Term Loan Facility has an interest rate equal to LIBOR plus a margin of 95 basis points. Depending on the Company’s credit rating, the margin under the Revolving Credit Facility ranges from 85 to 155 basis points and the facility fee ranges from 12.5 to 30 basis points, and the margin under the Term Loan Facility ranges from 90 to 175 basis points. The Credit Agreement contains customary representations and warranties and financial and other affirmative and negative covenants. The Credit Agreement also includes customary events of default, in certain cases subject to customary periods to cure. The occurrence of an event of default, following the applicable cure period, would permit the lenders to, among other things, declare the unpaid principal, accrued and unpaid interest and all other amounts payable under the Credit Agreement to be immediately due and payable. The Company’s obligations under the Credit Agreement are guaranteed by the Operating Partnership, pursuant to a guaranty dated as of October 20, 2015. SUBSEQUENT EVENTS The Operating Partnership evaluated subsequent events through the date its financial statements were issued and noted the following: UDR Lighthouse DownREIT L.P. Formation In connection with the acquisitions described below, on October 5, 2015, UDR, as the sole general partner and a limited partner, the Operating Partnership and UDR Texas Properties LLC, a Delaware limited liability company owned 0.5% by UDR and 99.5% by the Operating Partnership ("UDR Texas"), as limited partners, entered into the Agreement of Limited Partnership (the “Partnership Agreement”) of UDR Lighthouse DownREIT L.P. (the “DownREIT Partnership”). As the sole general partner of the DownREIT Partnership, UDR has full, complete and exclusive discretion to manage and control the business of the DownREIT Partnership and to make all decisions affecting the business and assets of the DownREIT Partnership, subject to certain limitations set forth in the Partnership Agreement. As of the closing of the transactions under the Contribution Agreement (as defined below), UDR, the Operating Partnership and UDR Texas owned approximately 8.5% , 32.5% and 9.1% , respectively, of the units of limited partnership interest in the DownREIT Partnership (“DownREIT Units”), which they received in exchange for their contribution of the following properties to the DownREIT Partnership: Property Location Ridge at Blue Hills (1) Braintree, MA Residences at the Domain (1) Austin, TX Inwood West (2) Woburn, MA Thirty377 (2) Dallas, TX Legacy Village (2) Plano, TX Delancey at Shirlington (2) Arlington, VA Circle Towers (2) Fairfax, VA Barton Creek Landing (3) Austin, TX The Whitmore (3) Arlington, VA (1) Contributed by UDR. (2) Contributed by the Operating Partnership. (3) Contributed by UDR Texas. As a result of the contribution of the seven properties to the DownREIT Partnership by the Operating Partnership and UDR Texas, the properties will no longer be consolidated in the Operating Partnership’s financial statements, resulting in a decrease in the real estate owned, debt, revenues and expenses of the Operating Partnership. A gain will be recorded for a portion of the Operating Partnership’s ownership interest in the seven properties that was disposed during the three months ended December 31, 2015. The Operating Partnership retained a 41.6% interest in those seven properties through its direct and indirect ownership interest in the DownREIT Partnership, which will be reported as Investment in and advances to unconsolidated joint ventures, net on the consolidated balance sheet and Income/(loss) from unconsolidated entities on the consolidated statement of operations in the Operating Partnership’s consolidated financial statements. The limited partners have no power to remove UDR as general partner of the DownREIT Partnership. The DownREIT Partnership is structured to make distributions in respect of DownREIT Units that will be equivalent to the distributions made to holders of UDR’s common stock. Subject to certain terms and conditions set forth in the Partnership Agreement, limited partners in the DownREIT Partnership (other than UDR and its affiliates) have the right, commencing one year after the date of issuance, to tender their DownREIT Units for redemption for cash or, at UDR’s election, for shares of its common stock on a one-for-one basis (subject to the anti-dilution adjustments provided in the Partnership Agreement). Property Acquisitions From October 6-8, 2015, UDR completed the acquisition of six Washington, DC area properties from Home Properties, L.P., a New York limited partnership (“Home OP”), for a total purchase price of $901 million , which was comprised of $565 million of newly issued DownREIT Units issued at $35 per unit (a total of 16.1 million units), the assumption of $89 million of debt, $221 million of reverse exchanges pursuant to Section 1031 of the Internal Revenue Code of 1986, as amended, and $26 million of cash. In addition, UDR issued approximately 13.7 million shares of its Series F Preferred Stock to former limited partners of Home OP, which had the right to subscribe for one share of Series F Preferred Stock for each DownREIT Unit issued in connection with the acquisitions. The acquisitions were made pursuant to the previously disclosed Contribution Agreement, dated as of June 22, 2015, as amended, by and among UDR, the Operating Partnership, Home OP and LSREF4 Lighthouse Acquisitions, LLC, a Delaware limited liability company (the “Contribution Agreement”). Of the six properties acquired from Home OP, four properties were acquired through the DownREIT Partnership, one property was acquired by the Operating Partnership through a reverse Section 1031 exchange and one property was acquired by an affiliate of UDR through a reverse Section 1031 exchange, as reflected in the following table: Property Location Eleven55 Ripley (1) Silver Spring, MD Arbor Park of Alexandria (1) Alexandria, VA Newport Village (1) Alexandria, VA The Courts at Dulles (1) Herndon, VA 1200 East West (2) Silver Spring, MD Courts at Huntington Station (3) Alexandria, VA (1) Acquired through the DownREIT Partnership. (2) Acquired by an affiliate of UDR through a reverse Section 1031 exchange. (3) Acquired by the Operating Partnership through a reverse Section 1031 exchange. Revolving Credit Facility On October 20, 2015, UDR, Inc., as borrower, entered into a credit agreement (the “Credit Agreement”), which provides for a $1.1 billion senior unsecured revolving credit facility (the “Revolving Credit Facility”) and a $350.0 million senior unsecured term loan facility (the “Term Loan Facility”). The Credit Agreement includes an accordion feature that allows the total commitments under the Revolving Credit Facility and the total borrowings under the Term Loan Facility to be increased to an aggregate maximum amount of up to $2.0 billion , subject to certain conditions, including obtaining commitments from any one or more lenders. The Revolving Credit Facility has a scheduled maturity date of January 31, 2020, with two six -month extension options, subject to certain conditions. The Term Loan Facility has a scheduled maturity date of January 29, 2021. The Credit Agreement replaces (i) UDR, Inc.’s $900 million revolving credit facility scheduled to mature in December 2017 (the “Prior Credit Agreement”) and (ii) UDR, Inc.’s $250 million term loan and UDR, Inc.’s $100 million term loan, both due June 2018 (together, the “Prior Term Loan Agreements”). On October 20, 2015, UDR, Inc. borrowed $200 million under the Revolving Credit Facility and $350 million under the Term Loan Facility to pay outstanding balances under the Prior Credit Agreement and the Prior Term Loan Agreements, respectively. Based on UDR, Inc.’s current credit rating, the Revolving Credit Facility has an interest rate equal to LIBOR plus a margin of 90 basis points and a facility fee of 15 basis points, and the Term Loan Facility has an interest rate equal to LIBOR plus a margin of 95 basis points. Depending on UDR, Inc.’s credit rating, the margin under the Revolving Credit Facility ranges from 85 to 155 basis points and the facility fee ranges from 12.5 to 30 basis points, and the margin under the Term Loan Facility ranges from 90 to 175 basis points. The Credit Agreement contains customary representations and warranties and financial and other affirmative and negative covenants. The Credit Agreement also includes customary events of default, in certain cases subject to customary periods to cure. The occurrence of an event of default, following the applicable cure period, would permit the lenders to, among other things, declare the unpaid principal, accrued and unpaid interest and all other amounts payable under the Credit Agreement to be immediately due and payable. UDR, Inc.’s obligations under the Credit Agreement are guaranteed by the Operating Partnership, pursuant to a guaranty dated as of October 20, 2015.

Subsequent Events (UNITED DOMIN

Subsequent Events (UNITED DOMINION REALTY, L.P.) (Notes)	9 Months Ended
	Sep. 30, 2015
Subsequent Event [Line Items]
Subsequent Events [Text Block]	SUBSEQUENT EVENTS The Company evaluated subsequent events through the date its financial statements were issued and noted the following: UDR Lighthouse DownREIT L.P. Formation In connection with the acquisitions described below, on October 5, 2015, the Company, as the sole general partner and a limited partner, the Operating Partnership and UDR Texas Properties LLC, a Delaware limited liability company owned 0.5% by the Company and 99.5% by the Operating Partnership ("UDR Texas"), as limited partners, entered into the Agreement of Limited Partnership (the “Partnership Agreement”) of UDR Lighthouse DownREIT L.P. (the “DownREIT Partnership”). As the sole general partner of the DownREIT Partnership, the Company has full, complete and exclusive discretion to manage and control the business of the DownREIT Partnership and to make all decisions affecting the business and assets of the DownREIT Partnership, subject to certain limitations set forth in the Partnership Agreement. As of the closing of the transactions under the Contribution Agreement (as defined below), the Company, the Operating Partnership and UDR Texas owned approximately 8.5% , 32.5% and 9.1% , respectively, of the units of limited partnership interest in the DownREIT Partnership (“DownREIT Units”), which they received in exchange for their contribution of the following properties to the DownREIT Partnership: Property Location Ridge at Blue Hills (1) Braintree, MA Residences at the Domain (1) Austin, TX Inwood West (2) Woburn, MA Thirty377 (2) Dallas, TX Legacy Village (2) Plano, TX Delancey at Shirlington (2) Arlington, VA Circle Towers (2) Fairfax, VA Barton Creek Landing (3) Austin, TX The Whitmore (3) Arlington, VA (1) Contributed by the Company. (2) Contributed by the Operating Partnership. (3) Contributed by UDR Texas. The limited partners have no power to remove the Company as general partner of the DownREIT Partnership. The DownREIT Partnership is structured to make distributions in respect of DownREIT Units that will be equivalent to the distributions made to holders of the Company’s common stock. Subject to certain terms and conditions set forth in the Partnership Agreement, limited partners in the DownREIT Partnership (other than the Company and its affiliates) have the right, commencing one year after the date of issuance, to tender their DownREIT Units for redemption for cash or, at the Company’s election, for shares of its common stock on a one-for-one basis (subject to the anti-dilution adjustments provided in the Partnership Agreement). Property Acquisitions From October 6-8, 2015, the Company completed the acquisition of six Washington, DC area properties from Home Properties, L.P., a New York limited partnership (“Home OP”), for a total purchase price of $901 million , which was comprised of $565 million of newly issued DownREIT Units issued at $35 per unit (a total of 16.1 million units), the assumption of $89 million of debt, $221 million of reverse exchanges pursuant to Section 1031 of the Internal Revenue Code of 1986, as amended, and $26 million of cash. In addition, the Company issued approximately 13.7 million shares of its Series F Preferred Stock to former limited partners of Home OP, which had the right to subscribe for one share of Series F Preferred Stock for each DownREIT Unit issued in connection with the acquisitions. The acquisitions were made pursuant to the previously disclosed Contribution Agreement, dated as of June 22, 2015, as amended, by and among the Company, the Operating Partnership, Home OP and LSREF4 Lighthouse Acquisitions, LLC, a Delaware limited liability company (the “Contribution Agreement”). Of the six properties acquired from Home OP, four properties were acquired through the DownREIT Partnership, one property was acquired by the Operating Partnership through a reverse Section 1031 exchange and one property was acquired by an affiliate of the Company through a reverse Section 1031 exchange, as reflected in the following table: Property Location Eleven55 Ripley (1) Silver Spring, MD Arbor Park of Alexandria (1) Alexandria, VA Newport Village (1) Alexandria, VA The Courts at Dulles (1) Herndon, VA 1200 East West (2) Silver Spring, MD Courts at Huntington Station (3) Alexandria, VA (1) Acquired through the DownREIT Partnership. (2) Acquired by an affiliate of the Company through a reverse Section 1031 exchange. (3) Acquired by the Operating Partnership through a reverse Section 1031 exchange. Revolving Credit Facility On October 20, 2015, the Company, as borrower, entered into a credit agreement (the “Credit Agreement”), which provides for a $1.1 billion senior unsecured revolving credit facility (the “Revolving Credit Facility”) and a $350.0 million senior unsecured term loan facility (the “Term Loan Facility”). The Credit Agreement includes an accordion feature that allows the total commitments under the Revolving Credit Facility and the total borrowings under the Term Loan Facility to be increased to an aggregate maximum amount of up to $2.0 billion , subject to certain conditions, including obtaining commitments from any one or more lenders. The Revolving Credit Facility has a scheduled maturity date of January 31, 2020, with two six -month extension options, subject to certain conditions. The Term Loan Facility has a scheduled maturity date of January 29, 2021. The Credit Agreement replaces (i) the Company’s $900 million revolving credit facility scheduled to mature in December 2017 (the “Prior Credit Agreement”) and (ii) the Company’s $250 million term loan and the Company’s $100 million term loan, both due June 2018 (together, the “Prior Term Loan Agreements”). On October 20, 2015, the Company borrowed $200 million under the Revolving Credit Facility and $350 million under the Term Loan Facility to pay outstanding balances under the Prior Credit Agreement and the Prior Term Loan Agreements, respectively. Based on the Company’s current credit rating, the Revolving Credit Facility has an interest rate equal to LIBOR plus a margin of 90 basis points and a facility fee of 15 basis points, and the Term Loan Facility has an interest rate equal to LIBOR plus a margin of 95 basis points. Depending on the Company’s credit rating, the margin under the Revolving Credit Facility ranges from 85 to 155 basis points and the facility fee ranges from 12.5 to 30 basis points, and the margin under the Term Loan Facility ranges from 90 to 175 basis points. The Credit Agreement contains customary representations and warranties and financial and other affirmative and negative covenants. The Credit Agreement also includes customary events of default, in certain cases subject to customary periods to cure. The occurrence of an event of default, following the applicable cure period, would permit the lenders to, among other things, declare the unpaid principal, accrued and unpaid interest and all other amounts payable under the Credit Agreement to be immediately due and payable. The Company’s obligations under the Credit Agreement are guaranteed by the Operating Partnership, pursuant to a guaranty dated as of October 20, 2015. SUBSEQUENT EVENTS The Operating Partnership evaluated subsequent events through the date its financial statements were issued and noted the following: UDR Lighthouse DownREIT L.P. Formation In connection with the acquisitions described below, on October 5, 2015, UDR, as the sole general partner and a limited partner, the Operating Partnership and UDR Texas Properties LLC, a Delaware limited liability company owned 0.5% by UDR and 99.5% by the Operating Partnership ("UDR Texas"), as limited partners, entered into the Agreement of Limited Partnership (the “Partnership Agreement”) of UDR Lighthouse DownREIT L.P. (the “DownREIT Partnership”). As the sole general partner of the DownREIT Partnership, UDR has full, complete and exclusive discretion to manage and control the business of the DownREIT Partnership and to make all decisions affecting the business and assets of the DownREIT Partnership, subject to certain limitations set forth in the Partnership Agreement. As of the closing of the transactions under the Contribution Agreement (as defined below), UDR, the Operating Partnership and UDR Texas owned approximately 8.5% , 32.5% and 9.1% , respectively, of the units of limited partnership interest in the DownREIT Partnership (“DownREIT Units”), which they received in exchange for their contribution of the following properties to the DownREIT Partnership: Property Location Ridge at Blue Hills (1) Braintree, MA Residences at the Domain (1) Austin, TX Inwood West (2) Woburn, MA Thirty377 (2) Dallas, TX Legacy Village (2) Plano, TX Delancey at Shirlington (2) Arlington, VA Circle Towers (2) Fairfax, VA Barton Creek Landing (3) Austin, TX The Whitmore (3) Arlington, VA (1) Contributed by UDR. (2) Contributed by the Operating Partnership. (3) Contributed by UDR Texas. As a result of the contribution of the seven properties to the DownREIT Partnership by the Operating Partnership and UDR Texas, the properties will no longer be consolidated in the Operating Partnership’s financial statements, resulting in a decrease in the real estate owned, debt, revenues and expenses of the Operating Partnership. A gain will be recorded for a portion of the Operating Partnership’s ownership interest in the seven properties that was disposed during the three months ended December 31, 2015. The Operating Partnership retained a 41.6% interest in those seven properties through its direct and indirect ownership interest in the DownREIT Partnership, which will be reported as Investment in and advances to unconsolidated joint ventures, net on the consolidated balance sheet and Income/(loss) from unconsolidated entities on the consolidated statement of operations in the Operating Partnership’s consolidated financial statements. The limited partners have no power to remove UDR as general partner of the DownREIT Partnership. The DownREIT Partnership is structured to make distributions in respect of DownREIT Units that will be equivalent to the distributions made to holders of UDR’s common stock. Subject to certain terms and conditions set forth in the Partnership Agreement, limited partners in the DownREIT Partnership (other than UDR and its affiliates) have the right, commencing one year after the date of issuance, to tender their DownREIT Units for redemption for cash or, at UDR’s election, for shares of its common stock on a one-for-one basis (subject to the anti-dilution adjustments provided in the Partnership Agreement). Property Acquisitions From October 6-8, 2015, UDR completed the acquisition of six Washington, DC area properties from Home Properties, L.P., a New York limited partnership (“Home OP”), for a total purchase price of $901 million , which was comprised of $565 million of newly issued DownREIT Units issued at $35 per unit (a total of 16.1 million units), the assumption of $89 million of debt, $221 million of reverse exchanges pursuant to Section 1031 of the Internal Revenue Code of 1986, as amended, and $26 million of cash. In addition, UDR issued approximately 13.7 million shares of its Series F Preferred Stock to former limited partners of Home OP, which had the right to subscribe for one share of Series F Preferred Stock for each DownREIT Unit issued in connection with the acquisitions. The acquisitions were made pursuant to the previously disclosed Contribution Agreement, dated as of June 22, 2015, as amended, by and among UDR, the Operating Partnership, Home OP and LSREF4 Lighthouse Acquisitions, LLC, a Delaware limited liability company (the “Contribution Agreement”). Of the six properties acquired from Home OP, four properties were acquired through the DownREIT Partnership, one property was acquired by the Operating Partnership through a reverse Section 1031 exchange and one property was acquired by an affiliate of UDR through a reverse Section 1031 exchange, as reflected in the following table: Property Location Eleven55 Ripley (1) Silver Spring, MD Arbor Park of Alexandria (1) Alexandria, VA Newport Village (1) Alexandria, VA The Courts at Dulles (1) Herndon, VA 1200 East West (2) Silver Spring, MD Courts at Huntington Station (3) Alexandria, VA (1) Acquired through the DownREIT Partnership. (2) Acquired by an affiliate of UDR through a reverse Section 1031 exchange. (3) Acquired by the Operating Partnership through a reverse Section 1031 exchange. Revolving Credit Facility On October 20, 2015, UDR, Inc., as borrower, entered into a credit agreement (the “Credit Agreement”), which provides for a $1.1 billion senior unsecured revolving credit facility (the “Revolving Credit Facility”) and a $350.0 million senior unsecured term loan facility (the “Term Loan Facility”). The Credit Agreement includes an accordion feature that allows the total commitments under the Revolving Credit Facility and the total borrowings under the Term Loan Facility to be increased to an aggregate maximum amount of up to $2.0 billion , subject to certain conditions, including obtaining commitments from any one or more lenders. The Revolving Credit Facility has a scheduled maturity date of January 31, 2020, with two six -month extension options, subject to certain conditions. The Term Loan Facility has a scheduled maturity date of January 29, 2021. The Credit Agreement replaces (i) UDR, Inc.’s $900 million revolving credit facility scheduled to mature in December 2017 (the “Prior Credit Agreement”) and (ii) UDR, Inc.’s $250 million term loan and UDR, Inc.’s $100 million term loan, both due June 2018 (together, the “Prior Term Loan Agreements”). On October 20, 2015, UDR, Inc. borrowed $200 million under the Revolving Credit Facility and $350 million under the Term Loan Facility to pay outstanding balances under the Prior Credit Agreement and the Prior Term Loan Agreements, respectively. Based on UDR, Inc.’s current credit rating, the Revolving Credit Facility has an interest rate equal to LIBOR plus a margin of 90 basis points and a facility fee of 15 basis points, and the Term Loan Facility has an interest rate equal to LIBOR plus a margin of 95 basis points. Depending on UDR, Inc.’s credit rating, the margin under the Revolving Credit Facility ranges from 85 to 155 basis points and the facility fee ranges from 12.5 to 30 basis points, and the margin under the Term Loan Facility ranges from 90 to 175 basis points. The Credit Agreement contains customary representations and warranties and financial and other affirmative and negative covenants. The Credit Agreement also includes customary events of default, in certain cases subject to customary periods to cure. The occurrence of an event of default, following the applicable cure period, would permit the lenders to, among other things, declare the unpaid principal, accrued and unpaid interest and all other amounts payable under the Credit Agreement to be immediately due and payable. UDR, Inc.’s obligations under the Credit Agreement are guaranteed by the Operating Partnership, pursuant to a guaranty dated as of October 20, 2015.

Significant Accounting Polici40

Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2015
Accounting Policies [Abstract]
Comprehensive Income, Policy [Policy Text Block]	Comprehensive Income/(Loss) Comprehensive income/(loss), which is defined as the change in equity during each period from transactions and other events and circumstances from nonowner sources, including all changes in equity during a period except for those resulting from investments by or distributions to stockholders, is displayed in the accompanying Consolidated Statements of Comprehensive Income/(Loss). For the three and nine months ended September 30, 2015 and 2014 , the Company’s other comprehensive income/(loss) consisted of the gain/(loss) (effective portion) on derivative instruments that are designated as and qualify as cash flow hedges, (gain)/loss on derivative instruments reclassified from other comprehensive income/(loss) into earnings, and the allocation of other comprehensive income/(loss) to redeemable noncontrolling interests. The (gain)/loss on derivative instruments reclassified from other comprehensive income/(loss) is included in Interest expense on the Consolidated Statements of Operations. See Note 10, Derivatives and Hedging Activity, for further discussion. The allocation of other comprehensive income/(loss) to redeemable noncontrolling interests was $(0.2) million and $0.1 million during the three months ended September 30, 2015 and 2014 , respectively, and $(0.2) million and $0.2 million during the nine months ended September 30, 2015 and 2014 , respectively.
New Accounting Pronouncements, Policy [Policy Text Block]	Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2014-09, Revenue from Contracts with Customers . The standard provides companies with a single model for use in accounting for revenue arising from contracts with customers and supersedes current revenue recognition guidance, including industry-specific revenue guidance. The updated standard will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. The standard specifically excludes lease contracts. The ASU allows for the use of either the full or modified retrospective transition method, and the standard will be effective for the Company on January 1, 2018; early adoption is permitted on January 1, 2017. The Company has not yet selected a transition method and we are currently evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures. In April 2015, the FASB issued ASU 2015-03, Simplifying the Presentation of Debt Issuance Costs, to revise the presentation of debt issuance costs. Under ASU 2015-03, entities will present debt issuance costs in their balance sheet as a direct deduction from the related debt liability rather than as an asset. Amortization of the deferred costs will continue to be included in interest expense. ASU 2015-03 does not directly address presentation or subsequent measurement of issuance costs related to line-of-credit arrangements. In August 2015, the FASB issued ASU 2015-15, Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements , which clarifies that such costs may be presented as an asset and subsequently amortized over the term of the line-of-credit arrangement. The cumulative guidance, which is to be applied retrospectively to all prior periods, is effective for fiscal years beginning after December 15, 2015, with early adoption permitted for financial statements that have not been previously issued. The Company does not expect ASU 2015-03 or ASU 2015-15 to have a significant effect on its consolidated financial statements. In February 2015, the FASB issued ASU 2015-02, Amendments to the Consolidation Analysis, which makes changes to both the variable interest model and the voting model. Among other changes, the new standard specifically eliminates the presumption in the current voting model that a general partner controls a limited partnership or similar entity unless that presumption can be overcome. The new standard will be effective for the Company beginning on January 1, 2016 and early adoption is permitted, including adoption in an interim period. The new standard must be applied using a modified retrospective approach by recording a cumulative-effect adjustment to equity/capital as of the beginning of the period of adoption or retrospectively to each period presented. The Company is currently evaluating the impact of adopting the new standard on its consolidated financial statements. Discontinued Operations In accordance with GAAP, a discontinued operation represents (1) a component of an entity or group of components that has been disposed of or is classified as held for sale in a single transaction and represents a strategic shift that has or will have a major effect on an entity’s financial results, or (2) an acquired business that is classified as held for sale on the date of acquisition. A strategic shift could include a disposal of (1) a separate major line of business, (2) a separate major geographic area of operations, (3) a major equity method investment, or (4) other major parts of an entity. We record sales of real estate that do not meet the definition of a discontinued operation in Gain/(loss) on sale of real estate owned, net of tax on the Consolidated Statements of Operations.
Revenue and real estate sales gain recognition	Revenue and Real Estate Sales Gain Recognition Rental income related to leases is recognized on an accrual basis when due from residents and tenants in accordance with GAAP. Rental payments are generally due on a monthly basis and recognized when earned. The Company recognizes interest income, management and other fees and incentives when earned, and the amounts are fixed and determinable. For sale transactions meeting the requirements for full accrual profit recognition, we remove the related assets and liabilities from our Consolidated Balance Sheets and record the gain or loss in the period the transaction closes. For sale transactions that do not meet the full accrual sale criteria due to our continuing involvement, we evaluate the nature of the continuing involvement and account for the transaction under an alternate method of accounting. Unless certain limited criteria are met, non-monetary transactions, including property exchanges, are accounted for at fair value. Sales to entities in which we retain or otherwise own an interest are accounted for as partial sales. If all other requirements for recognizing profit under the full accrual method have been satisfied and no other forms of continuing involvement are present, we recognize profit proportionate to the outside interest in the buyer and defer the gain on the interest we retain. The Company recognizes any deferred gain when the property is sold to a third party. In transactions accounted for by us as partial sales, we determine if the buyer of the majority equity interest in the venture was provided a preference as to cash flows in either an operating or a capital waterfall. If a cash flow preference has been provided, we recognize profit only to the extent that proceeds from the sale of the majority equity interest exceed costs related to the entire propert
Income Taxes	Income Taxes Due to the structure of the Company as a REIT and the nature of the operations for the operating properties, no provision for federal income taxes has been provided for at UDR. Historically, the Company has generally incurred only state and local excise and franchise taxes. UDR has elected for certain consolidated subsidiaries to be treated as taxable REIT subsidiaries (“TRS”). Income taxes for our TRS are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities from a change in tax rate is recognized in earnings in the period of the enactment date. The Company’s deferred tax assets are generally the result of differing depreciable lives on capitalized assets and timing of expense recognition for certain accrued liabilities. As of September 30, 2015 , UDR’s net deferred tax asset was $10.5 million (net of a valuation allowance of less than $0.1 million ), which is included in Other assets on the Consolidated Balance Sheets. GAAP defines a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. GAAP also provides guidance on derecognition, classification, interest and penalties, accounting for interim periods, disclosure and transition. The Company recognizes its tax positions and evaluates them using a two-step process. First, UDR determines whether a tax position is more likely than not (greater than 50 percent probability) to be sustained upon examination, including resolution of any related appeals or litigation processes, based on the technical merits of the position. Second, the Company will determine the amount of benefit to recognize and record the amount that is more likely than not to be realized upon ultimate settlement. UDR had no material unrecognized tax benefit, accrued interest or penalties at September 30, 2015 . UDR and its subsidiaries are subject to federal income tax as well as income tax of various state and local jurisdictions. The tax years 2011 through 2014 remain open to examination by tax jurisdictions to which we are subject. When applicable, UDR recognizes interest and/or penalties related to uncertain tax positions in Tax benefit/(expense), net on the Consolidated Statements of Operations.
Policy Loans Receivable, Policy [Policy Text Block]	Notes Receivable The following table summarizes our notes receivable, net as of September 30, 2015 and December 31, 2014 ( dollars in thousands): Interest rate at Balance outstanding September 30, September 30, December 31, 2014 Note due February 2017 (a) 10.00 % $ 12,994 $ 11,869 Note due July 2017 (b) 8.00 % 2,500 2,500 Total notes receivable, net $ 15,494 $ 14,369 (a) The Company has a secured note receivable with an unaffiliated third party with an aggregate commitment of $13.0 million . During the nine months ended September 30, 2015 , the Company loaned an additional $1.1 million . Interest payments are due monthly. The note matures at the earliest of the following: (a) the closing of any private or public capital raising in the amount of $5.0 million or greater; (b) an acquisition; (c) acceleration in the event of default; or (d) the fifth anniversary of the date of the note (February 2017). (b) The Company has a secured note receivable with an unaffiliated third party with an aggregate commitment of $2.5 million . Interest payments are due monthly. The note matures at the earliest of the following: (a) the closing of any private or public capital raising in the amount of $5.0 million or greater; (b) an acquisition; (c) acceleration in the event of default; or (d) the fifth anniversary of the date of the note (July 2017). The Company recognized $0.4 million of interest income from notes receivable during the three months ended September 30, 2015 and 2014 and $1.1 million and $3.0 million during the nine months ended September 30, 2015 and 2014 , respectively, none of which was related party interest income. Interest income is included in Interest income and other income/(expense), net on the Consolidated Statements of Operations.

