UDR (UDR) 10-Q 25 Apr 17 2017 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2017	Apr. 21, 2017
Entity Registrant Name	UDR, Inc.
Entity Central Index Key	74,208
Document Type	10-Q
Document Period End Date	Mar. 31, 2017
Amendment Flag	false
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q1
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		267,391,715
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	Mar. 31, 2017
Amendment Flag	false
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q1
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	Mar. 31, 2017	Dec. 31, 2016
Real estate owned:
Real estate held for investment	$ 9,393,732	$ 9,271,847
Less: accumulated depreciation	(3,026,660)	(2,923,072)
Real estate held for investment, net	6,367,072	6,348,775
Real estate under development (net of accumulated depreciation of $0 and $0, respectively)	393,837	342,282
Real estate held for disposition (net of accumulated depreciation of $0 and $533, respectively)	0	1,071
Total real estate owned, net of accumulated depreciation	6,760,909	6,692,128
Cash and cash equivalents	2,460	2,112
Restricted cash	19,757	19,994
Notes receivable, net	19,790	19,790
Investments in and advances to unconsolidated joint ventures, net	818,990	827,025
Other assets	114,005	118,535
Total assets	7,735,911	7,679,584
Liabilities:
Secured debt, net	1,031,507	1,130,858
Unsecured debt, net	2,505,785	2,270,620
Real estate taxes payable	23,105	17,388
Accrued interest payable	27,887	29,257
Security deposits and prepaid rent	36,894	34,238
Distributions payable	91,436	86,936
Accounts payable, accrued expenses, and other liabilities	74,608	103,835
Total liabilities	3,791,222	3,673,132
Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership	904,778	909,482
Equity:
Common stock, $0.01 par value; 350,000,000 shares authorized; 267,398,819 and 267,259,469 shares issued and outstanding at March 31, 2017 and December 31, 2016, respectively	2,674	2,673
Additional Paid in Capital	4,635,942	4,635,413
Distributions in excess of net income	(1,644,621)	(1,585,825)
Accumulated other comprehensive income/(loss), net	(4,288)	(5,609)
Total stockholders' equity	3,036,165	3,093,110
Noncontrolling interests	3,746	3,860
Total equity	3,039,911	3,096,970
Total liabilities and equity	7,735,911	7,679,584
Series E Preferred Stock [Member]
Equity:
Preferred stock, no par value; 50,000,000 shares authorized	46,457	46,457
Series F Preferred Stock [Member]
Equity:
Preferred stock, no par value; 50,000,000 shares authorized	$ 1	$ 1

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Real estate owned:
Real estate under development accumulated depreciation	$ 0	$ 0
Real estate held for disposition accumulated depreciation	$ 0	$ 553
Equity:
Preferred stock, shares authorized	50,000,000	50,000,000
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	350,000,000	350,000,000
Common stock, shares issued	267,398,819	267,259,469
Common stock, shares outstanding	267,398,819	267,259,469
Series F Preferred Stock [Member]
Equity:
Preferred stock, shares issued	16,155,807	16,196,889
Preferred stock, shares outstanding	16,155,807	16,196,889
Series E Preferred Stock [Member]
Equity:
Preferred Stock, Dividend Rate, Percentage	8.00%	8.00%
Preferred stock, shares issued	2,796,903	2,796,903
Preferred stock, shares outstanding	2,796,903	2,796,903

Consolidated Statements of Oper

Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
REVENUES
Rental income	$ 241,271	$ 231,957
Joint venture management and other fees	2,570	2,858
Total revenues	243,841	234,815
OPERATING EXPENSES
Property operating and maintenance	39,600	39,446
Real estate taxes and insurance	30,188	28,377
Property management	6,635	6,379
Other operating expenses	1,691	1,752
Real estate depreciation and amortization	105,032	105,339
General and administrative	13,075	13,844
Casualty-related (recoveries)/charges, net	502	0
Other depreciation and amortization	1,608	1,553
Total operating expenses	198,331	196,690
Operating income	45,510	38,125
Income/(loss) from unconsolidated entities	11,198	679
Interest expense	(30,539)	(31,104)
Interest income and other income/(expense), net	427	431
Income/(loss) before income taxes and gain/(loss) on sale of real estate owned	26,596	8,131
Income/(loss) from continuing operations	26,264	8,534
Gain/(loss) on sale of real estate owned, net of tax	2,132	3,070
Net income/(loss)	28,396	11,604
Net (income)/loss attributable to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership	(2,338)	(905)
Net (income)/loss attributable to noncontrolling interests	(91)	(306)
Net income/(loss) attributable to UDR, Inc.	25,967	10,393
Distributions to preferred stockholders - Series E (Convertible)	(929)	(929)
Net income/(loss) attributable to common stockholders	$ 25,038	$ 9,464
Common distributions declared per share	$ 0.310	$ 0.295
Income/(loss) per weighted average common share - basic	0.09	0.04
Income/(loss) per weighted average common share - diluted	$ 0.09	$ 0.04
Weighted average number of common shares outstanding — basic	266,790	262,456
Weighted average number of common shares outstanding — diluted	268,688	264,285
Continuing Operations [Member]
OPERATING EXPENSES
Tax (provision)/benefit, net	$ 332	$ (403)

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income / (Loss) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Net income/(loss)	$ 28,396	$ 11,604
Other comprehensive income/(loss), including portion attributable to noncontrolling interests:
Unrealized holding gain/(loss)	632	(811)
(Gain)/loss reclassified into earnings from other comprehensive income/(loss)	818	935
Other comprehensive income/(loss), including portion attributable to noncontrolling interests	1,450	124
Comprehensive income/(loss)	29,846	11,728
Comprehensive (income)/loss attributable to noncontrolling interests	(2,558)	(692)
Comprehensive income/(loss) attributable to UDR, Inc.	$ 27,288	$ 11,036

Consolidated Statements of Chan

Consolidated Statements of Changes in Equity (Unaudited) - 3 months ended Mar. 31, 2017 - USD ($) $ in Thousands	Total	Preferred Stock [Member]	Common Stock [Member]	Paid - in Capital [Member]	Distributions in Excess of Net Income [Member]	Accumulated Other Comprehensive Income/(Loss) [Member]	Noncontrolling Interest [Member]
Beginning Balance at Dec. 31, 2016	$ 3,096,970	$ 46,458	$ 2,673	$ 4,635,413	$ (1,585,825)	$ (5,609)	$ 3,860
Consolidted Statements of Changes in Equity
Net income/(loss) attributable to UDR, Inc.	25,967				25,967		0
Net income/(loss) attributable to noncontrolling interests	101					0	101
Contribution of noncontrolling interest in consolidated real estate	125						125
Long Term Incentive Plan Unit grants/(vesting), net	(340)						(340)
Adjustment for conversion of noncontrolling interest of unitholders in the Operating Partnership and DownREIT Partnership	1,850		0	1,850
Other comprehensive income/(loss)	1,321		0	0		1,321
Issuance/(forfeitures) of common and restricted shares, net	(1,878)		1	(1,879)
Common stock distributions declared ($0.310 per share)	(82,995)				(82,995)		0
Preferred stock distributions declared-Series E ($0.3322 per share)	(929)				(929)
Adjustment to reflect redemption value of redeemable noncontrolling interests	(281)				(281)
Ending Balance at Mar. 31, 2017	3,039,911	$ 46,458	$ 2,674	4,635,942	(1,644,621)	$ (4,288)	$ 3,746
Consolidted Statements of Changes in Equity
Cumulative effect upon adoption of ASU 2016-09 | Accounting Standards Update 2016-09 [Member]	$ 0			$ 558	$ (558)

Consolidated Statements of Cha7

Consolidated Statements of Changes in Equity (Unaudited) (Parenthetical)	3 Months Ended
	Mar. 31, 2017$ / shares
Common distributions declared per share	$ 0.310
Series E Preferred Stock [Member]
Preferred stock distributions declared	$ 0.3322

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating Activities
Net income/(loss)	$ 28,396	$ 11,604
Adjustments to reconcile net income/(loss) to net cash provided by/(used in) operating activities:
Depreciation and amortization	106,640	106,892
Gain/(loss) on sale of real estate owned, net of tax	(2,132)	(3,070)
(Income)/loss from unconsolidated entities	(11,198)	(679)
Return on investment in unconsolidated joint ventures	1,455	272
Amortization of share-base compensation	3,379	3,879
Other	4,264	2,497
Changes in operating assets and liabilities:
(Increase)/decrease in operating assets	3,856	(1,853)
Increase/(decrease) in operating liabilities	(14,528)	(6,378)
Net cash provided by/(used in) operating activities	120,464	112,761
Investing Activities
Acquisition of real estate assets	(65,381)	0
Proceeds from sale of real estate investments, net	3,250	21,951
Development of real estate assets	(63,022)	(36,045)
Capital expenditures and other major improvements - real estate assets, net of escrow reimbursement	(21,921)	(24,917)
Capital expenditures - non-real estate assets	(1,233)	(664)
Investment in unconsolidated joint ventures	(24,193)	(13,262)
Distributions received from unconsolidated joint venture	9,711	7,711
Net cash provided by/(used in) investing activities	(162,789)	(45,226)
Financing Activities
Payments on secured debt	(99,463)	(2,205)
Payments on unsecured debt	0	(83,373)
Proceeds from the issuance of unsecured debt	220,000	0
Net proceeds/(repayment) of revolving bank debt	14,790	(73,652)
Proceeds from the issuance of common shares through public offering, net	0	173,300
Distributions paid to redeemable noncontrolling interests	(7,476)	(7,085)
Distributions paid to preferred stockholders	(925)	(924)
Distributions paid to common stockholders	(78,942)	(72,704)
Other	(5,311)	(3,966)
Net cash provided by/(used in) financing activities	42,673	(70,609)
Net increase/(decrease) in cash and cash equivalents	348	(3,074)
Cash and cash equivalents, beginning of period	2,112	6,742
Cash and cash equivalents, end of period	2,460	3,668
Supplemental Information:
Interest paid during the period, net of amounts capitalized	32,463	31,918
Cash paid/(refunds received) for income taxes	171	267
Non-cash transactions:
Transfer of investment in and advances to unconsolidated joint ventures to real estate owned	32,260	0
Development costs and capital expenditures incurred but not yet paid	34,336	21,220
Conversion of Operating Partnership and DownREIT Partnership noncontrolling interests to common stock (50,689 shares in 2017 and 0 shares in 2016)	1,850	0
Dividends declared but not yet paid	91,436	86,963
Continuing Operations [Member]
Adjustments to reconcile net income/(loss) to net cash provided by/(used in) operating activities:
Tax provision/(benefit), net	(332)	403
2016 LTIP [Member]
Non-cash transactions:
Vesting of LTIP Units	$ 2,317	$ 0

Consolidated Statements of Cas9

Consolidated Statements of Cash Flows (Unaudited) (Parenthetical) - shares	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Non-cash transactions:
Conversion of OP Units into common shares	50,689	0

Consolidated Balance Sheets (UN

Consolidated Balance Sheets (UNITED DOMINION REALTY, L.P) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Real estate owned:
Real estate held for investment	$ 9,393,732	$ 9,271,847
Less: accumulated depreciation	(3,026,660)	(2,923,072)
Real estate held for investment, net	6,367,072	6,348,775
Real estate held for disposition (net of accumulated depreciation of $17,209 and $0, respectively)	0	1,071
Total real estate owned, net of accumulated depreciation	6,760,909	6,692,128
Cash and cash equivalents	2,460	2,112
Restricted cash	19,757	19,994
Investment in unconsolidated entities	818,990	827,025
Other assets	114,005	118,535
Total assets	7,735,911	7,679,584
LIABILITIES AND CAPITAL
Secured debt, net	1,031,507	1,130,858
Real estate taxes payable	23,105	17,388
Accrued interest payable	27,887	29,257
Security deposits and prepaid rent	36,894	34,238
Distributions payable	91,436	86,936
Accounts payable, accrued expenses, and other liabilities	74,608	103,835
Total liabilities	3,791,222	3,673,132
Partners' Capital:
Accumulated other comprehensive income/(loss), net	(4,288)	(5,609)
Total liabilities and equity	7,735,911	7,679,584
United Dominion Reality L.P. [Member]
Real estate owned:
Real estate held for investment	3,686,334	3,674,704
Less: accumulated depreciation	(1,445,528)	(1,408,815)
Total real estate owned, net of accumulated depreciation	2,240,806	2,265,889
Cash and cash equivalents	864	756
Restricted cash	12,141	11,694
Investment in unconsolidated entities	103,267	112,867
Other assets	21,475	24,329
Total assets	2,378,553	2,415,535
LIABILITIES AND CAPITAL
Secured debt, net	336,240	433,974
Notes payable due to General Partner	273,334	273,334
Real estate taxes payable	8,409	2,104
Accrued interest payable	1,184	1,410
Security deposits and prepaid rent	15,874	14,593
Distributions payable	57,025	54,192
Accounts payable, accrued expenses, and other liabilities	14,239	17,429
Total liabilities	706,305	797,036
Commitments and contingencies (Note 10)
Partners' Capital:
General partner: 110,883 OP Units outstanding at March 31, 2017 and December 31, 2016	1,000	1,026
Limited partners: 183,240,041 and 183,167,815 OP Units outstanding at March 31, 2017 and December 31, 2016	1,535,939	1,577,289
Accumulated other comprehensive income/(loss), net	(53)	(113)
Total partners' capital	1,536,886	1,578,202
Advances (to)/from General Partner	114,380	19,659
Noncontrolling interests	20,982	20,638
Total capital	1,672,248	1,618,499
Total liabilities and equity	$ 2,378,553	$ 2,415,535

Consolidated Balance Sheets (11

Consolidated Balance Sheets (UNITED DOMINION REALTY, L.P) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Real estate held for disposition accumulated depreciation	$ 0	$ 553
Partners' Capital:
OP units outstanding related to limited partner	183,350,924	183,278,698
United Dominion Reality L.P. [Member]
Partners' Capital:
OP units outstanding related to general partner	110,883	110,883
OP units outstanding related to limited partner	183,240,041	183,167,815

Consolidated Statements of Op12

Consolidated Statements of Operations (Unaudited) (UNITED DOMINION REALTY, L.P) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
REVENUES
Rental income	$ 241,271	$ 231,957
OPERATING EXPENSES
Property operating and maintenance	39,600	39,446
Real estate taxes and insurance	30,188	28,377
Property management	6,635	6,379
Other operating expenses	1,691	1,752
Real estate depreciation and amortization	105,032	105,339
General and administrative	13,075	13,844
Casualty-related (recoveries)/charges, net	502	0
Total operating expenses	198,331	196,690
Operating income	45,510	38,125
Income/(loss) from unconsolidated entities	11,198	679
Interest expense	(30,539)	(31,104)
Income/(loss) from continuing operations	26,264	8,534
Gain/(loss) on sale of real estate owned	2,132	3,070
Net income/(loss)	28,396	11,604
Net income/(loss) attributable to OP unitholders	25,967	10,393
United Dominion Reality L.P. [Member]
REVENUES
Rental income	102,605	98,786
OPERATING EXPENSES
Property operating and maintenance	16,518	16,060
Real estate taxes and insurance	11,024	10,174
Property management	2,822	2,717
Other operating expenses	1,548	1,500
Real estate depreciation and amortization	36,879	36,791
General and administrative	5,219	5,421
Casualty-related (recoveries)/charges, net	553	0
Total operating expenses	74,563	72,663
Operating income	28,042	26,123
Income/(loss) from unconsolidated entities	(5,424)	(13,387)
Interest expense	(5,558)	(4,552)
Interest expense on note payable due to General Partner	(3,053)	(3,053)
Net income/(loss)	14,007	5,131
Net (income)/loss attributable to noncontrolling interest	(350)	(344)
Net income/(loss) attributable to OP unitholders	$ 13,657	$ 4,787
Income/(loss) per OP unit- basic and diluted:
Net income/(loss) per weighted average OP unit - basic and diluted	$ 0.07	$ 0.03
Weighted average OP units outstanding - basic and diluted	183,324	183,279

Consolidated Statements of Co13

Consolidated Statements of Comprehensive Income / (Loss) (UNITED DOMINION REALTY, L.P.) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Net income/(loss)	$ 28,396	$ 11,604
Other comprehensive income/(loss), including portion attributable to noncontrolling interests:
Unrealized holding gain/(loss)	632	(811)
Other comprehensive income/(loss), including portion attributable to noncontrolling interests	1,450	124
Comprehensive income/(loss)	29,846	11,728
Comprehensive income/(loss) attributable to OP unitholders	27,288	11,036
United Dominion Reality L.P. [Member]
Net income/(loss)	14,007	5,131
Other comprehensive income/(loss), including portion attributable to noncontrolling interests:
Unrealized holding gain/(loss)	0	(2)
(Gain)/loss reclassified into earnings from other comprehensive income/(loss)	54	1
Other comprehensive income/(loss), including portion attributable to noncontrolling interests	54	(1)
Comprehensive income/(loss)	14,061	5,130
Comprehensive (income)/loss attributable to noncontrolling interests	(350)	(344)
Comprehensive income/(loss) attributable to OP unitholders	$ 13,711	$ 4,786

Consolidated Statements of Ch14

Consolidated Statements of Changes in Capital (UNITED DOMINION REALTY, L.P) (Unaudited) $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)
Long Term Incentive Plan Unit grants	$ (340)
United Dominion Reality L.P. [Member]
Balance, December 31, 2016	1,618,499
Net income/(loss)	14,007
Distributions	(57,024)
Adjustment to reflect limited partners' capital at redemption value	0
Long Term Incentive Plan Unit grants	1,991
Unrealized gain/(loss) on derivative financial investments	54
Net change in advances (to)/from General Partner	94,721
Balance, March 31, 2017	1,672,248
Payable/(Receivable) due to/(from) General Partner [Member] [Member] | United Dominion Reality L.P. [Member]
Balance, December 31, 2016	19,659
Net change in advances (to)/from General Partner	94,721
Balance, March 31, 2017	114,380
Accumulated Other Comprehensive Income (Loss) [Member] | United Dominion Reality L.P. [Member]
Balance, December 31, 2016	(113)
Unrealized gain/(loss) on derivative financial investments	60
Balance, March 31, 2017	(53)
Partnership Capital [Member] | United Dominion Reality L.P. [Member]
Balance, December 31, 2016	1,578,202
Net income/(loss)	13,657
Distributions	(57,024)
Adjustment to reflect limited partners' capital at redemption value	0
Long Term Incentive Plan Unit grants	1,991
Unrealized gain/(loss) on derivative financial investments	60
Balance, March 31, 2017	1,536,886
Noncontrolling Interest [Member] | United Dominion Reality L.P. [Member]
Balance, December 31, 2016	20,638
Net income/(loss)	350
Adjustment to reflect limited partners' capital at redemption value	0
Balance, March 31, 2017	20,982
Class A Limited Partner [Member] | United Dominion Reality L.P. [Member]
Balance, December 31, 2016	63,901
Net income/(loss)	130
Distributions	(582)
Adjustment to reflect limited partners' capital at redemption value	67
Balance, March 31, 2017	63,516
Limited Partners [Member] | United Dominion Reality L.P. [Member]
Balance, December 31, 2016	269,928
Net income/(loss)	549
Distributions	(2,428)
Adjustment to reflect limited partners' capital at redemption value	(2,965)
Long Term Incentive Plan Unit grants	1,991
Balance, March 31, 2017	267,075
Limited Partner [Member] | United Dominion Reality L.P. [Member]
Balance, December 31, 2016	1,243,460
Net income/(loss)	12,970
Distributions	(53,980)
Adjustment to reflect limited partners' capital at redemption value	2,898
Balance, March 31, 2017	1,205,348
General Partner [Member] | United Dominion Reality L.P. [Member]
Balance, December 31, 2016	1,026
Net income/(loss)	8
Distributions	(34)
Adjustment to reflect limited partners' capital at redemption value	0
Balance, March 31, 2017	1,000
Noncontrolling Interest [Member]
Long Term Incentive Plan Unit grants	(340)
Noncontrolling Interest [Member] | United Dominion Reality L.P. [Member]
Long Term Incentive Plan Unit grants	0
Unrealized gain/(loss) on derivative financial investments	$ (6)