Significant Accounting Polici41

Significant Accounting Policies (UNITED DOMINION REALTY, L.P.) (Policies)	9 Months Ended
	Sep. 30, 2015
Entity Information [Line Items]
New Accounting Pronouncements, Policy [Policy Text Block]	Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2014-09, Revenue from Contracts with Customers . The standard provides companies with a single model for use in accounting for revenue arising from contracts with customers and supersedes current revenue recognition guidance, including industry-specific revenue guidance. The updated standard will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. The standard specifically excludes lease contracts. The ASU allows for the use of either the full or modified retrospective transition method, and the standard will be effective for the Company on January 1, 2018; early adoption is permitted on January 1, 2017. The Company has not yet selected a transition method and we are currently evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures. In April 2015, the FASB issued ASU 2015-03, Simplifying the Presentation of Debt Issuance Costs, to revise the presentation of debt issuance costs. Under ASU 2015-03, entities will present debt issuance costs in their balance sheet as a direct deduction from the related debt liability rather than as an asset. Amortization of the deferred costs will continue to be included in interest expense. ASU 2015-03 does not directly address presentation or subsequent measurement of issuance costs related to line-of-credit arrangements. In August 2015, the FASB issued ASU 2015-15, Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements , which clarifies that such costs may be presented as an asset and subsequently amortized over the term of the line-of-credit arrangement. The cumulative guidance, which is to be applied retrospectively to all prior periods, is effective for fiscal years beginning after December 15, 2015, with early adoption permitted for financial statements that have not been previously issued. The Company does not expect ASU 2015-03 or ASU 2015-15 to have a significant effect on its consolidated financial statements. In February 2015, the FASB issued ASU 2015-02, Amendments to the Consolidation Analysis, which makes changes to both the variable interest model and the voting model. Among other changes, the new standard specifically eliminates the presumption in the current voting model that a general partner controls a limited partnership or similar entity unless that presumption can be overcome. The new standard will be effective for the Company beginning on January 1, 2016 and early adoption is permitted, including adoption in an interim period. The new standard must be applied using a modified retrospective approach by recording a cumulative-effect adjustment to equity/capital as of the beginning of the period of adoption or retrospectively to each period presented. The Company is currently evaluating the impact of adopting the new standard on its consolidated financial statements. Discontinued Operations In accordance with GAAP, a discontinued operation represents (1) a component of an entity or group of components that has been disposed of or is classified as held for sale in a single transaction and represents a strategic shift that has or will have a major effect on an entity’s financial results, or (2) an acquired business that is classified as held for sale on the date of acquisition. A strategic shift could include a disposal of (1) a separate major line of business, (2) a separate major geographic area of operations, (3) a major equity method investment, or (4) other major parts of an entity. We record sales of real estate that do not meet the definition of a discontinued operation in Gain/(loss) on sale of real estate owned, net of tax on the Consolidated Statements of Operations.
Revenue and real estate sales gain recognition	Revenue and Real Estate Sales Gain Recognition Rental income related to leases is recognized on an accrual basis when due from residents and tenants in accordance with GAAP. Rental payments are generally due on a monthly basis and recognized when earned. The Company recognizes interest income, management and other fees and incentives when earned, and the amounts are fixed and determinable. For sale transactions meeting the requirements for full accrual profit recognition, we remove the related assets and liabilities from our Consolidated Balance Sheets and record the gain or loss in the period the transaction closes. For sale transactions that do not meet the full accrual sale criteria due to our continuing involvement, we evaluate the nature of the continuing involvement and account for the transaction under an alternate method of accounting. Unless certain limited criteria are met, non-monetary transactions, including property exchanges, are accounted for at fair value. Sales to entities in which we retain or otherwise own an interest are accounted for as partial sales. If all other requirements for recognizing profit under the full accrual method have been satisfied and no other forms of continuing involvement are present, we recognize profit proportionate to the outside interest in the buyer and defer the gain on the interest we retain. The Company recognizes any deferred gain when the property is sold to a third party. In transactions accounted for by us as partial sales, we determine if the buyer of the majority equity interest in the venture was provided a preference as to cash flows in either an operating or a capital waterfall. If a cash flow preference has been provided, we recognize profit only to the extent that proceeds from the sale of the majority equity interest exceed costs related to the entire propert
Comprehensive Income, Policy [Policy Text Block]	Comprehensive Income/(Loss) Comprehensive income/(loss), which is defined as the change in equity during each period from transactions and other events and circumstances from nonowner sources, including all changes in equity during a period except for those resulting from investments by or distributions to stockholders, is displayed in the accompanying Consolidated Statements of Comprehensive Income/(Loss). For the three and nine months ended September 30, 2015 and 2014 , the Company’s other comprehensive income/(loss) consisted of the gain/(loss) (effective portion) on derivative instruments that are designated as and qualify as cash flow hedges, (gain)/loss on derivative instruments reclassified from other comprehensive income/(loss) into earnings, and the allocation of other comprehensive income/(loss) to redeemable noncontrolling interests. The (gain)/loss on derivative instruments reclassified from other comprehensive income/(loss) is included in Interest expense on the Consolidated Statements of Operations. See Note 10, Derivatives and Hedging Activity, for further discussion. The allocation of other comprehensive income/(loss) to redeemable noncontrolling interests was $(0.2) million and $0.1 million during the three months ended September 30, 2015 and 2014 , respectively, and $(0.2) million and $0.2 million during the nine months ended September 30, 2015 and 2014 , respectively.
Income taxes	Income Taxes Due to the structure of the Company as a REIT and the nature of the operations for the operating properties, no provision for federal income taxes has been provided for at UDR. Historically, the Company has generally incurred only state and local excise and franchise taxes. UDR has elected for certain consolidated subsidiaries to be treated as taxable REIT subsidiaries (“TRS”). Income taxes for our TRS are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities from a change in tax rate is recognized in earnings in the period of the enactment date. The Company’s deferred tax assets are generally the result of differing depreciable lives on capitalized assets and timing of expense recognition for certain accrued liabilities. As of September 30, 2015 , UDR’s net deferred tax asset was $10.5 million (net of a valuation allowance of less than $0.1 million ), which is included in Other assets on the Consolidated Balance Sheets. GAAP defines a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. GAAP also provides guidance on derecognition, classification, interest and penalties, accounting for interim periods, disclosure and transition. The Company recognizes its tax positions and evaluates them using a two-step process. First, UDR determines whether a tax position is more likely than not (greater than 50 percent probability) to be sustained upon examination, including resolution of any related appeals or litigation processes, based on the technical merits of the position. Second, the Company will determine the amount of benefit to recognize and record the amount that is more likely than not to be realized upon ultimate settlement. UDR had no material unrecognized tax benefit, accrued interest or penalties at September 30, 2015 . UDR and its subsidiaries are subject to federal income tax as well as income tax of various state and local jurisdictions. The tax years 2011 through 2014 remain open to examination by tax jurisdictions to which we are subject. When applicable, UDR recognizes interest and/or penalties related to uncertain tax positions in Tax benefit/(expense), net on the Consolidated Statements of Operations.
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
New Accounting Pronouncements, Policy [Policy Text Block]	Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2014-09, Revenue from Contracts with Customers . The standard provides companies with a single model for use in accounting for revenue arising from contracts with customers and supersedes current revenue recognition guidance, including industry-specific revenue guidance. The updated standard will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. The standard specifically excludes lease contracts. The ASU allows for the use of either the full or modified retrospective transition method, and the standard will be effective for the Operating Partnership on January 1, 2018; early adoption is permitted on January 1, 2017. The Operating Partnership has not yet selected a transition method and we are currently evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures. In April 2015, the FASB issued ASU 2015-03, Simplifying the Presentation of Debt Issuance Costs, to revise the presentation of debt issuance costs. Under ASU 2015-03, entities will present debt issuance costs in their balance sheet as a direct deduction from the related debt liability rather than as an asset. Amortization of the deferred costs will continue to be included in interest expense. ASU 2015-03 does not directly address presentation or subsequent measurement of issuance costs related to line-of-credit arrangements. In August 2015, the FASB issued ASU 2015-15, Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements , which clarifies that such costs may be presented as an asset and subsequently amortized over the term of the line-of-credit arrangement. The cumulative guidance, which is to be applied retrospectively to all prior periods, is effective for fiscal years beginning after December 15, 2015, with early adoption permitted for financial statements that have not been previously issued. The Operating Partnership does not expect ASU 2015-03 or ASU 2015-15 to have a significant effect on its consolidated financial statements. In February 2015, the FASB issued ASU 2015-02, Amendments to the Consolidation Analysis, which makes changes to both the variable interest model and the voting model. Among other changes, the new standard specifically eliminates the presumption in the current voting model that a general partner controls a limited partnership or similar entity unless that presumption can be overcome. The new standard will be effective for the Operating Partnership beginning on January 1, 2016 and early adoption is permitted, including adoption in an interim period. The new standard must be applied using a modified retrospective approach by recording a cumulative-effect adjustment to equity/capital as of the beginning of the period of adoption or retrospectively to each period presented. The Operating Partnership is currently evaluating the impact of adopting the new standard on its consolidated financial statements. Discontinued Operations In accordance with GAAP, a discontinued operation represents (1) a component of an entity or group of components that has been disposed of or is classified as held for sale in a single transaction and represents a strategic shift that has or will have a major effect on an entity’s financial results, or (2) an acquired business that is classified as held for sale on the date of acquisition. A strategic shift could include a disposal of (1) a separate major line of business, (2) a separate major geographic area of operations, (3) a major equity method investment, or (4) other major parts of an entity. We record sales of real estate that do not meet the definition of a discontinued operation in Gain/(loss) on sale of real estate owned, net of tax on the Consolidated Statements of Operations.
Earnings Per Share, Policy [Policy Text Block]	Income/(Loss) Per Operating Partnership Unit Basic income/(loss) per OP Unit is computed by dividing net income/(loss) attributable to general and limited partner unitholders by the weighted average number of general and limited partner units outstanding during the year. Diluted income/(loss) per OP Unit reflects the potential dilution that could occur if securities or other contracts to issue OP Units were exercised or converted into OP Units or resulted in the issuance of OP Units and then shared in the income/(loss) of the Operating Partnership.
Revenue and real estate sales gain recognition	Revenue and Real Estate Sales Gain Recognition Rental income related to leases is recognized on an accrual basis when due from residents and tenants in accordance with GAAP. Rental payments are generally due on a monthly basis and recognized when earned. The Operating Partnership recognizes interest income, fees and incentives when earned, fixed and determinable. For sale transactions meeting the requirements for full accrual profit recognition, we remove the related assets and liabilities from our Consolidated Balance Sheets and record the gain or loss in the period the transaction closes. For sale transactions that do not meet the full accrual sale criteria due to our continuing involvement, we evaluate the nature of the continuing involvement and account for the transaction under an alternate method of accounting. Unless certain limited criteria are met, non-monetary transactions, including property exchanges, are accounted for at fair value. Sales to entities in which we or our General Partner retain or otherwise own an interest are accounted for as partial sales. If all other requirements for recognizing profit under the full accrual method have been satisfied and no other forms of continuing involvement are present, we recognize profit proportionate to the outside interest in the buyer and defer the gain on the interest we or our General Partner retain. The Operating Partnership recognizes any deferred gain when the property is sold to a third party. In transactions accounted by us as partial sales, we determine if the buyer of the majority equity interest in the venture was provided a preference as to cash flows in either an operating or a capital waterfall. If a cash flow preference has been provided, we recognize profit only to the extent that proceeds from the sale of the majority equity interest exceed costs related to the entire property.
Comprehensive Income, Policy [Policy Text Block]	Comprehensive Income/(Loss) Comprehensive income/(loss), which is defined as the change in equity during each period from transactions and other events and circumstances from nonowner sources, including all changes in equity during a period except for those resulting from investments by or distributions to unitholders, is displayed in the accompanying Consolidated Statements of Comprehensive Income/(Loss). For the three and nine months ended September 30, 2015 and 2014 , the Operating Partnership’s other comprehensive income/(loss) consisted of the gain/(loss) (effective portion) on derivative instruments that are designated as and qualify as cash flow hedges and (gain)/loss reclassified from other comprehensive income/(loss) into earnings. The (gain)/loss reclassified from other comprehensive income/(loss) is included in Interest expense on the Consolidated Statements of Operations. See Note 7, Derivatives and Hedging Activity, for further discussion.
Income taxes	Income Taxes The taxable income or loss of the Operating Partnership is reported on the tax returns of the partners. Accordingly, no provision has been made in the accompanying financial statements for federal or state income taxes on income that is passed through to the partners. However, any state or local revenue, excise or franchise taxes that result from the operating activities of the Operating Partnership are recorded at the entity level. The Operating Partnership’s tax returns are subject to examination by federal and state taxing authorities. Net income for financial reporting purposes differs from the net income for income tax reporting purposes primarily due to temporary differences, principally real estate depreciation and the tax deferral of certain gains on property sales. The differences in depreciation result from differences in the book and tax basis of certain real estate assets and the differences in the methods of depreciation and lives of the real estate assets. The Operating Partnership evaluates the accounting and disclosure of tax positions taken or expected to be taken in the course of preparing the Operating Partnership’s tax returns to determine whether the tax positions are “more-likely-than-not” of being sustained by the applicable tax authority. Tax positions not deemed to meet the more-likely-than-not threshold would be recorded as a tax benefit or expense in the current year. Management of the Operating Partnership is required to analyze all open tax years, as defined by the statute of limitations, for all major jurisdictions, which include federal and certain states. The Operating Partnership has no examinations in progress and none are expected at this time. Management of the Operating Partnership has reviewed all open tax years ( 2011 through 2014 ) of tax jurisdictions and concluded there is no tax liability resulting from unrecognized tax benefits relating to uncertain income tax positions taken or expected to be taken in future tax returns.

Significant Accounting Polici42

Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2015
Accounting Policies [Abstract]
Notes receivable	The following table summarizes our notes receivable, net as of September 30, 2015 and December 31, 2014 ( dollars in thousands): Interest rate at Balance outstanding September 30, September 30, December 31, 2014 Note due February 2017 (a) 10.00 % $ 12,994 $ 11,869 Note due July 2017 (b) 8.00 % 2,500 2,500 Total notes receivable, net $ 15,494 $ 14,369

Real Estate Owned (Tables)

Real Estate Owned (Tables)	9 Months Ended
	Sep. 30, 2015
Real Estate [Abstract]
Summary of carrying amounts for real estate owned (at cost)	The following table summarizes the carrying amounts for our real estate owned (at cost) as of September 30, 2015 and December 31, 2014 (dollars in thousands): September 30, December 31, 2014 Land and land improvements $ 1,840,823 $ 1,980,221 Depreciable property — held and used: Building, improvements, and furniture, fixtures and equipment 6,321,640 6,225,406 Under development: Land and land improvements 78,085 24,584 Building, improvements, and furniture, fixtures and equipment 25,995 153,048 Real estate held for disposition: Land and land improvements 81,080 — Building, improvements, and furniture, fixtures and equipment 125,354 — Real estate owned 8,472,977 8,383,259 Accumulated depreciation (2,647,504 ) (2,434,772 ) Real estate owned, net $ 5,825,473 $ 5,948,487

Real Estate Owned (UNITED DOM44

Real Estate Owned (UNITED DOMINION REALTY, L.P.) (Tables)	9 Months Ended
	Sep. 30, 2015
Entity Information [Line Items]
Summary of carrying amounts for real estate owned (at cost)	The following table summarizes the carrying amounts for our real estate owned (at cost) as of September 30, 2015 and December 31, 2014 (dollars in thousands): September 30, December 31, 2014 Land and land improvements $ 1,840,823 $ 1,980,221 Depreciable property — held and used: Building, improvements, and furniture, fixtures and equipment 6,321,640 6,225,406 Under development: Land and land improvements 78,085 24,584 Building, improvements, and furniture, fixtures and equipment 25,995 153,048 Real estate held for disposition: Land and land improvements 81,080 — Building, improvements, and furniture, fixtures and equipment 125,354 — Real estate owned 8,472,977 8,383,259 Accumulated depreciation (2,647,504 ) (2,434,772 ) Real estate owned, net $ 5,825,473 $ 5,948,487
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
Summary of carrying amounts for real estate owned (at cost)	The following table summarizes the carrying amounts for our real estate owned (at cost) as of September 30, 2015 and December 31, 2014 (dollars in thousands) : September 30, December 31, 2014 Land $ 932,717 $ 1,008,014 Depreciable property — held and used: Buildings, improvements, and furniture, fixture and equipment 3,174,403 3,230,756 Real estate held for disposition: Land 75,160 — Buildings, improvements, and furniture, fixture and equipment 76,298 — Real estate owned 4,258,578 4,238,770 Accumulated depreciation (1,518,558 ) (1,403,303 ) Real estate owned, net $ 2,740,020 $ 2,835,467

Discontinued Operations (Tables

Discontinued Operations (Tables)	9 Months Ended
	Sep. 30, 2015
Discontinued Operations and Disposal Groups [Abstract]
Summary of income from discontinued operations	The following is a summary of income/(loss) from discontinued operations, net of tax for the three and nine months ended September 30, 2015 and 2014 ( dollars in thousands ): Three Months Ended Nine Months Ended September 30, September 30, 2015 2014 2015 2014 Rental income $ — $ 21 $ — $ 147 Rental expenses — 11 — 225 Property management — 1 — 4 Interest income and other (income)/expense, net — 3 — 21 Income/(loss) attributable to disposed properties and assets held for sale — 6 — (103 ) Net gain/(loss) on the sale of depreciable properties — 75 — 75 Income tax benefit/(expense) — (2 ) — 38 Income/(loss) from discontinued operations, net of tax $ — $ 79 $ — $ 10 Income/(loss) from discontinued operations attributable to UDR, Inc. $ — $ 73 $ — $ 6

Joint Ventures (Tables)

Joint Ventures (Tables)	9 Months Ended
	Sep. 30, 2015
Equity Method Investments and Joint Ventures [Abstract]
Combined Summary of Balance Sheets Relating to Unconsolidated Joint Ventures [Table Text Block]	We evaluate our investments in unconsolidated joint ventures and partnerships when events or changes in circumstances indicate that there may be an other-than-temporary decline in value. We consider various factors to determine if a decrease in the value of the investment is other-than-temporary. The Company did not recognize any other-than-temporary decreases in the value of its investments in unconsolidated joint ventures or partnerships during the three and nine months ended September 30, 2015 and 2014 . Combined summary balance sheets relating to all of the unconsolidated joint ventures and partnerships (not just our proportionate share) are presented below as of September 30, 2015 and December 31, 2014 ( dollars in thousands ): September 30, December 31, 2014 Total real estate, net $ 3,074,723 $ 2,941,803 Assets held for sale — 216,196 Cash and cash equivalents 37,768 32,544 Other assets 44,259 28,707 Total assets $ 3,156,750 $ 3,219,250 Amount due to UDR $ 7,465 $ 2,997 Third party debt 1,586,380 1,504,477 Liabilities held for sale — 229,706 Accounts payable and accrued liabilities 87,730 44,335 Total liabilities 1,681,575 1,781,515 Total equity 1,475,175 1,437,735 Total liabilities and equity $ 3,156,750 $ 3,219,250 UDR’s investment in unconsolidated joint ventures $ 921,925 $ 718,226
Schedule of Equity Method Investments [Table Text Block]	The following table summarizes the Company’s investment in and advances to unconsolidated joint ventures and partnerships, net, which are accounted for under the equity method of accounting as of September 30, 2015 and December 31, 2014 (dollars in thousands) : Joint Venture Location of Properties Number of Properties Number of Apartment Homes Investment at UDR’s Ownership Interest September 30, September 30, September 30, December 31, September 30, December 31, Operating and development: UDR/MetLife I Various 4 land parcels — $ 14,804 $ 13,306 16.4 % 15.7 % UDR/MetLife II Various 21 operating communities 4,642 425,963 431,277 50.0 % 50.0 % Other UDR/MetLife Development Joint Ventures 1 operating community; 4 development communities (a); Various 1 land parcel 1,437 163,961 134,939 50.6 % 50.6 % UDR/MetLife Vitruvian Park ® Addison, TX 3 operating communities 6 land parcels 1,130 73,618 80,302 50.0 % 50.0 % UDR/KFH Washington, D.C. 3 operating communities 660 18,308 21,596 30.0 % 30.0 % Texas (b) Texas — — — (25,901 ) — % 20.0 % Investment in and advances to unconsolidated joint ventures, net, before participating loan investment and preferred equity investment 695,980,000 696,654 655,519 Income from Investment Investment at Three Months Ended September 30, Nine Months Ended September 30, Location Rate Years To Maturity September 30, December 31, 2015 2014 2015 2014 Participating loan investment: Steele Creek Denver, CO 6.5% 1.8 89,498 62,707 $1,458 $ 642 $3,964 $ 1,419 Preferred equity investment: West Coast Development Joint Venture (c) Various 6.5% — 135,773 — $2,086 $ — $1,578 $ — Total investment in and advances to unconsolidated joint ventures, net $ 921,925 $ 718,226 (a) The number of apartment homes for the communities under development presented in the table above is based on the projected number of total homes. As of September 30, 2015 , no apartment homes had been completed in Other UDR/MetLife Development Joint Ventures. (b) In January 2015, the eight communities held by the Texas Joint Venture were sold, generating net proceeds to UDR of $43.5 million . The Company recorded promote and disposition fee income of $9.6 million and a gain of $59.1 million (including $24.2 million of previously deferred gains) in connection with the sale.
Financial information relating to unconsolidated joint ventures operations	Combined summary financial information relating to all of the unconsolidated joint ventures’ and partnerships’ operations (not just our proportionate share), is presented below for the three and nine months ended September 30, 2015 and 2014 ( dollars in thousands ) : Three Months Ended Nine Months Ended September 30, September 30, 2015 2014 2015 2014 Total revenues $ 55,948 $ 52,804 $ 165,944 $ 140,138 Property operating expenses (21,981 ) (19,837 ) (63,692 ) (52,197 ) Real estate depreciation and amortization (18,272 ) (19,158 ) (57,026 ) (50,654 ) Operating income/(loss) 15,695 13,809 45,226 37,287 Interest expense (16,310 ) (15,755 ) (48,540 ) (42,833 ) Other income/(expense) (182 ) — (190 ) — Income/(loss) from discontinued operations (37 ) (2,891 ) 182,452 (37,579 ) Net income/(loss) $ (834 ) $ (4,837 ) $ 178,948 $ (43,125 ) UDR income/(loss) from unconsolidated entities $ 2,691 $ (939 ) $ 61,277 $ (4,932 )
Combined summary of balance sheets relating to unconsolidated joint ventures	JOINT VENTURES AND PARTNERSHIPS UDR has entered into joint ventures and partnerships with unrelated third parties to acquire real estate assets that are either consolidated and included in Real estate owned on the Consolidated Balance Sheets or are accounted for under the equity method of accounting, and are included in Investment in and advances to unconsolidated joint ventures, net on the Consolidated Balance Sheets. The Company consolidates the entities that we control as well as any variable interest entity where we are the primary beneficiary. In addition, the Company consolidates any joint venture or partnership in which we are the general partner or managing member and the third party does not have the ability to substantively participate in the decision-making process nor the ability to remove us as general partner or managing member without cause. UDR’s joint ventures and partnerships are funded with a combination of debt and equity. Our losses are limited to our investment and except as noted below, the Company does not guarantee any debt, capital payout or other obligations associated with our joint ventures and partnerships. Unconsolidated Joint Ventures and Partnerships The Company recognizes income or losses from our investments in unconsolidated joint ventures and partnerships consisting of our proportionate share of the net income or losses of the joint ventures and partnerships. In addition, we may earn fees for providing management services to the unconsolidated joint ventures and partnerships. The following table summarizes the Company’s investment in and advances to unconsolidated joint ventures and partnerships, net, which are accounted for under the equity method of accounting as of September 30, 2015 and December 31, 2014 (dollars in thousands) : Joint Venture Location of Properties Number of Properties Number of Apartment Homes Investment at UDR’s Ownership Interest September 30, September 30, September 30, December 31, September 30, December 31, Operating and development: UDR/MetLife I Various 4 land parcels — $ 14,804 $ 13,306 16.4 % 15.7 % UDR/MetLife II Various 21 operating communities 4,642 425,963 431,277 50.0 % 50.0 % Other UDR/MetLife Development Joint Ventures 1 operating community; 4 development communities (a); Various 1 land parcel 1,437 163,961 134,939 50.6 % 50.6 % UDR/MetLife Vitruvian Park ® Addison, TX 3 operating communities 6 land parcels 1,130 73,618 80,302 50.0 % 50.0 % UDR/KFH Washington, D.C. 3 operating communities 660 18,308 21,596 30.0 % 30.0 % Texas (b) Texas — — — (25,901 ) — % 20.0 % Investment in and advances to unconsolidated joint ventures, net, before participating loan investment and preferred equity investment 695,980,000 696,654 655,519 Income from Investment Investment at Three Months Ended September 30, Nine Months Ended September 30, Location Rate Years To Maturity September 30, December 31, 2015 2014 2015 2014 Participating loan investment: Steele Creek Denver, CO 6.5% 1.8 89,498 62,707 $1,458 $ 642 $3,964 $ 1,419 Preferred equity investment: West Coast Development Joint Venture (c) Various 6.5% — 135,773 — $2,086 $ — $1,578 $ — Total investment in and advances to unconsolidated joint ventures, net $ 921,925 $ 718,226 (a) The number of apartment homes for the communities under development presented in the table above is based on the projected number of total homes. As of September 30, 2015 , no apartment homes had been completed in Other UDR/MetLife Development Joint Ventures. (b) In January 2015, the eight communities held by the Texas Joint Venture were sold, generating net proceeds to UDR of $43.5 million . The Company recorded promote and disposition fee income of $9.6 million and a gain of $59.1 million (including $24.2 million of previously deferred gains) in connection with the sale. (c) In May 2015, the Company entered into a joint venture agreement with real estate private equity firm, The Wolff Company (“Wolff”), and agreed to pay $136.3 million for a 48 percent interest in a portfolio of five communities that are currently under construction (the "West Coast Development Joint Venture"). As of September 30, 2015 , the Company had funded $129.6 million of its investment and had a remaining commitment of $6.7 million . The communities are located in three of the Company’s core, coastal markets: Metro Seattle, Los Angeles and Orange County, CA. UDR earns a 6.5 percent preferred return on its investment through each individual community’s date of stabilization, defined as when a community reaches 80 percent occupancy for ninety consecutive days, while Wolff is allocated all operating income and expense during the pre-stabilization period. Upon stabilization, income and expense will be shared based on each partner’s ownership percentage. The Company will serve as property manager and be paid a management fee during the lease-up phase and subsequent operation of each of the communities. Wolff is the general partner of the joint venture and the developer of the communities. The Company has a fixed price option to acquire Wolff’s remaining interest in each community beginning one year after completion. If the options are exercised for all five communities, the Company’s total price will be $597.4 million . In the event the Company does not exercise its options to purchase at least two communities, Wolff will be entitled to earn a contingent disposition fee equal to 6.5 percent return on its implied equity in the communities not acquired. Wolff is providing certain guaranties and there are construction loans on all five communities. Once completed, the five communities will contain 1,533 homes. The Company has concluded it does not control the joint venture and accounts for it under the equity method of accounting. The Company's recorded equity investment in the West Coast Development Joint Venture at September 30, 2015 of $135.8 million is inclusive of outside basis costs and our accrued but unpaid preferred return. During the three months ended September 30, 2015 , the Company earned a preferred return of $2.1 million . During the nine months ended September 30, 2015 , the Company earned a preferred return of $3.1 million , offset by its share of the West Coast Development Joint Venture transaction expenses of $1.5 million . As of September 30, 2015 and December 31, 2014 , the Company had deferred fees and deferred profit from the sale of properties to joint ventures or partnerships of $9.3 million and $28.5 million , respectively, which will be recognized through income over the weighted average life of the related properties, upon the disposition of the properties to a third party, or upon completion of certain development obligations. The Company recognized management fees for our management of the joint ventures and partnerships of $3.3 million and $2.7 million for the three months ended September 30, 2015 and 2014 , respectively, and $8.5 million and $8.3 million for the nine months ended September 30, 2015 and 2014 , respectively. The management fees are included in Joint venture management and other fees on the Consolidated Statements of Operations. The Company may, in the future, make additional capital contributions to certain of our joint ventures and partnerships should additional capital contributions be necessary to fund acquisitions or operations. We evaluate our investments in unconsolidated joint ventures and partnerships when events or changes in circumstances indicate that there may be an other-than-temporary decline in value. We consider various factors to determine if a decrease in the value of the investment is other-than-temporary. The Company did not recognize any other-than-temporary decreases in the value of its investments in unconsolidated joint ventures or partnerships during the three and nine months ended September 30, 2015 and 2014 . Combined summary balance sheets relating to all of the unconsolidated joint ventures and partnerships (not just our proportionate share) are presented below as of September 30, 2015 and December 31, 2014 ( dollars in thousands ): September 30, December 31, 2014 Total real estate, net $ 3,074,723 $ 2,941,803 Assets held for sale — 216,196 Cash and cash equivalents 37,768 32,544 Other assets 44,259 28,707 Total assets $ 3,156,750 $ 3,219,250 Amount due to UDR $ 7,465 $ 2,997 Third party debt 1,586,380 1,504,477 Liabilities held for sale — 229,706 Accounts payable and accrued liabilities 87,730 44,335 Total liabilities 1,681,575 1,781,515 Total equity 1,475,175 1,437,735 Total liabilities and equity $ 3,156,750 $ 3,219,250 UDR’s investment in unconsolidated joint ventures $ 921,925 $ 718,226 Combined summary financial information relating to all of the unconsolidated joint ventures’ and partnerships’ operations (not just our proportionate share), is presented below for the three and nine months ended September 30, 2015 and 2014 ( dollars in thousands ) : Three Months Ended Nine Months Ended September 30, September 30, 2015 2014 2015 2014 Total revenues $ 55,948 $ 52,804 $ 165,944 $ 140,138 Property operating expenses (21,981 ) (19,837 ) (63,692 ) (52,197 ) Real estate depreciation and amortization (18,272 ) (19,158 ) (57,026 ) (50,654 ) Operating income/(loss) 15,695 13,809 45,226 37,287 Interest expense (16,310 ) (15,755 ) (48,540 ) (42,833 ) Other income/(expense) (182 ) — (190 ) — Income/(loss) from discontinued operations (37 ) (2,891 ) 182,452 (37,579 ) Net income/(loss) $ (834 ) $ (4,837 ) $ 178,948 $ (43,125 ) UDR income/(loss) from unconsolidated entities $ 2,691 $ (939 ) $ 61,277 $ (4,932 )