Consolidated Statements of Ca15

Consolidated Statements of Cash Flows (UNITED DOMINION REALTY, L.P) (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating Activities
Net income/(loss)	$ 28,396	$ 11,604
Adjustments to reconcile net income/(loss) to net cash provided by/(used in) operating activities:
Depreciation and amortization	105,032	105,339
Gain/(loss) on sale of real estate owned	2,132	3,070
(Income)/loss from unconsolidated entities	(11,198)	(679)
Other	4,264	2,497
Changes in operating assets and liabilities:
(Increase)/decrease in operating assets	3,856	(1,853)
Increase/(decrease) in operating liabilities	(14,528)	(6,378)
Net cash provided by/(used in) operating activities	120,464	112,761
Investing Activities
Proceeds from sale of real estate investments, net	3,250	21,951
Development of real estate assets	(63,022)	(36,045)
Capital expenditures and other major improvements - real estate assets, net of escrow reimbursement	(21,921)	(24,917)
Distributions received from unconsolidated entities	9,711	7,711
Net cash provided by/(used in) investing activities	(162,789)	(45,226)
Financing Activities
Payments on secured debt	(99,463)	(2,205)
Net cash provided by/(used in) financing activities	42,673	(70,609)
Net increase/(decrease) in cash and cash equivalents	348	(3,074)
Cash and cash equivalents, beginning of period	2,112	6,742
Cash and cash equivalents, end of period	2,460	3,668
Supplemental Information:
Interest paid during the period, net of amounts capitalized	32,463	31,918
Non-cash transactions:
Development costs and capital expenditures incurred but not yet paid	34,336	21,220
Adjustment for conversion of noncontrolling interest of unitholders in the Operating Partnership and DownREIT Partnership	1,850	0
Long Term Incentive Plan Unit grants	(340)
Dividends declared but not yet paid	91,436	86,963
United Dominion Reality L.P. [Member]
Operating Activities
Net income/(loss)	14,007	5,131
Adjustments to reconcile net income/(loss) to net cash provided by/(used in) operating activities:
Depreciation and amortization	36,879	36,791
(Income)/loss from unconsolidated entities	5,424	13,387
Other	1,491	684
Changes in operating assets and liabilities:
(Increase)/decrease in operating assets	1,977	(3,742)
Increase/(decrease) in operating liabilities	4,122	8,274
Net cash provided by/(used in) operating activities	63,900	60,525
Investing Activities
Capital expenditures and other major improvements - real estate assets, net of escrow reimbursement	(12,149)	(10,744)
Distributions received from unconsolidated entities	4,176	3,977
Net cash provided by/(used in) investing activities	(7,973)	(6,767)
Financing Activities
Advances from/(to) General Partner, net	45,088	(53,157)
Payments on secured debt	(98,340)	(275)
Distributions paid to partnership unitholders	(2,567)	(2,327)
Net cash provided by/(used in) financing activities	(55,819)	(55,759)
Net increase/(decrease) in cash and cash equivalents	108	(2,001)
Cash and cash equivalents, beginning of period	756	3,103
Cash and cash equivalents, end of period	864	1,102
Supplemental Information:
Interest paid during the period, net of amounts capitalized	7,066	5,515
Non-cash transactions:
Development costs and capital expenditures incurred but not yet paid	4,816	4,505
Long Term Incentive Plan Unit grants	1,991	663
Dividends declared but not yet paid	$ 57,025	$ 54,173

Consolidation and Basis of Pres

Consolidation and Basis of Presentation	3 Months Ended
	Mar. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
CONSOLIDATION AND BASIS OF PRESENTATION	BASIS OF PRESENTATION 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”) and UDR Lighthouse DownREIT L.P. (the “DownREIT Partnership”). As of March 31, 2017 , there were 183,350,924 units in the Operating Partnership ("OP Units") outstanding, of which 174,233,691 OP Units, or 95.0% , were owned by UDR and 9,117,233 OP Units, or 5.0% , were owned by outside limited partners. As of March 31, 2017 , there were 32,367,380 units in the DownREIT Partnership (“DownREIT Units”) outstanding, of which 16,532,096 , or 51.1% , were owned by UDR (including 13,470,651 DownREIT Units, or 41.6% , that were held by the Operating Partnership) and 15,835,284 , or 48.9% , were owned by outside limited partners. The consolidated financial statements of UDR include the noncontrolling interests of the unitholders in the Operating Partnership and DownREIT 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 March 31, 2017 , and results of operations for the three months ended March 31, 2017 and 2016 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, 2016 appearing in UDR’s Annual Report on Form 10-K, filed with the Securities and Exchange Commission on February 21, 2017 . 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. The Company evaluated subsequent events through the date its financial statements were issued. No significant recognized or non-recognized subsequent events were noted.

Consolidation and Basis of Pr17

Consolidation and Basis of Presentation (UNITED DOMINION REALTY, L.P.)	3 Months Ended
	Mar. 31, 2017
Entity Information [Line Items]
CONSOLIDATION AND BASIS OF PRESENTATION	BASIS OF PRESENTATION 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”) and UDR Lighthouse DownREIT L.P. (the “DownREIT Partnership”). As of March 31, 2017 , there were 183,350,924 units in the Operating Partnership ("OP Units") outstanding, of which 174,233,691 OP Units, or 95.0% , were owned by UDR and 9,117,233 OP Units, or 5.0% , were owned by outside limited partners. As of March 31, 2017 , there were 32,367,380 units in the DownREIT Partnership (“DownREIT Units”) outstanding, of which 16,532,096 , or 51.1% , were owned by UDR (including 13,470,651 DownREIT Units, or 41.6% , that were held by the Operating Partnership) and 15,835,284 , or 48.9% , were owned by outside limited partners. The consolidated financial statements of UDR include the noncontrolling interests of the unitholders in the Operating Partnership and DownREIT 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 March 31, 2017 , and results of operations for the three months ended March 31, 2017 and 2016 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, 2016 appearing in UDR’s Annual Report on Form 10-K, filed with the Securities and Exchange Commission on February 21, 2017 . 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. The Company evaluated subsequent events through the date its financial statements were issued. No significant recognized or non-recognized subsequent events were noted.
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
CONSOLIDATION AND BASIS OF PRESENTATION	CONSOLIDATION AND BASIS OF PRESENTATION 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. During both the three months ended March 31, 2017 and 2016 , rental revenues of the Operating Partnership represented 43% of the General Partner’s consolidated rental revenues. As of March 31, 2017 , the Operating Partnership’s apartment portfolio consisted of 54 communities located in 14 markets consisting of 16,698 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 March 31, 2017 , there were 183,350,924 OP Units outstanding, of which 174,233,691 , or 95.0% , were owned by UDR and affiliated entities and 9,117,233 , or 5.0% , were owned by non-affiliated limited partners. See Note 9, 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 March 31, 2017 , and results of operations for the three months ended March 31, 2017 and 2016 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, 2016 included in the Annual Report on Form 10-K filed by UDR and the Operating Partnership with the SEC on February 21, 2017 . 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. The Operating Partnership evaluated subsequent events through the date its financial statements were issued. No recognized or non-recognized subsequent events were noted.

Significant Accounting Policies

Significant Accounting Policies	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
SIGNIFICANT ACCOUNTING POLICIES	SIGNIFICANT ACCOUNTING POLICIES Recent Accounting Pronouncements In January 2017, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2017-01, Business Combinations (Topic 805), Clarifying the Definition of a Business. The ASU changes the definition of a business to assist entities with evaluating whether a set of transferred assets is a business. As a result, the accounting for acquisitions of real estate could be impacted. The updated standard will be effective for the Company on January 1, 2018; early adoption is permitted. The ASU will be applied prospectively to any transactions occurring within the period of adoption. The Company expects that the updated standard will result in fewer acquisitions of real estate meeting the definition of a business and fewer acquisition-related costs being expensed in the period incurred. In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230), Restricted Cash . The ASU addresses the presentation of restricted cash and restricted cash equivalents in the statement of cash flows. The updated standard will be effective for the Company on January 1, 2018 and must be applied retrospectively to all periods presented; early adoption is permitted. The Company does not expect the updated standard to have a material impact on the consolidated financial statements and related disclosures. In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230), Classification of Certain Cash Receipts and Cash Payments . The ASU addresses specific cash flow items with the objective of reducing existing diversity in practice, including the treatment of distributions received from equity method investees. The updated standard will be effective for the Company on January 1, 2018 and must be applied retrospectively to all periods presented; early adoption is permitted. The Company elected to early adopt ASU 2016-15 in 2016 and elected to classify distributions received from equity method investees using the cumulative earnings approach. As a result, for the three months ended March 31, 2016, the following amounts classified under the adopted ASU as returns on investment in unconsolidated joint ventures were reclassified on the Consolidated Statements of Cash Flow (in thousands) : Three Months Ended March 31, 2016 Return on investment in unconsolidated joint ventures - as previously presented $ — Return on investment in unconsolidated joint ventures 272 Return on investment in unconsolidated joint ventures - as presented herein $ 272 Distributions received from unconsolidated joint ventures - as previously presented $ 7,983 Return on investment in unconsolidated joint ventures (272 ) Distributions received from unconsolidated joint ventures - as presented herein $ 7,711 In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments . The standard requires entities to estimate a lifetime expected credit loss for most financial assets, including trade and other receivables, held-to-maturity debt securities, loans and other financial instruments, and to present the net amount of the financial instrument expected to be collected. The updated standard will be effective for the Company on January 1, 2020; early adoption is permitted on January 1, 2019. The Company is currently evaluating the effect that the updated standard will have on the consolidated financial statements and related disclosures. In March 2016, the FASB issued ASU 2016-09, Compensation-Stock Compensation (Topic 718), Improvements to Employee Share-Based Payment Accounting . The ASU aims to simplify the accounting for share-based payments by amending the accounting for forfeitures, statutory tax withholding requirements, classification in the statements of cash flow and income taxes. The updated standard was effective for the Company on January 1, 2017, at which time the Company prospectively began accounting for forfeitures as incurred and began applying the updated rules for statutory withholdings. As a result of adopting the ASU, the Company recorded a one-time adjustment for existing estimated forfeitures of $0.6 million as of January 1, 2017 to Distributions in Excess of Net Income on January 1, 2017. In February 2016, the FASB issued ASU No. 2016-02, Leases . The standard amends the existing lease accounting guidance and requires lessees to recognize a lease liability and a right-of-use asset for all leases (except for short-term leases that have a duration of one year or less) on their balance sheets. Lessees will continue to recognize lease expense in a manner similar to current accounting. For lessors, accounting for leases under the new guidance is substantially the same as in prior periods, but eliminates current real estate-specific provisions and changes the treatment of initial direct costs. Entities are required to use a modified retrospective approach for leases that exist or are entered into after the beginning of the earliest comparable period presented, with an option to elect certain transition relief. Full retrospective application is prohibited. The standard will be effective for the Company on January 1, 2019, with early adoption permitted. While the Company is currently evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures, we expect to recognize right-of-use assets and related lease liabilities on our consolidated balance sheets related to ground leases on any communities where we are the lessee. In May 2014, the FASB issued 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 will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective, including industry-specific revenue guidance. The standard specifically excludes lease contracts. The ASU allows for the use of either the full or modified retrospective transition method and will be effective for the Company on January 1, 2018, at which time the Company expects to adopt the updated standard using the modified retrospective approach. However, as the majority of the Company’s revenue is from rental income related to leases, the Company does not expect the ASU to have a material impact on the consolidated financial statements and related disclosures. Principles of Consolidation The Company accounts for subsidiary partnerships, joint ventures and other similar entities in which it holds an ownership interest in accordance with the consolidation guidance. The Company first evaluates whether each entity is a variable interest entity ("VIE"). Under the VIE model, the Company consolidates an entity when it has control to direct the activities of the VIE and the obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE. Under the voting model, the Company consolidates an entity when it controls the entity through ownership of a majority voting interest. 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 of 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 March 31, 2017 and December 31, 2016 ( dollars in thousands): Interest rate at Balance outstanding March 31, March 31, December 31, 2016 Note due February 2020 (a) 10.00 % $ 12,994 $ 12,994 Note due July 2017 (b) 8.00 % 2,500 2,500 Note due October 2020 (c) 8.00 % 1,296 1,296 Note due April 2021 (d) 10.00 % 3,000 3,000 Total notes receivable, net $ 19,790 $ 19,790 (a) The Company has a secured note receivable with an unaffiliated third party with an aggregate commitment of $13.0 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 eighth anniversary of the date of the note (February 2020). (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). (c) The Company has a secured note receivable with an unaffiliated third party with an aggregate commitment of $2.0 million , of which, $1.3 million has been funded. Interest payments are due when the loan matures. The note matures at the earliest of the following: (a) the closing of any private or public capital raising in the amount of $10.0 million or greater; (b) an acquisition; (c) acceleration in the event of default; or (d) the fifth anniversary of the date of the note (October 2020). (d) The Company has a secured note receivable with an unaffiliated third party with an aggregate commitment of $15.0 million , of which, $3.0 million has been funded. 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 $25.0 million or greater; (b) an acquisition; (c) acceleration in the event of default; or (d) the fifth anniversary of the date of the note (April 2021). The Company recognized $0.5 million and $0.4 million of interest income from notes receivable during the three months ended March 31, 2017 and 2016 , 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 months ended March 31, 2017 and 2016 , 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 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 during the three months ended March 31, 2017 and 2016 was $0.1 million and $(0.5) million , 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 March 31, 2017 and December 31, 2016 , UDR’s net deferred tax asset was $0.4 million and $0.6 million , respectively. 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 March 31, 2017 . UDR and its subsidiaries are subject to federal income tax as well as income tax of various state and local jurisdictions. The tax years 2013 through 2016 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 (provision)/benefit, net on the Consolidated Statements of Operations.

Significant Accounting Polici19

Significant Accounting Policies (UNITED DOMINION REALTY, L.P.)	3 Months Ended
	Mar. 31, 2017
Entity Information [Line Items]
SIGNIFICANT ACCOUNTING POLICIES	SIGNIFICANT ACCOUNTING POLICIES Recent Accounting Pronouncements In January 2017, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2017-01, Business Combinations (Topic 805), Clarifying the Definition of a Business. The ASU changes the definition of a business to assist entities with evaluating whether a set of transferred assets is a business. As a result, the accounting for acquisitions of real estate could be impacted. The updated standard will be effective for the Company on January 1, 2018; early adoption is permitted. The ASU will be applied prospectively to any transactions occurring within the period of adoption. The Company expects that the updated standard will result in fewer acquisitions of real estate meeting the definition of a business and fewer acquisition-related costs being expensed in the period incurred. In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230), Restricted Cash . The ASU addresses the presentation of restricted cash and restricted cash equivalents in the statement of cash flows. The updated standard will be effective for the Company on January 1, 2018 and must be applied retrospectively to all periods presented; early adoption is permitted. The Company does not expect the updated standard to have a material impact on the consolidated financial statements and related disclosures. In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230), Classification of Certain Cash Receipts and Cash Payments . The ASU addresses specific cash flow items with the objective of reducing existing diversity in practice, including the treatment of distributions received from equity method investees. The updated standard will be effective for the Company on January 1, 2018 and must be applied retrospectively to all periods presented; early adoption is permitted. The Company elected to early adopt ASU 2016-15 in 2016 and elected to classify distributions received from equity method investees using the cumulative earnings approach. As a result, for the three months ended March 31, 2016, the following amounts classified under the adopted ASU as returns on investment in unconsolidated joint ventures were reclassified on the Consolidated Statements of Cash Flow (in thousands) : Three Months Ended March 31, 2016 Return on investment in unconsolidated joint ventures - as previously presented $ — Return on investment in unconsolidated joint ventures 272 Return on investment in unconsolidated joint ventures - as presented herein $ 272 Distributions received from unconsolidated joint ventures - as previously presented $ 7,983 Return on investment in unconsolidated joint ventures (272 ) Distributions received from unconsolidated joint ventures - as presented herein $ 7,711 In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments . The standard requires entities to estimate a lifetime expected credit loss for most financial assets, including trade and other receivables, held-to-maturity debt securities, loans and other financial instruments, and to present the net amount of the financial instrument expected to be collected. The updated standard will be effective for the Company on January 1, 2020; early adoption is permitted on January 1, 2019. The Company is currently evaluating the effect that the updated standard will have on the consolidated financial statements and related disclosures. In March 2016, the FASB issued ASU 2016-09, Compensation-Stock Compensation (Topic 718), Improvements to Employee Share-Based Payment Accounting . The ASU aims to simplify the accounting for share-based payments by amending the accounting for forfeitures, statutory tax withholding requirements, classification in the statements of cash flow and income taxes. The updated standard was effective for the Company on January 1, 2017, at which time the Company prospectively began accounting for forfeitures as incurred and began applying the updated rules for statutory withholdings. As a result of adopting the ASU, the Company recorded a one-time adjustment for existing estimated forfeitures of $0.6 million as of January 1, 2017 to Distributions in Excess of Net Income on January 1, 2017. In February 2016, the FASB issued ASU No. 2016-02, Leases . The standard amends the existing lease accounting guidance and requires lessees to recognize a lease liability and a right-of-use asset for all leases (except for short-term leases that have a duration of one year or less) on their balance sheets. Lessees will continue to recognize lease expense in a manner similar to current accounting. For lessors, accounting for leases under the new guidance is substantially the same as in prior periods, but eliminates current real estate-specific provisions and changes the treatment of initial direct costs. Entities are required to use a modified retrospective approach for leases that exist or are entered into after the beginning of the earliest comparable period presented, with an option to elect certain transition relief. Full retrospective application is prohibited. The standard will be effective for the Company on January 1, 2019, with early adoption permitted. While the Company is currently evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures, we expect to recognize right-of-use assets and related lease liabilities on our consolidated balance sheets related to ground leases on any communities where we are the lessee. In May 2014, the FASB issued 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 will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective, including industry-specific revenue guidance. The standard specifically excludes lease contracts. The ASU allows for the use of either the full or modified retrospective transition method and will be effective for the Company on January 1, 2018, at which time the Company expects to adopt the updated standard using the modified retrospective approach. However, as the majority of the Company’s revenue is from rental income related to leases, the Company does not expect the ASU to have a material impact on the consolidated financial statements and related disclosures. Principles of Consolidation The Company accounts for subsidiary partnerships, joint ventures and other similar entities in which it holds an ownership interest in accordance with the consolidation guidance. The Company first evaluates whether each entity is a variable interest entity ("VIE"). Under the VIE model, the Company consolidates an entity when it has control to direct the activities of the VIE and the obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE. Under the voting model, the Company consolidates an entity when it controls the entity through ownership of a majority voting interest. 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 of 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 March 31, 2017 and December 31, 2016 ( dollars in thousands): Interest rate at Balance outstanding March 31, March 31, December 31, 2016 Note due February 2020 (a) 10.00 % $ 12,994 $ 12,994 Note due July 2017 (b) 8.00 % 2,500 2,500 Note due October 2020 (c) 8.00 % 1,296 1,296 Note due April 2021 (d) 10.00 % 3,000 3,000 Total notes receivable, net $ 19,790 $ 19,790 (a) The Company has a secured note receivable with an unaffiliated third party with an aggregate commitment of $13.0 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 eighth anniversary of the date of the note (February 2020). (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). (c) The Company has a secured note receivable with an unaffiliated third party with an aggregate commitment of $2.0 million , of which, $1.3 million has been funded. Interest payments are due when the loan matures. The note matures at the earliest of the following: (a) the closing of any private or public capital raising in the amount of $10.0 million or greater; (b) an acquisition; (c) acceleration in the event of default; or (d) the fifth anniversary of the date of the note (October 2020). (d) The Company has a secured note receivable with an unaffiliated third party with an aggregate commitment of $15.0 million , of which, $3.0 million has been funded. 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 $25.0 million or greater; (b) an acquisition; (c) acceleration in the event of default; or (d) the fifth anniversary of the date of the note (April 2021). The Company recognized $0.5 million and $0.4 million of interest income from notes receivable during the three months ended March 31, 2017 and 2016 , 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 months ended March 31, 2017 and 2016 , 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 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 during the three months ended March 31, 2017 and 2016 was $0.1 million and $(0.5) million , 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 March 31, 2017 and December 31, 2016 , UDR’s net deferred tax asset was $0.4 million and $0.6 million , respectively. 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 March 31, 2017 . UDR and its subsidiaries are subject to federal income tax as well as income tax of various state and local jurisdictions. The tax years 2013 through 2016 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 (provision)/benefit, 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 January 2017, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2017-01, Business Combinations (Topic 805), Clarifying the Definition of a Business. The ASU changes the definition of a business to assist entities with evaluating whether a set of transferred assets is a business. As a result, the accounting for acquisitions of real estate could be impacted. The updated standard will be effective for the Operating Partnership on January 1, 2018; early adoption is permitted. The ASU will be applied prospectively to any transactions occurring within the period of adoption. The Operating Partnership expects that the updated standard will result in fewer acquisitions of real estate meeting the definition of a business and fewer acquisition-related costs being expensed in the period incurred. In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230), Restricted Cash . The ASU addresses the presentation of restricted cash and restricted cash equivalents in the statement of cash flows. The updated standard will be effective for the Operating Partnership on January 1, 2018 and must be applied retrospectively to all periods presented; early adoption is permitted. The Operating Partnership does not expect the updated standard to have a material impact on the consolidated financial statements and related disclosures. In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230), Classification of Certain Cash Receipts and Cash Payments . The ASU addresses specific cash flow items with the objective of reducing existing diversity in practice, including the treatment of distributions received from equity method investees. The updated standard will be effective for the Operating Partnership on January 1, 2018 and must be applied retrospectively to all periods presented; early adoption is permitted. The Operating Partnership elected to early adopt ASU 2016-15 in 2016. The adoption did not have an impact on the Operating Partnership's consolidated financial statements and related disclosures. In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments . The standard requires entities to estimate a lifetime expected credit loss for most financial assets, including trade and other receivables, held-to-maturity debt securities, loans and other financial instruments, and to present the net amount of the financial instrument expected to be collected. The updated standard will be effective for the Operating Partnership on January 1, 2020; early adoption is permitted on January 1, 2019. The Operating Partnership is currently evaluating the effect that the updated standard will have on the consolidated financial statements and related disclosures. In February 2016, the FASB issued ASU No. 2016-02, Leases . The standard amends the existing lease accounting guidance and requires lessees to recognize a lease liability and a right-of-use asset for all leases (except for short-term leases that have a duration of one year or less) on their balance sheets. Lessees will continue to recognize lease expense in a manner similar to current accounting. For lessors, accounting for leases under the new guidance is substantially the same as in prior periods, but eliminates current real estate-specific provisions and changes the treatment of initial direct costs. Entities are required to use a modified retrospective approach for leases that exist or are entered into after the beginning of the earliest comparable period presented, with an option to elect certain transition relief. Full retrospective application is prohibited. The standard will be effective for the Operating Partnership on January 1, 2019, with early adoption permitted. While the Operating Partnership is currently evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures, we expect to recognize right-of-use assets and related lease liabilities on our consolidated balance sheets related to ground leases on any communities where we are the lessee. In May 2014, the FASB issued 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 will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective, including industry-specific revenue guidance. The standard specifically excludes lease contracts. The ASU allows for the use of either the full or modified retrospective transition method and will be effective for the Operating Partnership on January 1, 2018, at which time the Operating Partnership expects to adopt the updated standard using the modified retrospective approach. However, as the majority of the Operating Partnership's revenue is from rental income related to leases, the Operating Partnership does not expect the ASU to have a material impact on the consolidated financial statements and related disclosures. Principles of Consolidation The Operating Partnership accounts for subsidiary partnerships, joint ventures and other similar entities in which it holds an ownership interest in accordance with the amended consolidation guidance. The Operating Partnership first evaluates whether each entity is a variable interest entity ("VIE"). Under the VIE model, the Operating Partnership consolidates an entity when it has control to direct the activities of the VIE and the obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE. Under the voting model, the Operating Partnership consolidates an entity when it controls the entity through ownership of a majority voting interest. 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 the 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 months ended March 31, 2017 and 2016 , 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 8, 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 ( 2013 through 2016 ) 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	3 Months Ended
	Mar. 31, 2017
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. As of March 31, 2017 , the Company owned and consolidated 128 communities in 10 states plus the District of Columbia totaling 39,698 apartment homes. The following table summarizes the carrying amounts for our real estate owned (at cost) as of March 31, 2017 and December 31, 2016 (dollars in thousands): March 31, December 31, 2016 Land $ 1,812,797 $ 1,801,576 Depreciable property — held and used: Land improvements 180,837 178,701 Building, improvements, and furniture, fixtures and equipment 7,400,098 7,291,570 Under development: Land and land improvements 111,028 111,028 Building, improvements, and furniture, fixtures and equipment 282,809 231,254 Real estate held for disposition: Land and land improvements — 1,104 Building, improvements, and furniture, fixtures and equipment — 520 Real estate owned 9,787,569 9,615,753 Accumulated depreciation (3,026,660 ) (2,923,625 ) Real estate owned, net $ 6,760,909 $ 6,692,128 Acquisitions During the three months ended March 31, 2017 , the Company exercised its fixed-price option to purchase its joint venture partner's ownership interest in a 244 home operating community in Seattle, Washington, thereby increasing its ownership interest from 49% to 100% , for a cash purchase price of approximately $66.0 million . As a result, the Company consolidated the operating community. The Company had previously accounted for its 49% ownership interest as a preferred equity investment in an unconsolidated joint venture (see Note 5, Joint Ventures and Partnerships ). As a result of the consolidation, the Company increased its real estate owned by approximately $97.0 million , recorded approximately $1.7 million of in-place lease intangibles and recorded a gain on consolidation of $12.2 million , which is included in Income/(loss) from unconsolidated entities on the Consolidated Statements of Operations. Dispositions During the three months ended March 31, 2017 , the Company sold a parcel of land in Richmond, Virginia for gross proceeds of $3.5 million , resulting in net proceeds of $3.3 million and a gain of $2.1 million . 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 $2.8 million and $2.0 million for the three months ended March 31, 2017 and 2016 , respectively. Total interest capitalized was $4.7 million and $4.2 million for the three months ended March 31, 2017 and 2016 , 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.)	3 Months Ended
	Mar. 31, 2017
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. As of March 31, 2017 , the Company owned and consolidated 128 communities in 10 states plus the District of Columbia totaling 39,698 apartment homes. The following table summarizes the carrying amounts for our real estate owned (at cost) as of March 31, 2017 and December 31, 2016 (dollars in thousands): March 31, December 31, 2016 Land $ 1,812,797 $ 1,801,576 Depreciable property — held and used: Land improvements 180,837 178,701 Building, improvements, and furniture, fixtures and equipment 7,400,098 7,291,570 Under development: Land and land improvements 111,028 111,028 Building, improvements, and furniture, fixtures and equipment 282,809 231,254 Real estate held for disposition: Land and land improvements — 1,104 Building, improvements, and furniture, fixtures and equipment — 520 Real estate owned 9,787,569 9,615,753 Accumulated depreciation (3,026,660 ) (2,923,625 ) Real estate owned, net $ 6,760,909 $ 6,692,128 Acquisitions During the three months ended March 31, 2017 , the Company exercised its fixed-price option to purchase its joint venture partner's ownership interest in a 244 home operating community in Seattle, Washington, thereby increasing its ownership interest from 49% to 100% , for a cash purchase price of approximately $66.0 million . As a result, the Company consolidated the operating community. The Company had previously accounted for its 49% ownership interest as a preferred equity investment in an unconsolidated joint venture (see Note 5, Joint Ventures and Partnerships ). As a result of the consolidation, the Company increased its real estate owned by approximately $97.0 million , recorded approximately $1.7 million of in-place lease intangibles and recorded a gain on consolidation of $12.2 million , which is included in Income/(loss) from unconsolidated entities on the Consolidated Statements of Operations. Dispositions During the three months ended March 31, 2017 , the Company sold a parcel of land in Richmond, Virginia for gross proceeds of $3.5 million , resulting in net proceeds of $3.3 million and a gain of $2.1 million . 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 $2.8 million and $2.0 million for the three months ended March 31, 2017 and 2016 , respectively. Total interest capitalized was $4.7 million and $4.2 million for the three months ended March 31, 2017 and 2016 , 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 consist of income producing operating properties, properties under development, land held for future development, and sold or held for disposition properties. At March 31, 2017 , the Operating Partnership owned and consolidated 54 communities in eight states plus the District of Columbia totaling 16,698 apartment homes. The following table summarizes the carrying amounts for our real estate owned (at cost) as of March 31, 2017 and December 31, 2016 (dollars in thousands) : March 31, December 31, 2016 Land $ 837,945 $ 836,644 Depreciable property — held and used: Buildings, improvements, and furniture, fixtures and equipment 2,848,389 2,838,060 Real estate owned 3,686,334 3,674,704 Accumulated depreciation (1,445,528 ) (1,408,815 ) Real estate owned, net $ 2,240,806 $ 2,265,889 The Operating Partnership did not have any acquisitions or sales of real estate during the three months ended March 31, 2017 . 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 $0.3 million and $0.3 million for the three months ended March 31, 2017 and 2016 , respectively. Total interest capitalized was less than $0.1 million and $0.1 million for the three months ended March 31, 2017 and 2016 , 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.