Secured and Unsecured Debt (Tab

Secured and Unsecured Debt (Tables)	9 Months Ended
	Sep. 30, 2015
Debt Disclosure [Abstract]
Secured debt instruments	The following is a summary of our secured and unsecured debt at September 30, 2015 and December 31, 2014 ( dollars in thousands ): Nine Months Ended Principal Outstanding September 30, 2015 September 30, December 31, 2014 Weighted Average Interest Rate Weighted Average Years to Maturity Number of Communities Encumbered Secured Debt: Fixed Rate Debt Mortgage notes payable (a) $ 406,183 $ 401,210 5.51 % 0.9 7 Fannie Mae credit facilities (b) 565,394 568,086 5.12 % 3.3 21 Total fixed rate secured debt 971,577 969,296 5.28 % 2.3 28 Variable Rate Debt Mortgage notes payable 31,337 31,337 2.00 % 1.3 1 Tax-exempt secured notes payable (c) 94,700 94,700 0.75 % 7.4 2 Fannie Mae credit facilities (b) 249,378 266,196 1.65 % 4.5 7 Total variable rate secured debt 375,415 392,233 1.45 % 5.0 10 Total Secured Debt 1,346,992 1,361,529 4.21 % 3.0 38 Unsecured Debt: Commercial Banks Borrowings outstanding under an unsecured credit facility due December 2017 (d) (g) 110,000 152,500 1.19 % 2.2 Senior Unsecured Notes 5.25% Medium-Term Notes due January 2015 (net of discounts of $0 and $6, respectively) (e) — 325,169 — % — 5.25% Medium-Term Notes due January 2016 83,260 83,260 5.25 % 0.3 6.21% Term Notes due July 2016 12,351 — 6.21 % 0.8 4.25% Medium-Term Notes due June 2018 (net of discounts of $1,144 and $1,465, respectively) (g) 298,856 298,535 4.25 % 2.7 1.70% Term Notes due June 2018 (g) 215,000 215,000 1.70 % 2.7 1.53% Term Notes due June 2018 (g) 100,000 100,000 1.53 % 2.7 1.35% Term Notes due June 2018 (g) 35,000 35,000 1.35 % 2.7 3.70% Medium-Term Notes due October 2020 (net of discounts of $40 and $46, respectively) (g) 299,960 299,954 3.70 % 5.0 4.63% Medium-Term Notes due January 2022 (net of discounts of $2,254 and $2,523, respectively) (g) 397,746 397,477 4.63 % 6.3 3.75% Medium-Term Notes due July 2024 (net of discount of $912 and $990, respectively) (g) 299,088 299,010 3.75 % 8.8 8.50% Debentures due September 2024 15,644 15,644 8.50 % 9.0 4.00% Medium-Term Notes due October 2025 (net of discount of $688 and $0, respectively) (f) (g) 299,312 — 4.00 % 10.0 Other 25 27 N/A N/A Total Unsecured Debt 2,166,242 2,221,576 3.72 % 5.5 Total Debt $ 3,513,234 $ 3,583,105 3.91 % 4.5
Secured credit facilities	Further information related to these credit facilities is as follows (dollars in thousands) : September 30, December 31, 2014 Borrowings outstanding $ 814,772 $ 834,282 Weighted average borrowings during the period ended 825,311 835,873 Maximum daily borrowings during the period ended 834,003 837,564 Weighted average interest rate during the period ended 4.0 % 4.1 % Weighted average interest rate at the end of the period 4.1 % 4.0 %
Schedule of Maturities of Long-term Debt [Table Text Block]	The aggregate maturities, including amortizing principal payments of unsecured and secured debt, of total debt for the next five calendar years subsequent to September 30, 2015 are as follows (dollars in thousands): Year Total Fixed Secured Debt Total Variable Secured Debt Total Secured Debt Total Unsecured Debt (a) Total Debt 2015 $ 187,916 $ — $ 187,916 $ 25 $ 187,941 2016 148,223 — 148,223 94,402 242,625 2017 177,882 96,337 274,219 110,000 384,219 2018 121,685 87,969 209,654 648,311 857,965 2019 245,871 67,700 313,571 — 313,571 Thereafter 90,000 123,409 213,409 1,313,504 1,526,913 Total $ 971,577 $ 375,415 $ 1,346,992 $ 2,166,242 $ 3,513,234

Debt (UNITED DOMINION REALTY,48

Debt (UNITED DOMINION REALTY, L.P.) (Tables)	9 Months Ended
	Sep. 30, 2015
Entity Information [Line Items]
Secured debt instruments	The following is a summary of our secured and unsecured debt at September 30, 2015 and December 31, 2014 ( dollars in thousands ): Nine Months Ended Principal Outstanding September 30, 2015 September 30, December 31, 2014 Weighted Average Interest Rate Weighted Average Years to Maturity Number of Communities Encumbered Secured Debt: Fixed Rate Debt Mortgage notes payable (a) $ 406,183 $ 401,210 5.51 % 0.9 7 Fannie Mae credit facilities (b) 565,394 568,086 5.12 % 3.3 21 Total fixed rate secured debt 971,577 969,296 5.28 % 2.3 28 Variable Rate Debt Mortgage notes payable 31,337 31,337 2.00 % 1.3 1 Tax-exempt secured notes payable (c) 94,700 94,700 0.75 % 7.4 2 Fannie Mae credit facilities (b) 249,378 266,196 1.65 % 4.5 7 Total variable rate secured debt 375,415 392,233 1.45 % 5.0 10 Total Secured Debt 1,346,992 1,361,529 4.21 % 3.0 38 Unsecured Debt: Commercial Banks Borrowings outstanding under an unsecured credit facility due December 2017 (d) (g) 110,000 152,500 1.19 % 2.2 Senior Unsecured Notes 5.25% Medium-Term Notes due January 2015 (net of discounts of $0 and $6, respectively) (e) — 325,169 — % — 5.25% Medium-Term Notes due January 2016 83,260 83,260 5.25 % 0.3 6.21% Term Notes due July 2016 12,351 — 6.21 % 0.8 4.25% Medium-Term Notes due June 2018 (net of discounts of $1,144 and $1,465, respectively) (g) 298,856 298,535 4.25 % 2.7 1.70% Term Notes due June 2018 (g) 215,000 215,000 1.70 % 2.7 1.53% Term Notes due June 2018 (g) 100,000 100,000 1.53 % 2.7 1.35% Term Notes due June 2018 (g) 35,000 35,000 1.35 % 2.7 3.70% Medium-Term Notes due October 2020 (net of discounts of $40 and $46, respectively) (g) 299,960 299,954 3.70 % 5.0 4.63% Medium-Term Notes due January 2022 (net of discounts of $2,254 and $2,523, respectively) (g) 397,746 397,477 4.63 % 6.3 3.75% Medium-Term Notes due July 2024 (net of discount of $912 and $990, respectively) (g) 299,088 299,010 3.75 % 8.8 8.50% Debentures due September 2024 15,644 15,644 8.50 % 9.0 4.00% Medium-Term Notes due October 2025 (net of discount of $688 and $0, respectively) (f) (g) 299,312 — 4.00 % 10.0 Other 25 27 N/A N/A Total Unsecured Debt 2,166,242 2,221,576 3.72 % 5.5 Total Debt $ 3,513,234 $ 3,583,105 3.91 % 4.5
Secured credit facilities	Further information related to these credit facilities is as follows (dollars in thousands) : September 30, December 31, 2014 Borrowings outstanding $ 814,772 $ 834,282 Weighted average borrowings during the period ended 825,311 835,873 Maximum daily borrowings during the period ended 834,003 837,564 Weighted average interest rate during the period ended 4.0 % 4.1 % Weighted average interest rate at the end of the period 4.1 % 4.0 %
Aggregate maturities of secured debt	The aggregate maturities, including amortizing principal payments of unsecured and secured debt, of total debt for the next five calendar years subsequent to September 30, 2015 are as follows (dollars in thousands): Year Total Fixed Secured Debt Total Variable Secured Debt Total Secured Debt Total Unsecured Debt (a) Total Debt 2015 $ 187,916 $ — $ 187,916 $ 25 $ 187,941 2016 148,223 — 148,223 94,402 242,625 2017 177,882 96,337 274,219 110,000 384,219 2018 121,685 87,969 209,654 648,311 857,965 2019 245,871 67,700 313,571 — 313,571 Thereafter 90,000 123,409 213,409 1,313,504 1,526,913 Total $ 971,577 $ 375,415 $ 1,346,992 $ 2,166,242 $ 3,513,234
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
Secured debt instruments	Secured debt consists of the following as of September 30, 2015 and December 31, 2014 ( dollars in thousands ): Nine Months Ended Principal Outstanding September 30, 2015 September 30, December 31, 2014 Weighted Average Interest Rate Weighted Average Years to Maturity Number of Communities Encumbered Fixed Rate Debt Mortgage notes payable $ 371,888 $ 378,371 5.50 % 0.9 5 Fannie Mae credit facilities 333,912 333,828 4.90 % 3.8 9 Total fixed rate secured debt 705,800 712,199 5.22 % 2.3 14 Variable Rate Debt Tax-exempt secured note payable 27,000 27,000 0.76 % 16.5 1 Fannie Mae credit facilities 177,509 192,760 1.89 % 5.4 5 Total variable rate secured debt 204,509 219,760 1.74 % 6.9 6 Total Secured Debt $ 910,309 $ 931,959 4.44 % 3.3 20
Secured credit facilities	The following information relates to the credit facilities allocated to the Operating Partnership (dollars in thousands) : September 30, December 31, 2014 Borrowings outstanding $ 511,421 $ 526,588 Weighted average borrowings during the period ended 518,036 527,592 Maximum daily borrowings during the period 523,492 528,659 Weighted average interest rate during the period ended 3.8 % 4.1 % Interest rate at the end of the period 3.9 % 4.0 %
Aggregate maturities of secured debt	The aggregate maturities of the Operating Partnership’s secured debt due during each of the next five calendar years subsequent to September 30, 2015 are as follows (dollars in thousands): Fixed Variable Year Mortgage Notes Payable Secured Credit Facilities Tax-Exempt Secured Notes Payable Secured Credit Facilities Total 2015 $ 186,592 $ 94 $ — $ — $ 186,686 2016 131,946 385 — — 132,331 2017 1,629 15,640 — 6,566 23,835 2018 1,685 111,256 — 81,559 194,500 2019 50,036 123,095 — — 173,131 Thereafter — 83,442 27,000 89,384 199,826 Total $ 371,888 $ 333,912 $ 27,000 $ 177,509 $ 910,309

Income_(Loss) Per Share (Tables

Income/(Loss) Per Share (Tables)	9 Months Ended
	Sep. 30, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]	The following table sets forth the additional shares of common stock outstanding by equity instrument if converted to common stock for each of the three and nine months ended September 30, 2015 and 2014 (shares in thousands) : Three Months Ended Nine Months Ended September 30, September 30, 2015 2014 2015 2014 OP Units 9,061 9,189 9,117 9,274 Preferred stock 3,029 3,036 3,033 3,036 Stock options and unvested restricted stock 2,093 2,077 2,080 1,974
(Loss)/earnings per share	The following table sets forth the computation of basic and diluted income/(loss) per share for the periods presented (dollars and shares in thousands, except per share data): Three Months Ended Nine Months Ended September 30, September 30, 2015 2014 2015 2014 Numerator for income/(loss) per share: Income/(loss) from continuing operations $ 13,695 $ 10,611 $ 100,954 $ 9,775 Gain/(loss) on sale of real estate owned, net of tax — 31,302 79,042 82,305 (Income)/loss from continuing operations attributable to redeemable noncontrolling interests in the Operating Partnership (405 ) (1,441 ) (6,022 ) (3,167 ) (Income)/loss from continuing operations attributable to noncontrolling interests 1 4 (6 ) (2 ) Income/(loss) from continuing operations attributable to UDR, Inc. 13,291 40,476 173,968 88,911 Distributions to preferred stockholders - Series E (Convertible) (930 ) (931 ) (2,792 ) (2,793 ) Income/(loss) from continuing operations attributable to common stockholders $ 12,361 $ 39,545 $ 171,176 $ 86,118 Income/(loss) from discontinued operations, net of tax $ — $ 79 $ — $ 10 (Income)/loss from discontinued operations attributable to redeemable noncontrolling interests in the Operating Partnership — (6 ) — (4 ) Income/(loss) from discontinued operations attributable to common stockholders $ — $ 73 $ — $ 6 Net income/(loss) attributable to common stockholders $ 12,361 $ 39,618 $ 171,176 $ 86,124 Denominator for income/(loss) per share: Weighted average common shares outstanding 260,302 252,891 259,151 251,860 Non-vested restricted stock awards (1,188 ) (1,236 ) (1,211 ) (1,159 ) Denominator for basic income/(loss) per share 259,114 251,655 257,940 250,701 Incremental shares issuable from assumed conversion of preferred stock, stock options, and unvested restricted stock 2,093 2,077 2,080 1,974 Denominator for diluted income/(loss) per share 261,207 253,732 260,020 252,675 Income/(loss) per weighted average common share-basic: Income/(loss) from continuing operations attributable to common stockholders $ 0.05 $ 0.16 $ 0.66 $ 0.34 Income/(loss) from discontinued operations attributable to common stockholders — — — — Net income/(loss) attributable to common stockholders $ 0.05 $ 0.16 $ 0.66 $ 0.34 Income/(loss) per weighted average common share-diluted: Income/(loss) from continuing operations attributable to common stockholders $ 0.05 $ 0.16 $ 0.66 $ 0.34 Income/(loss) from discontinued operations attributable to common stockholders — — — — Net income/(loss) attributable to common stockholders $ 0.05 $ 0.16 $ 0.66 $ 0.34

Noncontrolling Interests (Table

Noncontrolling Interests (Tables)	9 Months Ended
	Sep. 30, 2015
Noncontrolling Interest [Abstract]
Redeemable noncontrolling interests in the Operating Partnership	The following table sets forth redeemable noncontrolling interests in the Operating Partnership for the following period ( dollars in thousands ): Redeemable noncontrolling interests in the Operating Partnership, December 31, 2014 $ 282,480 Mark-to-market adjustment to redeemable noncontrolling interests in the Operating Partnership 35,508 Conversion of OP Units to Common Stock (3,818 ) Net income/(loss) attributable to redeemable noncontrolling interests in the Operating Partnership 6,022 Distributions to redeemable noncontrolling interests in the Operating Partnership (7,859 ) Allocation of other comprehensive income/(loss) (175 ) Redeemable noncontrolling interests in the Operating Partnership, September 30, 2015 $ 312,158 The following sets forth net income/(loss) attributable to common stockholders and transfers from redeemable noncontrolling interests in the Operating Partnership for the following periods (dollars in thousands) : Three Months Ended Nine Months Ended September 30, September 30, 2015 2014 2015 2014 Net income/(loss) attributable to common stockholders $ 12,361 $ 39,618 $ 171,176 $ 86,124 Conversion of OP Units to UDR Common stock 320 4,127 3,818 4,318 Change in equity from net income/(loss) attributable to common stockholders and conversion of OP Units to UDR Common Stock $ 12,681 $ 43,745 $ 174,994 $ 90,442

Fair Value of Derivatives and51

Fair Value of Derivatives and Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2015
Fair Value Disclosures [Abstract]
Estimated fair values	The estimated fair values of the Company’s financial instruments either recorded or disclosed on a recurring basis as of September 30, 2015 and December 31, 2014 are summarized as follows (dollars in thousands) : Fair Value at September 30, 2015, Using Total Carrying Amount in Statement of Financial Position at September 30, 2015 Fair Value Estimate at September 30, 2015 Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Description: Notes receivable (a) $ 15,494 $ 15,795 $ — $ — $ 15,795 Derivatives - Interest rate contracts (b) 6 6 — 6 — Total assets $ 15,500 $ 15,801 $ — $ 6 $ 15,795 Derivatives - Interest rate contracts (b) $ 3,205 $ 3,205 $ — $ 3,205 $ — Secured debt instruments - fixed rate: (c) Mortgage notes payable 406,183 416,287 — — 416,287 Fannie Mae credit facilities 565,394 595,907 — — 595,907 Secured debt instruments - variable rate: (c) Mortgage notes payable 31,337 31,337 — — 31,337 Tax-exempt secured notes payable 94,700 94,700 — — 94,700 Fannie Mae credit facilities 249,378 249,378 — — 249,378 Unsecured debt instruments: (c) Commercial bank 110,000 110,000 — — 110,000 Senior unsecured notes 2,056,242 2,128,901 — — 2,128,901 Total liabilities $ 3,516,439 $ 3,629,715 $ — $ 3,205 $ 3,626,510 Redeemable noncontrolling interests in the Operating Partnership (d) $ 312,158 $ 312,158 $ — $ 312,158 $ — Fair Value at December 31, 2014, Using Total Carrying Amount in Statement of Financial Position at December 31, 2014 Fair Value Estimate at December 31, 2014 Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Description: Notes receivable (a) $ 14,369 $ 14,808 $ — $ — $ 14,808 Derivatives - Interest rate contracts (b) 88 88 — 88 — Total assets $ 14,457 $ 14,896 $ — $ 88 $ 14,808 Derivatives- Interest rate contracts (b) $ 10,368 $ 10,368 $ — $ 10,368 $ — Secured debt instruments - fixed rate: (c) Mortgage notes payable 401,210 415,663 — — 415,663 Fannie Mae credit facilities 568,086 606,623 — — 606,623 Secured debt instruments - variable rate: (c) Mortgage notes payable 31,337 31,337 — — 31,337 Tax-exempt secured notes payable 94,700 94,700 — — 94,700 Fannie Mae credit facilities 266,196 266,196 — — 266,196 Unsecured debt instruments: (c) Commercial bank 152,500 152,500 — — 152,500 Senior unsecured notes 2,069,076 2,144,125 — — 2,144,125 Total liabilities $ 3,593,473 $ 3,721,512 $ — $ 10,368 $ 3,711,144 Redeemable noncontrolling interests in the Operating Partnership (d) $ 282,480 $ 282,480 $ — $ 282,480 $ — (a) See Note 2, Significant Accounting Policies. (b) See Note 10, Derivatives and Hedging Activity. (c) See Note 6, Secured and Unsecured Debt. (d) See Note 8, Noncontrolling Interests.

Fair Value of Derivatives and52

Fair Value of Derivatives and Financial Instruments (UNITED DOMINION REALTY, L.P.) (Tables)	9 Months Ended
	Sep. 30, 2015
Entity Information [Line Items]
Estimated fair values	The estimated fair values of the Company’s financial instruments either recorded or disclosed on a recurring basis as of September 30, 2015 and December 31, 2014 are summarized as follows (dollars in thousands) : Fair Value at September 30, 2015, Using Total Carrying Amount in Statement of Financial Position at September 30, 2015 Fair Value Estimate at September 30, 2015 Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Description: Notes receivable (a) $ 15,494 $ 15,795 $ — $ — $ 15,795 Derivatives - Interest rate contracts (b) 6 6 — 6 — Total assets $ 15,500 $ 15,801 $ — $ 6 $ 15,795 Derivatives - Interest rate contracts (b) $ 3,205 $ 3,205 $ — $ 3,205 $ — Secured debt instruments - fixed rate: (c) Mortgage notes payable 406,183 416,287 — — 416,287 Fannie Mae credit facilities 565,394 595,907 — — 595,907 Secured debt instruments - variable rate: (c) Mortgage notes payable 31,337 31,337 — — 31,337 Tax-exempt secured notes payable 94,700 94,700 — — 94,700 Fannie Mae credit facilities 249,378 249,378 — — 249,378 Unsecured debt instruments: (c) Commercial bank 110,000 110,000 — — 110,000 Senior unsecured notes 2,056,242 2,128,901 — — 2,128,901 Total liabilities $ 3,516,439 $ 3,629,715 $ — $ 3,205 $ 3,626,510 Redeemable noncontrolling interests in the Operating Partnership (d) $ 312,158 $ 312,158 $ — $ 312,158 $ — Fair Value at December 31, 2014, Using Total Carrying Amount in Statement of Financial Position at December 31, 2014 Fair Value Estimate at December 31, 2014 Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Description: Notes receivable (a) $ 14,369 $ 14,808 $ — $ — $ 14,808 Derivatives - Interest rate contracts (b) 88 88 — 88 — Total assets $ 14,457 $ 14,896 $ — $ 88 $ 14,808 Derivatives- Interest rate contracts (b) $ 10,368 $ 10,368 $ — $ 10,368 $ — Secured debt instruments - fixed rate: (c) Mortgage notes payable 401,210 415,663 — — 415,663 Fannie Mae credit facilities 568,086 606,623 — — 606,623 Secured debt instruments - variable rate: (c) Mortgage notes payable 31,337 31,337 — — 31,337 Tax-exempt secured notes payable 94,700 94,700 — — 94,700 Fannie Mae credit facilities 266,196 266,196 — — 266,196 Unsecured debt instruments: (c) Commercial bank 152,500 152,500 — — 152,500 Senior unsecured notes 2,069,076 2,144,125 — — 2,144,125 Total liabilities $ 3,593,473 $ 3,721,512 $ — $ 10,368 $ 3,711,144 Redeemable noncontrolling interests in the Operating Partnership (d) $ 282,480 $ 282,480 $ — $ 282,480 $ — (a) See Note 2, Significant Accounting Policies. (b) See Note 10, Derivatives and Hedging Activity. (c) See Note 6, Secured and Unsecured Debt. (d) See Note 8, Noncontrolling Interests.
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
Estimated fair values	The estimated fair values of the Operating Partnership’s financial instruments either recorded or disclosed on a recurring basis as of September 30, 2015 and December 31, 2014 are summarized as follows (dollars in thousands) : Fair Value at September 30, 2015, Using Total Carrying Amount in Statement of Financial Position at September 30, 2015 Fair Value Estimate at September 30, 2015 Quoted Prices in Significant Significant Description: Derivatives - Interest rate contracts (a) $ 4 $ 4 $ — $ 4 $ — Total assets $ 4 $ 4 $ — $ 4 $ — Derivatives - Interest rate contracts (a) $ 175 $ 175 $ — $ 175 $ — Secured debt instruments - fixed rate: (b) Mortgage notes payable 371,888 380,820 — — 380,820 Fannie Mae credit facilities 333,912 352,452 — — 352,452 Secured debt instruments - variable rate: (b) Tax-exempt secured notes payable 27,000 27,000 — — 27,000 Fannie Mae credit facilities 177,509 177,509 — — 177,509 Total liabilities $ 910,484 $ 937,956 $ — $ 175 $ 937,781 Fair Value at December 31, 2014, Using Total Carrying Amount in Statement of Financial Position at December 31, 2014 Fair Value Estimate at December 31, 2014 Quoted Prices in Significant Significant Description: Derivatives - Interest rate contracts (a) $ 39 $ 39 $ — $ 39 $ — Total assets $ 39 $ 39 $ — $ 39 $ — Derivatives - Interest rate contracts (a) $ 918 $ 918 $ — $ 918 $ — Secured debt instruments - fixed rate: (b) Mortgage notes payable 378,371 391,835 — — 391,835 Fannie Mae credit facilities 333,828 355,470 — — 355,470 Secured debt instruments - variable rate: (b) Tax-exempt secured notes payable 27,000 27,000 — — 27,000 Fannie Mae credit facilities 192,760 192,760 — — 192,760 Total liabilities $ 932,877 $ 967,983 $ — $ 918 $ 967,065 (a) See Note 7, Derivatives and Hedging Activity. (b) See Note 4, Debt.

Derivatives and Hedging Activ53

Derivatives and Hedging Activity (Tables)	9 Months Ended
	Sep. 30, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Outstanding interest rate derivatives	As of September 30, 2015 , the Company had the following outstanding interest rate derivatives that were designated as cash flow hedges of interest rate risk ( dollars in thousands ): Product Number of Instruments Notional Interest rate swaps 6 $ 365,000 Interest rate caps 2 $ 203,166 Derivatives not designated as hedges are not speculative and are used to manage the Company’s exposure to interest rate movements and other identified risks but do not meet the strict hedge accounting requirements of GAAP or the Company has elected to not apply hedge accounting. Changes in the fair value of derivatives not designated in hedging relationships are recorded directly in earnings and resulted in gain/(loss) of $(1,000) and $(25,000) for the three and nine months ended September 30, 2015 , respectively, and no adjustment to earnings for for the three and nine months ended September 30, 2014 . As of September 30, 2015 , the Company had the following outstanding derivatives that were not designated as hedges in qualifying hedging relationships ( dollars in thousands ): Product Number of Instruments Notional Interest rate caps 3 $ 133,107
Fair value of Company's derivative financial instruments and their classification on Consolidated Balance Sheet	The tables below present the fair value of the Company’s derivative financial instruments as well as their classification on the Consolidated Balance Sheets as of September 30, 2015 and December 31, 2014 ( dollars in thousands ): Asset Derivatives (included in Other assets ) Liability Derivatives (included in Other liabilities ) Fair Value at: Fair Value at: September 30, December 31, September 30, December 31, Derivatives designated as hedging instruments: Interest rate products $ 4 86 $ 3,205 $ 10,368 Derivatives not designated as hedging instruments: Interest rate products $ 2 $ 2 $ — $ —
Effect of Company's derivative financial instruments on Consolidated Statements of Operation	The tables below present the effect of the Company’s derivative financial instruments on the Consolidated Statements of Operations for the three and nine months ended September 30, 2015 and 2014 ( dollars in thousands ): Derivatives in Cash Flow Hedging Relationships Unrealized holding gain/(loss) Recognized in OCI (Effective Portion) Gain/(Loss) Reclassified from Accumulated OCI into Interest expense (Effective Portion) Gain/(Loss) Recognized in Interest expense (Ineffective Portion and Amount Excluded from Effectiveness Testing) 2015 2014 2015 2014 2015 2014 Three Months Ended September 30, Interest rate products $ (5,707 ) $ 362 $ (525 ) $ (1,130 ) $ (11 ) $ — Nine Months Ended September 30, Interest rate products $ (7,072 ) $ 611 $ (1,554 ) $ (3,809 ) $ (11 ) $ 3
Effect of Company's derivatives not designated as hedging instruments on the Consolidated Statements of Operations	Gain/(Loss) Recognized in Interest income and other income/(expense), net Derivatives Not Designated as Hedging Instruments 2015 2014 Three Months Ended September 30, Interest rate products $ (1 ) $ — Nine Months Ended September 30, Interest rate products $ (25 ) $ —
Offsetting Assets [Table Text Block]	Offsetting of Derivative Assets Gross Amounts of Recognized Assets Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts of Assets Presented in the Consolidated Balance Sheets (a) Gross Amounts Not Offset in the Consolidated Balance Sheets Financial Instruments Cash Collateral Received Net Amount September 30, 2015 $ 6 $ — $ 6 $ — $ — $ 6 December 31, 2014 $ 88 $ — $ 88 $ (27 ) $ — $ 61 (a) Amounts reconcile to the aggregate fair value of derivative assets in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Balance Sheet” located in this footnote.
Offsetting Liabilities [Table Text Block]	Offsetting of Derivative Liabilities Gross Amounts of Recognized Liabilities Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts of Liabilities Presented in the Consolidated Balance Sheets (b) Gross Amounts Not Offset in the Consolidated Balance Sheets Financial Instruments Cash Collateral Posted Net Amount September 30, 2015 $ 3,205 $ — $ 3,205 $ — $ — $ 3,205 December 31, 2014 $ 10,368 $ — $ 10,368 $ (27 ) $ — $ 10,341 (b) Amounts reconcile to the aggregate fair value of derivative liabilities in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Balance Sheet” located in this footnote.