Variable Interest Entities (Not

Variable Interest Entities (Notes)	3 Months Ended
	Mar. 31, 2017
Equity Method Investments and Joint Ventures [Abstract]
Variable Interest Entity Disclosure [Text Block]	VARIABLE INTEREST ENTITIES The Company has determined that the Operating Partnership and DownREIT Partnership are VIEs as the limited partners lack substantive kick-out rights and substantive participating rights. The Company has concluded that it is the primary beneficiary of, and therefore consolidates the Operating Partnership and DownREIT Partnership based on its role as the sole general partner of the Operating Partnership and DownREIT Partnership. The Company's role as community manager and its equity interests give us the power to direct the activities that most significantly impact the economic performance and the obligation to absorb potentially significant losses or the right to receive potentially significant benefits of the Operating Partnership and DownREIT Partnership. See the consolidated financial statements of the Operating Partnership presented within this Report and Note 4, Unconsolidated Entities , to the Operating Partnership's consolidated financial statements for the results of operations of the Operating Partnership and DownREIT Partnership, respectively.

Joint Ventures

Joint Ventures	3 Months Ended
	Mar. 31, 2017
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. The Company recognizes earnings or losses from our investments in unconsolidated joint ventures and partnerships consisting of our proportionate share of the net earnings 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 March 31, 2017 and December 31, 2016 (dollars in thousands) : Joint Venture Location of Properties Number of Properties Number of Apartment Homes Investment at UDR’s Ownership Interest March 31, March 31, March 31, December 31, March 31, December 31, Operating and development: UDR/MetLife I Los Angeles, CA 1 development community (a) 150 $ 29,182 $ 25,209 50.0 % 50.0 % UDR/MetLife II (b) Various 18 operating communities 4,059 309,409 311,282 50.0 % 50.0 % Other UDR/MetLife Development Joint Ventures 1 operating community; Various 4 development communities (a) 1,437 156,096 160,979 50.6 % 50.6 % UDR/MetLife Vitruvian Park® Addison, TX 3 operating communities; 1 development community (a); 5 land parcels 1,513 73,154 72,414 50.0 % 50.0 % UDR/KFH Washington, D.C. 3 operating communities 660 11,801 12,835 30.0 % 30.0 % Investment in and advances to unconsolidated joint ventures, net, before participating loan investment and preferred equity investment $ 579,642 $ 582,719 Income from investments for the three months ending March 31, Investment at Location Rate Years To Maturity March 31, December 31, 2017 2016 Participating loan investment: Steele Creek Denver, CO 6.5% 0.3 $ 94,002 $ 94,003 $ 1,533 $ 1,519 Preferred equity investment: West Coast Development Joint Ventures (c) Various 6.5% (c) N/A 145,346 150,303 $ 12,766 $ 1,427 Total investment in and advances to unconsolidated joint ventures, net $ 818,990 $ 827,025 (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 upon completion of development. As of March 31, 2017 , 1,018 apartment homes had been completed in Other UDR/MetLife Development Joint Ventures, and no apartment homes had been completed in UDR/MetLife I or in UDR/MetLife Vitruvian Park ® . (b) In September 2015, the 717 Olympic community, which is owned by the UDR/MetLife II joint venture, experienced extensive water damage due to a ruptured water pipe. For the three months ended March 31, 2017 and 2016 , the Company recorded casualty-related charges/(recoveries) of $0.9 million and $(1.1) million , respectively, representing its proportionate share of the total charges/(recoveries) recognized. (c) In May 2015, the Company entered into a joint venture agreement with an unaffiliated joint venture partner and agreed to pay $136.3 million for a 48% ownership interest in a portfolio of five communities that were under construction. The communities are located in three of the Company’s core, coastal markets: Seattle, Washington, Los Angeles and Orange County, California. UDR earns a 6.5% preferred return on its investment through each individual community’s date of stabilization, defined as when a community reaches 80% occupancy for 90 consecutive days, while the joint venture partner is allocated all operating income and expense during the pre-stabilization period. Upon stabilization, income and expense are shared based on each partner’s ownership percentage and the Company no longer receives a 6.5% preferred return on its investment in the stabilized community. The Company serves as property manager and earns a management fee during the lease-up phase and subsequent operation of each of the communities. The unaffiliated joint venture partner is the general partner of the joint venture and the developer of the communities. At inception of the agreement, the Company had a fixed-price option to acquire the remaining interest in each community beginning one year after completion. If the options are exercised for all five communities, the Company’s total purchase price will be $597.4 million . In the event the Company does not exercise its options to purchase at least two communities, the unaffiliated joint venture partner will be entitled to earn a contingent disposition fee equal to a 6.5% return on its implied equity in the communities not acquired. The unaffiliated joint venture partner is providing certain guaranties and there are construction loans on all five communities. During the three months ended March 31, 2017 , the Company exercised its fixed-price option to purchase the joint venture partner’s ownership interest in one of the five communities, a 244 home operating community in Seattle, Washington, thereby increasing its ownership interest from 49% to 100% , for a cash purchase price of approximately $66.0 million . As a result, the Company consolidated the operating community and it is no longer accounted for as a preferred equity investment in an unconsolidated joint venture (see Note 4, Real Estate Owned ). As a result of the consolidation, the Company recorded a gain on consolidation of $12.2 million , which is included in Income/(loss) from unconsolidated entities on the Consolidated Statements of Operations. As of March 31, 2017 , construction was completed on three of the four remaining communities. Two of the four remaining communities had achieved stabilization. The other two remaining communities have not achieved stabilization and the Company continues to receive a 6.5% preferred return on its investment in those communities. In March 2017, the Company entered into an additional joint venture agreement with the unaffiliated joint venture partner and agreed to pay $15.5 million for a 49% ownership interest in a 155 home community that is currently under construction in Seattle, Washington (together with the May 2015 joint venture described above, the “West Coast Development Joint Ventures”). Consistent with the terms of the May 2015 joint venture agreement, UDR earns a 6.5% preferred return on its investment through the community’s date of stabilization, as defined above, while our joint venture partner 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 and the Company will no longer receive a 6.5% preferred return on its investment in the stabilized community. The Company will serve as property manager and will earn a management fee during the lease-up phase and subsequent operation of the community. The unaffiliated joint venture partner is the general partner and the developer of the community. The Company has concluded it does not control the joint venture and accounts for it under the equity method of accounting. The Company has a fixed-price option to acquire the remaining interest in the community beginning one year after completion for a total price of $61.3 million . The unaffiliated joint venture partner is providing certain guaranties and there is a construction loan on the community. The Company's recorded equity investment in the West Coast Development Joint Ventures at March 31, 2017 and December 31, 2016 of $145.3 million and $150.3 million , respectively, is inclusive of outside basis costs and our accrued but unpaid preferred return. As of March 31, 2017 and December 31, 2016 , the Company had deferred fees and deferred profit of $9.7 million and $9.5 million , respectively, which will be recognized through earnings 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 of $2.6 million and $2.8 million for the three months ended March 31, 2017 and 2016 , respectively, for our management of the communities held by the joint ventures and partnerships. 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 months ended March 31, 2017 and 2016 . Combined summary balance sheets relating to the unconsolidated joint ventures and partnerships (not just our proportionate share) are presented below as of March 31, 2017 and December 31, 2016 ( dollars in thousands ): March 31, December 31, 2016 Total real estate, net $ 2,904,183 $ 2,901,067 Cash and cash equivalents 28,676 32,503 Other assets 17,288 19,047 Total assets $ 2,950,147 $ 2,952,617 Amount due to/(from) UDR $ 2,746 $ 521 Third party debt, net 1,811,490 1,794,379 Accounts payable and accrued liabilities 55,471 66,391 Total liabilities $ 1,869,707 $ 1,861,291 Total equity $ 1,080,440 $ 1,091,326 Combined summary financial information relating to the unconsolidated joint ventures ’ and partnerships ’ operations (not just our proportionate share) is presented below for the three months ended March 31, 2017 and 2016 ( dollars in thousands ) : Three Months Ended March 31, 2017 2016 Total revenues $ 58,524 $ 55,037 Property operating expenses (21,834 ) (23,413 ) Real estate depreciation and amortization (23,333 ) (18,943 ) Operating income/(loss) 13,357 12,681 Interest expense (17,690 ) (16,181 ) Net income/(loss) $ (4,333 ) $ (3,500 )

Unconsolidated Entities (UNITED

Unconsolidated Entities (UNITED DOMINION REALTY, L.P.) Unconsolidated Entities (UNITED DOMINION REALTY, L.P.)	3 Months Ended
	Mar. 31, 2017
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. The Company recognizes earnings or losses from our investments in unconsolidated joint ventures and partnerships consisting of our proportionate share of the net earnings 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 March 31, 2017 and December 31, 2016 (dollars in thousands) : Joint Venture Location of Properties Number of Properties Number of Apartment Homes Investment at UDR’s Ownership Interest March 31, March 31, March 31, December 31, March 31, December 31, Operating and development: UDR/MetLife I Los Angeles, CA 1 development community (a) 150 $ 29,182 $ 25,209 50.0 % 50.0 % UDR/MetLife II (b) Various 18 operating communities 4,059 309,409 311,282 50.0 % 50.0 % Other UDR/MetLife Development Joint Ventures 1 operating community; Various 4 development communities (a) 1,437 156,096 160,979 50.6 % 50.6 % UDR/MetLife Vitruvian Park® Addison, TX 3 operating communities; 1 development community (a); 5 land parcels 1,513 73,154 72,414 50.0 % 50.0 % UDR/KFH Washington, D.C. 3 operating communities 660 11,801 12,835 30.0 % 30.0 % Investment in and advances to unconsolidated joint ventures, net, before participating loan investment and preferred equity investment $ 579,642 $ 582,719 Income from investments for the three months ending March 31, Investment at Location Rate Years To Maturity March 31, December 31, 2017 2016 Participating loan investment: Steele Creek Denver, CO 6.5% 0.3 $ 94,002 $ 94,003 $ 1,533 $ 1,519 Preferred equity investment: West Coast Development Joint Ventures (c) Various 6.5% (c) N/A 145,346 150,303 $ 12,766 $ 1,427 Total investment in and advances to unconsolidated joint ventures, net $ 818,990 $ 827,025 (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 upon completion of development. As of March 31, 2017 , 1,018 apartment homes had been completed in Other UDR/MetLife Development Joint Ventures, and no apartment homes had been completed in UDR/MetLife I or in UDR/MetLife Vitruvian Park ® . (b) In September 2015, the 717 Olympic community, which is owned by the UDR/MetLife II joint venture, experienced extensive water damage due to a ruptured water pipe. For the three months ended March 31, 2017 and 2016 , the Company recorded casualty-related charges/(recoveries) of $0.9 million and $(1.1) million , respectively, representing its proportionate share of the total charges/(recoveries) recognized. (c) In May 2015, the Company entered into a joint venture agreement with an unaffiliated joint venture partner and agreed to pay $136.3 million for a 48% ownership interest in a portfolio of five communities that were under construction. The communities are located in three of the Company’s core, coastal markets: Seattle, Washington, Los Angeles and Orange County, California. UDR earns a 6.5% preferred return on its investment through each individual community’s date of stabilization, defined as when a community reaches 80% occupancy for 90 consecutive days, while the joint venture partner is allocated all operating income and expense during the pre-stabilization period. Upon stabilization, income and expense are shared based on each partner’s ownership percentage and the Company no longer receives a 6.5% preferred return on its investment in the stabilized community. The Company serves as property manager and earns a management fee during the lease-up phase and subsequent operation of each of the communities. The unaffiliated joint venture partner is the general partner of the joint venture and the developer of the communities. At inception of the agreement, the Company had a fixed-price option to acquire the remaining interest in each community beginning one year after completion. If the options are exercised for all five communities, the Company’s total purchase price will be $597.4 million . In the event the Company does not exercise its options to purchase at least two communities, the unaffiliated joint venture partner will be entitled to earn a contingent disposition fee equal to a 6.5% return on its implied equity in the communities not acquired. The unaffiliated joint venture partner is providing certain guaranties and there are construction loans on all five communities. During the three months ended March 31, 2017 , the Company exercised its fixed-price option to purchase the joint venture partner’s ownership interest in one of the five communities, a 244 home operating community in Seattle, Washington, thereby increasing its ownership interest from 49% to 100% , for a cash purchase price of approximately $66.0 million . As a result, the Company consolidated the operating community and it is no longer accounted for as a preferred equity investment in an unconsolidated joint venture (see Note 4, Real Estate Owned ). As a result of the consolidation, the Company recorded a gain on consolidation of $12.2 million , which is included in Income/(loss) from unconsolidated entities on the Consolidated Statements of Operations. As of March 31, 2017 , construction was completed on three of the four remaining communities. Two of the four remaining communities had achieved stabilization. The other two remaining communities have not achieved stabilization and the Company continues to receive a 6.5% preferred return on its investment in those communities. In March 2017, the Company entered into an additional joint venture agreement with the unaffiliated joint venture partner and agreed to pay $15.5 million for a 49% ownership interest in a 155 home community that is currently under construction in Seattle, Washington (together with the May 2015 joint venture described above, the “West Coast Development Joint Ventures”). Consistent with the terms of the May 2015 joint venture agreement, UDR earns a 6.5% preferred return on its investment through the community’s date of stabilization, as defined above, while our joint venture partner 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 and the Company will no longer receive a 6.5% preferred return on its investment in the stabilized community. The Company will serve as property manager and will earn a management fee during the lease-up phase and subsequent operation of the community. The unaffiliated joint venture partner is the general partner and the developer of the community. The Company has concluded it does not control the joint venture and accounts for it under the equity method of accounting. The Company has a fixed-price option to acquire the remaining interest in the community beginning one year after completion for a total price of $61.3 million . The unaffiliated joint venture partner is providing certain guaranties and there is a construction loan on the community. The Company's recorded equity investment in the West Coast Development Joint Ventures at March 31, 2017 and December 31, 2016 of $145.3 million and $150.3 million , respectively, is inclusive of outside basis costs and our accrued but unpaid preferred return. As of March 31, 2017 and December 31, 2016 , the Company had deferred fees and deferred profit of $9.7 million and $9.5 million , respectively, which will be recognized through earnings 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 of $2.6 million and $2.8 million for the three months ended March 31, 2017 and 2016 , respectively, for our management of the communities held by the joint ventures and partnerships. 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 months ended March 31, 2017 and 2016 . Combined summary balance sheets relating to the unconsolidated joint ventures and partnerships (not just our proportionate share) are presented below as of March 31, 2017 and December 31, 2016 ( dollars in thousands ): March 31, December 31, 2016 Total real estate, net $ 2,904,183 $ 2,901,067 Cash and cash equivalents 28,676 32,503 Other assets 17,288 19,047 Total assets $ 2,950,147 $ 2,952,617 Amount due to/(from) UDR $ 2,746 $ 521 Third party debt, net 1,811,490 1,794,379 Accounts payable and accrued liabilities 55,471 66,391 Total liabilities $ 1,869,707 $ 1,861,291 Total equity $ 1,080,440 $ 1,091,326 Combined summary financial information relating to the unconsolidated joint ventures ’ and partnerships ’ operations (not just our proportionate share) is presented below for the three months ended March 31, 2017 and 2016 ( dollars in thousands ) : Three Months Ended March 31, 2017 2016 Total revenues $ 58,524 $ 55,037 Property operating expenses (21,834 ) (23,413 ) Real estate depreciation and amortization (23,333 ) (18,943 ) Operating income/(loss) 13,357 12,681 Interest expense (17,690 ) (16,181 ) Net income/(loss) $ (4,333 ) $ (3,500 )
United Dominion Reality L.P. [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments and Joint Ventures Disclosure [Text Block]	UNCONSOLIDATED ENTITIES The DownREIT Partnership is accounted for by the Operating Partnership under the equity method of accounting and is included in Investment in unconsolidated entities on the Consolidated Balance Sheets. The Operating Partnership recognizes earnings or losses from its investments in unconsolidated entities consisting of our proportionate share of the net earnings or losses of the partnership in accordance with the Partnership Agreement. The DownREIT Partnership is a VIE as the limited partners lack substantive kick-out rights and substantive participating rights. The Operating Partnership is not the primary beneficiary of the DownREIT Partnership as it lacks the power to direct the activities that most significantly impact its economic performance and will continue to account for its interest as an equity method investment. See Note 2, Significant Accounting Policies . As of March 31, 2017 , the DownREIT Partnership owned 13 communities with 6,261 apartment homes. The Operating Partnership’s investment in the DownREIT Partnership was $103.3 million and $112.9 million as of March 31, 2017 and December 31, 2016 , respectively. Combined summary balance sheets relating to all of the DownREIT Partnership (not just our proportionate share) are presented below as of March 31, 2017 and December 31, 2016 ( dollars in thousands ): March 31, December 31, 2016 Total real estate, net $ 1,400,046 $ 1,413,983 Cash and cash equivalents 35 66 Note receivable from the General Partner 126,500 126,500 Other assets 4,498 4,843 Total assets $ 1,531,079 $ 1,545,392 Secured debt, net 442,172 443,607 Other liabilities 23,976 27,571 Total liabilities 466,148 471,178 Total capital 1,064,931 1,074,214 Total liabilities and capital $ 1,531,079 $ 1,545,392 Combined summary financial information relating to all of the DownREIT Partnership (not just our proportionate share) is presented below for the three months ended March 31, 2017 and 2016 ( dollars in thousands ) : Three Months Ended March 31, 2017 2016 Rental income $ 33,298 $ 31,617 Property operating expenses (13,976 ) (14,269 ) Real estate depreciation and amortization (20,608 ) (30,053 ) Operating income/(loss) (1,286 ) (12,705 ) Interest expense (3,860 ) (3,741 ) Interest income on note receivable from the General Partner 1,166 1,180 Net income/(loss) $ (3,980 ) $ (15,266 )