Derivatives and Hedging Activ54

Derivatives and Hedging Activity (UNITED DOMINION REALTY, L.P.) (Tables)	9 Months Ended
	Sep. 30, 2015
Entity Information [Line Items]
Outstanding interest rate derivatives	As of September 30, 2015 , the Company had the following outstanding interest rate derivatives that were designated as cash flow hedges of interest rate risk ( dollars in thousands ): Product Number of Instruments Notional Interest rate swaps 6 $ 365,000 Interest rate caps 2 $ 203,166 Derivatives not designated as hedges are not speculative and are used to manage the Company’s exposure to interest rate movements and other identified risks but do not meet the strict hedge accounting requirements of GAAP or the Company has elected to not apply hedge accounting. Changes in the fair value of derivatives not designated in hedging relationships are recorded directly in earnings and resulted in gain/(loss) of $(1,000) and $(25,000) for the three and nine months ended September 30, 2015 , respectively, and no adjustment to earnings for for the three and nine months ended September 30, 2014 . As of September 30, 2015 , the Company had the following outstanding derivatives that were not designated as hedges in qualifying hedging relationships ( dollars in thousands ): Product Number of Instruments Notional Interest rate caps 3 $ 133,107
Fair value of Company's derivative financial instruments and their classification on Consolidated Balance Sheet	The tables below present the fair value of the Company’s derivative financial instruments as well as their classification on the Consolidated Balance Sheets as of September 30, 2015 and December 31, 2014 ( dollars in thousands ): Asset Derivatives (included in Other assets ) Liability Derivatives (included in Other liabilities ) Fair Value at: Fair Value at: September 30, December 31, September 30, December 31, Derivatives designated as hedging instruments: Interest rate products $ 4 86 $ 3,205 $ 10,368 Derivatives not designated as hedging instruments: Interest rate products $ 2 $ 2 $ — $ —
Effect of Company's derivative financial instruments on Consolidated Statements of Operation	The tables below present the effect of the Company’s derivative financial instruments on the Consolidated Statements of Operations for the three and nine months ended September 30, 2015 and 2014 ( dollars in thousands ): Derivatives in Cash Flow Hedging Relationships Unrealized holding gain/(loss) Recognized in OCI (Effective Portion) Gain/(Loss) Reclassified from Accumulated OCI into Interest expense (Effective Portion) Gain/(Loss) Recognized in Interest expense (Ineffective Portion and Amount Excluded from Effectiveness Testing) 2015 2014 2015 2014 2015 2014 Three Months Ended September 30, Interest rate products $ (5,707 ) $ 362 $ (525 ) $ (1,130 ) $ (11 ) $ — Nine Months Ended September 30, Interest rate products $ (7,072 ) $ 611 $ (1,554 ) $ (3,809 ) $ (11 ) $ 3
Effect of Company's derivatives not designated as hedging instruments on the Consolidated Statements of Operations	Gain/(Loss) Recognized in Interest income and other income/(expense), net Derivatives Not Designated as Hedging Instruments 2015 2014 Three Months Ended September 30, Interest rate products $ (1 ) $ — Nine Months Ended September 30, Interest rate products $ (25 ) $ —
Offsetting Assets [Table Text Block]	Offsetting of Derivative Assets Gross Amounts of Recognized Assets Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts of Assets Presented in the Consolidated Balance Sheets (a) Gross Amounts Not Offset in the Consolidated Balance Sheets Financial Instruments Cash Collateral Received Net Amount September 30, 2015 $ 6 $ — $ 6 $ — $ — $ 6 December 31, 2014 $ 88 $ — $ 88 $ (27 ) $ — $ 61 (a) Amounts reconcile to the aggregate fair value of derivative assets in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Balance Sheet” located in this footnote.
Offsetting Liabilities [Table Text Block]	Offsetting of Derivative Liabilities Gross Amounts of Recognized Liabilities Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts of Liabilities Presented in the Consolidated Balance Sheets (b) Gross Amounts Not Offset in the Consolidated Balance Sheets Financial Instruments Cash Collateral Posted Net Amount September 30, 2015 $ 3,205 $ — $ 3,205 $ — $ — $ 3,205 December 31, 2014 $ 10,368 $ — $ 10,368 $ (27 ) $ — $ 10,341 (b) Amounts reconcile to the aggregate fair value of derivative liabilities in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Balance Sheet” located in this footnote.
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
Outstanding interest rate derivatives	As of September 30, 2015 , the Operating Partnership had the following outstanding interest rate derivatives designated as cash flow hedges of interest rate risk ( dollars in thousands ): Product Number of Instruments Notional Interest rate swaps 1 $ 46,357 Interest rate caps 1 $ 127,916 Derivatives not designated as hedges are not speculative and are used to manage the Operating Partnership’s exposure to interest rate movements and other identified risks but do not meet the strict hedge accounting requirements of GAAP or the Operating Partnership has elected to not apply hedge accounting. Changes in the fair value of derivatives not designated in hedging relationships are recorded directly in earnings and resulted in gain/(loss) of $(1,000) and $(24,000) for the three and nine months ended September 30, 2015 , respectively, and no adjustment to earnings for for the three and nine months ended September 30, 2014 . As of September 30, 2015 , we had the following outstanding derivatives that were not designated as a hedges in a qualifying hedging relationships ( dollars in thousands ): Product Number of Instruments Notional Interest rate caps 3 $ 124,856 As of September 30, 2015 , the Operating Partnership had the following outstanding interest rate derivatives designated as cash flow hedges of interest rate risk ( dollars in thousands ): Product Number of Instruments Notional Interest rate swaps 1 $ 46,357 Interest rate caps 1 $ 127,916 Derivatives not designated as hedges are not speculative and are used to manage the Operating Partnership’s exposure to interest rate movements and other identified risks but do not meet the strict hedge accounting requirements of GAAP or the Operating Partnership has elected to not apply hedge accounting. Changes in the fair value of derivatives not designated in hedging relationships are recorded directly in earnings and resulted in gain/(loss) of $(1,000) and $(24,000) for the three and nine months ended September 30, 2015 , respectively, and no adjustment to earnings for for the three and nine months ended September 30, 2014 . As of September 30, 2015 , we had the following outstanding derivatives that were not designated as a hedges in a qualifying hedging relationships ( dollars in thousands ): Product Number of Instruments Notional Interest rate caps 3 $ 124,856
Fair value of Company's derivative financial instruments and their classification on Consolidated Balance Sheet	The table below presents the fair value of the Operating Partnership’s derivative financial instruments as well as their classification on the Consolidated Balance Sheets as of September 30, 2015 and December 31, 2014 ( dollars in thousands ): Asset Derivatives (included in Other assets ) Liability Derivatives (included in Other liabilities ) Fair Value at: Fair Value at: September 30, December 31, September 30, December 31, Derivatives designated as hedging instruments: Interest rate products $ 2 $ 37 $ 175 $ 918 Derivatives not designated as hedging instruments: Interest rate products $ 2 $ 2 $ — $ —
Effect of Company's derivative financial instruments on Consolidated Statements of Operation	The tables below present the effect of the derivative financial instruments on the Consolidated Statements of Operations for the three and nine months ended September 30, 2015 and 2014 ( dollars in thousands ): Unrealized holding gain/(loss) Recognized in OCI (Effective Portion) Gain/(Loss) Reclassified from Accumulated OCI into Interest expense (Effective Portion) Gain/(Loss) Recognized in Interest expense (Ineffective Portion and Amount Excluded from Effectiveness Testing) Derivatives in Cash Flow Hedging Relationships 2015 2014 2015 2014 2015 2014 Three Months Ended September 30, Interest rate products $ (8 ) $ (3 ) $ (267 ) $ (588 ) $ (11 ) $ — Nine Months Ended September 30, Interest rate products $ (85 ) $ (194 ) $ (820 ) $ (1,784 ) $ (11 ) $ —
Effect of Company's derivatives not designated as hedging instruments on the Consolidated Statements of Operations	Gain/(Loss) Recognized in Interest income and other income/(expense), net Derivatives Not Designated as Hedging Instruments 2015 2014 Three Months Ended September 30, Interest rate products $ (1 ) $ — Nine Months Ended September 30, Interest rate products $ (24 ) $ —
Offsetting Assets [Table Text Block]	The General Partner has elected not to offset derivative positions in the consolidated financial statements. The table below presents the effect on the Operating Partnership’s financial position had the General Partner made the election to offset its derivative positions as of September 30, 2015 and December 31, 2014 : Offsetting of Derivative Assets Gross Amounts of Recognized Assets Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts of Assets Presented in the Consolidated Balance Sheets (a) Gross Amounts Not Offset in the Consolidated Balance Sheets Financial Instruments Cash Collateral Received Net Amount September 30, 2015 $ 4 $ — $ 4 $ — $ — $ 4 December 31, 2014 $ 39 $ — $ 39 $ — $ — $ 39 (a) Amounts reconcile to the aggregate fair value of derivative assets in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Balance Sheet” located in this footnote.
Offsetting Liabilities [Table Text Block]	Offsetting of Derivative Liabilities Gross Amounts of Recognized Liabilities Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts of Liabilities Presented in the Consolidated Balance Sheets (b) Gross Amounts Not Offset in the Consolidated Balance Sheets Financial Instruments Cash Collateral Posted Net Amount September 30, 2015 $ 175 $ — $ 175 $ — $ — $ 175 December 31, 2014 $ 918 $ — $ 918 $ — $ — $ 918 (b) Amounts reconcile to the aggregate fair value of derivative liabilities in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Balance Sheet” located in this footnote.

Commitments and Contingencies55

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2015
Commitments and Contingencies Disclosure [Abstract]
Real estate commitments	The following summarizes the Company’s real estate commitments at September 30, 2015 ( dollars in thousands ): Number of Properties Costs Incurred as of September 30, 2015 (a) Expected Costs to Complete Average Ownership Stake Wholly-owned — under development 1 $ 104,080 (b) $ 237,920 100 % Wholly-owned — redevelopment 1 7,383 (b) 7,617 100 % Joint ventures: Unconsolidated joint ventures 4 427,545 117,195 (c) Various Participating loan investments 1 89,498 (d) 3,960 (e) 0 % Preferred equity investments 5 129,592 (f) 6,735 (g) 48 % $ 758,098 $ 373,427 (a) Represents 100% of project costs incurred as of September 30, 2015 . (b) Costs incurred to date include $2.8 million and $1.2 million of accrued fixed assets for development and redevelopment, respectively. (c) Represents UDR’s proportionate share of expected remaining costs to complete. (d) Represents the participating loan balance funded as of September 30, 2015 . (e) Represents UDR’s remaining participating loan commitment for Steele Creek. (f) Represents UDR's share of capital contributed to the West Coast Development Joint Venture as of September 30, 2015 . (g) Represents UDR's remaining funding commitment on Katella Grand II.

Reportable Segment (Tables)

Reportable Segment (Tables)	9 Months Ended
	Sep. 30, 2015
Segment Reporting [Abstract]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations	The following table details rental income and NOI from continuing and discontinued operations for UDR’s reportable segments for the three and nine months ended September 30, 2015 and 2014 , and reconciles NOI to Net Income/(Loss) Attributable to UDR, Inc . in the Consolidated Statements of Operations (dollars in thousands) : Three Months Ended Nine Months Ended September 30, (a) September 30, (b) 2015 2014 2015 2014 Reportable apartment home segment rental income Same-Store Communities West Region $ 77,837 $ 72,014 $ 197,831 $ 183,887 Mid-Atlantic Region 40,029 39,351 119,546 117,384 Southeast Region 26,293 24,682 77,420 73,151 Northeast Region 21,914 20,721 64,242 60,817 Southwest Region 14,599 13,859 43,068 40,949 Non-Mature Communities/Other 37,093 32,981 135,469 122,857 Total consolidated rental income $ 217,765 $ 203,608 $ 637,576 $ 599,045 Reportable apartment home segment NOI Same-Store Communities West Region $ 58,071 $ 52,128 $ 147,725 $ 133,037 Mid-Atlantic Region 26,995 27,015 82,046 81,285 Southeast Region 17,562 15,869 51,875 48,494 Northeast Region 16,161 15,571 47,996 45,576 Southwest Region 8,967 8,509 26,500 25,130 Non-Mature Communities/Other 25,809 20,722 91,430 78,808 Total consolidated NOI 153,565 139,814 447,572 412,330 Reconciling items: Joint venture management and other fees 3,653 3,165 19,457 9,599 Property management (5,988 ) (5,599 ) (17,533 ) (16,474 ) Other operating expenses (2,639 ) (2,012 ) (6,174 ) (6,118 ) Real estate depreciation and amortization (90,568 ) (89,339 ) (269,689 ) (266,748 ) General and administrative (15,824 ) (11,554 ) (41,697 ) (36,078 ) Casualty-related recoveries/(charges), net (541 ) — (2,380 ) (500 ) Other depreciation and amortization (1,457 ) (1,385 ) (4,780 ) (3,658 ) Income/(loss) from unconsolidated entities 2,691 (939 ) 61,277 (4,932 ) Interest expense (30,232 ) (33,087 ) (88,705 ) (97,662 ) Interest income and other income/(expense), net 402 9,061 1,144 11,902 Tax benefit/(expense), net 633 2,490 2,462 8,049 Gain/(loss) on sale of real estate owned, net of tax — 31,377 79,042 82,380 Net (income)/loss attributable to redeemable noncontrolling interests in the Operating Partnership (405 ) (1,447 ) (6,022 ) (3,171 ) Net (income)/loss attributable to noncontrolling interests 1 4 (6 ) (2 ) Net income/(loss) attributable to UDR, Inc. $ 13,291 $ 40,549 $ 173,968 $ 88,917 (a) Same-Store Community population consisted of 34,774 apartment homes. (b) Same-Store Community population consisted of 33,495 apartment homes.
Details of assets of UDR's reportable segments	The following table details the assets of UDR’s reportable segments as of September 30, 2015 and December 31, 2014 (dollars in thousands) : September 30, December 31, Reportable apartment home segment assets: Same-Store Communities: West Region $ 2,963,025 $ 2,935,430 Mid-Atlantic Region 1,464,514 1,453,532 Southeast Region 726,186 716,427 Northeast Region 1,083,935 1,076,656 Southwest Region 446,145 440,721 Non-Mature Communities/Other 1,789,172 1,760,493 Total assets 8,472,977 8,383,259 Accumulated depreciation (2,647,504 ) (2,434,772 ) Total assets — net book value 5,825,473 5,948,487 Reconciling items: Cash and cash equivalents 1,321 15,224 Restricted cash 23,722 22,340 Deferred financing costs, net 20,206 22,686 Notes receivable, net 15,494 14,369 Investment in and advances to unconsolidated joint ventures, net 921,925 718,226 Other assets 114,589 105,202 Total consolidated assets $ 6,922,730 $ 6,846,534

Reportable Segments (UNITED D57

Reportable Segments (UNITED DOMINION REALTY, L.P.) (Tables)	9 Months Ended
	Sep. 30, 2015
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
Reportable segments information	The following table details rental income and NOI from continuing and discontinued operations for the Operating Partnership’s reportable segments for the three and nine months ended September 30, 2015 and 2014 , and reconciles NOI to Net income/(loss) attributable to OP unitholders in the Consolidated Statements of Operations (dollars in thousands) : Three Months Ended Nine Months Ended September 30, (a) September 30, (b) 2015 2014 2015 2014 Reportable apartment home segment rental income Same-Store Communities West Region $ 52,731 $ 48,536 $ 136,298 $ 125,653 Mid-Atlantic Region 16,702 16,364 49,907 49,331 Southeast Region 11,363 10,677 33,535 31,757 Northeast Region 15,810 14,968 46,379 43,894 Southwest Region 6,989 6,667 20,594 19,873 Non-Mature Communities/Other 11,578 10,232 51,713 44,148 Total consolidated rental income $ 115,173 $ 107,444 $ 338,426 $ 314,656 Reportable apartment home segment NOI Same-Store Communities West Region $ 39,121 $ 35,066 $ 101,855 $ 91,363 Mid-Atlantic Region 10,639 10,873 32,845 33,185 Southeast Region 7,602 6,882 22,357 20,999 Northeast Region 12,025 11,609 35,672 33,662 Southwest Region 4,383 4,192 12,956 12,578 Non-Mature Communities/Other 8,520 7,131 37,003 31,351 Total consolidated NOI 82,290 75,753 242,688 223,138 Reconciling items: Property management (3,167 ) (2,955 ) (9,307 ) (8,653 ) Other operating expenses (1,482 ) (1,484 ) (4,468 ) (4,371 ) Real estate depreciation and amortization (43,829 ) (45,043 ) (132,411 ) (134,011 ) General and administrative (7,935 ) (6,939 ) (20,606 ) (21,368 ) Casualty-related recoveries/(charges), net (16 ) — (888 ) (500 ) Interest expense (10,909 ) (10,457 ) (32,587 ) (30,629 ) Gain/(loss) on sale of real estate owned — — 56,998 40,687 Net (income)/loss attributable to noncontrolling interests (335 ) (238 ) (1,075 ) (697 ) Net income/(loss) attributable to OP unitholders $ 14,617 $ 8,637 $ 98,344 $ 63,596 (a) Same-Store Community population consisted of 19,024 apartment homes. (b) Same-Store Community population consisted of 18,060 apartment homes The following table details the assets of the Operating Partnership’s reportable segments as of September 30, 2015 and December 31, 2014 (dollars in thousands) : September 30, December 31, 2014 Reportable apartment home segment assets Same-Store Communities West Region $ 1,873,029 $ 1,853,283 Mid-Atlantic Region 691,799 686,708 Southeast Region 320,578 316,788 Northeast Region 782,366 777,376 Southwest Region 231,748 228,997 Non-Mature Communities/Other 359,058 375,618 Total assets 4,258,578 4,238,770 Accumulated depreciation (1,518,558 ) (1,403,303 ) Total assets - net book value 2,740,020 2,835,467 Reconciling items: Cash and cash equivalents 131 502 Restricted cash 14,710 13,811 Deferred financing costs, net 3,355 4,475 Other assets 24,740 24,029 Total consolidated assets $ 2,782,956 $ 2,878,284

Consolidation and Basis of Pr58

Consolidation and Basis of Presentation (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Other Interest and Dividend Income	$ 0.4	$ 0.4	$ 1.1	$ 3
Deferred Tax Assets, Net	$ 10.5		$ 10.5
Operating Partnership outstanding units	183,278,698		183,278,698
General Partners Capital Account Units Owned Percentage	95.10%		95.10%
Percentage of units outstanding in Heritage OP	4.90%		4.90%
Limited Partner [Member]
Operating Partnership outstanding units	9,053,299		9,053,299
General Partner [Member]
Operating Partnership outstanding units	174,225,399		174,225,399

Consolidation and Basis of Pr59

Consolidation and Basis of Presentation (UNITED DOMINION REALTY, L.P.) (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2015CommunitiesApartment_HomesMarketsshares	Sep. 30, 2014	Sep. 30, 2015CommunitiesApartment_HomesMarketsshares	Sep. 30, 2014	Dec. 31, 2014shares
Entity Information [Line Items]
Number of Real Estate Properties | Communities	136		136
Number of apartments owned (in apartments homes) | Apartment_Homes	39,405		39,405
Operating Partnership outstanding units	183,278,698		183,278,698
Percentage of units outstanding in Heritage OP	4.90%		4.90%
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
Rental revenues percent of General Partner's consolidated rental revenues	53.00%	52.77547%	53.0801%	52.53916%
Number of Real Estate Properties | Communities	67		67
Number of markets operating within (in markets) | Markets	17		17
Number of apartments owned (in apartments homes) | Apartment_Homes	20,569		20,569
OP units outstanding related to general partner	110,883		110,883		110,883
OP units outstanding related to limited partner	183,167,815		183,167,815		183,167,815
Limited Partner [Member]
Entity Information [Line Items]
Operating Partnership outstanding units	9,053,299		9,053,299
General Partner [Member]
Entity Information [Line Items]
Operating Partnership outstanding units	174,225,399		174,225,399

Significant Accounting Polici60

Significant Accounting Policies (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Accounting Policies [Line Items]
Current Income Tax Expense (Benefit)			$ 0
Deferred Tax Assets, Net	$ 10,500,000		10,500,000
Significant Accounting Policies (Textual) [Abstract]
Notes receivable	15,494,000		15,494,000		$ 14,369,000
Note maturity public capital threshold			5,000,000
Note receivable interest income	400,000	$ 400,000	1,100,000	$ 3,000,000
Net of a valuation allowance	100,000		100,000
Tax benefit/(expense), net	(633,000)	(2,492,000)	$ (2,462,000)	(8,011,000)
Recognition and evaluation of tax position, whether a tax position is more likely			not (greater than 50 percent probability)
Unrecognized tax benefit, accrued interest or penalties due to examination	$ 0		$ 0
Proceeds from Sale and Collection of Notes Receivable			(1,125,000)	64,715,000
Interest Income, Related Party			0	0
Note due February 2017 [Member]
Accounting Policies [Line Items]
Increase (Decrease) in Notes Receivables			$ 1,100,000
Note Receivable Interest Rate	10.00%		10.00%
Significant Accounting Policies (Textual) [Abstract]
Notes receivable					11,869,000
Note maturity public capital threshold			$ 5,000,000
Aggregate Commitment on Note Receivable	$ 12,994,000		$ 12,994,000
Other [Member]
Accounting Policies [Line Items]
Note Receivable Interest Rate	8.00%		8.00%
Significant Accounting Policies (Textual) [Abstract]
Notes receivable	$ 2,500,000		$ 2,500,000		$ 2,500,000
Aggregate Commitment on Note Receivable	2,500,000		2,500,000
RedeemableNoncontrollingInterest [Member]
Accounting Policies [Line Items]
Comprehensive (loss)/income attributable to non-controlling interests	$ (200,000)	$ 100,000	$ (175,000)	$ 200,000

Real Estate Owned (Details)

Real Estate Owned (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Summary of carrying amounts for real estate owned (at cost)
Land	$ 1,840,823	$ 1,980,221
Depreciable property - held and used:
Building, Improvements, and Furniture, Fixtures and Equipment	6,321,640	6,225,406
Under development:
Real estate under development (net of accumulated depreciation of $0)	104,080	177,632
Real estate held for disposition (net of accumulated depreciation of $90,014 and $0)	116,420	0
Real estate owned	8,472,977	8,383,259
Real Estates Owned Accumulated Depreciation	2,647,504	2,434,772
Real Estate Investments, Net	5,825,473	5,948,487
Land [Member]
Under development:
Real estate under development (net of accumulated depreciation of $0)	78,085	24,584
Real estate held for disposition (net of accumulated depreciation of $90,014 and $0)	81,080	0
Construction in progress [Member]
Under development:
Real estate under development (net of accumulated depreciation of $0)	25,995	153,048
Real estate held for disposition (net of accumulated depreciation of $90,014 and $0)	$ 125,354	$ 0

Real Estate Owned (Details Text

Real Estate Owned (Details Textual) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2015USD ($)ft²CommunitiesApartment_HomesStates	Jun. 30, 2015USD ($)	Sep. 30, 2014USD ($)	Sep. 30, 2015USD ($)ft²CommunitiesApartment_HomesStates	Sep. 30, 2014USD ($)	Sep. 30, 2013USD ($)
Real Estate Properties [Line Items]
Communities Held For Sale			1		1
Real Estate Owned (Textual) [Abstract]
Number of states in which there are owned and consolidated communities	10			10
Number of apartment homes owned and consolidated by the Company | Apartment_Homes	39,405			39,405
Number of Real Estate Properties | Communities	136			136
Development costs excluding direct costs and capitlized interest	$ 1,700		$ 1,700	$ 5,500	$ 7,200
Interest capitalized during period	3,600		5,200	12,200	15,400
Other Cost and Expense, Operating	2,639		2,009	6,174	6,097
Proceeds from Sale of Property, Plant, and Equipment				109,900
Payments for (Proceeds from) Investments				90,543	233,913
Gains/(loss) on sales of real estate owned, net of tax	0		31,302	79,042	82,305
Acquisition of real estate				24,067	0
Gain (Loss) on Disposition of Property Plant Equipment			100
Casualty-related (recoveries)/charges, net	(541)		0	(2,380)	(500)
Casualty (Recoveries)/Charges	$ (541)		0	$ (2,380)	(500)
Communities Sold | Communities				3
Apartment Homes Sold | Apartment_Homes				812
Unconsolidated Joint Venture Four Texas [Member]
Real Estate Owned (Textual) [Abstract]
Proceeds from Sale of Property, Plant, and Equipment				$ 43,500
Gain (Loss) on Disposition of Property Plant Equipment				$ 59,100
1745 Shea [Member]
Real Estate Owned (Textual) [Abstract]
Square Footage | ft²	120,000			120,000
United Dominion Reality L.P. [Member]
Real Estate Owned (Textual) [Abstract]
Number of states in which there are owned and consolidated communities | States	9			9
Number of apartment homes owned and consolidated by the Company | Apartment_Homes	20,569			20,569
Number of Real Estate Properties | Communities	67			67
Development costs excluding direct costs and capitlized interest	$ 200		500	$ 500	1,800
Interest capitalized during period	100		800	100	2,800
Other Cost and Expense, Operating	1,482		1,484	4,468	4,371
Proceeds from Sale of Property, Plant, and Equipment				45,300
Payments for (Proceeds from) Investments				27,700
Gains/(loss) on sales of real estate owned, net of tax	0	$ 32,400	0	56,998	40,687
Casualty-related (recoveries)/charges, net	16		0	888		$ 500
Casualty (Recoveries)/Charges	$ (16)		0	$ (888)	(500)
Communities Sold | Communities				1
Apartment Homes Sold | Apartment_Homes				240
Operating Community [Member]
Real Estate Owned (Textual) [Abstract]
Gain (Loss) on Disposition of Property Plant Equipment			$ 31,300		81,200
Operating Community [Member] | Unconsolidated Joint Venture Vitruvian Park [Member]
Real Estate Owned (Textual) [Abstract]
Number of Real Estate Properties	3			3
Operating Community [Member] | Unconsolidated Joint Venture Four Texas [Member]
Real Estate Owned (Textual) [Abstract]
Number of Real Estate Properties | Communities	8			8
Development Community [Member] | Unconsolidated Joint Venture Four Texas [Member]
Real Estate Owned (Textual) [Abstract]
Number of Real Estate Properties	0			0
Land [Member]
Real Estate Owned (Textual) [Abstract]
Gain (Loss) on Disposition of Property Plant Equipment					$ 1,100
Office Building [Member] | 1745 Shea [Member]
Real Estate Owned (Textual) [Abstract]
Property, Plant and Equipment, Additions				$ 24,000

Real Estate Owned (UNITED DOM63

Real Estate Owned (UNITED DOMINION REALTY, L.P.) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Summary of carrying amounts for real estate owned (at cost)
Land	$ 1,840,823	$ 1,980,221
Under development:
Real estate under development (net of accumulated depreciation of $0 and $0, respectively)	104,080	177,632
Real estate held for disposition (net of accumulated depreciation of $50,610 and $0)	116,420	0
Real estate owned	8,472,977	8,383,259
Real Estates Owned Accumulated Depreciation	2,647,504	2,434,772
Real estate owned, net	5,825,473	5,948,487
Land [Member]
Under development:
Real estate under development (net of accumulated depreciation of $0 and $0, respectively)	78,085	24,584
Real estate held for disposition (net of accumulated depreciation of $50,610 and $0)	81,080	0
Construction in progress [Member]
Under development:
Real estate under development (net of accumulated depreciation of $0 and $0, respectively)	25,995	153,048
Real estate held for disposition (net of accumulated depreciation of $50,610 and $0)	125,354	0
United Dominion Reality L.P. [Member]
Summary of carrying amounts for real estate owned (at cost)
Land	932,717	1,008,014
Depreciable property - held and used:
Building, improvements, and furniture, fixture and equipment	3,174,403	3,230,756
Under development:
Real estate held for disposition (net of accumulated depreciation of $50,610 and $0)	100,848	0
Real estate owned	4,258,578	4,238,770
Real Estates Owned Accumulated Depreciation	1,518,558	1,403,303
Real estate owned, net	2,740,020	2,835,467
United Dominion Reality L.P. [Member] | Land [Member]
Under development:
Real estate held for disposition (net of accumulated depreciation of $50,610 and $0)	75,160	0
United Dominion Reality L.P. [Member] | Construction in progress [Member]
Under development:
Real estate held for disposition (net of accumulated depreciation of $50,610 and $0)	$ 76,298	$ 0