Secured and Unsecured Debt

Secured and Unsecured Debt	3 Months Ended
	Mar. 31, 2017
Debt Disclosure [Abstract]
Debt Disclosure [Text Block]	SECURED AND UNSECURED DEBT, NET The following is a summary of our secured and unsecured debt at March 31, 2017 and December 31, 2016 ( dollars in thousands ): Three Months Ended Principal Outstanding March 31, 2017 March 31, December 31, 2016 Weighted Average Weighted Average Number of Communities Secured Debt: Fixed Rate Debt Mortgage notes payable (a) $ 401,135 $ 402,996 4.04 % 6.1 7 Fannie Mae credit facilities (b) 355,836 355,836 5.06 % 2.6 10 Deferred financing costs (2,482 ) (2,681 ) Total fixed rate secured debt, net 754,489 756,151 4.53 % 4.4 17 Variable Rate Debt Tax-exempt secured notes payable (c) 94,700 94,700 1.42 % 5.9 2 Fannie Mae credit facilities (b) 182,606 280,946 2.05 % 1.3 5 Deferred financing costs (288 ) (939 ) Total variable rate secured debt, net 277,018 374,707 1.84 % 2.9 7 Total Secured Debt, net 1,031,507 1,130,858 3.80 % 4.0 24 Unsecured Debt: Variable Rate Debt Borrowings outstanding under unsecured credit facility due January 2020 (d) (h) — — — % 2.8 Borrowings outstanding under unsecured commercial paper program due April 2017 (e) (h) 220,000 — 1.24 % 0.0 Borrowings outstanding under unsecured working capital credit facility due January 2019 (f) 36,140 21,350 1.88 % 1.8 Term Loan Facility due January 2021 (d) (h) 35,000 35,000 1.73 % 3.8 Fixed Rate Debt 4.25% Medium-Term Notes due June 2018 (net of discounts of $501 and $608, respectively) (h) 299,499 299,392 4.25 % 1.2 3.70% Medium-Term Notes due October 2020 (net of discounts of $28 and $30, respectively) (h) 299,972 299,970 3.70 % 3.5 2.34% Term Loan Facility due January 2021 (d) (h) 315,000 315,000 2.34 % 3.8 4.63% Medium-Term Notes due January 2022 (net of discounts of $1,715 and $1,805 respectively) (h) 398,285 398,195 4.63 % 4.8 3.75% Medium-Term Notes due July 2024 (net of discounts of $756 and $782, respectively) (h) 299,244 299,218 3.75 % 7.3 8.50% Debentures due September 2024 15,644 15,644 8.50 % 7.5 4.00% Medium-Term Notes due October 2025 (net of discounts of $585 and $602, respectively) (g) (h) 299,415 299,398 4.00 % 8.5 2.95% Medium-Term Notes due September 2026 (h) 300,000 300,000 2.95 % 9.4 Other 21 21 Deferred financing costs (12,435 ) (12,568 ) Total Unsecured Debt, net 2,505,785 2,270,620 3.52 % 4.9 Total Debt, net $ 3,537,292 $ 3,401,478 3.67 % 4.6 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. Our secured debt instruments generally feature either monthly interest and principal or monthly interest-only payments with balloon payments due at maturity. As of March 31, 2017 , secured debt encumbered $1.9 billion or 19.7% of UDR’s total real estate owned based upon gross book value ( $7.9 billion or 80.3% of UDR’s real estate owned based on gross book value is unencumbered). (a) At March 31, 2017 , fixed rate mortgage notes payable are generally due in monthly installments of principal and interest and mature at various dates from May 2019 through November 2026 and carry interest rates ranging from 3.15% to 5.86% . 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 value to interest expense over the life of the underlying debt instrument. During the three months ended March 31, 2017 and 2016 , the Company had $0.7 million and $0.8 million , respectively, of amortization of the fair market adjustment of debt assumed in the acquisition of properties, which was included in Interest expense on the Consolidated Statements of Operations. The unamortized fair market adjustment was a net premium of $10.4 million and $11.2 million at March 31, 2017 and December 31, 2016 , respectively. (b) UDR had three secured credit facilities with Fannie Mae with an aggregate commitment of $538.4 million at March 31, 2017 . The Fannie Mae credit facilities mature at various dates from May 2017 through July 2020 and bear interest at floating and fixed rates. At March 31, 2017 , $355.8 million of the outstanding balance was fixed and had a weighted average interest rate of 5.06% and the remaining balance of $182.6 million had a weighted average variable interest rate of 2.05% . During the three months ended March 31, 2017 , the Company prepaid $98.3 million of its secured credit facilities with borrowings under the Company's unsecured commercial paper program. Further information related to these credit facilities is as follows (dollars in thousands) : March 31, December 31, 2016 Borrowings outstanding $ 538,442 $ 636,782 Weighted average borrowings during the period ended 604,002 737,802 Maximum daily borrowings during the period ended 636,782 813,544 Weighted average interest rate during the period ended 3.9 % 3.9 % Weighted average interest rate at the end of the period 4.0 % 3.8 % (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 ranging from 1.39% to 1.44% as of March 31, 2017 . (d) The Company has a $1.1 billion unsecured revolving credit facility (the “Revolving Credit Facility”) and a $350.0 million unsecured term loan facility (the “Term Loan Facility”). The credit agreement for these facilities (the "Credit Agreement") 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 . 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, 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 following is a summary of short-term bank borrowings under the Revolving Credit Facility at March 31, 2017 and December 31, 2016 (dollars in thousands): March 31, December 31, 2016 Total revolving credit facility $ 1,100,000 $ 1,100,000 Borrowings outstanding at end of period (1) — — Weighted average daily borrowings during the period ended 9,222 161,505 Maximum daily borrowings during the period ended 120,000 340,000 Weighted average interest rate during the period ended 1.6 % 1.4 % Interest rate at end of the period — % — % (1) Excludes $2.9 million and $2.9 million of letters of credit at March 31, 2017 and December 31, 2016 , respectively. (e) On January 23, 2017, the Company entered into an unsecured commercial paper program. Under the terms of the program, the Company may issue unsecured commercial paper up to a maximum aggregate amount outstanding of $500 million . The notes are sold under customary terms in the United States commercial paper market and rank pari passu with all of the Company’s other unsecured indebtedness. The notes are fully and unconditionally guaranteed by the Operating Partnership. The following is a summary of short-term bank borrowings under the unsecured commercial paper program at March 31, 2017 and December 31, 2016 (dollars in thousands): March 31, December 31, 2016 Total unsecured commercial paper program $ 500,000 $ — Borrowings outstanding at end of period 220,000 — Weighted average daily borrowings during the period ended 80,228 — Maximum daily borrowings during the period ended 220,000 — Weighted average interest rate during the period ended 1.2 % — % Interest rate at end of the period 1.2 % — % (f) The Company has a working capital credit facility, which provides for a $75 million unsecured revolving credit facility (the “Working Capital Credit Facility”) with a scheduled maturity date of January 1, 2019. Based on the Company’s current credit rating, the Working Capital Credit Facility has an interest rate equal to LIBOR plus a margin of 90 basis points. Depending on the Company’s credit rating, the margin ranges from 85 to 155 basis points. The following is a summary of short-term bank borrowings under the Working Capital Credit Facility at March 31, 2017 and December 31, 2016 (dollars in thousands): March 31, December 31, 2016 Total revolving working capital credit facility $ 75,000 $ 75,000 Borrowings outstanding at end of period 36,140 21,350 Weighted average daily borrowings during the period ended 26,714 21,936 Maximum daily borrowings during the period ended 67,799 69,633 Weighted average interest rate during the period ended 1.7 % 1.4 % Interest rate at end of the period 1.9 % 1.7 % (g) The Company previously entered into forward starting interest rate swaps to hedge against interest rate risk on $200 million of this debt. The all-in weighted average interest rate, inclusive of the impact of these interest rate swaps, was 4.55% . (h) 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 ten calendar years subsequent to March 31, 2017 are as follows (dollars in thousands): Year Total Fixed Secured Debt Total Variable Secured Debt Total Secured Debt Total Unsecured Debt Total Debt 2017 $ 3,310 $ 46,568 $ 49,878 $ 220,000 $ 269,878 2018 74,637 136,038 210,675 300,000 510,675 2019 249,395 67,700 317,095 36,140 353,235 2020 198,076 — 198,076 300,000 498,076 2021 1,117 — 1,117 350,000 351,117 2022 1,157 — 1,157 400,000 401,157 2023 41,245 — 41,245 — 41,245 2024 — — — 315,644 315,644 2025 127,600 — 127,600 300,000 427,600 2026 50,000 — 50,000 300,000 350,000 Thereafter — 27,000 27,000 — 27,000 Subtotal 746,537 277,306 1,023,843 2,521,784 3,545,627 Non-cash (a) 7,952 (288 ) 7,664 (15,999 ) (8,335 ) Total $ 754,489 $ 277,018 $ 1,031,507 $ 2,505,785 $ 3,537,292 (a) Includes the unamortized balance of fair market value adjustments, premiums/discounts and deferred financing costs. For the three months ended March 31, 2017 and 2016 , the Company amortized $1.1 million and $1.3 million , respectively, of deferred financing costs into Interest expense . We were in compliance with the covenants of our debt instruments at March 31, 2017 .

Debt (UNITED DOMINION REALTY, L

Debt (UNITED DOMINION REALTY, L.P.)	3 Months Ended
	Mar. 31, 2017
Entity Information [Line Items]
DEBT	SECURED AND UNSECURED DEBT, NET The following is a summary of our secured and unsecured debt at March 31, 2017 and December 31, 2016 ( dollars in thousands ): Three Months Ended Principal Outstanding March 31, 2017 March 31, December 31, 2016 Weighted Average Weighted Average Number of Communities Secured Debt: Fixed Rate Debt Mortgage notes payable (a) $ 401,135 $ 402,996 4.04 % 6.1 7 Fannie Mae credit facilities (b) 355,836 355,836 5.06 % 2.6 10 Deferred financing costs (2,482 ) (2,681 ) Total fixed rate secured debt, net 754,489 756,151 4.53 % 4.4 17 Variable Rate Debt Tax-exempt secured notes payable (c) 94,700 94,700 1.42 % 5.9 2 Fannie Mae credit facilities (b) 182,606 280,946 2.05 % 1.3 5 Deferred financing costs (288 ) (939 ) Total variable rate secured debt, net 277,018 374,707 1.84 % 2.9 7 Total Secured Debt, net 1,031,507 1,130,858 3.80 % 4.0 24 Unsecured Debt: Variable Rate Debt Borrowings outstanding under unsecured credit facility due January 2020 (d) (h) — — — % 2.8 Borrowings outstanding under unsecured commercial paper program due April 2017 (e) (h) 220,000 — 1.24 % 0.0 Borrowings outstanding under unsecured working capital credit facility due January 2019 (f) 36,140 21,350 1.88 % 1.8 Term Loan Facility due January 2021 (d) (h) 35,000 35,000 1.73 % 3.8 Fixed Rate Debt 4.25% Medium-Term Notes due June 2018 (net of discounts of $501 and $608, respectively) (h) 299,499 299,392 4.25 % 1.2 3.70% Medium-Term Notes due October 2020 (net of discounts of $28 and $30, respectively) (h) 299,972 299,970 3.70 % 3.5 2.34% Term Loan Facility due January 2021 (d) (h) 315,000 315,000 2.34 % 3.8 4.63% Medium-Term Notes due January 2022 (net of discounts of $1,715 and $1,805 respectively) (h) 398,285 398,195 4.63 % 4.8 3.75% Medium-Term Notes due July 2024 (net of discounts of $756 and $782, respectively) (h) 299,244 299,218 3.75 % 7.3 8.50% Debentures due September 2024 15,644 15,644 8.50 % 7.5 4.00% Medium-Term Notes due October 2025 (net of discounts of $585 and $602, respectively) (g) (h) 299,415 299,398 4.00 % 8.5 2.95% Medium-Term Notes due September 2026 (h) 300,000 300,000 2.95 % 9.4 Other 21 21 Deferred financing costs (12,435 ) (12,568 ) Total Unsecured Debt, net 2,505,785 2,270,620 3.52 % 4.9 Total Debt, net $ 3,537,292 $ 3,401,478 3.67 % 4.6 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. Our secured debt instruments generally feature either monthly interest and principal or monthly interest-only payments with balloon payments due at maturity. As of March 31, 2017 , secured debt encumbered $1.9 billion or 19.7% of UDR’s total real estate owned based upon gross book value ( $7.9 billion or 80.3% of UDR’s real estate owned based on gross book value is unencumbered). (a) At March 31, 2017 , fixed rate mortgage notes payable are generally due in monthly installments of principal and interest and mature at various dates from May 2019 through November 2026 and carry interest rates ranging from 3.15% to 5.86% . 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 value to interest expense over the life of the underlying debt instrument. During the three months ended March 31, 2017 and 2016 , the Company had $0.7 million and $0.8 million , respectively, of amortization of the fair market adjustment of debt assumed in the acquisition of properties, which was included in Interest expense on the Consolidated Statements of Operations. The unamortized fair market adjustment was a net premium of $10.4 million and $11.2 million at March 31, 2017 and December 31, 2016 , respectively. (b) UDR had three secured credit facilities with Fannie Mae with an aggregate commitment of $538.4 million at March 31, 2017 . The Fannie Mae credit facilities mature at various dates from May 2017 through July 2020 and bear interest at floating and fixed rates. At March 31, 2017 , $355.8 million of the outstanding balance was fixed and had a weighted average interest rate of 5.06% and the remaining balance of $182.6 million had a weighted average variable interest rate of 2.05% . During the three months ended March 31, 2017 , the Company prepaid $98.3 million of its secured credit facilities with borrowings under the Company's unsecured commercial paper program. Further information related to these credit facilities is as follows (dollars in thousands) : March 31, December 31, 2016 Borrowings outstanding $ 538,442 $ 636,782 Weighted average borrowings during the period ended 604,002 737,802 Maximum daily borrowings during the period ended 636,782 813,544 Weighted average interest rate during the period ended 3.9 % 3.9 % Weighted average interest rate at the end of the period 4.0 % 3.8 % (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 ranging from 1.39% to 1.44% as of March 31, 2017 . (d) The Company has a $1.1 billion unsecured revolving credit facility (the “Revolving Credit Facility”) and a $350.0 million unsecured term loan facility (the “Term Loan Facility”). The credit agreement for these facilities (the "Credit Agreement") 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 . 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, 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 following is a summary of short-term bank borrowings under the Revolving Credit Facility at March 31, 2017 and December 31, 2016 (dollars in thousands): March 31, December 31, 2016 Total revolving credit facility $ 1,100,000 $ 1,100,000 Borrowings outstanding at end of period (1) — — Weighted average daily borrowings during the period ended 9,222 161,505 Maximum daily borrowings during the period ended 120,000 340,000 Weighted average interest rate during the period ended 1.6 % 1.4 % Interest rate at end of the period — % — % (1) Excludes $2.9 million and $2.9 million of letters of credit at March 31, 2017 and December 31, 2016 , respectively. (e) On January 23, 2017, the Company entered into an unsecured commercial paper program. Under the terms of the program, the Company may issue unsecured commercial paper up to a maximum aggregate amount outstanding of $500 million . The notes are sold under customary terms in the United States commercial paper market and rank pari passu with all of the Company’s other unsecured indebtedness. The notes are fully and unconditionally guaranteed by the Operating Partnership. The following is a summary of short-term bank borrowings under the unsecured commercial paper program at March 31, 2017 and December 31, 2016 (dollars in thousands): March 31, December 31, 2016 Total unsecured commercial paper program $ 500,000 $ — Borrowings outstanding at end of period 220,000 — Weighted average daily borrowings during the period ended 80,228 — Maximum daily borrowings during the period ended 220,000 — Weighted average interest rate during the period ended 1.2 % — % Interest rate at end of the period 1.2 % — % (f) The Company has a working capital credit facility, which provides for a $75 million unsecured revolving credit facility (the “Working Capital Credit Facility”) with a scheduled maturity date of January 1, 2019. Based on the Company’s current credit rating, the Working Capital Credit Facility has an interest rate equal to LIBOR plus a margin of 90 basis points. Depending on the Company’s credit rating, the margin ranges from 85 to 155 basis points. The following is a summary of short-term bank borrowings under the Working Capital Credit Facility at March 31, 2017 and December 31, 2016 (dollars in thousands): March 31, December 31, 2016 Total revolving working capital credit facility $ 75,000 $ 75,000 Borrowings outstanding at end of period 36,140 21,350 Weighted average daily borrowings during the period ended 26,714 21,936 Maximum daily borrowings during the period ended 67,799 69,633 Weighted average interest rate during the period ended 1.7 % 1.4 % Interest rate at end of the period 1.9 % 1.7 % (g) The Company previously entered into forward starting interest rate swaps to hedge against interest rate risk on $200 million of this debt. The all-in weighted average interest rate, inclusive of the impact of these interest rate swaps, was 4.55% . (h) 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 ten calendar years subsequent to March 31, 2017 are as follows (dollars in thousands): Year Total Fixed Secured Debt Total Variable Secured Debt Total Secured Debt Total Unsecured Debt Total Debt 2017 $ 3,310 $ 46,568 $ 49,878 $ 220,000 $ 269,878 2018 74,637 136,038 210,675 300,000 510,675 2019 249,395 67,700 317,095 36,140 353,235 2020 198,076 — 198,076 300,000 498,076 2021 1,117 — 1,117 350,000 351,117 2022 1,157 — 1,157 400,000 401,157 2023 41,245 — 41,245 — 41,245 2024 — — — 315,644 315,644 2025 127,600 — 127,600 300,000 427,600 2026 50,000 — 50,000 300,000 350,000 Thereafter — 27,000 27,000 — 27,000 Subtotal 746,537 277,306 1,023,843 2,521,784 3,545,627 Non-cash (a) 7,952 (288 ) 7,664 (15,999 ) (8,335 ) Total $ 754,489 $ 277,018 $ 1,031,507 $ 2,505,785 $ 3,537,292 (a) Includes the unamortized balance of fair market value adjustments, premiums/discounts and deferred financing costs. For the three months ended March 31, 2017 and 2016 , the Company amortized $1.1 million and $1.3 million , respectively, of deferred financing costs into Interest expense . We were in compliance with the covenants of our debt instruments at March 31, 2017 .
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
DEBT	DEBT, NET 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 March 31, 2017 and December 31, 2016 ( dollars in thousands ): Principal Outstanding For the Three Months Ended March 31, 2017 March 31, December 31, 2016 Weighted Average Interest Rate Weighted Average Years to Maturity Number of Communities Encumbered Fixed Rate Debt Fannie Mae credit facilities $ 228,870 $ 244,912 5.07 % 2.6 6 Deferred financing costs (718 ) (1,070 ) Total fixed rate secured debt, net 228,152 243,842 5.07 % 2.6 6 Variable Rate Debt Tax-exempt secured note payable 27,000 27,000 1.39 % 15.0 1 Fannie Mae credit facilities 81,339 163,637 2.34 % 1.7 2 Deferred financing costs (251 ) (505 ) Total variable rate secured debt, net 108,088 190,132 2.10 % 5.0 3 Total Secured Debt, net $ 336,240 $ 433,974 4.26 % 3.4 9 As of March 31, 2017 , an aggregate commitment of $310.2 million of the General Partner's secured credit facilities with Fannie Mae was owed by the Operating Partnership based on the ownership of the assets securing the debt. The entire commitment was outstanding at March 31, 2017 . The portions of the Fannie Mae credit facilities owed by the Operating Partnership mature at various dates from December 2018 through July 2020 and bear interest at floating and fixed rates. At March 31, 2017 , $228.9 million of the outstanding balance was fixed and had a weighted average interest rate of 5.07% and the remaining balance of $81.3 million on these facilities had a weighted average variable interest rate of 2.34% . The following information relates to the credit facilities owed by the Operating Partnership (dollars in thousands) : March 31, December 31, 2016 Borrowings outstanding $ 310,209 $ 408,549 Weighted average borrowings during the period ended 375,770 414,759 Maximum daily borrowings during the period ended 408,549 421,001 Weighted average interest rate during the period ended 4.1 % 3.9 % Interest rate at the end of the period 4.4 % 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 Operating Partnership did not have any unamortized fair value adjustments associated with the fixed rate debt instruments on the Operating Partnership’s properties. Fixed Rate Debt At March 31, 2017 , the General Partner had borrowings against its fixed rate facilities of $355.8 million , of which $228.9 million was owed by the Operating Partnership based on the ownership of the assets securing the debt. As of March 31, 2017 , the fixed rate Fannie Mae credit facilities owed by the Operating Partnership had a weighted average fixed interest rate of 5.07% . 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 1.39% as of March 31, 2017 . Secured credit facilities. At March 31, 2017 , the General Partner had borrowings against its variable rate facilities of $182.6 million , of which $81.3 million was owed by the Operating Partnership based on the ownership of the assets securing the debt. As of March 31, 2017 , the variable rate borrowings under the Fannie Mae credit facilities owed by the Operating Partnership had a weighted average floating interest rate of 2.34% . The aggregate maturities of the Operating Partnership’s secured debt due during each of the next ten calendar years subsequent to March 31, 2017 are as follows (dollars in thousands): Fixed Variable Year Secured Credit Facilities Tax-Exempt Secured Notes Payable Secured Credit Facilities Total 2017 $ — $ — $ — $ — 2018 41,854 — 81,339 123,193 2019 133,204 — — 133,204 2020 53,812 — — 53,812 2021 — — — — 2022 — — — — 2023 — — — — 2024 — — — — 2025 — — — — 2026 — — — — Thereafter — 27,000 — 27,000 Subtotal 228,870 27,000 81,339 337,209 Non-cash (a) (718 ) (84 ) (167 ) (969 ) Total $ 228,152 $ 26,916 $ 81,172 $ 336,240 (a) Includes the unamortized balance of fair market value adjustments, premiums/discounts, deferred hedge gains, and deferred financing costs. For the three months ended March 31, 2017 and 2016 , the Operating Partnership amortized $0.1 million and $0.2 million , respectively, of deferred financing costs into Interest expense . 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 $1.1 billion and unsecured commercial paper program with an aggregate borrowing capacity of $500 million , $300 million of medium-term notes due June 2018 , $300 million of medium-term notes due October 2020 , a $350 million term loan facility due January 2021 , $400 million of medium-term notes due January 2022 , $300 million of medium-term notes due July 2024 , $300 million of medium-term notes due October 2025 and $300 million of medium-term notes due September 2026 . As of March 31, 2017 and December 31, 2016 , the General Partner did not have an outstanding balance under the unsecured revolving credit facility

Income_(Loss) Per Share

Income/(Loss) Per Share	3 Months Ended
	Mar. 31, 2017
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 March 31, 2017 2016 Numerator for income/(loss) per share: Income/(loss) from continuing operations $ 26,264 $ 8,534 Gain/(loss) on sale of real estate owned, net of tax 2,132 3,070 Net (income)/loss attributable to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (2,338 ) (905 ) Net (income)/loss attributable to noncontrolling interests (91 ) (306 ) Net income/(loss) attributable to UDR, Inc. 25,967 10,393 Distributions to preferred stockholders — Series E (Convertible) (929 ) (929 ) Income/(loss) attributable to common stockholders - basic and diluted $ 25,038 $ 9,464 Denominator for income/(loss) per share: Weighted average common shares outstanding 267,402 263,355 Non-vested restricted stock awards (612 ) (899 ) Denominator for basic income/(loss) per share 266,790 262,456 Incremental shares issuable from assumed conversion of stock options, unvested LTIP Units and unvested restricted stock 1,898 1,829 Denominator for diluted income/(loss) per share 268,688 264,285 Income/(loss) per weighted average common share: Basic $ 0.09 $ 0.04 Diluted $ 0.09 $ 0.04 Basic income/(loss) per common share is computed based upon the weighted average number of common shares outstanding. Diluted income/(loss) per common 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 and DownREIT Units, convertible preferred stock, stock options, unvested long-term incentive plan units ("LTIP Units") and unvested 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. For the three months ended March 31, 2017 and 2016 , the effect of the conversion of the OP Units, DownREIT Units and convertible preferred stock was not dilutive and therefore not included in the above calculation. 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 months ended March 31, 2017 and 2016 (shares in thousands) : Three Months Ended March 31, 2017 2016 OP/DownREIT Units 24,962 25,191 Convertible preferred stock 3,028 3,028 Stock options, unvested LTIP Units and unvested restricted stock 1,898 1,829

Noncontrolling Interests

Noncontrolling Interests	3 Months Ended
	Mar. 31, 2017
Noncontrolling Interest [Abstract]
NONCONTROLLING INTERESTS	NONCONTROLLING INTERESTS Redeemable Noncontrolling Interests in the Operating Partnership and DownREIT Partnership Interests in the Operating Partnership and the DownREIT Partnership held by limited partners are represented by OP Units and DownREIT Units, respectively. The income is allocated to holders of OP Units/DownREIT Units based upon net income attributable to common stockholders and the weighted average number of OP Units/DownREIT Units outstanding to total common shares plus OP Units/DownREIT Units outstanding during the period. Capital contributions, distributions, and profits and losses are allocated to noncontrolling interests in accordance with the terms of the partnership agreements of the Operating Partnership and the DownREIT Partnership. Limited partners of the Operating Partnership and the DownREIT Partnership have the right to require such partnership to redeem all or a portion of the OP Units/DownREIT Units held by the limited partner at a redemption price equal to and in the form of the Cash Amount (as defined in the partnership agreement of the Operating Partnership or the DownREIT Partnership, as applicable), provided that such OP Units/DownREIT Units have been outstanding for at least one year, subject to certain exceptions. UDR, as the general partner of the Operating Partnership and the DownREIT Partnership may, in its sole discretion, purchase the OP Units/DownREIT 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/DownREIT Unit), as defined in the partnership agreement of the Operating Partnership or the DownREIT Partnership, as applicable. Accordingly, the Company records the OP Units/DownREIT Units outside of permanent equity and reports the OP Units/DownREIT 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 and DownREIT Partnership for the following period ( dollars in thousands ): Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership, December 31, 2016 $ 909,482 Mark-to-market adjustment to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership 281 Conversion of OP Units/DownREIT Units to Common Stock (1,850 ) Net income/(loss) attributable to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership 2,338 Distributions to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (7,919 ) Vesting of Long-Term Incentive Plan Units 2,317 Allocation of other comprehensive income/(loss) 129 Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership, March 31, 2017 $ 904,778 Noncontrolling Interests Noncontrolling interests represent interests of unrelated partners and unvested LTIP Units in certain consolidated affiliates, and is presented as part of equity in the Consolidated Balance Sheets since these interests are not redeemable. During the three months ended March 31, 2017 and 2016 , Net (income)/loss attributable to noncontrolling interests was $(0.1) million and $(0.3) million , respectively. The Company grants LTIP Units to certain employees and non-employee directors. The LTIP Units represent an ownership interest in the Operating Partnership and have vesting terms of between one and three years, specific to the individual grants. Noncontrolling interests related to long-term incentive plan units represent the unvested LTIP Units of these employees and non-employee directors in the Operating Partnership. The net income/(loss) allocated to the unvested LTIP Units is included in Net (income)/loss attributable to noncontrolling interests on the Consolidated Statements of Operations.

Related Party Transactions (UNI

Related Party Transactions (UNITED DOMINION REALTY, L.P.)	3 Months Ended
	Mar. 31, 2017
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 the General Partner of $114.4 million and $19.7 million at March 31, 2017 and December 31, 2016 , respectively, which are reflected as increases/(decreases) of capital on the Consolidated Balance Sheets. Allocation of General and Administrative Expenses The General Partner shares various general and administrative costs, employees and other overhead costs with the Operating Partnership including legal assistance, acquisitions analysis, marketing, human resources, IT, accounting, rent, supplies and advertising, and allocates these costs to the Operating Partnership first on the basis of direct usage when identifiable, with the remainder allocated based on the reasonably anticipated benefits to the parties. The general and administrative expenses allocated to the Operating Partnership by UDR were $4.5 million and $4.6 million during the three months ended March 31, 2017 and 2016 , 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 March 31, 2017 and 2016 , the Operating Partnership reimbursed the General Partner $3.6 million and $3.6 million , respectively, for shared services related to corporate level property management costs incurred by the General Partner. These shared costs reimbursements and related party management fees are initially recorded within the line item General and administrative on the Consolidated Statements of Operations, and a portion related to management costs is reclassified to Property management on the Consolidated Statements of Operations. (See further discussion below.) Shared Services/Management Fee The Operating Partnership self-manages its own properties and is party to an Inter-Company Employee and Cost Sharing Agreement with the General Partner. This agreement provides for reimbursements to the General Partner for the Operating Partnership’s allocable share of costs incurred by the General Partner for (a) shared services of corporate level property management employees and related support functions and costs, and (b) general and administrative costs. As discussed above, the reimbursement for shared services is classified in Property management on the Consolidated Statements of Operations. Notes Payable to the General Partner As of both March 31, 2017 and December 31, 2016 , the Operating Partnership had $273.3 million of unsecured notes payable to the General Partner at annual interest rates between 4.12% and 5.34% . Certain limited partners of the Operating Partnership have provided guarantees or reimbursement agreements 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 , December 31, 2023 and April 1, 2026 , and interest payments are made monthly. The Operating Partnership recognized interest expense on the notes payable of $3.1 million and $3.1 million during the three months ended March 31, 2017 and 2016 , respectively.

Fair Value of Derivatives and F

Fair Value of Derivatives and Financial Instruments	3 Months Ended
	Mar. 31, 2017
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 March 31, 2017 and December 31, 2016 are summarized as follows (dollars in thousands) : Fair Value at March 31, 2017, Using Total Carrying Amount in Statement of Financial Position at March 31, 2017 Fair Value Estimate at March 31, 2017 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) $ 19,790 $ 19,735 $ — $ — $ 19,735 Derivatives - Interest rate contracts (b) 5,067 5,067 — 5,067 — Total assets $ 24,857 $ 24,802 $ — $ 5,067 $ 19,735 Derivatives - Interest rate contracts (b) $ 9 $ 9 $ — $ 9 $ — Secured debt instruments - fixed rate: (c) Mortgage notes payable 401,135 395,504 — — 395,504 Fannie Mae credit facilities 355,836 365,391 — — 365,391 Secured debt instruments - variable rate: (c) Tax-exempt secured notes payable 94,700 94,700 — — 94,700 Fannie Mae credit facilities 182,606 182,606 — — 182,606 Unsecured debt instruments: (c) Working capital credit facility 36,140 36,140 — — 36,140 Commercial paper program 220,000 220,000 — — 220,000 Unsecured notes 2,262,059 2,302,863 — — 2,302,863 Total liabilities $ 3,552,485 $ 3,597,213 $ — $ 9 $ 3,597,204 Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (d) $ 904,778 $ 904,778 $ — $ 904,778 $ — Fair Value at December 31, 2016, Using Total Carrying Amount in Statement of Financial Position at December 31, 2016 Fair Value Estimate at December 31, 2016 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) $ 19,790 $ 19,645 $ — $ — $ 19,645 Derivatives - Interest rate contracts (b) 4,360 4,360 — 4,360 — Total assets $ 24,150 $ 24,005 $ — $ 4,360 $ 19,645 Derivatives- Interest rate contracts (b) $ 413 $ 413 $ — $ 413 $ — Secured debt instruments - fixed rate: (c) Mortgage notes payable 402,996 396,045 — — 396,045 Fannie Mae credit facilities 355,836 365,693 — — 365,693 Secured debt instruments - variable rate: (c) Tax-exempt secured notes payable 94,700 94,700 — — 94,700 Fannie Mae credit facilities 280,946 280,946 — — 280,946 Unsecured debt instruments: (c) Working capital credit facility 21,350 21,350 — — 21,350 Unsecured notes 2,261,838 2,304,492 — — 2,304,492 Total liabilities $ 3,418,079 $ 3,463,639 $ — $ 413 $ 3,463,226 Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (d) $ 909,482 $ 909,482 $ — $ 909,482 $ — (a) See Note 2, Significant Accounting Policies. (b) See Note 10, Derivatives and Hedging Activity. (c) See Note 6, Secured Debt and Unsecured Debt, Net. (d) See Note 8, Noncontrolling Interests. There were no transfers into or out of any of the levels of the fair value hierarchy during the three months ended March 31, 2017 . 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 March 31, 2017 and December 31, 2016 , 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 and DownREIT 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 and DownREIT Partnership are classified as Level 2. Financial Instruments Not Carried at Fair Value At March 31, 2017 and December 31, 2016 , 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 months ended March 31, 2017 and 2016 . 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 and31

Fair Value of Derivatives and Financial Instruments (UNITED DOMINION REALTY, L.P.)	3 Months Ended
	Mar. 31, 2017
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 March 31, 2017 and December 31, 2016 are summarized as follows (dollars in thousands) : Fair Value at March 31, 2017, Using Total Carrying Amount in Statement of Financial Position at March 31, 2017 Fair Value Estimate at March 31, 2017 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) $ 19,790 $ 19,735 $ — $ — $ 19,735 Derivatives - Interest rate contracts (b) 5,067 5,067 — 5,067 — Total assets $ 24,857 $ 24,802 $ — $ 5,067 $ 19,735 Derivatives - Interest rate contracts (b) $ 9 $ 9 $ — $ 9 $ — Secured debt instruments - fixed rate: (c) Mortgage notes payable 401,135 395,504 — — 395,504 Fannie Mae credit facilities 355,836 365,391 — — 365,391 Secured debt instruments - variable rate: (c) Tax-exempt secured notes payable 94,700 94,700 — — 94,700 Fannie Mae credit facilities 182,606 182,606 — — 182,606 Unsecured debt instruments: (c) Working capital credit facility 36,140 36,140 — — 36,140 Commercial paper program 220,000 220,000 — — 220,000 Unsecured notes 2,262,059 2,302,863 — — 2,302,863 Total liabilities $ 3,552,485 $ 3,597,213 $ — $ 9 $ 3,597,204 Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (d) $ 904,778 $ 904,778 $ — $ 904,778 $ — Fair Value at December 31, 2016, Using Total Carrying Amount in Statement of Financial Position at December 31, 2016 Fair Value Estimate at December 31, 2016 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) $ 19,790 $ 19,645 $ — $ — $ 19,645 Derivatives - Interest rate contracts (b) 4,360 4,360 — 4,360 — Total assets $ 24,150 $ 24,005 $ — $ 4,360 $ 19,645 Derivatives- Interest rate contracts (b) $ 413 $ 413 $ — $ 413 $ — Secured debt instruments - fixed rate: (c) Mortgage notes payable 402,996 396,045 — — 396,045 Fannie Mae credit facilities 355,836 365,693 — — 365,693 Secured debt instruments - variable rate: (c) Tax-exempt secured notes payable 94,700 94,700 — — 94,700 Fannie Mae credit facilities 280,946 280,946 — — 280,946 Unsecured debt instruments: (c) Working capital credit facility 21,350 21,350 — — 21,350 Unsecured notes 2,261,838 2,304,492 — — 2,304,492 Total liabilities $ 3,418,079 $ 3,463,639 $ — $ 413 $ 3,463,226 Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (d) $ 909,482 $ 909,482 $ — $ 909,482 $ — (a) See Note 2, Significant Accounting Policies. (b) See Note 10, Derivatives and Hedging Activity. (c) See Note 6, Secured Debt and Unsecured Debt, Net. (d) See Note 8, Noncontrolling Interests. There were no transfers into or out of any of the levels of the fair value hierarchy during the three months ended March 31, 2017 . 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 March 31, 2017 and December 31, 2016 , 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 and DownREIT 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 and DownREIT Partnership are classified as Level 2. Financial Instruments Not Carried at Fair Value At March 31, 2017 and December 31, 2016 , 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 months ended March 31, 2017 and 2016 . 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 March 31, 2017 and December 31, 2016 are summarized as follows (dollars in thousands) : Fair Value at March 31, 2017, Using Total Carrying Amount in Statement of Financial Position at March 31, 2017 Fair Value Estimate at March 31, 2017 Quoted Prices in Significant Significant Description: Secured debt instruments - fixed rate: (a) Fannie Mae credit facilities $ 228,870 $ 235,159 $ — $ — $ 235,159 Secured debt instruments - variable rate: (a) Tax-exempt secured notes payable 27,000 27,000 — — 27,000 Fannie Mae credit facilities 81,339 81,339 — — 81,339 Total liabilities $ 337,209 $ 343,498 $ — $ — $ 343,498 Fair Value at December 31, 2016, Using Total Carrying Amount in Statement of Financial Position at December 31, 2016 Fair Value Estimate at December 31, 2016 Quoted Prices in Significant Significant Description: Derivatives - Interest rate contracts (b) $ 1 $ 1 $ — $ 1 $ — Total assets $ 1 $ 1 $ — $ 1 $ — Secured debt instruments - fixed rate: (a) Fannie Mae credit facilities $ 244,912 $ 251,664 $ — $ — $ 251,664 Secured debt instruments - variable rate: (a) Tax-exempt secured notes payable 27,000 27,000 — — 27,000 Fannie Mae credit facilities 163,637 163,637 — — 163,637 Total liabilities $ 435,549 $ 442,301 $ — $ — $ 442,301 (a) See Note 5, Debt, Net. (b) See Note 8, Derivatives and Hedging Activity. There were no transfers into or out of any of the levels of the fair value hierarchy during the three months ended March 31, 2017 . 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 March 31, 2017 and December 31, 2016 , 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 March 31, 2017 , 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. The General Partner estimates the fair value of our 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 (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	3 Months Ended
	Mar. 31, 2017
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 months ended March 31, 2017 and 2016 , such derivatives were used to hedge the variable cash flows associated with existing variable-rate debt. The ineffective portion of the change in fair value of the derivatives is recognized directly in earnings. During the three months ended March 31, 2017 , the Company recognized a loss of less than $0.1 million 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 months ended March 31, 2016 , the Company recorded no ineffectiveness to earnings. Amounts reported in Accumulated other comprehensive income/(loss), net in the Consolidated Balance Sheets related to derivatives that will be reclassified to interest expense as interest payments are made on the Company’s variable-rate debt. Through March 31, 2018 , the Company estimates that an additional $0.5 million will be reclassified as an increase to interest expense. As of March 31, 2017 , 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 (a) 4 $ 315,000 Interest rate caps 2 $ 203,166 (a) Of the four interest rate swaps noted in the table above, two swaps with an aggregate notional value of $215.0 million mature in April 2017 and two swaps with an aggregate notional value of $100.0 million mature in January 2020. The Company has entered into two forward starting interest rate swaps with an aggregate notional value of $215.0 million and a maturity in January 2020, which are effective upon the expiration of the swaps maturing in April 2017. 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. Changes in the fair value of derivatives not designated in hedging relationships are recorded directly in earnings and resulted in a loss of less than $0.1 million for the three months ended March 31, 2017 and 2016 . As of March 31, 2017 , 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 Sheet The table below presents the fair value of the Company’s derivative financial instruments as well as their classification on the Consolidated Balance Sheets as of March 31, 2017 and December 31, 2016 ( dollars in thousands ): Asset Derivatives (included in Other assets ) Liability Derivatives (included in Other liabilities ) Fair Value at: Fair Value at: March 31, December 31, March 31, December 31, Derivatives designated as hedging instruments: Interest rate products $ 5,067 $ 4,359 $ 9 $ 413 Derivatives not designated as hedging instruments: Interest rate products $ — $ 1 $ — $ — 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 months ended March 31, 2017 and 2016 ( 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) 2017 2016 2017 2016 2017 2016 Three Months Ended March 31, Interest rate products $ 632 $ (811 ) $ (764 ) $ (935 ) $ (54 ) $ — Gain/(Loss) Recognized in Interest income and other income/(expense), net Derivatives Not Designated as Hedging Instruments 2017 2016 Three Months Ended March 31, Interest rate products $ (1 ) $ — 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. At March 31, 2017 and December 31, 2016 , no cash collateral was posted or required to be posted by the Company or by a counterparty. 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 applicable agreement. The Company has certain agreements with some of its derivative counterparties that contain a provision where, in the event of default by the Company 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 agreement, 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 March 31, 2017 , the fair value of derivatives was in a net asset position, which includes accrued interest but excludes any adjustment for nonperformance risk related to these agreements, of $4.9 million . As of March 31, 2017 , the Company has not posted any collateral related to these agreements. Tabular Disclosure of Offsetting Derivatives The 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 March 31, 2017 and December 31, 2016 (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 March 31, 2017 $ 5,067 $ — $ 5,067 $ (5 ) $ — $ 5,062 December 31, 2016 $ 4,360 $ — $ 4,360 $ (221 ) $ — $ 4,139 (a) Amounts reconcile to the aggregate fair value of derivative assets in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Consolidated Balance Sheets” 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 (a) Gross Amounts Not Offset in the Consolidated Balance Sheets Financial Instruments Cash Collateral Posted Net Amount March 31, 2017 $ 9 $ — $ 9 $ (5 ) $ — $ 4 December 31, 2016 $ 413 $ — $ 413 $ (221 ) $ — $ 192 (a) Amounts reconcile to the aggregate fair value of derivative liabilities in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Consolidated Balance Sheets” located in this footnote.