Real Estate Owned (UNITED DOM64

Real Estate Owned (UNITED DOMINION REALTY, L.P.) (Details Textual) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2015USD ($)CommunitiesApartment_HomesStates	Jun. 30, 2015USD ($)	Sep. 30, 2014USD ($)	Sep. 30, 2015USD ($)CommunitiesApartment_HomesStates	Sep. 30, 2014USD ($)	Sep. 30, 2013USD ($)	Dec. 31, 2014USD ($)
Real Estate Owned (Textual) [Abstract]
Number of communities owned (in communities) | Communities	136			136
Number of states operating within (in states)	10			10
Number of apartments owned (in apartments homes) | Apartment_Homes	39,405			39,405
Number of communities acquired apartment homes are within | Communities	0
Development costs excluding direct costs and capitlized interest	$ 1,700		$ 1,700	$ 5,500	$ 7,200
Interest capitalized during period	3,600		5,200	12,200	15,400
Other Cost and Expense, Operating	2,639		2,009	6,174	6,097
Proceeds from Sale of Property, Plant, and Equipment				109,900
Gains/(loss) on sales of real estate owned, net of tax	0		31,302	79,042	82,305
Deferred profit from the sale of properties	9,300			9,300			$ 28,500
Casualty-related (recoveries)/charges, net	(541)		0	(2,380)	(500)
Casualty (Recoveries)/Charges	$ (541)		0	(2,380)	(500)
Gain (Loss) on Disposition of Property Plant Equipment			100
Payments for (Proceeds from) Investments				90,543	233,913
Acquisition of real estate				$ 24,067	0
Communities Sold | Communities				3
Apartment Homes Sold | Apartment_Homes				812
United Dominion Reality L.P. [Member]
Real Estate Owned (Textual) [Abstract]
Number of communities owned (in communities) | Communities	67			67
Number of states operating within (in states) | States	9			9
Number of apartments owned (in apartments homes) | Apartment_Homes	20,569			20,569
Development costs excluding direct costs and capitlized interest	$ 200		500	$ 500	1,800
Interest capitalized during period	100		800	100	2,800
Other Cost and Expense, Operating	1,482		1,484	4,468	4,371
Proceeds from Sale of Property, Plant, and Equipment				45,300
Gains/(loss) on sales of real estate owned, net of tax	0	$ 32,400	0	56,998	40,687
Deferred profit from the sale of properties	0			0			$ 24,622
Casualty-related (recoveries)/charges, net	16		0	888		$ 500
Casualty (Recoveries)/Charges	$ (16)		$ 0	(888)	$ (500)
Payments for (Proceeds from) Investments				$ 27,700
Communities Sold | Communities				1
Apartment Homes Sold | Apartment_Homes				240

Discontinued Operations (Detail

Discontinued Operations (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015USD ($)	Sep. 30, 2014USD ($)	Sep. 30, 2015USD ($)	Sep. 30, 2014USD ($)
Discontinued Operation, Tax Effect of Discontinued Operation	$ 0	$ 2	$ 0	$ (38)
Disposal Group, Including Discontinued Operation, Interest Expense	0	1	0	4
Disposal Group, Including Discontinued Operation, Operating Expense	0	(3)	0	(21)
Disposal Group, Including Discontinued Operation, Operating Income (Loss)	0	(6)	0	103
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax	0	75	0	$ 75
Gain (Loss) on Disposition of Property Plant Equipment		$ 100
Discontinued Operations (Textual) [Abstract]
Communities held for sale (in communities)		1		1
Summary of income from discontinued operations
Rental expenses	0	$ 21	0	$ 147
Real estate depreciation	0	11	0	225
Income/(loss) from discontinued operations, net of tax	0	79	0	10
Income/(loss) from discontinued operations attributable to common stockholders	$ 0	73	$ 0	6
Operating Community [Member]
Gain (Loss) on Disposition of Property Plant Equipment		$ 31,300		81,200
Land [Member]
Gain (Loss) on Disposition of Property Plant Equipment				$ 1,100

Joint Ventures (Details)

Joint Ventures (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2015USD ($)Communities	Sep. 30, 2014USD ($)	Sep. 30, 2015USD ($)Communities	Sep. 30, 2014USD ($)	Sep. 30, 2013USD ($)	Dec. 31, 2014USD ($)
Financial information relating to unconsolidated joint ventures operations
UDR income/(loss) from unconsolidated entities	$ 2,691,000	$ (939,000)	$ 61,277,000	$ (4,932,000)
Combined summary of balance sheets relating to unconsolidated joint ventures
Investment in and advances to unconsolidated joint ventures, net	921,925,000		921,925,000			$ 718,226,000
Deferred gains on the sale of depreciable property	$ 9,300,000		$ 9,300,000			28,500,000
Number of Real Estate Properties | Communities	136		136
Unconsolidated Joint Ventures [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment Summarized Financial Information Income/(loss) from discontinued operations	$ (37,000)	(2,891,000)	$ 182,452,000	(37,579,000)
Financial information relating to unconsolidated joint ventures operations
Total revenues	55,948,000	52,804,000	165,944,000		$ 140,138,000
Equity Method Investment Summarized Financial Information Property Operating Expense	(21,981,000)	(19,837,000)	(63,692,000)	(52,197,000)
Real estate depreciation and amortization	(18,272,000)	(19,158,000)	(57,026,000)		(50,654,000)
Net income /(loss)	(834,000)	(4,837,000)	178,948,000		$ (43,125,000)
Combined summary of balance sheets relating to unconsolidated joint ventures
Total real estate, net	3,074,723,000		3,074,723,000			2,941,803,000
Equity Method of Investment Summarized Financial Information, Assets Sold or Held For Sale	0		0			216,196,000
Equity Method Investment Summarized Financial Information Cash and cash equivalents	37,768,000		37,768,000			32,544,000
Equity Method Investment Summarized Financial Information Other assets	44,259,000		44,259,000			28,707,000
Total assets	3,156,750,000		3,156,750,000			3,219,250,000
Amount due to UDR	7,465,000		7,465,000			2,997,000
Third party debt	1,586,380,000		1,586,380,000			1,504,477,000
Equity Method of Investment Summarized Financial Information, Liabilities Sold or Held For Sale	0		0			229,706,000
Equity Method Investment Summarized Financial Information Accounts payable and accrued liabilities	87,730,000		87,730,000			44,335,000
Total liabilities	1,681,575,000		1,681,575,000			1,781,515,000
Total equity	1,475,175,000		1,475,175,000			1,437,735,000
Equity Method Investment, Summarized Financial Information, Liabilities and Equity	3,156,750,000		3,156,750,000			3,219,250,000
Investment in and advances to unconsolidated joint ventures, net	696,654,000		696,654,000			655,519,000
Equity Method of Investment Summarized Financial Information Operating income/(loss)	15,695,000	13,809,000	45,226,000	37,287,000
Equity Method Investment Summarized Financial Information Interest expense	(16,310,000)	(15,755,000)	(48,540,000)	(42,833,000)
Equity Method Investment Summarized Financial Information Other income/(expense)	(182,000)	0	(190,000)	0
Unconsolidated Joint Venture Four Texas [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Deferred gains on the sale of depreciable property	24,200,000		24,200,000
Operating Community [Member] | Unconsolidated Joint Venture UDR Met Life I Partnership [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Investment in and advances to unconsolidated joint ventures, net	$ 14,804,000		$ 14,804,000			$ 13,306,000
Equity Method Investment, Ownership Percentage	16.41%		16.41%			15.70%
Number of apartment homes	0		0
Number of Real Estate Properties	4		4
Operating Community [Member] | Unconsolidated Joint Venture UDR MetLife II Partnership [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Investment in and advances to unconsolidated joint ventures, net	$ 425,963,000		$ 425,963,000			$ 431,277,000
Equity Method Investment, Ownership Percentage	50.00%		50.00%			50.00%
Number of apartment homes	4,642		4,642
Number of Real Estate Properties	21		21
Operating Community [Member] | Unconsolidated Joint Venture Vitruvian Park [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Investment in and advances to unconsolidated joint ventures, net	$ 73,618,000		$ 73,618,000			$ 80,302,000
Equity Method Investment, Ownership Percentage	50.00%		50.00%			50.00%
Number of apartment homes	1,130		1,130
Number of Real Estate Properties	3		3
Operating Community [Member] | Unconsolidated Joint Venture Three [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Investment in and advances to unconsolidated joint ventures, net	$ 18,308,000		$ 18,308,000			$ 21,596,000
Equity Method Investment, Ownership Percentage	30.00%		30.00%			30.00%
Number of apartment homes	660		660
Number of Real Estate Properties	3		3
Operating Community [Member] | Unconsolidated Joint Venture Four Texas [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Equity Method Investment, Ownership Percentage	0.00%		0.00%			20.00%
Number of Real Estate Properties | Communities	8		8
Operating Community [Member] | Unconsolidated Joint Venture Other MetLife [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Investment in and advances to unconsolidated joint ventures, net	$ 163,961,000		$ 163,961,000			$ 134,939,000
Equity Method Investment, Ownership Percentage	50.60%		50.60%			50.60%
Number of apartment homes	1,437		1,437
Number of Real Estate Properties	1		1
Land Parcel [Member] | Unconsolidated Joint Venture Vitruvian Park [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Number of Real Estate Properties	6		6
Development Community [Member] | Unconsolidated Joint Venture Four Texas [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Investment in and advances to unconsolidated joint ventures, net	$ 0		$ 0			$ (25,901,000)
Number of apartment homes	0		0
Number of Real Estate Properties	0		0
Development Community [Member] | Unconsolidated Joint Venture Other MetLife [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Number of Real Estate Properties	4		4
Development Community [Member] | Participating Loan Investment Steele Creek Denver Colorado [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Investment in and advances to unconsolidated joint ventures, net	$ 89,498,000		$ 89,498,000			62,707,000
Income from Participating Loan	$ 1,458,000	642,000	$ 3,964,000	1,419,000
Participating Loan, Interest Rate, Stated Percentage	6.50%		6.50%
Participating Loan Years to Maturity			1 year 9 months 30 days
Development Community [Member] | Preferred Equity Investment West Coast Development JV [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Investment in and advances to unconsolidated joint ventures, net	$ 135,773,000		$ 135,773,000			$ 0
Income from Participating Loan	$ 2,086	$ 0	$ 1,578	$ 0
Participating Loan, Interest Rate, Stated Percentage	6.50%		6.50%
Land [Member] | Unconsolidated Joint Venture Other MetLife [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Number of Real Estate Properties	1		1

Joint Ventures (Details Textual

Joint Ventures (Details Textual) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015USD ($)Communities	Sep. 30, 2014USD ($)	Sep. 30, 2015USD ($)Communities	Sep. 30, 2014USD ($)	Dec. 31, 2014USD ($)
Schedule of Equity Method Investments [Line Items]
Proceeds from Sale of Property, Plant, and Equipment			$ 109,900
Number of Real Estate Properties | Communities	136		136
Community Threshold, Period Above Occupancy Threshold			3 months
Secured Debt	$ 1,346,992		$ 1,346,992		$ 1,361,529
Joint Ventures
Real Estate Owned Gross	8,472,977		8,472,977		8,383,259
Unamortized discount	4,400		4,400		6,700
First installment of payable incurred in partial consideration for acquisition of ownership interest in joint venture	187,941		187,941
Second installment of payable incurred in partial consideration for acquisition of ownership interest in joint venture	242,625		242,625
Interest expense	(30,232)	$ (33,087)	(88,705)	$ (97,662)
Company's equity investment in joint venture	921,925		921,925		718,226
Deferred profit from the sale of properties	9,300		9,300		$ 28,500
Management fees for our involvement in the joint ventures	3,300	2,700	8,500	8,300
Gain (Loss) on Disposition of Property Plant Equipment		100
Unconsolidated Joint Venture Four Texas [Member]
Schedule of Equity Method Investments [Line Items]
Proceeds from Sale of Property, Plant, and Equipment			43,500
Joint Ventures
Deferred profit from the sale of properties	24,200		24,200
Fee Income from the Sale of Real Estate			9,600
Gain (Loss) on Disposition of Property Plant Equipment			59,100
Unconsolidated Joint Venture 399 Fremont [Member]
Schedule of Equity Method Investments [Line Items]
Number of apartments of development community					0
Unconsolidated Joint Venture Wolff [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment Cost of Ownership Interest, Funded	129,600		129,600
Equity Method Investment Cost of Ownership Interest, Remaining Commitment	$ 6,700		6,700
Total Fixed Price Option Sales Price			$ 597,400
Number of Markets Operating Within	3		3
Preferred Return Interest Rate			650.00%
Community Threshold, Percent Occupancy Threshold			8000.00%
Community Threshold, Period Above Occupancy Threshold			90 days
Fixed Price Option Period			1 year
Joint Ventures
Equity Method Investment Cost of Ownership Interest	$ 136,300		$ 136,300
Equity Method Investment, Ownership Percentage	4800.00%		4800.00%
Land [Member]
Joint Ventures
Gain (Loss) on Disposition of Property Plant Equipment				1,100
Land [Member] | Unconsolidated Joint Venture Other MetLife [Member]
Schedule of Equity Method Investments [Line Items]
Number of Real Estate Properties	1		1
Operating Community [Member]
Joint Ventures
Gain (Loss) on Disposition of Property Plant Equipment		31,300		$ 81,200
Operating Community [Member] | Unconsolidated Joint Venture Vitruvian Park [Member]
Schedule of Equity Method Investments [Line Items]
Number of Real Estate Properties	3		3
Number of apartment homes	1,130		1,130
Joint Ventures
Company's equity investment in joint venture	$ 73,618		$ 73,618		$ 80,302
Equity Method Investment, Ownership Percentage	50.00%		50.00%		50.00%
Operating Community [Member] | Unconsolidated Joint Venture UDR Met Life I Partnership [Member]
Schedule of Equity Method Investments [Line Items]
Number of Real Estate Properties	4		4
Number of apartment homes	0		0
Joint Ventures
Company's equity investment in joint venture	$ 14,804		$ 14,804		$ 13,306
Equity Method Investment, Ownership Percentage	16.41%		16.41%		15.70%
Operating Community [Member] | Unconsolidated Joint Venture UDR MetLife II Partnership [Member]
Schedule of Equity Method Investments [Line Items]
Number of Real Estate Properties	21		21
Number of apartment homes	4,642		4,642
Joint Ventures
Company's equity investment in joint venture	$ 425,963		$ 425,963		$ 431,277
Equity Method Investment, Ownership Percentage	50.00%		50.00%		50.00%
Operating Community [Member] | Unconsolidated Joint Venture Three Washington DC [Member]
Schedule of Equity Method Investments [Line Items]
Number of Real Estate Properties	3		3
Number of apartment homes	660		660
Joint Ventures
Company's equity investment in joint venture	$ 18,308		$ 18,308		$ 21,596
Equity Method Investment, Ownership Percentage	30.00%		30.00%		30.00%
Operating Community [Member] | Unconsolidated Joint Venture Four Texas [Member]
Schedule of Equity Method Investments [Line Items]
Number of Real Estate Properties | Communities	8		8
Joint Ventures
Equity Method Investment, Ownership Percentage	0.00%		0.00%		20.00%
Operating Community [Member] | Unconsolidated Joint Venture Other MetLife [Member]
Schedule of Equity Method Investments [Line Items]
Number of Real Estate Properties	1		1
Number of apartment homes	1,437		1,437
Joint Ventures
Company's equity investment in joint venture	$ 163,961		$ 163,961		$ 134,939
Equity Method Investment, Ownership Percentage	50.60%		50.60%		50.60%
Operating Community [Member] | Unconsolidated Joint Venture Wolff [Member]
Schedule of Equity Method Investments [Line Items]
Number of Real Estate Properties	2		2
Number of apartment homes	1,533		1,533
Development Community [Member] | Unconsolidated Joint Venture Four Texas [Member]
Schedule of Equity Method Investments [Line Items]
Number of Real Estate Properties	0		0
Number of apartment homes	0		0
Joint Ventures
Company's equity investment in joint venture	$ 0		$ 0		$ (25,901)
Development Community [Member] | Unconsolidated Joint Venture Other MetLife [Member]
Schedule of Equity Method Investments [Line Items]
Number of Real Estate Properties	4		4
Development Community [Member] | Unconsolidated Joint Venture Wolff [Member]
Schedule of Equity Method Investments [Line Items]
Number of Real Estate Properties	5		5
Development Community [Member] | Preferred Equity Investment West Coast Development JV [Member]
Joint Ventures
Company's equity investment in joint venture	$ 135,773		$ 135,773		$ 0
Equity Method Investment, Preferred Return		$ 2,100	3,100
Equity Method Investment, Transaction Expenses			$ 1,500

Secured and Unsecured Debt (Det

Secured and Unsecured Debt (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2015USD ($)	Sep. 30, 2015USD ($)	Dec. 31, 2014USD ($)
Secured debt instruments
Weighted average interest rate	3.91%
Long-term Debt	$ 3,513,234	$ 3,513,234	$ 3,583,105
Unsecured Debt	2,166,242	$ 2,166,242	2,221,576
Weighted Average Years to Maturity		4 years 6 months 7 days
Line of Credit Facility, Amount Outstanding	2,300	$ 2,300	1,900
Fixed Rate Debt [Member]
Secured debt instruments
Principal outstanding	$ 971,577	$ 971,577	969,296
Weighted average interest rate	5.28%
Weighted Average Years to Maturity		2 years 3 months 14 days
Number of Communities Encumbered	28
Variable Rate Debt [Member]
Secured debt instruments
Principal outstanding	$ 375,415	$ 375,415	392,233
Weighted average interest rate	1.45%
Weighted Average Years to Maturity		5 years
Number of Communities Encumbered	10
Mortgages Notes Payable [Member] | Fixed Rate Debt [Member]
Secured debt instruments
Weighted average interest rate	5.51%
Weighted Average Years to Maturity		10 months 20 days
Number of Communities Encumbered	7
Mortgages Notes Payable [Member] | Variable Rate Debt [Member]
Secured debt instruments
Weighted average interest rate	2.00%
Weighted Average Years to Maturity		1 year 3 months 26 days
Number of Communities Encumbered	1
Tax-exempt secured notes payable [Member] | Variable Rate Debt [Member]
Secured debt instruments
Weighted average interest rate	0.75%
Weighted Average Years to Maturity		7 years 5 months 8 days
Number of Communities Encumbered	2
Fannie Mae credit facilities [Member] | Fixed Rate Debt [Member]
Secured debt instruments
Debt, Weighted Average Interest Rate	5.12%	5.12%
Weighted Average Years to Maturity		3 years 3 months 14 days
Number of Communities Encumbered	21
Fannie Mae credit facilities [Member] | Variable Rate Debt [Member]
Secured debt instruments
Debt Instrument, Interest Rate at Period End	1.65%	1.65%
Weighted Average Years to Maturity		4 years 6 months 10 days
Number of Communities Encumbered	7
Secured Debt [Member]
Secured debt instruments
Principal outstanding	$ 1,346,992	$ 1,346,992	1,361,529
Weighted average interest rate	4.21%
Long-term Debt	$ 1,346,992	$ 1,346,992
Weighted Average Years to Maturity		3 years 14 days
Number of Communities Encumbered	38
Secured Debt [Member] | Fixed Rate Debt [Member]
Secured debt instruments
Long-term Debt	$ 971,577	$ 971,577
Secured Debt [Member] | Variable Rate Debt [Member]
Secured debt instruments
Long-term Debt	$ 375,415	$ 375,415
Unsecured Revolving Credit Facility due October 2015 [Member]
Secured debt instruments
Weighted average interest rate	1.19%
Weighted Average Years to Maturity		2 years 2 months 6 days
Line of Credit Facility, Amount Outstanding	$ 110,000	$ 110,000	152,500
ThreePointSevenTermNotesDueOctober2020 [Member]
Secured debt instruments
Weighted average interest rate		3.70%
Senior Notes	$ 299,960	$ 299,960	299,954
Weighted Average Years to Maturity		5 years 1 day
Four Point Six Three Percent Term Medium Notes Due January Two Thousand Twenty-Two [Member]
Secured debt instruments
Weighted average interest rate	4.63%
Senior Notes	$ 397,746	$ 397,746	397,477
Weighted Average Years to Maturity		6 years 3 months 10 days
3.75 MTN Due July 2024 [Member]
Secured debt instruments
Weighted average interest rate	3.75%
Senior Notes	$ 299,088	$ 299,088	299,010
Weighted Average Years to Maturity		8 years 9 months 1 day
1.67% Term Notes due December 2016 [Member]
Secured debt instruments
Weighted average interest rate		1.35%
Senior Notes	35,000	$ 35,000	35,000
Weighted Average Years to Maturity		2 years 8 months 6 days
2.68% Term Notes due December 2016 [Member]
Secured debt instruments
Weighted average interest rate		1.53%
Senior Notes	100,000	$ 100,000	100,000
Weighted Average Years to Maturity		2 years 8 months 6 days
Five Point Two Five Percent, Medium Term Notes, Due January 2015 [Member]
Secured debt instruments
Weighted average interest rate		0.00%
Senior Notes	0	$ 0	325,169
Weighted Average Years to Maturity		0 years
Five Point Two Five Percent, Medium Term Notes, Due January 2016 [Member]
Secured debt instruments
Weighted average interest rate		5.25%
Senior Notes	83,260	$ 83,260	83,260
Weighted Average Years to Maturity		3 months 15 days
6.21 Medium Term Note, Due January 2016 [Member]
Secured debt instruments
Weighted average interest rate		6.21%
Senior Notes	12,351	$ 12,351	0
Weighted Average Years to Maturity		9 months 5 days
2.90% Term Notes due January 2016 [Member]
Secured debt instruments
Weighted average interest rate		1.70%
Senior Notes	$ 215,000	$ 215,000	215,000
Weighted Average Years to Maturity		2 years 8 months 6 days
Eight Point Five Zero Percent, Debentures, Due September 2024 [Member]
Secured debt instruments
Weighted average interest rate	8.50%
Senior Notes	$ 15,644	$ 15,644	15,644
Weighted Average Years to Maturity		8 years 11 months 15 days
4.00% MTN Due October 2025 [Member]
Secured debt instruments
Weighted average interest rate	4.00%
Senior Notes	$ 299,312	$ 299,312	0
Weighted Average Years to Maturity		10 years 1 day
Four Point Two Five Percentage Medium-Term Notes due June 2018 [Member]
Secured debt instruments
Weighted average interest rate		4.25%
Senior Notes	298,856	$ 298,856	298,535
Weighted Average Years to Maturity		2 years 8 months 1 day
Other [Member]
Secured debt instruments
Senior Notes	$ 25	$ 25	27
Unsecured Debt [Member]
Secured debt instruments
Weighted average interest rate	3.72%
Long-term Debt	$ 2,166,242	2,166,242
Unsecured Debt	2,166,242	$ 2,166,242	2,221,576
Weighted Average Years to Maturity		5 years 6 months
Fair Value, Measurements, Recurring [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Mortgages Notes Payable [Member] | Mortgages Notes Payable [Member] | Fixed Rate Debt [Member]
Secured debt instruments
Principal outstanding	406,183	$ 406,183	401,210
Fair Value, Measurements, Recurring [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Mortgages Notes Payable [Member] | Mortgages Notes Payable [Member] | Variable Rate Debt [Member]
Secured debt instruments
Principal outstanding	31,337	31,337	31,337
Fair Value, Measurements, Recurring [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Fannie Mae credit facilities [Member] | Fannie Mae credit facilities [Member] | Fixed Rate Debt [Member]
Secured debt instruments
Principal outstanding	565,394	565,394	568,086
Fair Value, Measurements, Recurring [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Fannie Mae credit facilities [Member] | Fannie Mae credit facilities [Member] | Variable Rate Debt [Member]
Secured debt instruments
Principal outstanding	$ 249,378	$ 249,378	$ 266,196

Secured and Unsecured Debt (D69

Secured and Unsecured Debt (Details 1) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2013	Dec. 31, 2014
Line of Credit Facility [Line Items]
Unamortized discount	$ 4,400		$ 6,700
Secured credit facilities
Borrowings outstanding	2,300		1,900
Five Point Two Five Percent, Medium Term Notes, Due January 2015 [Member]
Line of Credit Facility [Line Items]
Unamortized discount	0		6
Fannie Mae [Member]
Secured credit facilities
Borrowings outstanding	814,772		$ 834,282
Weighted average daily borrowings during the period ended	825,311	$ 835,873
Maximum daily borrowings during the period ended	$ 834,003	$ 837,564
Weighted average interest rate during the period ended	4.03%	4.10%
Interest rate at the end of the period	4.06%		4.00%
Four Point Two Five Percentage Medium-Term Notes due June 2018 [Member]
Line of Credit Facility [Line Items]
Unamortized discount	$ 1,144		$ 1,465
Three point seven percent medium term note due October 2020 [Member]
Line of Credit Facility [Line Items]
Unamortized discount	40		46
Four Point Six Three Percent Term Medium Notes Due January Two Thousand Twenty-Two [Member]
Line of Credit Facility [Line Items]
Unamortized discount	2,254		2,523
3.75 MTN Due July 2024 [Member]
Line of Credit Facility [Line Items]
Unamortized discount	912		990
4.00% MTN Due October 2025 [Member]
Line of Credit Facility [Line Items]
Unamortized discount	$ 688		$ 0

Secured and Unsecured Debt (D70

Secured and Unsecured Debt (Details 2) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Secured Debt, Encumbers Real Estate Owned, Amount	$ 2,300,000
Secured Debt, Encumbers Real Estate Owned, Percent	26.60%
Debt Instrument Weighted Average Years to Maturity	4 years 6 months 7 days
Unamortized discount	$ 4,400	$ 6,700
Aggregate maturities of secured debt
2,014	187,941
2,015	242,625
2,016	384,219
2,017	857,965
2,018	313,571
Thereafter	1,526,913
Total	1,346,992	1,361,529
Secured Debt, Unencumbered Real Estate Owned, Amount	$ 6,200,000
Secured Debt, Unencumbered Real Estate Owned, Percent	73.40%
Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	2 years 3 months 14 days
Variable Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	5 years
ThreePointSevenTermNotesDueOctober2020 [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	5 years 1 day
2.68% Term Notes due December 2016 [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	2 years 8 months 6 days
Four Point Six Three Percent Term Medium Notes Due January Two Thousand Twenty-Two [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	6 years 3 months 10 days
Unamortized discount	$ 2,254	2,523
Mortgages Notes Payable [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	10 months 20 days
Mortgages Notes Payable [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	1 year 3 months 26 days
Tax Exempt Notes Payable [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	7 years 5 months 8 days
Fannie Mae credit facilities [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	3 years 3 months 14 days
Fannie Mae credit facilities [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	4 years 6 months 10 days
3.75 MTN Due July 2024 [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	8 years 9 months 1 day
Unamortized discount	$ 912	990
Five Point Two Five Percent, Medium Term Notes, Due January 2015 [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	0 years
Unamortized discount	$ 0	$ 6

Secured and Unsecured Debt (D71

Secured and Unsecured Debt (Details 3) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Summary of unsecured debt
Unsecured Debt, Total	$ 2,166,242	$ 2,221,576
Unamortized discount	4,400	6,700
4.63% Medium-Term Notes due January 2022 [Member]
Summary of unsecured debt
Senior Unsecured Notes	397,746	397,477
Unamortized discount	2,254	2,523
1.67% Term Notes due December 2016 [Member]
Summary of unsecured debt
Senior Unsecured Notes	35,000	35,000
2.68% Term Notes due December 2016 [Member]
Summary of unsecured debt
Senior Unsecured Notes	100,000	100,000
5.25% Medium-Term Notes due January 2015 [Member]
Summary of unsecured debt
Senior Unsecured Notes	0	325,169
Unamortized discount	0	6
5.25% Medium-Term Notes due January 2016 [Member]
Summary of unsecured debt
Senior Unsecured Notes	83,260	83,260
2.90% Term Notes due January 2016 [Member]
Summary of unsecured debt
Senior Unsecured Notes	215,000	215,000
8.50% Debentures due September 2024 [Member]
Summary of unsecured debt
Senior Unsecured Notes	15,644	15,644
4.25% Medium-Term Notes due June 2018 [Member]
Summary of unsecured debt
Senior Unsecured Notes	298,856	298,535
Unamortized discount	1,144	1,465
Other [Member]
Summary of unsecured debt
Senior Unsecured Notes	$ 25	$ 27

Secured and Unsecured Debt (D72

Secured and Unsecured Debt (Details 4) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Summary of short-term bank borrowings under unsecured commercial bank credit facility
Borrowings outstanding at end of period	$ 2,300
Unsecured Commercial Bank Credit Facility [Member]
Summary of short-term bank borrowings under unsecured commercial bank credit facility
Total revolving credit facility	900,000		$ 900,000
Weighted average daily borrowings during the period ended	409,215	$ 291,761
Maximum daily borrowings during the period ended	$ 541,500	$ 625,000
Weighted average interest rate during the period ended	1.20%	1.20%
Interest rate at the end of the period	1.20%		1.10%
Unsecured Revolving Credit Facility due October 2015 [Member]
Summary of short-term bank borrowings under unsecured commercial bank credit facility
Borrowings outstanding at end of period	$ 110,000