Derivatives and Hedging Activ33

Derivatives and Hedging Activity (UNITED DOMINION REALTY, L.P.)	3 Months Ended
	Mar. 31, 2017
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 months ended March 31, 2017 and 2016 , such derivatives were used to hedge the variable cash flows associated with existing variable-rate debt. The ineffective portion of the change in fair value of the derivatives is recognized directly in earnings. During the three months ended March 31, 2017 , the Company recognized a loss of less than $0.1 million 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 months ended March 31, 2016 , the Company recorded no ineffectiveness to earnings. Amounts reported in Accumulated other comprehensive income/(loss), net in the Consolidated Balance Sheets related to derivatives that will be reclassified to interest expense as interest payments are made on the Company’s variable-rate debt. Through March 31, 2018 , the Company estimates that an additional $0.5 million will be reclassified as an increase to interest expense. As of March 31, 2017 , 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 (a) 4 $ 315,000 Interest rate caps 2 $ 203,166 (a) Of the four interest rate swaps noted in the table above, two swaps with an aggregate notional value of $215.0 million mature in April 2017 and two swaps with an aggregate notional value of $100.0 million mature in January 2020. The Company has entered into two forward starting interest rate swaps with an aggregate notional value of $215.0 million and a maturity in January 2020, which are effective upon the expiration of the swaps maturing in April 2017. 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. Changes in the fair value of derivatives not designated in hedging relationships are recorded directly in earnings and resulted in a loss of less than $0.1 million for the three months ended March 31, 2017 and 2016 . As of March 31, 2017 , 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 Sheet The table below presents the fair value of the Company’s derivative financial instruments as well as their classification on the Consolidated Balance Sheets as of March 31, 2017 and December 31, 2016 ( dollars in thousands ): Asset Derivatives (included in Other assets ) Liability Derivatives (included in Other liabilities ) Fair Value at: Fair Value at: March 31, December 31, March 31, December 31, Derivatives designated as hedging instruments: Interest rate products $ 5,067 $ 4,359 $ 9 $ 413 Derivatives not designated as hedging instruments: Interest rate products $ — $ 1 $ — $ — 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 months ended March 31, 2017 and 2016 ( 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) 2017 2016 2017 2016 2017 2016 Three Months Ended March 31, Interest rate products $ 632 $ (811 ) $ (764 ) $ (935 ) $ (54 ) $ — Gain/(Loss) Recognized in Interest income and other income/(expense), net Derivatives Not Designated as Hedging Instruments 2017 2016 Three Months Ended March 31, Interest rate products $ (1 ) $ — 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. At March 31, 2017 and December 31, 2016 , no cash collateral was posted or required to be posted by the Company or by a counterparty. 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 applicable agreement. The Company has certain agreements with some of its derivative counterparties that contain a provision where, in the event of default by the Company 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 agreement, 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 March 31, 2017 , the fair value of derivatives was in a net asset position, which includes accrued interest but excludes any adjustment for nonperformance risk related to these agreements, of $4.9 million . As of March 31, 2017 , the Company has not posted any collateral related to these agreements. Tabular Disclosure of Offsetting Derivatives The 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 March 31, 2017 and December 31, 2016 (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 March 31, 2017 $ 5,067 $ — $ 5,067 $ (5 ) $ — $ 5,062 December 31, 2016 $ 4,360 $ — $ 4,360 $ (221 ) $ — $ 4,139 (a) Amounts reconcile to the aggregate fair value of derivative assets in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Consolidated Balance Sheets” 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 (a) Gross Amounts Not Offset in the Consolidated Balance Sheets Financial Instruments Cash Collateral Posted Net Amount March 31, 2017 $ 9 $ — $ 9 $ (5 ) $ — $ 4 December 31, 2016 $ 413 $ — $ 413 $ (221 ) $ — $ 192 (a) Amounts reconcile to the aggregate fair value of derivative liabilities in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Consolidated Balance Sheets” 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 are owed by the Operating Partnership based on the General Partner’s underlying debt instruments owed by the Operating Partnership. (See Note 5, Debt, Net. ) 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 months ended March 31, 2017 and 2016 , such derivatives were used to hedge the variable cash flows associated with existing variable-rate debt. The ineffective portion of the change in fair value of the derivatives is recognized directly in earnings. During the three months ended March 31, 2017 , the Operating Partnership recognized a loss of less than $0.1 million reclassified from Accumulated other comprehensive income/(loss), net to Interest expense due to the de-designation of a cash flow hedge and recorded no other ineffectiveness to earnings. During the three months ended March 31, 2016 , the Operating Partnership recorded no gain or loss from ineffectiveness. 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 owed by the Operating Partnership. Through March 31, 2018 , we estimate that less than $0.1 million will be reclassified as an increase to interest expense. As of March 31, 2017 , 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 caps 1 $ 82,494 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. Changes in the fair value of derivatives not designated in hedging relationships are recorded directly in earnings and resulted in an adjustment to earnings of less than $0.1 million for the three months ended March 31, 2017 and 2016 . As of March 31, 2017 , we 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 $ 87,580 Tabular Disclosure of Fair Values of Derivative Instruments on the Consolidated Balance Sheets 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 March 31, 2017 and December 31, 2016 ( dollars in thousands ): Asset Derivatives (included in Other assets ) Liability Derivatives (included in Other liabilities ) Fair Value at: Fair Value at: March 31, December 31, March 31, December 31, Derivatives designated as hedging instruments: Interest rate products $ — $ — $ — $ — Derivatives not designated as hedging instruments: Interest rate products $ — $ 1 $ — $ — 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 months ended March 31, 2017 and 2016 ( 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 2017 2016 2017 2016 2017 2016 Three Months Ended March 31, Interest rate products $ — $ (2 ) $ — $ (1 ) $ (54 ) $ — Gain/(Loss) Recognized in Interest income and other income/(expense), net Derivatives Not Designated as Hedging Instruments 2017 2016 Three Months Ended March 31, Interest rate products $ (1 ) $ — 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 March 31, 2017 and December 31, 2016 , 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 agreement, 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 March 31, 2017 , the fair value of derivatives in a net liability position that were owed by the Operating Partnership, which includes accrued interest but excludes any adjustment for nonperformance risk, related to these agreements was zero . 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 March 31, 2017 and December 31, 2016 : 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 March 31, 2017 $ — $ — $ — $ — $ — $ — December 31, 2016 $ 1 $ — $ 1 $ — $ — $ 1 (a) Amounts reconcile to the aggregate fair value of derivative assets in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Consolidated Balance Sheets” 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 (a) Gross Amounts Not Offset in the Consolidated Balance Sheets Financial Instruments Cash Collateral Posted Net Amount March 31, 2017 $ — $ — $ — $ — $ — $ — December 31, 2016 $ — $ — $ — $ — $ — $ — (a) Amounts reconcile to the aggregate fair value of derivative liabilities in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Consolidated Balance Sheets” located in this footnote.

Stock Based Compensation

Stock Based Compensation	3 Months Ended
	Mar. 31, 2017
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 $3.4 million and $3.9 million during the three months ended March 31, 2017 and 2016 , respectively.

Capital Structure (UNITED DOMIN

Capital Structure (UNITED DOMINION REALTY, L.P.)	3 Months Ended
	Mar. 31, 2017
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 March 31, 2017 and December 31, 2016 , all of which were held by UDR. Limited Partnership Units As of March 31, 2017 and December 31, 2016 , there were 183,240,041 and 183,167,815 , respectively, of limited partnership units outstanding, of which 1,873,332 were Class A Limited Partnership Units. UDR owned 174,122,808 , or 95.0% , and 174,119,201 , or 95.1% , of OP Units outstanding at March 31, 2017 and December 31, 2016 , respectively, of which 121,661 were Class A Limited Partnership Units. The remaining 9,117,233 , or 5.0% , and 9,048,614 , or 4.9% , of OP Units outstanding were held by non-affiliated partners at March 31, 2017 and December 31, 2016 , 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 $330.6 million and $330.1 million as of March 31, 2017 and December 31, 2016 , 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 Class A Limited Partnership Units, (iv) enter into a merger or acquisition, or (v) amend or modify the Operating Partnership Agreement in a manner that adversely affects the relative rights, preferences or privileges of the Class A Limited Partnership Units. The following table shows OP Units outstanding and OP Unit activity as of and for the three months ended March 31, 2017 : Class A Limited Partners UDR, Inc. Limited Partners Limited Partner Class A Limited Partner General Partner Total Ending balance at December 31, 2016 1,751,671 7,296,943 173,997,540 121,661 110,883 183,278,698 Vesting of LTIP Units — 72,226 — — 72,226 OP redemptions for UDR stock — (3,607 ) 3,607 — — — Ending balance at March 31, 2017 1,751,671 7,365,562 174,001,147 121,661 110,883 183,350,924 LTIP Units UDR grants long-term incentive plan units ("LTIP Units") to certain employees and non-employee directors. The LTIP Units represent an ownership interest in the Operating Partnership and have voting and distribution rights consistent with OP Units. The LTIP Units are subject to the terms of UDR's long-term incentive plan. Two classes of LTIP Units are granted, Class 1 LTIP Units and Class 2 LTIP Units. Class 1 LTIP Units are granted to non-employee directors and vest after one year. Class 2 LTIP Units are granted to certain employees and vest over a period from one to three years subject to certain performance and market conditions being achieved. Vested LTIP Units may be converted into OP Units provided that such LTIP Units have been outstanding for at least two years from the date of grant. 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	3 Months Ended
	Mar. 31, 2017
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 March 31, 2017 ( dollars in thousands ): Number of Properties Costs Incurred to Date (a) Expected Costs to Complete Average Ownership Stake Wholly-owned — under development 2 $ 393,837 (b) $ 314,663 100 % Wholly-owned — redevelopment 1 3,699 (b) 5,801 100 % Joint ventures: Unconsolidated joint ventures 6 721,462 66,525 (c) 50 % Participating loan investments 1 94,002 (d) — (e) 0 % Preferred equity investments 2 42,013 (f) — 49 % Total $ 1,255,013 $ 386,989 (a) Represents 100% of project costs incurred as of March 31, 2017 . (b) Costs incurred as of March 31, 2017 include $25.3 million and $0.7 million of accrued fixed assets for development and redevelopment, respectively. (c) Represents UDR’s proportionate share of expected remaining costs to complete the developments. (d) Represents the participating loan balance funded as of March 31, 2017 . (e) Represents UDR's remaining participating loan commitment for Steele Creek. (f) Represents UDR's investment in the West Coast Development Joint Ventures for the properties under development as of March 31, 2017 . 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.)	3 Months Ended
	Mar. 31, 2017
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 March 31, 2017 ( dollars in thousands ): Number of Properties Costs Incurred to Date (a) Expected Costs to Complete Average Ownership Stake Wholly-owned — under development 2 $ 393,837 (b) $ 314,663 100 % Wholly-owned — redevelopment 1 3,699 (b) 5,801 100 % Joint ventures: Unconsolidated joint ventures 6 721,462 66,525 (c) 50 % Participating loan investments 1 94,002 (d) — (e) 0 % Preferred equity investments 2 42,013 (f) — 49 % Total $ 1,255,013 $ 386,989 (a) Represents 100% of project costs incurred as of March 31, 2017 . (b) Costs incurred as of March 31, 2017 include $25.3 million and $0.7 million of accrued fixed assets for development and redevelopment, respectively. (c) Represents UDR’s proportionate share of expected remaining costs to complete the developments. (d) Represents the participating loan balance funded as of March 31, 2017 . (e) Represents UDR's remaining participating loan commitment for Steele Creek. (f) Represents UDR's investment in the West Coast Development Joint Ventures for the properties under development as of March 31, 2017 . 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 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	3 Months Ended
	Mar. 31, 2017
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 January 1, 2016 and held as of March 31, 2017 . 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 communities, 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 months ended March 31, 2017 and 2016 . The following table details rental income and NOI for UDR’s reportable segments for the three months ended March 31, 2017 and 2016 , and reconciles NOI to Net Income/(Loss) Attributable to UDR, Inc . in the Consolidated Statements of Operations (dollars in thousands) : Three Months Ended March 31, (a) 2017 2016 Reportable apartment home segment rental income Same-Store Communities West Region $ 82,220 $ 78,409 Mid-Atlantic Region 52,109 50,154 Northeast Region 37,921 36,460 Southeast Region 28,657 27,137 Southwest Region 10,679 10,125 Non-Mature Communities/Other 29,685 29,672 Total segment and consolidated rental income $ 241,271 $ 231,957 Reportable apartment home segment NOI Same-Store Communities West Region $ 61,895 $ 59,146 Mid-Atlantic Region 36,315 33,729 Northeast Region 26,901 26,360 Southeast Region 19,661 18,797 Southwest Region 6,678 6,331 Non-Mature Communities/Other 20,033 19,771 Total segment and consolidated NOI 171,483 164,134 Reconciling items: Joint venture management and other fees 2,570 2,858 Property management (6,635 ) (6,379 ) Other operating expenses (1,691 ) (1,752 ) Real estate depreciation and amortization (105,032 ) (105,339 ) General and administrative (13,075 ) (13,844 ) Casualty-related (charges)/recoveries, net (502 ) — Other depreciation and amortization (1,608 ) (1,553 ) Income/(loss) from unconsolidated entities 11,198 679 Interest expense (30,539 ) (31,104 ) Interest income and other income/(expense), net 427 431 Tax (provision)/benefit, net (332 ) 403 Gain/(loss) on sale of real estate owned, net of tax 2,132 3,070 Net (income)/loss attributable to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (2,338 ) (905 ) Net (income)/loss attributable to noncontrolling interests (91 ) (306 ) Net income/(loss) attributable to UDR, Inc. $ 25,967 $ 10,393 (a) Same-Store Community population consisted of 35,689 apartment homes. The following table details the assets of UDR’s reportable segments as of March 31, 2017 and December 31, 2016 (dollars in thousands) : March 31, December 31, Reportable apartment home segment assets: Same-Store Communities: West Region $ 2,944,437 $ 2,938,073 Mid-Atlantic Region 2,221,312 2,216,067 Northeast Region 1,858,432 1,857,193 Southeast Region 750,147 746,762 Southwest Region 283,979 283,260 Non-Mature Communities/Other 1,729,262 1,574,398 Total segment assets 9,787,569 9,615,753 Accumulated depreciation (3,026,660 ) (2,923,625 ) Total segment assets — net book value 6,760,909 6,692,128 Reconciling items: Cash and cash equivalents 2,460 2,112 Restricted cash 19,757 19,994 Notes receivable, net 19,790 19,790 Investment in and advances to unconsolidated joint ventures, net 818,990 827,025 Other assets 114,005 118,535 Total consolidated assets $ 7,735,911 $ 7,679,584 Capital expenditures related to our Same-Store Communities totaled $15.3 million and $12.9 million for the three months ended March 31, 2017 and 2016 , respectively. Capital expenditures related to our Non-Mature Communities/Other totaled $0.8 million and $2.7 million for the three months ended March 31, 2017 and 2016 , respectively. Markets included in the above geographic segments are as follows: i. West Region — San Francisco, Orange County, Seattle, Los Angeles, Monterey Peninsula, Other Southern California and Portland ii. Mid-Atlantic Region — Metropolitan D.C., Richmond and Baltimore iii. Northeast Region — New York and Boston iv. Southeast Region — Orlando, Tampa, Nashville and Other Florida v. Southwest Region — Dallas and Austin

Reportable Segments (UNITED DOM

Reportable Segments (UNITED DOMINION REALTY, L.P.)	3 Months Ended
	Mar. 31, 2017
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 January 1, 2016 and held as of March 31, 2017 . 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 communities, 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 months ended March 31, 2017 and 2016 . The following table details rental income and NOI for UDR’s reportable segments for the three months ended March 31, 2017 and 2016 , and reconciles NOI to Net Income/(Loss) Attributable to UDR, Inc . in the Consolidated Statements of Operations (dollars in thousands) : Three Months Ended March 31, (a) 2017 2016 Reportable apartment home segment rental income Same-Store Communities West Region $ 82,220 $ 78,409 Mid-Atlantic Region 52,109 50,154 Northeast Region 37,921 36,460 Southeast Region 28,657 27,137 Southwest Region 10,679 10,125 Non-Mature Communities/Other 29,685 29,672 Total segment and consolidated rental income $ 241,271 $ 231,957 Reportable apartment home segment NOI Same-Store Communities West Region $ 61,895 $ 59,146 Mid-Atlantic Region 36,315 33,729 Northeast Region 26,901 26,360 Southeast Region 19,661 18,797 Southwest Region 6,678 6,331 Non-Mature Communities/Other 20,033 19,771 Total segment and consolidated NOI 171,483 164,134 Reconciling items: Joint venture management and other fees 2,570 2,858 Property management (6,635 ) (6,379 ) Other operating expenses (1,691 ) (1,752 ) Real estate depreciation and amortization (105,032 ) (105,339 ) General and administrative (13,075 ) (13,844 ) Casualty-related (charges)/recoveries, net (502 ) — Other depreciation and amortization (1,608 ) (1,553 ) Income/(loss) from unconsolidated entities 11,198 679 Interest expense (30,539 ) (31,104 ) Interest income and other income/(expense), net 427 431 Tax (provision)/benefit, net (332 ) 403 Gain/(loss) on sale of real estate owned, net of tax 2,132 3,070 Net (income)/loss attributable to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (2,338 ) (905 ) Net (income)/loss attributable to noncontrolling interests (91 ) (306 ) Net income/(loss) attributable to UDR, Inc. $ 25,967 $ 10,393 (a) Same-Store Community population consisted of 35,689 apartment homes. The following table details the assets of UDR’s reportable segments as of March 31, 2017 and December 31, 2016 (dollars in thousands) : March 31, December 31, Reportable apartment home segment assets: Same-Store Communities: West Region $ 2,944,437 $ 2,938,073 Mid-Atlantic Region 2,221,312 2,216,067 Northeast Region 1,858,432 1,857,193 Southeast Region 750,147 746,762 Southwest Region 283,979 283,260 Non-Mature Communities/Other 1,729,262 1,574,398 Total segment assets 9,787,569 9,615,753 Accumulated depreciation (3,026,660 ) (2,923,625 ) Total segment assets — net book value 6,760,909 6,692,128 Reconciling items: Cash and cash equivalents 2,460 2,112 Restricted cash 19,757 19,994 Notes receivable, net 19,790 19,790 Investment in and advances to unconsolidated joint ventures, net 818,990 827,025 Other assets 114,005 118,535 Total consolidated assets $ 7,735,911 $ 7,679,584 Capital expenditures related to our Same-Store Communities totaled $15.3 million and $12.9 million for the three months ended March 31, 2017 and 2016 , respectively. Capital expenditures related to our Non-Mature Communities/Other totaled $0.8 million and $2.7 million for the three months ended March 31, 2017 and 2016 , respectively. Markets included in the above geographic segments are as follows: i. West Region — San Francisco, Orange County, Seattle, Los Angeles, Monterey Peninsula, Other Southern California and Portland ii. Mid-Atlantic Region — Metropolitan D.C., Richmond and Baltimore iii. Northeast Region — New York and Boston iv. Southeast Region — Orlando, Tampa, Nashville and Other Florida 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 are property management costs, which are the Operating Partnership’s allocable share of costs incurred by the General Partner for shared services of corporate level property management employees and related support functions and costs. 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 January 1, 2016 and held as of March 31, 2017 . 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 3 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 communities, 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 our 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 months ended March 31, 2017 and 2016 . The following table details rental income and NOI for the Operating Partnership’s reportable segments for the three months ended March 31, 2017 and 2016 , and reconciles NOI to Net income/(loss) attributable to OP unitholders in the Consolidated Statements of Operations (dollars in thousands) : Three Months Ended March 31, (a) 2017 2016 Reportable apartment home segment rental income Same-Store Communities West Region $ 50,482 $ 47,636 Mid-Atlantic Region 14,748 14,167 Northeast Region 13,559 13,006 Southeast Region 12,271 11,696 Non-Mature Communities/Other 11,545 12,281 Total segment and consolidated rental income $ 102,605 $ 98,786 Reportable apartment home segment NOI Same-Store Communities West Region $ 38,445 $ 36,159 Mid-Atlantic Region 10,095 9,362 Northeast Region 10,131 10,057 Southeast Region 8,283 8,043 Non-Mature Communities/Other 8,109 8,931 Total segment and consolidated NOI 75,063 72,552 Reconciling items: Property management (2,822 ) (2,717 ) Other operating expenses (1,548 ) (1,500 ) Real estate depreciation and amortization (36,879 ) (36,791 ) General and administrative (5,219 ) (5,421 ) Casualty-related recoveries/(charges), net (553 ) — Income/(loss) from unconsolidated entities (5,424 ) (13,387 ) Interest expense (8,611 ) (7,605 ) Net (income)/loss attributable to noncontrolling interests (350 ) (344 ) Net income/(loss) attributable to OP unitholders $ 13,657 $ 4,787 (a) Same-Store Community population consisted of 15,058 apartment homes. The following table details the assets of the Operating Partnership’s reportable segments as of March 31, 2017 and December 31, 2016 (dollars in thousands) : March 31, December 31, 2016 Reportable apartment home segment assets Same-Store Communities West Region $ 1,601,136 $ 1,596,815 Mid-Atlantic Region 656,850 655,693 Northeast Region 675,407 674,928 Southeast Region 330,214 328,729 Non-Mature Communities/Other 422,727 418,539 Total segment assets 3,686,334 3,674,704 Accumulated depreciation (1,445,528 ) (1,408,815 ) Total segment assets - net book value 2,240,806 2,265,889 Reconciling items: Cash and cash equivalents 864 756 Restricted cash 12,141 11,694 Investment in unconsolidated entities 103,267 112,867 Other assets 21,475 24,329 Total consolidated assets $ 2,378,553 $ 2,415,535 Capital expenditures related to the Operating Partnership’s Same-Store Communities totaled $8.0 million and $5.3 million for the three months ended March 31, 2017 and 2016 , respectively. Capital expenditures related to the Operating Partnership’s Non-Mature Communities/Other totaled $0.4 million and $0.3 million for the three months ended March 31, 2017 and 2016 , respectively. Markets included in the above geographic segments are as follows: i. West Region — San Francisco, Orange County, Seattle, Los Angeles, Monterey Peninsula, Other Southern California and Portland ii. Mid-Atlantic Region — Metropolitan, D.C. and Baltimore iii. Northeast Region — New York and Boston iv. Southeast Region — Tampa, Nashville and Other Florida

Significant Accounting Polici40

Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2017
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 months ended March 31, 2017 and 2016 , 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 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.
New Accounting Pronouncements, Policy [Policy Text Block]	Recent Accounting Pronouncements In January 2017, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2017-01, Business Combinations (Topic 805), Clarifying the Definition of a Business. The ASU changes the definition of a business to assist entities with evaluating whether a set of transferred assets is a business. As a result, the accounting for acquisitions of real estate could be impacted. The updated standard will be effective for the Company on January 1, 2018; early adoption is permitted. The ASU will be applied prospectively to any transactions occurring within the period of adoption. The Company expects that the updated standard will result in fewer acquisitions of real estate meeting the definition of a business and fewer acquisition-related costs being expensed in the period incurred. In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230), Restricted Cash . The ASU addresses the presentation of restricted cash and restricted cash equivalents in the statement of cash flows. The updated standard will be effective for the Company on January 1, 2018 and must be applied retrospectively to all periods presented; early adoption is permitted. The Company does not expect the updated standard to have a material impact on the consolidated financial statements and related disclosures. In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230), Classification of Certain Cash Receipts and Cash Payments . The ASU addresses specific cash flow items with the objective of reducing existing diversity in practice, including the treatment of distributions received from equity method investees. The updated standard will be effective for the Company on January 1, 2018 and must be applied retrospectively to all periods presented; early adoption is permitted. The Company elected to early adopt ASU 2016-15 in 2016 and elected to classify distributions received from equity method investees using the cumulative earnings approach. As a result, for the three months ended March 31, 2016, the following amounts classified under the adopted ASU as returns on investment in unconsolidated joint ventures were reclassified on the Consolidated Statements of Cash Flow (in thousands) : Three Months Ended March 31, 2016 Return on investment in unconsolidated joint ventures - as previously presented $ — Return on investment in unconsolidated joint ventures 272 Return on investment in unconsolidated joint ventures - as presented herein $ 272 Distributions received from unconsolidated joint ventures - as previously presented $ 7,983 Return on investment in unconsolidated joint ventures (272 ) Distributions received from unconsolidated joint ventures - as presented herein $ 7,711 In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments . The standard requires entities to estimate a lifetime expected credit loss for most financial assets, including trade and other receivables, held-to-maturity debt securities, loans and other financial instruments, and to present the net amount of the financial instrument expected to be collected. The updated standard will be effective for the Company on January 1, 2020; early adoption is permitted on January 1, 2019. The Company is currently evaluating the effect that the updated standard will have on the consolidated financial statements and related disclosures. In March 2016, the FASB issued ASU 2016-09, Compensation-Stock Compensation (Topic 718), Improvements to Employee Share-Based Payment Accounting . The ASU aims to simplify the accounting for share-based payments by amending the accounting for forfeitures, statutory tax withholding requirements, classification in the statements of cash flow and income taxes. The updated standard was effective for the Company on January 1, 2017, at which time the Company prospectively began accounting for forfeitures as incurred and began applying the updated rules for statutory withholdings. As a result of adopting the ASU, the Company recorded a one-time adjustment for existing estimated forfeitures of $0.6 million as of January 1, 2017 to Distributions in Excess of Net Income on January 1, 2017. In February 2016, the FASB issued ASU No. 2016-02, Leases . The standard amends the existing lease accounting guidance and requires lessees to recognize a lease liability and a right-of-use asset for all leases (except for short-term leases that have a duration of one year or less) on their balance sheets. Lessees will continue to recognize lease expense in a manner similar to current accounting. For lessors, accounting for leases under the new guidance is substantially the same as in prior periods, but eliminates current real estate-specific provisions and changes the treatment of initial direct costs. Entities are required to use a modified retrospective approach for leases that exist or are entered into after the beginning of the earliest comparable period presented, with an option to elect certain transition relief. Full retrospective application is prohibited. The standard will be effective for the Company on January 1, 2019, with early adoption permitted. While the Company is currently evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures, we expect to recognize right-of-use assets and related lease liabilities on our consolidated balance sheets related to ground leases on any communities where we are the lessee. In May 2014, the FASB issued 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 will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective, including industry-specific revenue guidance. The standard specifically excludes lease contracts. The ASU allows for the use of either the full or modified retrospective transition method and will be effective for the Company on January 1, 2018, at which time the Company expects to adopt the updated standard using the modified retrospective approach. However, as the majority of the Company’s revenue is from rental income related to leases, the Company does not expect the ASU to have a material impact on the consolidated financial statements and related disclosures. Principles of Consolidation The Company accounts for subsidiary partnerships, joint ventures and other similar entities in which it holds an ownership interest in accordance with the consolidation guidance. The Company first evaluates whether each entity is a variable interest entity ("VIE"). Under the VIE model, the Company consolidates an entity when it has control to direct the activities of the VIE and the obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE. Under the voting model, the Company consolidates an entity when it controls the entity through ownership of a majority voting interest. 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 of 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 March 31, 2017 and December 31, 2016 , UDR’s net deferred tax asset was $0.4 million and $0.6 million , respectively. 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 March 31, 2017 . UDR and its subsidiaries are subject to federal income tax as well as income tax of various state and local jurisdictions. The tax years 2013 through 2016 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 (provision)/benefit, 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 March 31, 2017 and December 31, 2016 ( dollars in thousands): Interest rate at Balance outstanding March 31, March 31, December 31, 2016 Note due February 2020 (a) 10.00 % $ 12,994 $ 12,994 Note due July 2017 (b) 8.00 % 2,500 2,500 Note due October 2020 (c) 8.00 % 1,296 1,296 Note due April 2021 (d) 10.00 % 3,000 3,000 Total notes receivable, net $ 19,790 $ 19,790 (a) The Company has a secured note receivable with an unaffiliated third party with an aggregate commitment of $13.0 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 eighth anniversary of the date of the note (February 2020). (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). (c) The Company has a secured note receivable with an unaffiliated third party with an aggregate commitment of $2.0 million , of which, $1.3 million has been funded. Interest payments are due when the loan matures. The note matures at the earliest of the following: (a) the closing of any private or public capital raising in the amount of $10.0 million or greater; (b) an acquisition; (c) acceleration in the event of default; or (d) the fifth anniversary of the date of the note (October 2020). (d) The Company has a secured note receivable with an unaffiliated third party with an aggregate commitment of $15.0 million , of which, $3.0 million has been funded. 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 $25.0 million or greater; (b) an acquisition; (c) acceleration in the event of default; or (d) the fifth anniversary of the date of the note (April 2021). The Company recognized $0.5 million and $0.4 million of interest income from notes receivable during the three months ended March 31, 2017 and 2016 , 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)	3 Months Ended
	Mar. 31, 2017
Entity Information [Line Items]
New Accounting Pronouncements, Policy [Policy Text Block]	Recent Accounting Pronouncements In January 2017, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2017-01, Business Combinations (Topic 805), Clarifying the Definition of a Business. The ASU changes the definition of a business to assist entities with evaluating whether a set of transferred assets is a business. As a result, the accounting for acquisitions of real estate could be impacted. The updated standard will be effective for the Company on January 1, 2018; early adoption is permitted. The ASU will be applied prospectively to any transactions occurring within the period of adoption. The Company expects that the updated standard will result in fewer acquisitions of real estate meeting the definition of a business and fewer acquisition-related costs being expensed in the period incurred. In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230), Restricted Cash . The ASU addresses the presentation of restricted cash and restricted cash equivalents in the statement of cash flows. The updated standard will be effective for the Company on January 1, 2018 and must be applied retrospectively to all periods presented; early adoption is permitted. The Company does not expect the updated standard to have a material impact on the consolidated financial statements and related disclosures. In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230), Classification of Certain Cash Receipts and Cash Payments . The ASU addresses specific cash flow items with the objective of reducing existing diversity in practice, including the treatment of distributions received from equity method investees. The updated standard will be effective for the Company on January 1, 2018 and must be applied retrospectively to all periods presented; early adoption is permitted. The Company elected to early adopt ASU 2016-15 in 2016 and elected to classify distributions received from equity method investees using the cumulative earnings approach. As a result, for the three months ended March 31, 2016, the following amounts classified under the adopted ASU as returns on investment in unconsolidated joint ventures were reclassified on the Consolidated Statements of Cash Flow (in thousands) : Three Months Ended March 31, 2016 Return on investment in unconsolidated joint ventures - as previously presented $ — Return on investment in unconsolidated joint ventures 272 Return on investment in unconsolidated joint ventures - as presented herein $ 272 Distributions received from unconsolidated joint ventures - as previously presented $ 7,983 Return on investment in unconsolidated joint ventures (272 ) Distributions received from unconsolidated joint ventures - as presented herein $ 7,711 In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments . The standard requires entities to estimate a lifetime expected credit loss for most financial assets, including trade and other receivables, held-to-maturity debt securities, loans and other financial instruments, and to present the net amount of the financial instrument expected to be collected. The updated standard will be effective for the Company on January 1, 2020; early adoption is permitted on January 1, 2019. The Company is currently evaluating the effect that the updated standard will have on the consolidated financial statements and related disclosures. In March 2016, the FASB issued ASU 2016-09, Compensation-Stock Compensation (Topic 718), Improvements to Employee Share-Based Payment Accounting . The ASU aims to simplify the accounting for share-based payments by amending the accounting for forfeitures, statutory tax withholding requirements, classification in the statements of cash flow and income taxes. The updated standard was effective for the Company on January 1, 2017, at which time the Company prospectively began accounting for forfeitures as incurred and began applying the updated rules for statutory withholdings. As a result of adopting the ASU, the Company recorded a one-time adjustment for existing estimated forfeitures of $0.6 million as of January 1, 2017 to Distributions in Excess of Net Income on January 1, 2017. In February 2016, the FASB issued ASU No. 2016-02, Leases . The standard amends the existing lease accounting guidance and requires lessees to recognize a lease liability and a right-of-use asset for all leases (except for short-term leases that have a duration of one year or less) on their balance sheets. Lessees will continue to recognize lease expense in a manner similar to current accounting. For lessors, accounting for leases under the new guidance is substantially the same as in prior periods, but eliminates current real estate-specific provisions and changes the treatment of initial direct costs. Entities are required to use a modified retrospective approach for leases that exist or are entered into after the beginning of the earliest comparable period presented, with an option to elect certain transition relief. Full retrospective application is prohibited. The standard will be effective for the Company on January 1, 2019, with early adoption permitted. While the Company is currently evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures, we expect to recognize right-of-use assets and related lease liabilities on our consolidated balance sheets related to ground leases on any communities where we are the lessee. In May 2014, the FASB issued 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 will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective, including industry-specific revenue guidance. The standard specifically excludes lease contracts. The ASU allows for the use of either the full or modified retrospective transition method and will be effective for the Company on January 1, 2018, at which time the Company expects to adopt the updated standard using the modified retrospective approach. However, as the majority of the Company’s revenue is from rental income related to leases, the Company does not expect the ASU to have a material impact on the consolidated financial statements and related disclosures. Principles of Consolidation The Company accounts for subsidiary partnerships, joint ventures and other similar entities in which it holds an ownership interest in accordance with the consolidation guidance. The Company first evaluates whether each entity is a variable interest entity ("VIE"). Under the VIE model, the Company consolidates an entity when it has control to direct the activities of the VIE and the obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE. Under the voting model, the Company consolidates an entity when it controls the entity through ownership of a majority voting interest. 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 of 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 months ended March 31, 2017 and 2016 , 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 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.
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 March 31, 2017 and December 31, 2016 , UDR’s net deferred tax asset was $0.4 million and $0.6 million , respectively. 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 March 31, 2017 . UDR and its subsidiaries are subject to federal income tax as well as income tax of various state and local jurisdictions. The tax years 2013 through 2016 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 (provision)/benefit, 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 January 2017, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2017-01, Business Combinations (Topic 805), Clarifying the Definition of a Business. The ASU changes the definition of a business to assist entities with evaluating whether a set of transferred assets is a business. As a result, the accounting for acquisitions of real estate could be impacted. The updated standard will be effective for the Operating Partnership on January 1, 2018; early adoption is permitted. The ASU will be applied prospectively to any transactions occurring within the period of adoption. The Operating Partnership expects that the updated standard will result in fewer acquisitions of real estate meeting the definition of a business and fewer acquisition-related costs being expensed in the period incurred. In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230), Restricted Cash . The ASU addresses the presentation of restricted cash and restricted cash equivalents in the statement of cash flows. The updated standard will be effective for the Operating Partnership on January 1, 2018 and must be applied retrospectively to all periods presented; early adoption is permitted. The Operating Partnership does not expect the updated standard to have a material impact on the consolidated financial statements and related disclosures. In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230), Classification of Certain Cash Receipts and Cash Payments . The ASU addresses specific cash flow items with the objective of reducing existing diversity in practice, including the treatment of distributions received from equity method investees. The updated standard will be effective for the Operating Partnership on January 1, 2018 and must be applied retrospectively to all periods presented; early adoption is permitted. The Operating Partnership elected to early adopt ASU 2016-15 in 2016. The adoption did not have an impact on the Operating Partnership's consolidated financial statements and related disclosures. In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments . The standard requires entities to estimate a lifetime expected credit loss for most financial assets, including trade and other receivables, held-to-maturity debt securities, loans and other financial instruments, and to present the net amount of the financial instrument expected to be collected. The updated standard will be effective for the Operating Partnership on January 1, 2020; early adoption is permitted on January 1, 2019. The Operating Partnership is currently evaluating the effect that the updated standard will have on the consolidated financial statements and related disclosures. In February 2016, the FASB issued ASU No. 2016-02, Leases . The standard amends the existing lease accounting guidance and requires lessees to recognize a lease liability and a right-of-use asset for all leases (except for short-term leases that have a duration of one year or less) on their balance sheets. Lessees will continue to recognize lease expense in a manner similar to current accounting. For lessors, accounting for leases under the new guidance is substantially the same as in prior periods, but eliminates current real estate-specific provisions and changes the treatment of initial direct costs. Entities are required to use a modified retrospective approach for leases that exist or are entered into after the beginning of the earliest comparable period presented, with an option to elect certain transition relief. Full retrospective application is prohibited. The standard will be effective for the Operating Partnership on January 1, 2019, with early adoption permitted. While the Operating Partnership is currently evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures, we expect to recognize right-of-use assets and related lease liabilities on our consolidated balance sheets related to ground leases on any communities where we are the lessee. In May 2014, the FASB issued 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 will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective, including industry-specific revenue guidance. The standard specifically excludes lease contracts. The ASU allows for the use of either the full or modified retrospective transition method and will be effective for the Operating Partnership on January 1, 2018, at which time the Operating Partnership expects to adopt the updated standard using the modified retrospective approach. However, as the majority of the Operating Partnership's revenue is from rental income related to leases, the Operating Partnership does not expect the ASU to have a material impact on the consolidated financial statements and related disclosures. Principles of Consolidation The Operating Partnership accounts for subsidiary partnerships, joint ventures and other similar entities in which it holds an ownership interest in accordance with the amended consolidation guidance. The Operating Partnership first evaluates whether each entity is a variable interest entity ("VIE"). Under the VIE model, the Operating Partnership consolidates an entity when it has control to direct the activities of the VIE and the obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE. Under the voting model, the Operating Partnership consolidates an entity when it controls the entity through ownership of a majority voting interest. 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 the 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 months ended March 31, 2017 and 2016 , 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 8, 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 ( 2013 through 2016 ) 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)	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Notes receivable	The following table summarizes our notes receivable, net as of March 31, 2017 and December 31, 2016 ( dollars in thousands): Interest rate at Balance outstanding March 31, March 31, December 31, 2016 Note due February 2020 (a) 10.00 % $ 12,994 $ 12,994 Note due July 2017 (b) 8.00 % 2,500 2,500 Note due October 2020 (c) 8.00 % 1,296 1,296 Note due April 2021 (d) 10.00 % 3,000 3,000 Total notes receivable, net $ 19,790 $ 19,790