Secured and Unsecured Debt (D73

Secured and Unsecured Debt (Details 5) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Aggregate maturities of unsecured debt
2,014	$ 187,941
2,015	242,625
2,016	384,219
2,017	857,965
2,018	313,571
Thereafter	1,526,913
Unsecured Debt, Total	2,166,242	$ 2,221,576
Long-term Debt	3,513,234	3,583,105
Secured Debt [Member]
Aggregate maturities of unsecured debt
2,014	187,916
2,015	148,223
2,016	274,219
2,017	209,654
2,018	313,571
Thereafter	213,409
Long-term Debt	1,346,992
Unsecured Debt [Member]
Aggregate maturities of unsecured debt
2,014	25
2,015	94,402
2,016	110,000
2,017	648,311
2,018	0
Thereafter	1,313,504
Unsecured Debt, Total	2,166,242	$ 2,221,576
Long-term Debt	2,166,242
Fixed Rate Debt [Member] | Secured Debt [Member]
Aggregate maturities of unsecured debt
2,014	187,916
2,015	148,223
2,016	177,882
2,017	121,685
2,018	245,871
Thereafter	90,000
Long-term Debt	971,577
Variable Rate Debt [Member] | Secured Debt [Member]
Aggregate maturities of unsecured debt
2,014	0
2,015	0
2,016	96,337
2,017	87,969
2,018	67,700
Thereafter	123,409
Long-term Debt	$ 375,415

Secured and Unsecured Debt (D74

Secured and Unsecured Debt (Details Textual) - USD ($) $ in Thousands	Jun. 27, 2014	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Secured Debt (Textual) [Abstract]
Secured debt amount which encumbers real estate owned based upon book value		$ 2,300,000		$ 2,300,000
Percentage of secured debt which encumbers real estate owned based upon book value		26.60%		26.60%
Secured debt amount of real estate owned which is unencumbered		$ 6,200,000		$ 6,200,000
Percentage of secured debt of real estate owned which is unencumbered		73.40%		73.40%
Weighted average interest rate		3.91%
Unamortized fair market adjustment		$ 4,400		$ 4,400		$ 6,700
Borrowings outstanding		2,300		$ 2,300		1,900
Extension period of option on loan				6 months
Line of Credit Facility, Interest Rate Description				100
Line of Credit Facility, Commitment Fee Description				15
Fixed Rate Debt [Member]
Secured Debt (Textual) [Abstract]
Secured debt including debt on real estate held for sale		$ 971,577		$ 971,577		969,296
Weighted average interest rate		5.28%
Variable Rate Debt [Member]
Secured Debt (Textual) [Abstract]
Secured debt including debt on real estate held for sale		$ 375,415		375,415		392,233
Weighted average interest rate		1.45%
3.75 MTN Due July 2024 [Member]
Secured Debt (Textual) [Abstract]
Weighted average interest rate		3.75%
Unamortized fair market adjustment		$ 912		$ 912		990
Debt Instrument, Maturity Date	Jul. 1, 2024
Mortgages Notes Payable [Member] | Fixed Rate Debt [Member]
Secured Debt (Textual) [Abstract]
Weighted average interest rate		5.51%
Debt Instrument, Maturity Date Range, Start				Dec. 9, 2015
Debt instrument, maturity date range, end				May 1, 2019
Notes payable minimum interest rates range				3.43%
Notes payable maximum interest rates range				6.16%
Mortgages Notes Payable [Member] | Variable Rate Debt [Member]
Secured Debt (Textual) [Abstract]
Weighted average interest rate		2.00%
Debt Assumed As Part of Acquisition [Member]
Secured Debt (Textual) [Abstract]
Amortization of Debt Discount (Premium)		$ 1,300	$ 1,300	$ 3,700	$ 3,800
Tax Exempt Notes Payable [Member] | Variable Rate Debt [Member]
Secured Debt (Textual) [Abstract]
Weighted average interest rate		0.75%
Fannie Mae credit facilities [Member] | Fixed Rate Debt [Member]
Secured Debt (Textual) [Abstract]
Debt, Weighted Average Interest Rate		5.12%		5.12%
Debt Instrument, Maturity Date Range, Start				May 1, 2017
Debt instrument, maturity date range, end				Jul. 1, 2023
Fannie Mae credit facilities [Member] | Variable Rate Debt [Member]
Secured Debt (Textual) [Abstract]
Debt Instrument, Interest Rate at Period End		1.65%		1.65%
Tax Exempt Secured Notes Payable [Member] | Variable Rate Debt [Member]
Secured Debt (Textual) [Abstract]
Debt Instrument, Maturity Date Range, Start				Aug. 1, 2019
Debt instrument, maturity date range, end				Mar. 20, 2032
Notes payable minimum interest rates range				0.75%
Notes payable maximum interest rates range				0.76%
Fannie Mae [Member]
Secured Debt (Textual) [Abstract]
Borrowings outstanding		$ 814,772		$ 814,772		834,282
1.67% Term Notes due December 2016 [Member]
Secured Debt (Textual) [Abstract]
Weighted average interest rate				1.35%
Debt Instrument, Maturity Date				Jun. 1, 2018
UDR Bank Credit Facility [Member]
Secured Debt (Textual) [Abstract]
Credit facilities with aggregate commitment		900,000		$ 900,000		900,000
Increment in Unsecured Revolving Credit Facility Under Certain Circumstances		1,450,000		1,450,000
Fannie Mae credit facilities [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Fair Value, Measurements, Recurring [Member] | Fannie Mae credit facilities [Member] | Fixed Rate Debt [Member]
Secured Debt (Textual) [Abstract]
Secured debt including debt on real estate held for sale		565,394		565,394		568,086
Fannie Mae credit facilities [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Fair Value, Measurements, Recurring [Member] | Fannie Mae credit facilities [Member] | Variable Rate Debt [Member]
Secured Debt (Textual) [Abstract]
Secured debt including debt on real estate held for sale		249,378		249,378		266,196
Mortgages Notes Payable [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Fair Value, Measurements, Recurring [Member] | Mortgages Notes Payable [Member] | Fixed Rate Debt [Member]
Secured Debt (Textual) [Abstract]
Secured debt including debt on real estate held for sale		406,183		406,183		401,210
Mortgages Notes Payable [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Fair Value, Measurements, Recurring [Member] | Mortgages Notes Payable [Member] | Variable Rate Debt [Member]
Secured Debt (Textual) [Abstract]
Secured debt including debt on real estate held for sale		$ 31,337		$ 31,337		$ 31,337

Secured and Unsecured Debt (D75

Secured and Unsecured Debt (Details Textual 1) - USD ($) $ in Thousands	Sep. 26, 2013	Sep. 30, 2015	Sep. 30, 2015	Sep. 22, 2015	Dec. 31, 2014	Sep. 30, 2014
Unsecured Debt (Textual) [Abstract]
Credit facility interest rate			100
Line of Credit Facility, Commitment Fee Description			15
Line of Credit Facility, Amount Outstanding		$ 2,300	$ 2,300		$ 1,900
Unamortized discount		$ 4,400	$ 4,400		6,700
Debt Instrument, Interest Rate During Period		3.91%
4.00% MTN Due October 2025 [Member]
Unsecured Debt (Textual) [Abstract]
Debt Instrument, Maturity Date			Oct. 1, 2025
Unamortized discount		$ 688	$ 688		0
Senior Notes		$ 299,312	299,312		0
Debt Instrument, Interest Rate During Period		4.00%
Medium-term Notes				$ 300,000
Debt Instrument, Interest Rate, Stated Percentage				4.00%
Percentage of Debt Instrument Price				99.77%
Portion of Medium Term Note subject to Interest Rate Swaps				$ 200,000
Long-term Debt, Weighted Average Interest Rate						4.55%
ThreePointSevenTermNotesDueOctober2020 [Member]
Unsecured Debt (Textual) [Abstract]
Debt Instrument, Maturity Date	Oct. 31, 2020
Senior Notes		$ 299,960	$ 299,960		299,954
Debt Instrument, Interest Rate During Period			3.70%
1.67% Term Notes due December 2016 [Member]
Unsecured Debt (Textual) [Abstract]
Debt Instrument, Maturity Date			Jun. 1, 2018
Senior Notes		35,000	$ 35,000		35,000
Debt Instrument, Interest Rate During Period			1.35%
2.90% Term Notes due January 2016 [Member]
Unsecured Debt (Textual) [Abstract]
Senior Notes		215,000	$ 215,000		215,000
Debt Instrument, Interest Rate During Period			1.70%
4.63% Medium-Term Notes due January 2022 [Member]
Unsecured Debt (Textual) [Abstract]
Unamortized discount		2,254	$ 2,254		2,523
Senior Notes		$ 397,746	397,746		397,477
Debt Instrument, Interest Rate During Period		4.63%
2.68% Term Notes due December 2016 [Member]
Unsecured Debt (Textual) [Abstract]
Senior Notes		$ 100,000	$ 100,000		100,000
Debt Instrument, Interest Rate During Period			1.53%
UDR Bank Credit Facility [Member]
Unsecured Debt (Textual) [Abstract]
Total revolving credit facility		900,000	$ 900,000		$ 900,000
Increase in maximum borrowing capacity of unsecured revolving credit facility		$ 1,450,000	$ 1,450,000
Interest rate		1.20%	1.20%		1.10%

Debt (UNITED DOMINION REALTY,76

Debt (UNITED DOMINION REALTY, L.P.) (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2015USD ($)	Sep. 30, 2015USD ($)Communities	Dec. 31, 2014USD ($)
Debt Instrument [Line Items]
Weighted average interest rate	3.91%
Debt Instrument Weighted Average Years to Maturity		4 years 6 months 7 days
Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Principal outstanding	$ 971,577	$ 971,577	$ 969,296
Weighted average interest rate	5.28%
Debt Instrument Weighted Average Years to Maturity		2 years 3 months 14 days
Number of Communities Encumbered (in communities)	28
Fixed Rate Debt [Member] | Mortgages Notes Payable [Member]
Debt Instrument [Line Items]
Weighted average interest rate	5.51%
Debt Instrument Weighted Average Years to Maturity		10 months 20 days
Number of Communities Encumbered (in communities)	7
Fixed Rate Debt [Member] | Fannie Mae credit facilities [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity		3 years 3 months 14 days
Number of Communities Encumbered (in communities)	21
Variable Rate Debt [Member]
Debt Instrument [Line Items]
Principal outstanding	$ 375,415	$ 375,415	392,233
Weighted average interest rate	1.45%
Debt Instrument Weighted Average Years to Maturity		5 years
Number of Communities Encumbered (in communities)	10
Variable Rate Debt [Member] | Mortgages Notes Payable [Member]
Debt Instrument [Line Items]
Weighted average interest rate	2.00%
Debt Instrument Weighted Average Years to Maturity		1 year 3 months 26 days
Number of Communities Encumbered (in communities)	1
Variable Rate Debt [Member] | Fannie Mae credit facilities [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity		4 years 6 months 10 days
Number of Communities Encumbered (in communities)	7
Variable Rate Debt [Member] | Tax Exempt Notes Payable [Member]
Debt Instrument [Line Items]
Weighted average interest rate	0.75%
Debt Instrument Weighted Average Years to Maturity		7 years 5 months 8 days
Number of Communities Encumbered (in communities)	2
United Dominion Reality L.P. [Member]
Debt Instrument [Line Items]
Principal outstanding	$ 910,309	$ 910,309	931,959
Weighted average interest rate		4.44%
Debt Instrument Weighted Average Years to Maturity		3 years 3 months 18 days
Number of Communities Encumbered (in communities) | Communities		20
United Dominion Reality L.P. [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Principal outstanding	705,800	$ 705,800	712,199
Weighted average interest rate		5.22%
Debt Instrument Weighted Average Years to Maturity		2 years 3 months 3 days
Number of Communities Encumbered (in communities) | Communities		14
United Dominion Reality L.P. [Member] | Fixed Rate Debt [Member] | Mortgages Notes Payable [Member]
Debt Instrument [Line Items]
Principal outstanding	371,888	$ 371,888	378,371
Weighted average interest rate		5.50%
Debt Instrument Weighted Average Years to Maturity		10 months 9 days
Number of Communities Encumbered (in communities) | Communities		5
United Dominion Reality L.P. [Member] | Fixed Rate Debt [Member] | Fannie Mae credit facilities [Member]
Debt Instrument [Line Items]
Weighted average interest rate		4.90%
Debt Instrument Weighted Average Years to Maturity		3 years 9 months 25 days
Number of Communities Encumbered (in communities) | Communities		9
United Dominion Reality L.P. [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Principal outstanding	204,509	$ 204,509	219,760
Weighted average interest rate		1.74%
Debt Instrument Weighted Average Years to Maturity		6 years 10 months 17 days
Number of Communities Encumbered (in communities) | Communities		6
United Dominion Reality L.P. [Member] | Variable Rate Debt [Member] | Fannie Mae credit facilities [Member]
Debt Instrument [Line Items]
Weighted average interest rate		1.89%
Debt Instrument Weighted Average Years to Maturity		5 years 5 months 1 day
Number of Communities Encumbered (in communities) | Communities		5
United Dominion Reality L.P. [Member] | Variable Rate Debt [Member] | Tax Exempt Notes Payable [Member]
Debt Instrument [Line Items]
Principal outstanding	27,000	$ 27,000	27,000
Weighted average interest rate		0.76%
Debt Instrument Weighted Average Years to Maturity		16 years 5 months 19 days
Number of Communities Encumbered (in communities) | Communities		1
Fannie Mae credit facilities [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Fair Value, Measurements, Recurring [Member] | Fixed Rate Debt [Member] | Fannie Mae credit facilities [Member]
Debt Instrument [Line Items]
Principal outstanding	565,394	$ 565,394	568,086
Fannie Mae credit facilities [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Fair Value, Measurements, Recurring [Member] | Variable Rate Debt [Member] | Fannie Mae credit facilities [Member]
Debt Instrument [Line Items]
Principal outstanding	249,378	249,378	266,196
Fannie Mae credit facilities [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Fair Value, Measurements, Recurring [Member] | United Dominion Reality L.P. [Member] | Fixed Rate Debt [Member] | Fannie Mae credit facilities [Member]
Debt Instrument [Line Items]
Principal outstanding	333,912	333,912	333,828
Fannie Mae credit facilities [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Fair Value, Measurements, Recurring [Member] | United Dominion Reality L.P. [Member] | Variable Rate Debt [Member] | Fannie Mae credit facilities [Member]
Debt Instrument [Line Items]
Principal outstanding	$ 177,509	$ 177,509	$ 192,760

Debt (UNITED DOMINION REALTY,77

Debt (UNITED DOMINION REALTY, L.P.) (Details 1) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2013	Dec. 31, 2014
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	4 years 6 months 7 days
Borrowings outstanding	$ 2,300		$ 1,900
Fannie Mae [Member]
Debt Instrument [Line Items]
Borrowings outstanding	814,772		$ 834,282
Weighted average daily borrowings during the period ended	825,311	$ 835,873
Maximum daily borrowings during the period ended	$ 834,003	$ 837,564
Weighted average interest rate during the period ended	4.03%	4.10%
Interest rate at the end of the period	4.06%		4.00%
United Dominion Reality L.P. [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	3 years 3 months 18 days
United Dominion Reality L.P. [Member] | Fannie Mae [Member]
Debt Instrument [Line Items]
Borrowings outstanding	$ 511,421		$ 526,588
Weighted average daily borrowings during the period ended	518,036	$ 527,592
Maximum daily borrowings during the period ended	$ 523,492	$ 528,659
Weighted average interest rate during the period ended	3.80%	4.10%
Interest rate at the end of the period	3.90%		4.00%
Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	2 years 3 months 14 days
Fixed Rate Debt [Member] | Mortgages [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	10 months 20 days
Fixed Rate Debt [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	3 years 3 months 14 days
Fixed Rate Debt [Member] | United Dominion Reality L.P. [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	2 years 3 months 3 days
Fixed Rate Debt [Member] | United Dominion Reality L.P. [Member] | Mortgages [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	10 months 9 days
Fixed Rate Debt [Member] | United Dominion Reality L.P. [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	3 years 9 months 25 days
Variable Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	5 years
Variable Rate Debt [Member] | Mortgages [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	1 year 3 months 26 days
Variable Rate Debt [Member] | Tax Exempt Notes Payable [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	7 years 5 months 8 days
Variable Rate Debt [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	4 years 6 months 10 days
Variable Rate Debt [Member] | United Dominion Reality L.P. [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	6 years 10 months 17 days
Variable Rate Debt [Member] | United Dominion Reality L.P. [Member] | Tax Exempt Notes Payable [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	16 years 5 months 19 days
Variable Rate Debt [Member] | United Dominion Reality L.P. [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	5 years 5 months 1 day

Debt (UNITED DOMINION REALTY,78

Debt (UNITED DOMINION REALTY, L.P.) (Details 2) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
2,014	$ 187,941
2,015	242,625
2,016	384,219
2,017	857,965
2,018	313,571
Thereafter	1,526,913
Total	1,346,992	$ 1,361,529
United Dominion Reality L.P. [Member]
Debt Instrument [Line Items]
2,014	186,686
2,015	132,331
2,016	23,835
2,017	194,500
2,018	173,131
Thereafter	199,826
Total	910,309	$ 931,959
United Dominion Reality L.P. [Member] | Mortgages Notes Payable [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
2,014	186,592
2,015	131,946
2,016	1,629
2,017	1,685
2,018	50,036
Thereafter	0
Total	371,888
United Dominion Reality L.P. [Member] | Fannie Mae credit facilities [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
2,014	94
2,015	385
2,016	15,640
2,017	111,256
2,018	123,095
Thereafter	83,442
Total	333,912
United Dominion Reality L.P. [Member] | Fannie Mae credit facilities [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
2,014	0
2,015	0
2,016	6,566
2,017	81,559
2,018	0
Thereafter	89,384
Total	177,509
United Dominion Reality L.P. [Member] | Tax Exempt Notes Payable [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
2,014	0
2,015	0
2,016	0
2,017	0
2,018	0
Thereafter	27,000
Total	$ 27,000

Debt (UNITED DOMINION REALTY,79

Debt (UNITED DOMINION REALTY, L.P.) (Details Textual) - USD ($)	Jun. 27, 2014	Sep. 26, 2013	Sep. 30, 2015	Sep. 30, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Borrowings outstanding			$ 2,300,000	$ 2,300,000	$ 1,900,000
Weighted average interest rate			3.91%
Unamortized fair market adjustment			$ 4,400,000	4,400,000	6,700,000
UDR Bank Credit Facility [Member]
Debt Instrument [Line Items]
Total revolving credit facility			900,000,000	900,000,000	900,000,000
Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Secured debt including debt on real estate held for sale			$ 971,577,000	971,577,000	969,296,000
Weighted average interest rate			5.28%
Variable Rate Debt [Member]
Debt Instrument [Line Items]
Secured debt including debt on real estate held for sale			$ 375,415,000	375,415,000	392,233,000
Weighted average interest rate			1.45%
Fannie Mae [Member]
Debt Instrument [Line Items]
Borrowings outstanding			$ 814,772,000	$ 814,772,000	834,282,000
Fannie Mae credit facilities [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date Range, Start				May 1, 2017
Debt Instrument, Maturity Date Range, End				Jul. 1, 2023
Debt, Weighted Average Interest Rate			5.12%	5.12%
Fannie Mae credit facilities [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate at Period End			1.65%	1.65%
Mortgages [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date Range, Start				Dec. 9, 2015
Weighted average interest rate			5.51%
Notes payable minimum interest rates range				3.43%
Notes payable maximum interest rates range				6.16%
Debt Instrument, Maturity Date Range, End				May 1, 2019
Mortgages [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Weighted average interest rate			2.00%
Tax Exempt Notes Payable [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Weighted average interest rate			0.75%
Unsecured Revolving Credit Facility due October 2015 [Member]
Debt Instrument [Line Items]
Borrowings outstanding			$ 110,000,000	$ 110,000,000	152,500,000
Weighted average interest rate			1.19%
2.90% Term Notes due January 2016 [Member]
Debt Instrument [Line Items]
Weighted average interest rate				1.70%
Five Point Two Five Percent, Medium Term Notes, Due January 2016 [Member]
Debt Instrument [Line Items]
Weighted average interest rate				5.25%
4.25% Medium-Term Notes due June 2018 [Member]
Debt Instrument [Line Items]
Weighted average interest rate				4.25%
Unamortized fair market adjustment			$ 1,144,000	$ 1,144,000	1,465,000
Three point seven percent medium term note due October 2020 [Member]
Debt Instrument [Line Items]
Unamortized fair market adjustment			$ 40,000	$ 40,000	46,000
ThreePointSevenTermNotesDueOctober2020 [Member]
Debt Instrument [Line Items]
Weighted average interest rate				3.70%
Debt Instrument, Maturity Date		Oct. 31, 2020
4.63% Medium-Term Notes due January 2022 [Member]
Debt Instrument [Line Items]
Weighted average interest rate			4.63%
Unamortized fair market adjustment			$ 2,254,000	$ 2,254,000	2,523,000
3.75 MTN Due July 2024 [Member]
Debt Instrument [Line Items]
Weighted average interest rate			3.75%
Unamortized fair market adjustment			$ 912,000	912,000	990,000
Debt Instrument, Maturity Date	Jul. 1, 2024
4.00% MTN Due October 2025 [Member]
Debt Instrument [Line Items]
Weighted average interest rate			4.00%
Unamortized fair market adjustment			$ 688,000	$ 688,000	0
Debt Instrument, Maturity Date				Oct. 1, 2025
United Dominion Reality L.P. [Member]
Debt Instrument [Line Items]
Debt Instrument, Unamortized Premium			3,300,000	$ 3,300,000	6,200,000
Secured debt including debt on real estate held for sale			910,309,000	$ 910,309,000	931,959,000
Weighted average interest rate				4.44%
United Dominion Reality L.P. [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Secured debt including debt on real estate held for sale			705,800,000	$ 705,800,000	712,199,000
Weighted average interest rate				5.22%
United Dominion Reality L.P. [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Secured debt including debt on real estate held for sale			204,509,000	$ 204,509,000	219,760,000
Weighted average interest rate				1.74%
United Dominion Reality L.P. [Member] | Fannie Mae [Member]
Debt Instrument [Line Items]
Borrowings outstanding			511,421,000	$ 511,421,000	526,588,000
United Dominion Reality L.P. [Member] | Fannie Mae credit facilities [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Weighted average interest rate				4.90%
United Dominion Reality L.P. [Member] | Fannie Mae credit facilities [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Weighted average interest rate				1.89%
United Dominion Reality L.P. [Member] | Mortgages [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Secured debt including debt on real estate held for sale			371,888,000	$ 371,888,000	378,371,000
Weighted average interest rate				5.50%
Notes payable maximum interest rates range				5.94%
United Dominion Reality L.P. [Member] | Tax Exempt Notes Payable [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Secured debt including debt on real estate held for sale			27,000,000	$ 27,000,000	27,000,000
Weighted average interest rate				0.76%
Debt Instrument, Maturity Date Range, End				Mar. 1, 2032
United Dominion Reality L.P. [Member] | 2.90% Term Notes due January 2016 [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date Range, End				Jun. 1, 2018
United Dominion Reality L.P. [Member] | 2.90% Term Notes due January 2016 [Member] | Financial Guarantee [Member]
Debt Instrument [Line Items]
Guarantor borrowing capacity			250,000,000	$ 250,000,000
United Dominion Reality L.P. [Member] | 1.68% Term Notes due December 2016 [Member] | Financial Guarantee [Member]
Debt Instrument [Line Items]
Guarantor borrowing capacity			100,000,000	$ 100,000,000
United Dominion Reality L.P. [Member] | Five Point Two Five Percent, Medium Term Notes, Due January 2016 [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date Range, End				Jun. 1, 2018
United Dominion Reality L.P. [Member] | 4.25% Medium-Term Notes due June 2018 [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date Range, End				Jun. 1, 2018
United Dominion Reality L.P. [Member] | 4.25% Medium-Term Notes due June 2018 [Member] | Financial Guarantee [Member]
Debt Instrument [Line Items]
Guarantor borrowing capacity			300,000,000	$ 300,000,000
United Dominion Reality L.P. [Member] | Three point seven percent medium term note due October 2020 [Member] | Financial Guarantee [Member]
Debt Instrument [Line Items]
Guarantor borrowing capacity			300,000,000	$ 300,000,000
United Dominion Reality L.P. [Member] | 4.63% Medium-Term Notes due January 2022 [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date Range, End				Jan. 1, 2022
United Dominion Reality L.P. [Member] | 4.63% Medium-Term Notes due January 2022 [Member] | Financial Guarantee [Member]
Debt Instrument [Line Items]
Guarantor borrowing capacity			400,000,000	$ 400,000,000
United Dominion Reality L.P. [Member] | 3.75 MTN Due July 2024 [Member] | Financial Guarantee [Member]
Debt Instrument [Line Items]
Guarantor borrowing capacity			300,000,000	300,000,000
United Dominion Reality L.P. [Member] | 4.00% MTN Due October 2025 [Member] | Financial Guarantee [Member]
Debt Instrument [Line Items]
Guarantor borrowing capacity			300,000,000	300,000,000
Mortgages [Member] | Fair Value, Measurements, Recurring [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Mortgages [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Secured debt including debt on real estate held for sale			406,183,000	406,183,000	401,210,000
Mortgages [Member] | Fair Value, Measurements, Recurring [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Mortgages [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Secured debt including debt on real estate held for sale			31,337,000	31,337,000	31,337,000
Mortgages [Member] | Fair Value, Measurements, Recurring [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member]
Debt Instrument [Line Items]
Fixed Rate Secured Debt Instruments Fair Value			371,888,000	371,888,000	378,371,000
Fannie Mae credit facilities [Member] | Fair Value, Measurements, Recurring [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Fannie Mae credit facilities [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Secured debt including debt on real estate held for sale			565,394,000	565,394,000	568,086,000
Fannie Mae credit facilities [Member] | Fair Value, Measurements, Recurring [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Fannie Mae credit facilities [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Secured debt including debt on real estate held for sale			249,378,000	249,378,000	266,196,000
Fannie Mae credit facilities [Member] | Fair Value, Measurements, Recurring [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member]
Debt Instrument [Line Items]
Variable Rate Secured Debt Instruments Fair Value			177,509,000	177,509,000	192,760,000
Fixed Rate Secured Debt Instruments Fair Value			333,912,000	333,912,000	333,828,000
Fannie Mae credit facilities [Member] | Fair Value, Measurements, Recurring [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Fannie Mae credit facilities [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Secured debt including debt on real estate held for sale			333,912,000	333,912,000	333,828,000
Fannie Mae credit facilities [Member] | Fair Value, Measurements, Recurring [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Fannie Mae credit facilities [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Secured debt including debt on real estate held for sale			$ 177,509,000	$ 177,509,000	$ 192,760,000

Income_(Loss) Per Share (Detail

Income/(Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Income/(loss) from continuing operations	$ 13,695	$ 10,611	$ 100,954	$ 9,775
Gains/(loss) on sales of real estate owned, net of tax	0	31,302	79,042	82,305
Net Income (Loss) Attributable to Noncontrolling Interest	(1)	(4)	6	2
Income/(loss) from continuing operations attributable to UDR, Inc.	13,291	40,476	173,968	88,911
Distributions to preferred stockholders - Series E (Convertible)	(930)	(931)	(2,792)	(2,793)
Income/(loss) from continuing operations operations attributable to common stockholders	12,361	39,545	171,176	86,118
Income/(loss) from discontinued operations, net of tax	0	79	0	10
(Income)/loss from discontinued operations attributable to redeemable noncontrolling interest in the Operating Partnership	0	(6)	0	(4)
Income/(loss) from discontinued operations attributable to common stockholders	0	73	0	6
Net income/(loss)	13,695	41,992	179,996	92,090
Net (income)/loss attributable to noncontrolling interests			(6)
Net (income)/loss attributable to redeemable non-controlling interests in Operating Partnership	405	1,447	6,022	3,171
Net (loss)/income attributable to common stockholders	$ 12,361	$ 39,618	$ 171,176	$ 86,124
Denominator for earnings per share - basic and diluted:
Weighted average common shares outstanding	260,302	252,891	259,151	251,860
Incremental Common Shares Attributable to Participating Nonvested Shares with Non-forfeitable Dividend Rights	(1,188)	(1,236)	(1,211)	(1,159)
Weighted average number of common shares outstanding — basic	259,114	251,655	257,940	250,701
Incremental shares issuable for assumed conversion of: Stock options and unvested restricted stock	(2,093)	(2,077)	(2,080)	(1,974)
Weighted average number of common shares outstanding — diluted	261,207	253,732	260,020	252,675
Income/(loss) from continuing operations attributable to common stockholders	$ 0.05	$ 0.16	$ 0.66	$ 0.34
Net income/(loss) attributable to common stockholders	0.05	0.16	0.66	0.34
Income/(loss) from discontinued operations attributable to common stockholders,	0	0	0	0
Income/(loss) from continuing operations attributable to common stockholders,	0.05	0.16	0.66	0.34
Income from discontinued operations attributable to common stockholders	0	0	0	0
Net income/(loss) attributable to common stockholders	$ 0.05	$ 0.16	$ 0.66	$ 0.34
OP Units [Member]
Denominator for earnings per share - basic and diluted:
Antidilutive securities	9,061	9,189	9,117		9,274
Convertible Preferred Stock [Member]
Denominator for earnings per share - basic and diluted:
Antidilutive securities	3,029	3,036	3,033		3,036
Stock options and unvested restricted stock [Member]
Denominator for earnings per share - basic and diluted:
Antidilutive securities	2,093	2,077	2,080		1,974
RedeemableNoncontrollingInterest [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
(Income)/loss from continuing operations attributable to noncontrolling interest	$ (405)	$ (1,441)	$ (6,022)	$ (3,167)

Noncontrolling Interests (Detai

Noncontrolling Interests (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Noncontrolling Interest [Line Items]
Net Income (Loss) Attributable to Noncontrolling Interest	$ (1)	$ (4)	$ 6	$ 2
Redeemable noncontrolling interests in the Operating Partnership	312,158		312,158		$ 282,480
Net Income (Loss) Available to Common Stockholders, Basic	12,361	39,618	171,176	86,124
Change in equity from net income(loss) attributable to common stockholders and conversion of OP Units to UDR Common Stock	12,681	43,745	174,994	90,442
Redeemable noncontrolling interests in the Operating Partnership
Mark to market adjustment to redeemable noncontrolling interests in the Operating Partnership			35,508
Adjustment for conversion of noncontrolling interest of unitholders in Operating Partnership	(320)	(4,127)	(3,818)	(4,318)
Net (income)/loss attributable to redeemable non-controlling interests in Operating Partnership	405	$ 1,447	6,022	$ 3,171
Distributions to redeemable noncontrolling interests in the Operating Partnership			7,859
Redeemable non-controlling interests in operating partnership	$ 312,158		312,158
Net income attributable to non-controlling interests			$ 6

Related Party Transactions (U82

Related Party Transactions (UNITED DOMINION REALTY, L.P.) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Related Party Transaction [Line Items]
Related party management fees	$ 4,700	$ 3,200	$ 13,300	$ 9,400
United Dominion Reality L.P. [Member]
Related Party Transaction [Line Items]
Limited partnership units owned	183,167,815		183,167,815		183,167,815
Net receivable balances from General Partner	$ 10,162		$ 10,162		$ 13,624
Related Party Transaction, Management Fee Percentage			2.75%
Interest Expense, Related Party	1,151	1,151	$ 3,452	3,453
Notes payable due to General Partner	88,696		88,696		88,696
United Dominion Reality L.P. [Member] | Taxable REIT Subsidiaries [Member]
Related Party Transaction [Line Items]
Net receivable balances from General Partner	(10,162)		$ (10,162)		(13,624)
Related Party Transaction, Management Fee Percentage			2.75%
United Dominion Reality L.P. [Member] | UDR, Inc. [Member]
Related Party Transaction [Line Items]
General and administrative expenses allocated to the Operating Partnership by UDR	$ 6,500	$ 6,600	$ 16,300	$ 20,500
United Dominion Reality L.P. [Member] | UDR, Inc. [Member] | Bottom Dollar Guaranty [Member]
Related Party Transaction [Line Items]
Notes payable due to General Partner					$ 88,700
Note for 83.2 million [Member] | United Dominion Reality L.P. [Member] | UDR, Inc. [Member] | Guaranty Related To Community Acquisition [Member]
Related Party Transaction [Line Items]
Related party guaranty note payable interest rate	5.18%		5.18%
Debt Instrument, Maturity Date Range, End			Aug. 31, 2021
Note for 5 million [Member] | United Dominion Reality L.P. [Member] | UDR, Inc. [Member] | Guaranty Related To Community Acquisition [Member]
Related Party Transaction [Line Items]
Related party guaranty note payable interest rate	5.34%		5.34%
Debt Instrument, Maturity Date Range, End			Dec. 31, 2023

Fair Value of Derivatives and83

Fair Value of Derivatives and Financial Instruments (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes receivable, net	$ 15,494	$ 14,369
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net	0
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Derivative Asset	6	88
Derivative Liability	3,205	10,368
Secured debt instruments - variable rate
Borrowings outstanding	2,300	1,900
Unsecured debt instruments
Redeemable Noncontrolling Interest, Equity, Carrying Amount	312,158
Redeemable noncontrolling interests in the Operating Partnership (d)	312,158	282,480
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes receivable, net	15,494	14,369
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Total assets	15,500	14,457
Unsecured debt instruments
Total liabilities	3,516,439	3,593,473
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Senior Unsecured Notes [Member] | Fair Value, Measurements, Recurring [Member]
Unsecured debt instruments
Unsecured debt instruments (c)	2,056,242	2,069,076
Estimate of Fair Value, Fair Value Disclosure [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Notes receivable (a)	15,795	14,808
Total assets	15,801	14,896
Unsecured debt instruments
Total liabilities	3,629,715	3,721,512
Redeemable noncontrolling interests in the Operating Partnership (d)	312,158	282,480
Estimate of Fair Value, Fair Value Disclosure [Member] | Interest Rate Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Derivatives - Interest rate contracts	6	88
Derivatives - Interest rate contracts (b)	3,205	10,368
Estimate of Fair Value, Fair Value Disclosure [Member] | Mortgages Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	416,287	415,663
Secured debt instruments - variable rate
Secured debt instruments - variable rate	31,337	31,337
Estimate of Fair Value, Fair Value Disclosure [Member] | Tax Exempt Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - variable rate
Secured debt instruments - variable rate	94,700	94,700
Estimate of Fair Value, Fair Value Disclosure [Member] | Line of Credit [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	595,907	606,623
Secured debt instruments - variable rate
Secured debt instruments - variable rate	249,378	266,196
Unsecured debt instruments
Unsecured debt instruments (c)	110,000	152,500
Estimate of Fair Value, Fair Value Disclosure [Member] | Senior Unsecured Notes [Member] | Fair Value, Measurements, Recurring [Member]
Unsecured debt instruments
Unsecured debt instruments (c)	2,128,901	2,144,125
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Notes receivable (a)	0	0
Total assets	0	0
Unsecured debt instruments
Total liabilities	0	0
Redeemable noncontrolling interests in the Operating Partnership (d)	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 1 [Member] | Interest Rate Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Derivatives - Interest rate contracts	0	0
Derivatives - Interest rate contracts (b)	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 1 [Member] | Mortgages Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	0	0
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 1 [Member] | Tax Exempt Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 1 [Member] | Line of Credit [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	0	0
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 1 [Member] | Commercial bank [Member] | Fair Value, Measurements, Recurring [Member]
Unsecured debt instruments
Unsecured debt instruments (c)	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 1 [Member] | Senior Unsecured Notes [Member] | Fair Value, Measurements, Recurring [Member]
Unsecured debt instruments
Unsecured debt instruments (c)	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 2 [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Notes receivable (a)	0	0
Total assets	6	88
Unsecured debt instruments
Total liabilities	3,205	10,368
Redeemable noncontrolling interests in the Operating Partnership (d)	312,158	282,480
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 2 [Member] | Interest Rate Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Derivatives - Interest rate contracts	6	88
Derivatives - Interest rate contracts (b)	3,205	10,368
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 2 [Member] | Mortgages Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	0	0
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 2 [Member] | Tax Exempt Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 2 [Member] | Line of Credit [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	0	0
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 2 [Member] | Commercial bank [Member] | Fair Value, Measurements, Recurring [Member]
Unsecured debt instruments
Unsecured debt instruments (c)	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 2 [Member] | Senior Unsecured Notes [Member] | Fair Value, Measurements, Recurring [Member]
Unsecured debt instruments
Unsecured debt instruments (c)	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Notes receivable (a)	15,795	14,808
Total assets	15,795	14,808
Unsecured debt instruments
Total liabilities	3,626,510	3,711,144
Redeemable noncontrolling interests in the Operating Partnership (d)	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 3 [Member] | Interest Rate Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Derivatives - Interest rate contracts	0	0
Derivatives - Interest rate contracts (b)	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 3 [Member] | Mortgages Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	416,287	415,663
Secured debt instruments - variable rate
Secured debt instruments - variable rate	31,337	31,337
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 3 [Member] | Tax Exempt Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - variable rate
Secured debt instruments - variable rate	94,700	94,700
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 3 [Member] | Line of Credit [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	595,907	606,623
Secured debt instruments - variable rate
Secured debt instruments - variable rate	249,378	266,196
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 3 [Member] | Commercial bank [Member] | Fair Value, Measurements, Recurring [Member]
Unsecured debt instruments
Unsecured debt instruments (c)	110,000	152,500
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 3 [Member] | Senior Unsecured Notes [Member] | Fair Value, Measurements, Recurring [Member]
Unsecured debt instruments
Unsecured debt instruments (c)	2,128,901	2,144,125
Unsecured Revolving Credit Facility due October 2015 [Member]
Secured debt instruments - variable rate
Borrowings outstanding	110,000	152,500
Variable Rate Debt [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Secured debt including debt on real estate held for sale	375,415	392,233
Variable Rate Debt [Member] | Tax Exempt Notes Payable [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Tax Exempt Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Secured debt including debt on real estate held for sale	94,700	94,700
Variable Rate Debt [Member] | Line of Credit [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Line of Credit [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Secured debt including debt on real estate held for sale	249,378	266,196
Variable Rate Debt [Member] | Mortgages Notes Payable [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Mortgages Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Secured debt including debt on real estate held for sale	31,337	31,337
Fixed Rate Debt [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Secured debt including debt on real estate held for sale	971,577	969,296
Fixed Rate Debt [Member] | Line of Credit [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Line of Credit [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Secured debt including debt on real estate held for sale	565,394	568,086
Fixed Rate Debt [Member] | Mortgages Notes Payable [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Mortgages Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Secured debt including debt on real estate held for sale	$ 406,183	$ 401,210

Fair Value of Derivatives and84

Fair Value of Derivatives and Financial Instruments (UNITED DOMINION REALTY, L.P.) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Total assets	$ 15,500	$ 14,457
Secured debt instruments - variable rate
Total liabilities	3,516,439	3,593,473
Carrying (Reported) Amount, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Total assets	4	39
Secured debt instruments - variable rate
Total liabilities	910,484	932,877
Carrying (Reported) Amount, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Interest Rate Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Derivatives - Interest rate contracts	4	39
Derivative Liability Designated as Hedging Instrument, Fair Value	175	918
Carrying (Reported) Amount, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Mortgages Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	371,888	378,371
Carrying (Reported) Amount, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Tax Exempt Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - variable rate
Secured debt instruments - variable rate	27,000	27,000
Carrying (Reported) Amount, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Line of Credit [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	333,912	333,828
Secured debt instruments - variable rate
Secured debt instruments - variable rate	177,509	192,760
United Dominion Reality L.P. [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Derivatives - Interest rate contracts	4	39
Derivative Liability Designated as Hedging Instrument, Fair Value	175	918
Estimate of Fair Value, Fair Value Disclosure [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Total assets	15,801	14,896
Secured debt instruments - variable rate
Total liabilities	3,629,715	3,721,512
Estimate of Fair Value, Fair Value Disclosure [Member] | Interest Rate Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Derivatives - Interest rate contracts	6	88
Derivative Liability Designated as Hedging Instrument, Fair Value	3,205	10,368
Estimate of Fair Value, Fair Value Disclosure [Member] | Mortgages Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	416,287	415,663
Secured debt instruments - variable rate
Secured debt instruments - variable rate	31,337	31,337
Estimate of Fair Value, Fair Value Disclosure [Member] | Tax Exempt Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - variable rate
Secured debt instruments - variable rate	94,700	94,700
Estimate of Fair Value, Fair Value Disclosure [Member] | Line of Credit [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	595,907	606,623
Secured debt instruments - variable rate
Secured debt instruments - variable rate	249,378	266,196
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Total assets	0	0
Secured debt instruments - variable rate
Total liabilities	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 1 [Member] | Interest Rate Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Derivatives - Interest rate contracts	0	0
Derivative Liability Designated as Hedging Instrument, Fair Value	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 1 [Member] | Mortgages Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	0	0
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 1 [Member] | Tax Exempt Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 1 [Member] | Line of Credit [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	0	0
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 2 [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Total assets	6	88
Secured debt instruments - variable rate
Total liabilities	3,205	10,368
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 2 [Member] | Interest Rate Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Derivatives - Interest rate contracts	6	88
Derivative Liability Designated as Hedging Instrument, Fair Value	3,205	10,368
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 2 [Member] | Mortgages Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	0	0
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 2 [Member] | Tax Exempt Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 2 [Member] | Line of Credit [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	0	0
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Total assets	15,795	14,808
Secured debt instruments - variable rate
Total liabilities	3,626,510	3,711,144
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 3 [Member] | Interest Rate Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Derivatives - Interest rate contracts	0	0
Derivative Liability Designated as Hedging Instrument, Fair Value	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 3 [Member] | Mortgages Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	416,287	415,663
Secured debt instruments - variable rate
Secured debt instruments - variable rate	31,337	31,337
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 3 [Member] | Tax Exempt Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - variable rate
Secured debt instruments - variable rate	94,700	94,700
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 3 [Member] | Line of Credit [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	595,907	606,623
Secured debt instruments - variable rate
Secured debt instruments - variable rate	249,378	266,196
Estimate of Fair Value, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Total assets	4	39
Secured debt instruments - variable rate
Total liabilities	937,956	967,983
Estimate of Fair Value, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Interest Rate Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Derivatives - Interest rate contracts	4	39
Derivative Liability Designated as Hedging Instrument, Fair Value	175	918
Estimate of Fair Value, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Mortgages Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	380,820	391,835
Estimate of Fair Value, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Tax Exempt Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - variable rate
Secured debt instruments - variable rate	27,000	27,000
Estimate of Fair Value, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Line of Credit [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	352,452	355,470
Secured debt instruments - variable rate
Secured debt instruments - variable rate	177,509	192,760
Estimate of Fair Value, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Total assets	0	0
Secured debt instruments - variable rate
Total liabilities	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Level 1 [Member] | Interest Rate Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Derivatives - Interest rate contracts	0	0
Derivative Liability Designated as Hedging Instrument, Fair Value	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Level 1 [Member] | Mortgages Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Level 1 [Member] | Tax Exempt Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Level 1 [Member] | Line of Credit [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	0	0
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Level 2 [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Total assets	4	39
Secured debt instruments - variable rate
Total liabilities	175	918
Estimate of Fair Value, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Level 2 [Member] | Interest Rate Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Derivatives - Interest rate contracts	4	39
Derivative Liability Designated as Hedging Instrument, Fair Value	175	918
Estimate of Fair Value, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Level 2 [Member] | Mortgages Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Level 2 [Member] | Tax Exempt Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Level 2 [Member] | Line of Credit [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	0	0
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Total assets	0	0
Secured debt instruments - variable rate
Total liabilities	937,781	967,065
Estimate of Fair Value, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Level 3 [Member] | Interest Rate Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Derivatives - Interest rate contracts	0	0
Derivative Liability Designated as Hedging Instrument, Fair Value	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Level 3 [Member] | Mortgages Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	380,820	391,835
Estimate of Fair Value, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Level 3 [Member] | Tax Exempt Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - variable rate
Secured debt instruments - variable rate	27,000	27,000
Estimate of Fair Value, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Level 3 [Member] | Line of Credit [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	352,452	355,470
Secured debt instruments - variable rate
Secured debt instruments - variable rate	$ 177,509	$ 192,760

Derivatives and Hedging Activ85

Derivatives and Hedging Activity (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2015USD ($)instruments	Sep. 30, 2014
Derivative [Line Items]
Ineffectiveness on Interest Rate Fair Value Hedges is Immaterial	0	0	3
Designated as Hedging Instrument [Member] | Interest rate swaps [Member]
Derivative [Line Items]
Number instruments		6
Notional		$ 365,000
Designated as Hedging Instrument [Member] | Interest rate caps [Member]
Derivative [Line Items]
Number instruments		2
Notional		$ 203,166
Not Designated as Hedging Instrument [Member] | Interest rate caps [Member]
Derivative [Line Items]
Number instruments | instruments		3
Notional		$ 133,107

Derivatives and Hedging Activ86

Derivatives and Hedging Activity (Details 1) $ in Thousands	Sep. 30, 2015USD ($)instruments	Dec. 31, 2014USD ($)
Interest Rate Products [Member] | Other Assets [Member] | Designated as Hedging Instrument [Member]
Fair value of Company's derivative financial instruments and their classification on Consolidated Balance Sheet
Derivative Asset Designated as Hedging Instrument, Fair Value	$ 4	$ 86
Interest Rate Products [Member] | Other Assets [Member] | Not Designated as Hedging Instrument [Member]
Fair value of Company's derivative financial instruments and their classification on Consolidated Balance Sheet
Derivative Asset Not Designated as Hedging Instrument, Fair Value	2	2
Interest Rate Products [Member] | Other Liabilities [Member] | Designated as Hedging Instrument [Member]
Fair value of Company's derivative financial instruments and their classification on Consolidated Balance Sheet
Derivative Liability Designated as Hedging Instrument, Fair Value	3,205	10,368
Interest Rate Products [Member] | Other Liabilities [Member] | Not Designated as Hedging Instrument [Member]
Fair value of Company's derivative financial instruments and their classification on Consolidated Balance Sheet
Derivative Liability Not Designated as Hedging Instrument, Fair Value	$ 0	$ 0
Interest rate caps [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Number of Interest Rate Derivatives Held	2
Fair value of Company's derivative financial instruments and their classification on Consolidated Balance Sheet
Notional	$ 203,166
Interest rate caps [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Number of Interest Rate Derivatives Held | instruments	3
Fair value of Company's derivative financial instruments and their classification on Consolidated Balance Sheet
Notional	$ 133,107

Derivatives and Hedging Activ87

Derivatives and Hedging Activity (Details 2) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Effect of derivative instruments on the Consolidated Statements of Operations
Unrealized holding gain/(loss)	$ (5,707)	$ 362	$ (7,072)	$ 611
Amount of Gain or (Loss) Recognized in Income on Derivative	(1)	0	(25)	0
Interest Rate Products [Member] | Interest Expense [Member] | Cash Flow Hedging [Member]
Effect of derivative instruments on the Consolidated Statements of Operations
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	(525)	(1,130)	(1,554)	(3,809)
Amount of Gain or (Loss) Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness Testing)	$ (11)	$ 0	$ (11)	$ 3

Derivatives and Hedging Activ88

Derivatives and Hedging Activity (Details 3) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Offsetting Derivative Assets [Abstract]
Gross Amounts Offset in the Consolidated Balance Sheets	$ 0	$ 0
Net Amounts of Assets Presented in the Consolidated Balance Sheets (a)	6	88
Gross Amounts Not Offset in the Consolidated Balance Sheets, Financial Instruments	0	(27)
Gross Amounts Not Offset in the Consolidated Balance Sheets, Cash Collateral Received	0	0
Net Amount	6	61
Offsetting Derivative Liabilities [Abstract]
Gross Amounts Offset in the Consolidated Balance Sheets	0	0
Net Amounts of Liabilities Presented in the Consolidated Balance Sheets (b)	3,205	10,368
Gross Amounts Not Offset in the Consolidated Balance Sheets, Financial Instruments	0	(27)
Gross Amounts Not Offset in the Consolidated Balance Sheets, Cash Collateral Received	0	0
Net Amount	$ 3,205	$ 10,341

Derivatives and Hedging Activ89

Derivatives and Hedging Activity (Details Textual) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Derivative, Collateral, Obligation to Return Cash	$ 0		$ 0		$ 0
Derivatives And Hedging Activity (Textual) [Abstract]
Estimated additional accumulated other comprehensive Income/(Loss) transferred to interest expense	3,500,000		3,500,000
Derivative instruments not designated as hedging instruments, gain (loss), net	(1,000)	$ 0	(25,000)	$ 0
Payment required to pay for contract termination	3,400,000		3,400,000
Other Income Expense [Member] | Interest Rate Contracts [Member]
Derivatives And Hedging Activity (Textual) [Abstract]
Derivative instruments not designated as hedging instruments, gain (loss), net	(1,000)	0	(25,000)	0
Cash Flow Hedging [Member] | Interest Expense [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net	$ (11,000)	$ 0	$ (11,000)	$ 3,000

Derivatives and Hedging Activ90

Derivatives and Hedging Activity (UNITED DOMINION REALTY, L.P.) (Details) $ in Thousands	Sep. 30, 2015USD ($)instruments
Designated as Hedging Instrument [Member] | Interest rate swaps [Member]
Derivative [Line Items]
Number instruments	6
Outstanding interest rate derivatives not designated as hedging instrument
Notional	$ 365,000
Designated as Hedging Instrument [Member] | Interest rate caps [Member]
Derivative [Line Items]
Number instruments	2
Outstanding interest rate derivatives not designated as hedging instrument
Notional	$ 203,166
Not Designated as Hedging Instrument [Member] | Interest rate caps [Member]
Derivative [Line Items]
Number instruments | instruments	3
Outstanding interest rate derivatives not designated as hedging instrument
Notional	$ 133,107
United Dominion Reality L.P. [Member] | Designated as Hedging Instrument [Member] | Interest rate swaps [Member]
Derivative [Line Items]
Number instruments	1
Outstanding interest rate derivatives not designated as hedging instrument
Notional	$ 46,357
United Dominion Reality L.P. [Member] | Designated as Hedging Instrument [Member] | Interest rate caps [Member]
Derivative [Line Items]
Number instruments	1
Outstanding interest rate derivatives not designated as hedging instrument
Notional	$ 127,916
United Dominion Reality L.P. [Member] | Not Designated as Hedging Instrument [Member] | Interest rate caps [Member]
Derivative [Line Items]
Number instruments | instruments	3
Outstanding interest rate derivatives not designated as hedging instrument
Notional	$ 124,856

Derivatives and Hedging Activ91

Derivatives and Hedging Activity (UNITED DOMINION REALTY, L.P.) (Details 1) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Interest Rate Products [Member] | Other Assets [Member] | Designated as Hedging Instrument [Member]
Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract]
Derivative Asset Designated as Hedging Instrument, Fair Value	$ 4	$ 86
Interest Rate Products [Member] | Other Assets [Member] | Not Designated as Hedging Instrument [Member]
Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract]
Derivative Asset Not Designated as Hedging Instrument, Fair Value	2	2
Interest Rate Products [Member] | Other Liabilities [Member] | Designated as Hedging Instrument [Member]
Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract]
Derivative Liability Designated as Hedging Instrument, Fair Value	3,205	10,368
Interest Rate Products [Member] | Other Liabilities [Member] | Not Designated as Hedging Instrument [Member]
Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract]
Derivative Liability Not Designated as Hedging Instrument, Fair Value	0	0
United Dominion Reality L.P. [Member]
Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract]
Derivative Asset Designated as Hedging Instrument, Fair Value	4	39
Derivative Liability Designated as Hedging Instrument, Fair Value	175	918
United Dominion Reality L.P. [Member] | Interest Rate Products [Member] | Other Assets [Member] | Designated as Hedging Instrument [Member]
Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract]
Derivative Asset Designated as Hedging Instrument, Fair Value	2	37
United Dominion Reality L.P. [Member] | Interest Rate Products [Member] | Other Assets [Member] | Not Designated as Hedging Instrument [Member]
Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract]
Derivative Asset Not Designated as Hedging Instrument, Fair Value	2	2
United Dominion Reality L.P. [Member] | Interest Rate Products [Member] | Other Liabilities [Member] | Designated as Hedging Instrument [Member]
Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract]
Derivative Liability Designated as Hedging Instrument, Fair Value	175	918
United Dominion Reality L.P. [Member] | Interest Rate Products [Member] | Other Liabilities [Member] | Not Designated as Hedging Instrument [Member]
Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract]
Derivative Liability Not Designated as Hedging Instrument, Fair Value	$ 0	$ 0

Derivatives and Hedging Activ92

Derivatives and Hedging Activity (UNITED DOMINION REALTY, L.P.) (Details 2) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized holding gain/(loss)	$ (5,707,000)	$ 362,000	$ (7,072,000)	$ 611,000
Amount of Gain or (Loss) Recognized in Income on Derivative	(1,000)	0	(25,000)	0
Interest Rate Products [Member] | Other Income Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Income on Derivative	(1,000)	0	(25,000)	0
Interest Rate Products [Member] | Interest Expense [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	(525,000)	(1,130,000)	(1,554,000)	(3,809,000)
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net	(11,000)	0	(11,000)	3,000
United Dominion Reality L.P. [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized holding gain/(loss)	(8,000)	(3,000)	(85,000)	(194,000)
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	278,000	588,000	831,000	1,784,000
Amount of Gain or (Loss) Recognized in Income on Derivative	(1,000)	0	(24,000)
United Dominion Reality L.P. [Member] | Interest Rate Products [Member] | Other Income Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Income on Derivative					$ 0
United Dominion Reality L.P. [Member] | Interest Rate Products [Member] | Interest Expense [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	(267,000)	(588,000)	(820,000)		$ (1,784,000)
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net	$ (11,000)	$ 0	$ (11,000)	$ 0

Derivatives and Hedging Activ93

Derivatives and Hedging Activity (UNITED DOMINION REALTY, L.P.) (Details 3) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Offsetting Derivative Assets [Abstract]
Gross Amounts Offset in the Consolidated Balance Sheets	$ 0	$ 0
Net Amounts of Assets Presented in the Consolidated Balance Sheets (a)	6	88
Gross Amounts Not Offset in the Consolidated Balance Sheets, Financial Instruments	0	27
Gross Amounts Not Offset in the Consolidated Balance Sheets, Cash Collateral Received	0	0
Net Amount	6	61
Offsetting Derivative Liabilities [Abstract]
Gross Amounts Offset in the Consolidated Balance Sheets	0	0
Net Amounts of Liabilities Presented in the Consolidated Balance Sheets (b)	3,205	10,368
Gross Amounts Not Offset in the Consolidated Balance Sheets, Financial Instruments	0	27
Gross Amounts Not Offset in the Consolidated Balance Sheets, Cash Collateral Received	0	0
Net Amount	3,205	10,341
United Dominion Reality L.P. [Member]
Offsetting Derivative Assets [Abstract]
Derivative Asset Designated as Hedging Instrument, Fair Value	4	39
Gross Amounts Offset in the Consolidated Balance Sheets	0	0
Net Amounts of Assets Presented in the Consolidated Balance Sheets (a)	4	39
Gross Amounts Not Offset in the Consolidated Balance Sheets, Financial Instruments	0	0
Gross Amounts Not Offset in the Consolidated Balance Sheets, Cash Collateral Received	0	0
Net Amount	4	39
Offsetting Derivative Liabilities [Abstract]
Derivative Liability Designated as Hedging Instrument, Fair Value	175	918
Gross Amounts Offset in the Consolidated Balance Sheets	0	0
Net Amounts of Liabilities Presented in the Consolidated Balance Sheets (b)	175	918
Gross Amounts Not Offset in the Consolidated Balance Sheets, Financial Instruments	0	0
Gross Amounts Not Offset in the Consolidated Balance Sheets, Cash Collateral Received	0	0
Net Amount	$ 175	$ 918

Derivatives and Hedging Activ94

Derivatives and Hedging Activity (UNITED DOMINION REALTY, L.P.) (Details Textual) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Entity Information [Line Items]
Cash flow hedge ineffectiveness in earnings materiality		0	0	3
Estimated additional accumulated other comprehensive Income/(Loss) transferred to interest expense	$ 3,500,000		$ 3,500,000
Losses in the fair value of derivatives not designated in hedging relationships	1,000	$ 0	25,000	$ 0
Payment required to pay for contract termination	3,400,000		3,400,000
Derivative, Collateral, Obligation to Return Cash	$ 0		$ 0		$ 0
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
Cash flow hedge ineffectiveness in earnings materiality	0	0	0	0
Estimated additional accumulated other comprehensive Income/(Loss) transferred to interest expense	$ 200,000		$ 200,000
Losses in the fair value of derivatives not designated in hedging relationships	1,000	$ 0	24,000
Fair value of derivatives in a net liability position	200,000		200,000
Derivative, Collateral, Obligation to Return Cash	$ 0		$ 0		$ 0

Stock Based Compensation (Detai

Stock Based Compensation (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Stock Based Compensation (Textual) [Abstract]
Stock based compensation expense	$ 4.4	$ 3.3	$ 13.5	$ 10.2

Capital Structure (UNITED DOM96

Capital Structure (UNITED DOMINION REALTY, L.P.) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2015USD ($)$ / Unitsshares	Dec. 31, 2014USD ($)shares
Limited Partners' Capital Account [Line Items]
Redeemable Noncontrolling Interest, Equity, Carrying Amount | $	$ 312,158
Percentage of units	4.90%
Redeemable noncontrolling interests in the Operating Partnership | $	$ 312,158	$ 282,480
United Dominion Reality L.P. [Member]
Limited Partners' Capital Account [Line Items]
General Partnership units outstanding	110,883	110,883
Limited partnership units owned	183,167,815	183,167,815
Limited Partners' Capital Account, Required Period To Be Outstanding Before Unit is Redeemable	1 year
UDR, Inc. [Member]
Limited Partners' Capital Account [Line Items]
Limited partnership units owned	174,114,516	174,002,342
Percentage of units	95.10%	95.00%
Non-affiliated Partners [Member]
Limited Partners' Capital Account [Line Items]
Limited partnership units owned	9,053,299	9,165,473
Percentage of units	4.90%	5.00%
Class A Limited Partner [Member]
Limited Partners' Capital Account [Line Items]
Limited partnership units owned	1,751,671	1,751,671
Cumulative, annual, non-compounded preferred return on Class A Partnership units	8.00%
Value of Class A Partnership units (in dollars per unit) | $ / Units	16.61
Class A Limited Partner [Member] | United Dominion Reality L.P. [Member]
Limited Partners' Capital Account [Line Items]
Limited partnership units owned	1,873,332	1,873,332
Class A Limited Partner [Member] | UDR, Inc. [Member]
Limited Partners' Capital Account [Line Items]
Limited partnership units owned	121,661	121,661

Commitments and Contingencies97

Commitments and Contingencies (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2015USD ($)Communities
Real Estate Properties [Line Items]
Number of communities owned (in communities) | Communities	136
Costs Incurred to Date	$ 758,098
Expected Costs to Complete	373,427
Wholly owned — under development [Member]
Real Estate Properties [Line Items]
Capital Expenditures Incurred but Not yet Paid	$ 2,800
Number of communities owned (in communities)	1
Costs Incurred to Date	$ 104,080
Expected Costs to Complete	$ 237,920
Average Ownership Stake	100.00%
Wholly owned — redevelopment [Member]
Real Estate Properties [Line Items]
Capital Expenditures Incurred but Not yet Paid	$ 1,200
Number of communities owned (in communities)	1
Costs Incurred to Date	$ 7,383
Expected Costs to Complete	$ 7,617
Average Ownership Stake	100.00%
Unconsolidated joint ventures [Member]
Real Estate Properties [Line Items]
Number of communities owned (in communities)	4
Costs Incurred to Date	$ 427,545
Expected Costs to Complete	$ 117,195
Participating Loan Investment Steele Creek Denver Colorado [Member]
Real Estate Properties [Line Items]
Number of communities owned (in communities)	1
Costs Incurred to Date	$ 89,498
Expected Costs to Complete	$ 3,960
Average Ownership Stake	0.00%
Preferred Equity Investment West Coast Development JV [Member]
Real Estate Properties [Line Items]
Number of communities owned (in communities)	5
Costs Incurred to Date	$ 129,592
Expected Costs to Complete	$ 6,735
Average Ownership Stake	48.00%

Commitments and Contingencies98

Commitments and Contingencies (UNITED DOMINION REALTY, L.P.) Commitments and Contingencies (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2015USD ($)Communities
Loss Contingencies [Line Items]
Number of communities owned (in communities) | Communities	136
Cost Incurred to Date	$ 758,098
Expected Costs to Complete	$ 373,427
United Dominion Reality L.P. [Member]
Loss Contingencies [Line Items]
Number of communities owned (in communities) | Communities	67
Wholly owned — redevelopment [Member]
Loss Contingencies [Line Items]
Capital Expenditures Incurred but Not yet Paid	$ 1,200
Number of communities owned (in communities)	1
Cost Incurred to Date	$ 7,383
Expected Costs to Complete	7,617
Wholly owned — redevelopment [Member] | United Dominion Reality L.P. [Member]
Loss Contingencies [Line Items]
Capital Expenditures Incurred but Not yet Paid	$ 1,200
Number of communities owned (in communities)	1
Cost Incurred to Date	$ 7,383
Expected Costs to Complete	7,617
Wholly owned — under development [Member]
Loss Contingencies [Line Items]
Capital Expenditures Incurred but Not yet Paid	$ 2,800
Number of communities owned (in communities)	1
Cost Incurred to Date	$ 104,080
Expected Costs to Complete	$ 237,920

Reportable Segments (Details)

Reportable Segments (Details) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2015USD ($)Segments	Jun. 30, 2015USD ($)	Sep. 30, 2014USD ($)	Sep. 30, 2015USD ($)	Sep. 30, 2014USD ($)	Sep. 30, 2013USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)
Segment Reporting Information [Line Items]
Same Store Communities	34,774			33,495
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	$ 221,418		$ 206,752	$ 657,033	$ 608,497
Reportable apartment home segment NOI	153,565		139,814	447,572	412,330
Reconciling items:
Joint venture management and other fees	3,653		3,165	19,457	9,599
Property management	5,988		5,599	(17,533)	(16,474)
Other operating expenses	(2,639)		(2,012)	(6,174)	(6,118)
Segment Reporting Reconciling Items Cost of Services Depreciation and Amortization	(90,568)		(89,339)	(269,689)	(266,748)
General and administrative	(15,824)		(11,554)	(41,697)	(36,078)
Casualty (Recoveries)/Charges	(541)		0	(2,380)	(500)
Casualty-related (recoveries)/charges, net	541		0	2,380	500
Other depreciation and amortization	(1,457)		(1,385)	(4,780)	(3,658)
Income/(loss) from unconsolidated entities	(2,691)		939	(61,277)	4,932
Interest expense	30,232		33,087	88,705	97,662
Interest and other income/(expense), net	402		9,061	1,144	11,902
Gains/(loss) on sales of real estate owned, net of tax	0		31,302	79,042	82,305
Tax benefit, net	633		2,490	2,462	8,049
Gain on sale of real estate owned, net of tax				79,042	82,380
Gain Loss on the Sale of Real Estate, Including Discontinued Operations	0			79,042
Net (income)/loss attributable to redeemable noncontrolling interests in the Operating Partnership	(405)		(1,447)	(6,022)	(3,171)
Net (income)/loss attributable to noncontrolling interests	(1)		(4)	(6)	(2)
Net income/(loss) attributable to UDR, Inc.	13,291		40,549	173,968	88,917
Reportable apartment home segment assets:
Total segment assets	8,472,977			8,472,977			$ 8,383,259
Accumulated depreciation	(2,647,504)			(2,647,504)			(2,434,772)
Total real estate owned, net of accumulated depreciation	5,825,473			5,825,473			5,948,487
Reconciling items:
Cash and cash equivalents	1,321		$ 14,605	1,321	$ 14,605		15,224	$ 30,249
Restricted cash	23,722			23,722			22,340
Deferred financing costs, net	20,206			20,206			22,686
Notes receivable, net	15,494			15,494			14,369
Investment in and advances to unconsolidated joint ventures, net	921,925			921,925			718,226
Other assets	114,589			114,589			105,202
Total assets	$ 6,922,730			$ 6,922,730			6,846,534
Reportable Segment (Textual) [Abstract]
Number of reportable segments | Segments	2
Condition for Community considered to have stabilized occupancy				0.9
Number of Tenants or related group of tenants that contributed 10% or more of company total revenue	0		0	0	0
Same Communities [Member]
Reportable Segment (Textual) [Abstract]
SEC Schedule III, Real Estate, Improvements	$ 22,300		$ 14,000	$ 54,500	$ 33,900
Same Store Communities Western Region [Member]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	77,837		72,014	197,831	183,887
Reportable apartment home segment NOI	58,071		52,128	147,725	133,037
Reportable apartment home segment assets:
Total segment assets	2,963,025			2,963,025			2,935,430
Same Store Communities Mid-Atlantic Region [Member]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	40,029		39,351	119,546	117,384
Reportable apartment home segment NOI	26,995		27,015	82,046	81,285
Reportable apartment home segment assets:
Total segment assets	1,464,514			1,464,514			1,453,532
Same Store Communities Northeast Region [Member]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	21,914		20,721	64,242	60,817
Reportable apartment home segment NOI	16,161		15,571	47,996	45,576
Reportable apartment home segment assets:
Total segment assets	1,083,935			1,083,935			1,076,656
Same Store Communities Southeastern Region [Member]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	26,293		24,682	77,420	73,151
Reportable apartment home segment NOI	17,562		15,869	51,875	48,494
Reportable apartment home segment assets:
Total segment assets	726,186			726,186			716,427
Same Store Communities Southwestern Region [Member]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	14,599		13,859	43,068	40,949
Reportable apartment home segment NOI	8,967		8,509	26,500	25,130
Reportable apartment home segment assets:
Total segment assets	446,145			446,145			440,721
Non-Mature communities/Other [Member]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	37,093		32,981	135,469	122,857
Reportable apartment home segment NOI	25,809		20,722	91,430	78,808
Reportable apartment home segment assets:
Total segment assets	1,789,172			1,789,172			1,760,493
Reportable Segment (Textual) [Abstract]
SEC Schedule III, Real Estate, Improvements	3,100		2,400	8,500	7,600
Total Communities [Member]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	$ 217,765		203,608	$ 637,576	599,045
Segment Reconciling Items [Member]
Reconciling items:
Gain Loss on the Sale of Real Estate, Including Discontinued Operations			31,377		82,380
United Dominion Reality L.P. [Member]
Segment Reporting Information [Line Items]
Same Store Communities	19,024			18,060
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment NOI	$ 82,290		75,753	$ 242,688		$ 223,138
Reconciling items:
Property management	(3,167)		(2,955)	(9,307)		(8,653)
Other operating expenses	(1,482)		(1,484)	(4,468)		(4,371)
Real estate depreciation and amortization	43,829		45,043	132,411	134,011
General and administrative	(7,935)		(6,939)	(20,606)		(21,368)
Casualty (Recoveries)/Charges	(16)		0	(888)	(500)
Casualty-related (recoveries)/charges, net	(16)		0	(888)		(500)
Interest expense	10,909		10,457	32,587		30,629
Gains/(loss) on sales of real estate owned, net of tax	0	$ 32,400	0	56,998	40,687
Net (income)/loss attributable to noncontrolling interests	(335)		(238)	(1,075)		(697)
Net income/(loss) attributable to UDR, Inc.	14,617		8,637	98,344	63,596	63,596
Reportable apartment home segment assets:
Total segment assets	4,258,578			4,258,578			4,238,770
Accumulated depreciation	(1,518,558)			(1,518,558)			(1,403,303)
Total real estate owned, net of accumulated depreciation	2,740,020			2,740,020			2,835,467
Reconciling items:
Cash and cash equivalents	131		$ 1,484	131	$ 1,484		502	$ 1,897
Deferred financing costs, net	3,355			3,355			4,475
Other assets	24,740			24,740			24,029
Total assets	$ 2,782,956			$ 2,782,956			2,878,284
Reportable Segment (Textual) [Abstract]
Related Party Transaction, Management Fee Percentage				2.75%
Number of reportable segments | Segments	2
Number of Tenants or related group of tenants that contributed 10% or more of company total revenue	0		0		0
United Dominion Reality L.P. [Member] | Same-Store [Member]
Reportable Segment (Textual) [Abstract]
SEC Schedule III, Real Estate, Improvements	$ 13,600		$ 8,000	$ 32,800	$ 19,100
United Dominion Reality L.P. [Member] | Same Store Communities Western Region [Member]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	52,731		48,536	136,298		125,653
Reportable apartment home segment NOI	39,121		35,066	101,855		91,363
Reportable apartment home segment assets:
Total segment assets	1,873,029			1,873,029			1,853,283
United Dominion Reality L.P. [Member] | Same Store Communities Mid-Atlantic Region [Member]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	16,702		16,364	49,907		49,331
Reportable apartment home segment NOI	10,639		10,873	32,845		33,185
Reportable apartment home segment assets:
Total segment assets	691,799			691,799			686,708
United Dominion Reality L.P. [Member] | Same Store Communities Northeast Region [Member]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	6,989		6,667	20,594		19,873
Reportable apartment home segment NOI	4,383		4,192	12,956		12,578
Reportable apartment home segment assets:
Total segment assets	782,366			782,366			777,376
United Dominion Reality L.P. [Member] | Same Store Communities Southeastern Region [Member]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	11,363		10,677	33,535		31,757
Reportable apartment home segment NOI	7,602		6,882	22,357		20,999
Reportable apartment home segment assets:
Total segment assets	320,578			320,578			316,788
United Dominion Reality L.P. [Member] | Same Store Communities Southwestern Region [Member]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	15,810		14,968	46,379		43,894
Reportable apartment home segment NOI	12,025		11,609	35,672		33,662
Reportable apartment home segment assets:
Total segment assets	231,748			231,748			228,997
United Dominion Reality L.P. [Member] | Non-Mature communities/Other [Member]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	11,578		10,232	51,713		44,148
Reportable apartment home segment NOI	8,520		7,131	37,003		31,351
Reportable apartment home segment assets:
Total segment assets	359,058			359,058			$ 375,618
Reportable Segment (Textual) [Abstract]
SEC Schedule III, Real Estate, Improvements	900		700	3,200	$ 1,400
United Dominion Reality L.P. [Member] | Total Communities [Member]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	115,173		107,444	$ 338,426		314,656
Taxable REIT Subsidiaries [Member] | United Dominion Reality L.P. [Member]
Reportable Segment (Textual) [Abstract]
Related Party Transaction, Management Fee Percentage				2.75%
Segment Reconciling Items [Member] | United Dominion Reality L.P. [Member]
Reconciling items:
Real estate depreciation and amortization	$ 43,829		$ 45,043	$ 132,411		$ 134,011

Reportable Segments (UNITED 100

Reportable Segments (UNITED DOMINION REALTY, L.P.) (Details) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2015USD ($)Segments	Jun. 30, 2015USD ($)	Sep. 30, 2014USD ($)	Sep. 30, 2015USD ($)	Sep. 30, 2014USD ($)	Sep. 30, 2013USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)
Segment Reporting Information [Line Items]
Same Store Communities	34,774			33,495
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	$ 221,418		$ 206,752	$ 657,033	$ 608,497
Reportable apartment home segment NOI	(153,565)		(139,814)	(447,572)	(412,330)
Reconciling items:
Property management	5,988		5,599	(17,533)	(16,474)
Other operating expenses	(2,639)		(2,012)	(6,174)	(6,118)
General and administrative	(15,824)		(11,554)	(41,697)	(36,078)
Casualty-related (recoveries)/charges, net	541		0	2,380	500
Interest expense	30,232		33,087	88,705	97,662
Gains/(loss) on sales of real estate owned	0		31,302	79,042	82,305
Net (income)/loss attributable to noncontrolling interests	(1)		(4)	(6)	(2)
Net income/(loss) attributable to OP unitholders	13,291		40,549	173,968	88,917
Reportable apartment home segment assets:
Total segment assets	8,472,977			8,472,977			$ 8,383,259
Real Estate Investment Property, Accumulated Depreciation	2,557,490			2,557,490			2,434,772
Accumulated depreciation	(2,647,504)			(2,647,504)			(2,434,772)
Total segment asset - net book value	5,825,473			5,825,473			5,948,487
Reconciling items:
Cash and cash equivalents	1,321		$ 14,605	1,321	$ 14,605		15,224	$ 30,249
Deferred financing costs, net	20,206			20,206			22,686
Other assets	114,589			114,589			105,202
Total assets	$ 6,922,730			$ 6,922,730			6,846,534
Reportable Segment (Textual) [Abstract]
Number of reportable segments | Segments	2
Condition for Community considered to have stabilized occupancy				0.9
Time to maintain percent occupancy to be considered a community				3 months
Number of Tenants or related group of tenants that contributed 10% or more of company total revenue	0		0	0	0
Same Store Communities Western Region [Member]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	$ 77,837		$ 72,014	$ 197,831	$ 183,887
Reportable apartment home segment NOI	(58,071)		(52,128)	(147,725)	(133,037)
Reportable apartment home segment assets:
Total segment assets	2,963,025			2,963,025			2,935,430
Same Store Communities Mid-Atlantic Region [Member]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	40,029		39,351	119,546	117,384
Reportable apartment home segment NOI	(26,995)		(27,015)	(82,046)	(81,285)
Reportable apartment home segment assets:
Total segment assets	1,464,514			1,464,514			1,453,532
Same Store Communities Northeast Region [Member]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	21,914		20,721	64,242	60,817
Reportable apartment home segment NOI	(16,161)		(15,571)	(47,996)	(45,576)
Reportable apartment home segment assets:
Total segment assets	1,083,935			1,083,935			1,076,656
Same Store Communities Southeastern Region [Member]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	26,293		24,682	77,420	73,151
Reportable apartment home segment NOI	(17,562)		(15,869)	(51,875)	(48,494)
Reportable apartment home segment assets:
Total segment assets	726,186			726,186			716,427
Same Store Communities Southwestern Region [Member]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	14,599		13,859	43,068	40,949
Reportable apartment home segment NOI	(8,967)		(8,509)	(26,500)	(25,130)
Reportable apartment home segment assets:
Total segment assets	446,145			446,145			440,721
Non-Mature communities/Other [Member]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	37,093		32,981	135,469	122,857
Reportable apartment home segment NOI	(25,809)		(20,722)	(91,430)	(78,808)
Reportable apartment home segment assets:
Total segment assets	1,789,172			1,789,172			1,760,493
Reportable Segment (Textual) [Abstract]
SEC Schedule III, Real Estate, Improvements	3,100		2,400	8,500	7,600
Total Communities [Member]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	$ 217,765		203,608	$ 637,576	599,045
United Dominion Reality L.P. [Member]
Segment Reporting Information [Line Items]
Same Store Communities	19,024			18,060
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment NOI	$ (82,290)		(75,753)	$ (242,688)		$ (223,138)
Reconciling items:
Property management	(3,167)		(2,955)	(9,307)		(8,653)
Other operating expenses	(1,482)		(1,484)	(4,468)		(4,371)
Real estate depreciation and amortization	43,829		45,043	132,411	134,011
General and administrative	(7,935)		(6,939)	(20,606)		(21,368)
Casualty-related (recoveries)/charges, net	(16)		0	(888)		(500)
Interest expense	10,909		10,457	32,587		30,629
Gains/(loss) on sales of real estate owned	0	$ 32,400	0	56,998	40,687
Net (income)/loss attributable to noncontrolling interests	(335)		(238)	(1,075)		(697)
Net income/(loss) attributable to OP unitholders	14,617		8,637	98,344	63,596	63,596
Reportable apartment home segment assets:
Total segment assets	4,258,578			4,258,578			4,238,770
Real Estate Investment Property, Accumulated Depreciation	1,467,948			1,467,948			1,403,303
Accumulated depreciation	(1,518,558)			(1,518,558)			(1,403,303)
Total segment asset - net book value	2,740,020			2,740,020			2,835,467
Reconciling items:
Cash and cash equivalents	131		$ 1,484	131	$ 1,484		502	$ 1,897
Restricted Cash	14,710			14,710			13,811
Deferred financing costs, net	3,355			3,355			4,475
Other assets	24,740			24,740			24,029
Total assets	$ 2,782,956			$ 2,782,956			2,878,284
Reportable Segment (Textual) [Abstract]
Number of reportable segments | Segments	2
Number of Tenants or related group of tenants that contributed 10% or more of company total revenue	0		0		0
Related Party Transaction, Management Fee Percentage				2.75%
United Dominion Reality L.P. [Member] | Same-Store [Member]
Reportable Segment (Textual) [Abstract]
SEC Schedule III, Real Estate, Improvements	$ 13,600		$ 8,000	$ 32,800	$ 19,100
United Dominion Reality L.P. [Member] | Same Store Communities Western Region [Member]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	52,731		48,536	136,298		125,653
Reportable apartment home segment NOI	(39,121)		(35,066)	(101,855)		(91,363)
Reportable apartment home segment assets:
Total segment assets	1,873,029			1,873,029			1,853,283
United Dominion Reality L.P. [Member] | Same Store Communities Mid-Atlantic Region [Member]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	16,702		16,364	49,907		49,331
Reportable apartment home segment NOI	(10,639)		(10,873)	(32,845)		(33,185)
Reportable apartment home segment assets:
Total segment assets	691,799			691,799			686,708
United Dominion Reality L.P. [Member] | Same Store Communities Northeast Region [Member]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	6,989		6,667	20,594		19,873
Reportable apartment home segment NOI	(4,383)		(4,192)	(12,956)		(12,578)
Reportable apartment home segment assets:
Total segment assets	782,366			782,366			777,376
United Dominion Reality L.P. [Member] | Same Store Communities Southeastern Region [Member]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	11,363		10,677	33,535		31,757
Reportable apartment home segment NOI	(7,602)		(6,882)	(22,357)		(20,999)
Reportable apartment home segment assets:
Total segment assets	320,578			320,578			316,788
United Dominion Reality L.P. [Member] | Same Store Communities Southwestern Region [Member]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	15,810		14,968	46,379		43,894
Reportable apartment home segment NOI	(12,025)		(11,609)	(35,672)		(33,662)
Reportable apartment home segment assets:
Total segment assets	231,748			231,748			228,997
United Dominion Reality L.P. [Member] | Non-Mature communities/Other [Member]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	11,578		10,232	51,713		44,148
Reportable apartment home segment NOI	(8,520)		(7,131)	(37,003)		(31,351)
Reportable apartment home segment assets:
Total segment assets	359,058			359,058			$ 375,618
Reportable Segment (Textual) [Abstract]
SEC Schedule III, Real Estate, Improvements	900		700	3,200	$ 1,400
United Dominion Reality L.P. [Member] | Total Communities [Member]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	115,173		107,444	338,426		314,656
Segment Reconciling Items [Member] | United Dominion Reality L.P. [Member]
Reconciling items:
Real estate depreciation and amortization	$ 43,829		$ 45,043	$ 132,411		$ 134,011

Subsequent Events (Details)

Subsequent Events (Details) $ / shares in Units, $ in Thousands, shares in Millions	Oct. 08, 2015USD ($)shares	Oct. 20, 2015USD ($)	Sep. 30, 2015USD ($)	Sep. 30, 2014USD ($)	Oct. 06, 2015$ / shares	Dec. 31, 2014USD ($)
Subsequent Event [Line Items]
Extension period of option on loan			6 months
Acquisition of real estate			$ 24,067	$ 0
Line of Credit Facility, Interest Rate Description			100
Line of Credit Facility, Commitment Fee Description			15
Subsequent Event [Member]
Subsequent Event [Line Items]
Number of extension options on loan		2
Extension period of option on loan		6 months
Gains/(loss) on sales of real estate owned	$ 221,000
Series F Preferred Stock [Member] | Preferred Stock [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Stock Issued During Period, Shares, New Issues | shares	13.7
Home Acquisition [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Number of Properties Purchased	6
Cash Acquired from Acquisition	$ 26,000
Fair Value of Assets Acquired	$ 901,000
Business Acquisition, Share Price | $ / shares					$ 35
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares | shares	16.1
Acquisition of real estate	$ 89,000
UDR DownREIT Unit [Member] | Home Acquisition [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Stock Issued During Period, Value, Acquisitions	$ 565,000
United Dominion Reality L.P. [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Equity Method Investment, Ownership Percentage					41.60%
United Dominion Reality L.P. [Member] | Home Acquisition [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Number of Properties Purchased	1
Affiliated Entity [Member] | Home Acquisition [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Number of Properties Purchased	1
Term Loan Facility [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Proceeds from Unsecured Lines of Credit		$ 350,000
Revolving Credit Facility [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Proceeds from Unsecured Lines of Credit		200,000
UDR Bank Credit Facility [Member]
Subsequent Event [Line Items]
Total revolving credit facility			$ 900,000			$ 900,000
UDR Bank Credit Facility [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Total revolving credit facility		$ 2,000,000
Revolving Credit Facility [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Line of Credit Facility, Interest Rate Description		90
Line of Credit Facility, Commitment Fee Description		15
Line of Credit Facility, Description Range Low		85
Line of Credit Facility, Description Range High		155
Line of Credit Facility, Commitment Fee Description Range Low		12.5
Line of Credit Facility, Commitment Fee Description Range High		30
Revolving Credit Facility [Member] | UDR Bank Credit Facility [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Total revolving credit facility		$ 1,100,000
Unsecured Debt [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Line of Credit Facility, Interest Rate Description		95
Line of Credit Facility, Description Range Low		90
Line of Credit Facility, Description Range High		175
Unsecured Debt [Member] | UDR Bank Credit Facility [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Total revolving credit facility		$ 350,000
UDR Texas [Member] | UDR DownREIT Unit [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Equity Method Investment, Ownership Percentage					9.10%
UDR Texas [Member] | UDR Lighthouse DownREIT L.P. [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Equity Method Investment, Ownership Percentage					99.50%
United Dominion Reality L.P. [Member] | UDR DownREIT Unit [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Equity Method Investment, Ownership Percentage					32.50%
United Dominion Reality L.P. [Member] | UDR Lighthouse DownREIT L.P. [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Equity Method Investment, Ownership Percentage					0.50%
UDR, Inc. [Member] | UDR DownREIT Unit [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Equity Method Investment, Ownership Percentage					8.50%

Subsequent Events (UNITED DO102

Subsequent Events (UNITED DOMINION REALTY, L.P.) (Details) $ / shares in Units, $ in Thousands, shares in Millions	Oct. 08, 2015USD ($)shares	Oct. 20, 2015USD ($)	Sep. 30, 2015USD ($)Communities	Jun. 30, 2015USD ($)	Sep. 30, 2014USD ($)	Sep. 30, 2015USD ($)Communities	Sep. 30, 2014USD ($)	Oct. 06, 2015$ / shares	Dec. 31, 2014USD ($)
Subsequent Event [Line Items]
Number of Real Estate Properties | Communities			136			136
Acquisition of real estate						$ 24,067	$ 0
Gains/(loss) on sales of real estate owned			$ 0		$ 31,302	$ 79,042	82,305
Extension period of option on loan						6 months
Line of Credit Facility, Interest Rate Description						100
Line of Credit Facility, Commitment Fee Description						15
Subsequent Event [Member]
Subsequent Event [Line Items]
Number of extension options on loan		2
Extension period of option on loan		6 months
Home Acquisition [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Number of Properties Purchased	6
Business Acquisition, Share Price | $ / shares								$ 35
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares | shares	16.1
Acquisition of real estate	$ 89,000
Cash Acquired from Acquisition	26,000
UDR DownREIT Unit [Member] | Home Acquisition [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Stock Issued During Period, Value, Acquisitions	$ 565,000
Series F Preferred Stock [Member] | Preferred Stock [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Stock Issued During Period, Shares, New Issues | shares	13.7
United Dominion Reality L.P. [Member] | UDR DownREIT Unit [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Equity Method Investment, Ownership Percentage								32.50%
UDR Texas [Member] | UDR DownREIT Unit [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Equity Method Investment, Ownership Percentage								9.10%
UDR, Inc. [Member] | UDR DownREIT Unit [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Equity Method Investment, Ownership Percentage								8.50%
UDR Lighthouse DownREIT L.P. [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Number of Real Estate Properties								7
UDR Lighthouse DownREIT L.P. [Member] | United Dominion Reality L.P. [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Equity Method Investment, Ownership Percentage								0.50%
UDR Lighthouse DownREIT L.P. [Member] | UDR Texas [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Equity Method Investment, Ownership Percentage								99.50%
United Dominion Reality L.P. [Member]
Subsequent Event [Line Items]
Number of Real Estate Properties | Communities			67			67
Gains/(loss) on sales of real estate owned			$ 0	$ 32,400	$ 0	$ 56,998	$ 40,687
United Dominion Reality L.P. [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Equity Method Investment, Ownership Percentage								41.60%
United Dominion Reality L.P. [Member] | Home Acquisition [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Number of Properties Purchased	1
Revolving Credit Facility [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Line of Credit Facility, Interest Rate Description		90
Line of Credit Facility, Commitment Fee Description		15
Line of Credit Facility, Description Range Low		85
Line of Credit Facility, Description Range High		155
Line of Credit Facility, Commitment Fee Description Range Low		12.5
Line of Credit Facility, Commitment Fee Description Range High		30
Unsecured Debt [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Line of Credit Facility, Interest Rate Description		95
Line of Credit Facility, Description Range Low		90
Line of Credit Facility, Description Range High		175
UDR Bank Credit Facility [Member]
Subsequent Event [Line Items]
Total revolving credit facility			900,000			900,000			$ 900,000
UDR Bank Credit Facility [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Total revolving credit facility		$ 2,000,000
UDR Bank Credit Facility [Member] | Revolving Credit Facility [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Total revolving credit facility		1,100,000
UDR Bank Credit Facility [Member] | Unsecured Debt [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Total revolving credit facility		350,000
Financial Guarantee [Member] | 2.90% Term Notes due January 2016 [Member] | United Dominion Reality L.P. [Member]
Subsequent Event [Line Items]
Guarantor borrowing capacity			250,000			250,000
Financial Guarantee [Member] | 1.68% Term Notes due December 2016 [Member] | United Dominion Reality L.P. [Member]
Subsequent Event [Line Items]
Guarantor borrowing capacity			$ 100,000			$ 100,000
Revolving Credit Facility [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Proceeds from Unsecured Lines of Credit		200,000
Term Loan Facility [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Proceeds from Unsecured Lines of Credit		$ 350,000