Real Estate Owned (Tables)

Real Estate Owned (Tables)	3 Months Ended
	Mar. 31, 2017
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 March 31, 2017 and December 31, 2016 (dollars in thousands): March 31, December 31, 2016 Land $ 1,812,797 $ 1,801,576 Depreciable property — held and used: Land improvements 180,837 178,701 Building, improvements, and furniture, fixtures and equipment 7,400,098 7,291,570 Under development: Land and land improvements 111,028 111,028 Building, improvements, and furniture, fixtures and equipment 282,809 231,254 Real estate held for disposition: Land and land improvements — 1,104 Building, improvements, and furniture, fixtures and equipment — 520 Real estate owned 9,787,569 9,615,753 Accumulated depreciation (3,026,660 ) (2,923,625 ) Real estate owned, net $ 6,760,909 $ 6,692,128

Real Estate Owned (UNITED DOM44

Real Estate Owned (UNITED DOMINION REALTY, L.P.) (Tables)	3 Months Ended
	Mar. 31, 2017
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 March 31, 2017 and December 31, 2016 (dollars in thousands): March 31, December 31, 2016 Land $ 1,812,797 $ 1,801,576 Depreciable property — held and used: Land improvements 180,837 178,701 Building, improvements, and furniture, fixtures and equipment 7,400,098 7,291,570 Under development: Land and land improvements 111,028 111,028 Building, improvements, and furniture, fixtures and equipment 282,809 231,254 Real estate held for disposition: Land and land improvements — 1,104 Building, improvements, and furniture, fixtures and equipment — 520 Real estate owned 9,787,569 9,615,753 Accumulated depreciation (3,026,660 ) (2,923,625 ) Real estate owned, net $ 6,760,909 $ 6,692,128
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 March 31, 2017 and December 31, 2016 (dollars in thousands) : March 31, December 31, 2016 Land $ 837,945 $ 836,644 Depreciable property — held and used: Buildings, improvements, and furniture, fixtures and equipment 2,848,389 2,838,060 Real estate owned 3,686,334 3,674,704 Accumulated depreciation (1,445,528 ) (1,408,815 ) Real estate owned, net $ 2,240,806 $ 2,265,889

Joint Ventures (Tables)

Joint Ventures (Tables)	3 Months Ended
	Mar. 31, 2017
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 months ended March 31, 2017 and 2016 . Combined summary balance sheets relating to the unconsolidated joint ventures and partnerships (not just our proportionate share) are presented below as of March 31, 2017 and December 31, 2016 ( dollars in thousands ): March 31, December 31, 2016 Total real estate, net $ 2,904,183 $ 2,901,067 Cash and cash equivalents 28,676 32,503 Other assets 17,288 19,047 Total assets $ 2,950,147 $ 2,952,617 Amount due to/(from) UDR $ 2,746 $ 521 Third party debt, net 1,811,490 1,794,379 Accounts payable and accrued liabilities 55,471 66,391 Total liabilities $ 1,869,707 $ 1,861,291 Total equity $ 1,080,440 $ 1,091,326
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 March 31, 2017 and December 31, 2016 (dollars in thousands) : Joint Venture Location of Properties Number of Properties Number of Apartment Homes Investment at UDR’s Ownership Interest March 31, March 31, March 31, December 31, March 31, December 31, Operating and development: UDR/MetLife I Los Angeles, CA 1 development community (a) 150 $ 29,182 $ 25,209 50.0 % 50.0 % UDR/MetLife II (b) Various 18 operating communities 4,059 309,409 311,282 50.0 % 50.0 % Other UDR/MetLife Development Joint Ventures 1 operating community; Various 4 development communities (a) 1,437 156,096 160,979 50.6 % 50.6 % UDR/MetLife Vitruvian Park® Addison, TX 3 operating communities; 1 development community (a); 5 land parcels 1,513 73,154 72,414 50.0 % 50.0 % UDR/KFH Washington, D.C. 3 operating communities 660 11,801 12,835 30.0 % 30.0 % Investment in and advances to unconsolidated joint ventures, net, before participating loan investment and preferred equity investment $ 579,642 $ 582,719 Income from investments for the three months ending March 31, Investment at Location Rate Years To Maturity March 31, December 31, 2017 2016 Participating loan investment: Steele Creek Denver, CO 6.5% 0.3 $ 94,002 $ 94,003 $ 1,533 $ 1,519 Preferred equity investment: West Coast Development Joint Ventures (c) Various 6.5% (c) N/A 145,346 150,303 $ 12,766 $ 1,427 Total investment in and advances to unconsolidated joint ventures, net $ 818,990 $ 827,025 (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 upon completion of development. As of March 31, 2017 , 1,018 apartment homes had been completed in Other UDR/MetLife Development Joint Ventures, and no apartment homes had been completed in UDR/MetLife I or in UDR/MetLife Vitruvian Park ® . (b) In September 2015, the 717 Olympic community, which is owned by the UDR/MetLife II joint venture, experienced extensive water damage due to a ruptured water pipe. For the three months ended March 31, 2017 and 2016 , the Company recorded casualty-related charges/(recoveries) of $0.9 million and $(1.1) million , respectively, representing its proportionate share of the total charges/(recoveries) recognized
Financial information relating to unconsolidated joint ventures operations	Combined summary financial information relating to the unconsolidated joint ventures ’ and partnerships ’ operations (not just our proportionate share) is presented below for the three months ended March 31, 2017 and 2016 ( dollars in thousands ) : Three Months Ended March 31, 2017 2016 Total revenues $ 58,524 $ 55,037 Property operating expenses (21,834 ) (23,413 ) Real estate depreciation and amortization (23,333 ) (18,943 ) Operating income/(loss) 13,357 12,681 Interest expense (17,690 ) (16,181 ) Net income/(loss) $ (4,333 ) $ (3,500 )
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. The Company recognizes earnings or losses from our investments in unconsolidated joint ventures and partnerships consisting of our proportionate share of the net earnings 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 March 31, 2017 and December 31, 2016 (dollars in thousands) : Joint Venture Location of Properties Number of Properties Number of Apartment Homes Investment at UDR’s Ownership Interest March 31, March 31, March 31, December 31, March 31, December 31, Operating and development: UDR/MetLife I Los Angeles, CA 1 development community (a) 150 $ 29,182 $ 25,209 50.0 % 50.0 % UDR/MetLife II (b) Various 18 operating communities 4,059 309,409 311,282 50.0 % 50.0 % Other UDR/MetLife Development Joint Ventures 1 operating community; Various 4 development communities (a) 1,437 156,096 160,979 50.6 % 50.6 % UDR/MetLife Vitruvian Park® Addison, TX 3 operating communities; 1 development community (a); 5 land parcels 1,513 73,154 72,414 50.0 % 50.0 % UDR/KFH Washington, D.C. 3 operating communities 660 11,801 12,835 30.0 % 30.0 % Investment in and advances to unconsolidated joint ventures, net, before participating loan investment and preferred equity investment $ 579,642 $ 582,719 Income from investments for the three months ending March 31, Investment at Location Rate Years To Maturity March 31, December 31, 2017 2016 Participating loan investment: Steele Creek Denver, CO 6.5% 0.3 $ 94,002 $ 94,003 $ 1,533 $ 1,519 Preferred equity investment: West Coast Development Joint Ventures (c) Various 6.5% (c) N/A 145,346 150,303 $ 12,766 $ 1,427 Total investment in and advances to unconsolidated joint ventures, net $ 818,990 $ 827,025 (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 upon completion of development. As of March 31, 2017 , 1,018 apartment homes had been completed in Other UDR/MetLife Development Joint Ventures, and no apartment homes had been completed in UDR/MetLife I or in UDR/MetLife Vitruvian Park ® . (b) In September 2015, the 717 Olympic community, which is owned by the UDR/MetLife II joint venture, experienced extensive water damage due to a ruptured water pipe. For the three months ended March 31, 2017 and 2016 , the Company recorded casualty-related charges/(recoveries) of $0.9 million and $(1.1) million , respectively, representing its proportionate share of the total charges/(recoveries) recognized. (c) In May 2015, the Company entered into a joint venture agreement with an unaffiliated joint venture partner and agreed to pay $136.3 million for a 48% ownership interest in a portfolio of five communities that were under construction. The communities are located in three of the Company’s core, coastal markets: Seattle, Washington, Los Angeles and Orange County, California. UDR earns a 6.5% preferred return on its investment through each individual community’s date of stabilization, defined as when a community reaches 80% occupancy for 90 consecutive days, while the joint venture partner is allocated all operating income and expense during the pre-stabilization period. Upon stabilization, income and expense are shared based on each partner’s ownership percentage and the Company no longer receives a 6.5% preferred return on its investment in the stabilized community. The Company serves as property manager and earns a management fee during the lease-up phase and subsequent operation of each of the communities. The unaffiliated joint venture partner is the general partner of the joint venture and the developer of the communities. At inception of the agreement, the Company had a fixed-price option to acquire the remaining interest in each community beginning one year after completion. If the options are exercised for all five communities, the Company’s total purchase price will be $597.4 million . In the event the Company does not exercise its options to purchase at least two communities, the unaffiliated joint venture partner will be entitled to earn a contingent disposition fee equal to a 6.5% return on its implied equity in the communities not acquired. The unaffiliated joint venture partner is providing certain guaranties and there are construction loans on all five communities. During the three months ended March 31, 2017 , the Company exercised its fixed-price option to purchase the joint venture partner’s ownership interest in one of the five communities, a 244 home operating community in Seattle, Washington, thereby increasing its ownership interest from 49% to 100% , for a cash purchase price of approximately $66.0 million . As a result, the Company consolidated the operating community and it is no longer accounted for as a preferred equity investment in an unconsolidated joint venture (see Note 4, Real Estate Owned ). As a result of the consolidation, the Company recorded a gain on consolidation of $12.2 million , which is included in Income/(loss) from unconsolidated entities on the Consolidated Statements of Operations. As of March 31, 2017 , construction was completed on three of the four remaining communities. Two of the four remaining communities had achieved stabilization. The other two remaining communities have not achieved stabilization and the Company continues to receive a 6.5% preferred return on its investment in those communities. In March 2017, the Company entered into an additional joint venture agreement with the unaffiliated joint venture partner and agreed to pay $15.5 million for a 49% ownership interest in a 155 home community that is currently under construction in Seattle, Washington (together with the May 2015 joint venture described above, the “West Coast Development Joint Ventures”). Consistent with the terms of the May 2015 joint venture agreement, UDR earns a 6.5% preferred return on its investment through the community’s date of stabilization, as defined above, while our joint venture partner 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 and the Company will no longer receive a 6.5% preferred return on its investment in the stabilized community. The Company will serve as property manager and will earn a management fee during the lease-up phase and subsequent operation of the community. The unaffiliated joint venture partner is the general partner and the developer of the community. The Company has concluded it does not control the joint venture and accounts for it under the equity method of accounting. The Company has a fixed-price option to acquire the remaining interest in the community beginning one year after completion for a total price of $61.3 million . The unaffiliated joint venture partner is providing certain guaranties and there is a construction loan on the community. The Company's recorded equity investment in the West Coast Development Joint Ventures at March 31, 2017 and December 31, 2016 of $145.3 million and $150.3 million , respectively, is inclusive of outside basis costs and our accrued but unpaid preferred return. As of March 31, 2017 and December 31, 2016 , the Company had deferred fees and deferred profit of $9.7 million and $9.5 million , respectively, which will be recognized through earnings 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 of $2.6 million and $2.8 million for the three months ended March 31, 2017 and 2016 , respectively, for our management of the communities held by the joint ventures and partnerships. 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 months ended March 31, 2017 and 2016 . Combined summary balance sheets relating to the unconsolidated joint ventures and partnerships (not just our proportionate share) are presented below as of March 31, 2017 and December 31, 2016 ( dollars in thousands ): March 31, December 31, 2016 Total real estate, net $ 2,904,183 $ 2,901,067 Cash and cash equivalents 28,676 32,503 Other assets 17,288 19,047 Total assets $ 2,950,147 $ 2,952,617 Amount due to/(from) UDR $ 2,746 $ 521 Third party debt, net 1,811,490 1,794,379 Accounts payable and accrued liabilities 55,471 66,391 Total liabilities $ 1,869,707 $ 1,861,291 Total equity $ 1,080,440 $ 1,091,326 Combined summary financial information relating to the unconsolidated joint ventures ’ and partnerships ’ operations (not just our proportionate share) is presented below for the three months ended March 31, 2017 and 2016 ( dollars in thousands ) : Three Months Ended March 31, 2017 2016 Total revenues $ 58,524 $ 55,037 Property operating expenses (21,834 ) (23,413 ) Real estate depreciation and amortization (23,333 ) (18,943 ) Operating income/(loss) 13,357 12,681 Interest expense (17,690 ) (16,181 ) Net income/(loss) $ (4,333 ) $ (3,500 )

Unconsolidated Entities (UNIT46

Unconsolidated Entities (UNITED DOMINION REALTY, L.P.) Unconsolidated Entities (UNITED DOMINION REALTY, L.P.) (Tables)	3 Months Ended
	Mar. 31, 2017
Schedule of Equity Method Investments [Line Items]
Summarized Income Statement Relating to Unconsolidated Joint Ventures [Table Text Block]	Combined summary financial information relating to the unconsolidated joint ventures ’ and partnerships ’ operations (not just our proportionate share) is presented below for the three months ended March 31, 2017 and 2016 ( dollars in thousands ) : Three Months Ended March 31, 2017 2016 Total revenues $ 58,524 $ 55,037 Property operating expenses (21,834 ) (23,413 ) Real estate depreciation and amortization (23,333 ) (18,943 ) Operating income/(loss) 13,357 12,681 Interest expense (17,690 ) (16,181 ) Net income/(loss) $ (4,333 ) $ (3,500 )
United Dominion Reality L.P. [Member]
Schedule of Equity Method Investments [Line Items]
Summarized Income Statement Relating to Unconsolidated Joint Ventures [Table Text Block]	Combined summary balance sheets relating to all of the DownREIT Partnership (not just our proportionate share) are presented below as of March 31, 2017 and December 31, 2016 ( dollars in thousands ): March 31, December 31, 2016 Total real estate, net $ 1,400,046 $ 1,413,983 Cash and cash equivalents 35 66 Note receivable from the General Partner 126,500 126,500 Other assets 4,498 4,843 Total assets $ 1,531,079 $ 1,545,392 Secured debt, net 442,172 443,607 Other liabilities 23,976 27,571 Total liabilities 466,148 471,178 Total capital 1,064,931 1,074,214 Total liabilities and capital $ 1,531,079 $ 1,545,392 Combined summary financial information relating to all of the DownREIT Partnership (not just our proportionate share) is presented below for the three months ended March 31, 2017 and 2016 ( dollars in thousands ) : Three Months Ended March 31, 2017 2016 Rental income $ 33,298 $ 31,617 Property operating expenses (13,976 ) (14,269 ) Real estate depreciation and amortization (20,608 ) (30,053 ) Operating income/(loss) (1,286 ) (12,705 ) Interest expense (3,860 ) (3,741 ) Interest income on note receivable from the General Partner 1,166 1,180 Net income/(loss) $ (3,980 ) $ (15,266 )

Secured and Unsecured Debt (Tab

Secured and Unsecured Debt (Tables)	3 Months Ended
	Mar. 31, 2017
Short-term Debt [Line Items]
Schedule of Short-term Debt [Table Text Block]	The following is a summary of short-term bank borrowings under the unsecured commercial paper program at March 31, 2017 and December 31, 2016 (dollars in thousands): March 31, December 31, 2016 Total unsecured commercial paper program $ 500,000 $ — Borrowings outstanding at end of period 220,000 — Weighted average daily borrowings during the period ended 80,228 — Maximum daily borrowings during the period ended 220,000 — Weighted average interest rate during the period ended 1.2 % — % Interest rate at end of the period 1.2 % — %
Secured debt instruments	The following is a summary of our secured and unsecured debt at March 31, 2017 and December 31, 2016 ( dollars in thousands ): Three Months Ended Principal Outstanding March 31, 2017 March 31, December 31, 2016 Weighted Average Weighted Average Number of Communities Secured Debt: Fixed Rate Debt Mortgage notes payable (a) $ 401,135 $ 402,996 4.04 % 6.1 7 Fannie Mae credit facilities (b) 355,836 355,836 5.06 % 2.6 10 Deferred financing costs (2,482 ) (2,681 ) Total fixed rate secured debt, net 754,489 756,151 4.53 % 4.4 17 Variable Rate Debt Tax-exempt secured notes payable (c) 94,700 94,700 1.42 % 5.9 2 Fannie Mae credit facilities (b) 182,606 280,946 2.05 % 1.3 5 Deferred financing costs (288 ) (939 ) Total variable rate secured debt, net 277,018 374,707 1.84 % 2.9 7 Total Secured Debt, net 1,031,507 1,130,858 3.80 % 4.0 24 Unsecured Debt: Variable Rate Debt Borrowings outstanding under unsecured credit facility due January 2020 (d) (h) — — — % 2.8 Borrowings outstanding under unsecured commercial paper program due April 2017 (e) (h) 220,000 — 1.24 % 0.0 Borrowings outstanding under unsecured working capital credit facility due January 2019 (f) 36,140 21,350 1.88 % 1.8 Term Loan Facility due January 2021 (d) (h) 35,000 35,000 1.73 % 3.8 Fixed Rate Debt 4.25% Medium-Term Notes due June 2018 (net of discounts of $501 and $608, respectively) (h) 299,499 299,392 4.25 % 1.2 3.70% Medium-Term Notes due October 2020 (net of discounts of $28 and $30, respectively) (h) 299,972 299,970 3.70 % 3.5 2.34% Term Loan Facility due January 2021 (d) (h) 315,000 315,000 2.34 % 3.8 4.63% Medium-Term Notes due January 2022 (net of discounts of $1,715 and $1,805 respectively) (h) 398,285 398,195 4.63 % 4.8 3.75% Medium-Term Notes due July 2024 (net of discounts of $756 and $782, respectively) (h) 299,244 299,218 3.75 % 7.3 8.50% Debentures due September 2024 15,644 15,644 8.50 % 7.5 4.00% Medium-Term Notes due October 2025 (net of discounts of $585 and $602, respectively) (g) (h) 299,415 299,398 4.00 % 8.5 2.95% Medium-Term Notes due September 2026 (h) 300,000 300,000 2.95 % 9.4 Other 21 21 Deferred financing costs (12,435 ) (12,568 ) Total Unsecured Debt, net 2,505,785 2,270,620 3.52 % 4.9 Total Debt, net $ 3,537,292 $ 3,401,478 3.67 % 4.6
Secured credit facilities	Further information related to these credit facilities is as follows (dollars in thousands) : March 31, December 31, 2016 Borrowings outstanding $ 538,442 $ 636,782 Weighted average borrowings during the period ended 604,002 737,802 Maximum daily borrowings during the period ended 636,782 813,544 Weighted average interest rate during the period ended 3.9 % 3.9 % Weighted average interest rate at the end of the period 4.0 % 3.8 %
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 ten calendar years subsequent to March 31, 2017 are as follows (dollars in thousands): Year Total Fixed Secured Debt Total Variable Secured Debt Total Secured Debt Total Unsecured Debt Total Debt 2017 $ 3,310 $ 46,568 $ 49,878 $ 220,000 $ 269,878 2018 74,637 136,038 210,675 300,000 510,675 2019 249,395 67,700 317,095 36,140 353,235 2020 198,076 — 198,076 300,000 498,076 2021 1,117 — 1,117 350,000 351,117 2022 1,157 — 1,157 400,000 401,157 2023 41,245 — 41,245 — 41,245 2024 — — — 315,644 315,644 2025 127,600 — 127,600 300,000 427,600 2026 50,000 — 50,000 300,000 350,000 Thereafter — 27,000 27,000 — 27,000 Subtotal 746,537 277,306 1,023,843 2,521,784 3,545,627 Non-cash (a) 7,952 (288 ) 7,664 (15,999 ) (8,335 ) Total $ 754,489 $ 277,018 $ 1,031,507 $ 2,505,785 $ 3,537,292

Debt (UNITED DOMINION REALTY,48

Debt (UNITED DOMINION REALTY, L.P.) (Tables)	3 Months Ended
	Mar. 31, 2017
Entity Information [Line Items]
Secured debt instruments	The following is a summary of our secured and unsecured debt at March 31, 2017 and December 31, 2016 ( dollars in thousands ): Three Months Ended Principal Outstanding March 31, 2017 March 31, December 31, 2016 Weighted Average Weighted Average Number of Communities Secured Debt: Fixed Rate Debt Mortgage notes payable (a) $ 401,135 $ 402,996 4.04 % 6.1 7 Fannie Mae credit facilities (b) 355,836 355,836 5.06 % 2.6 10 Deferred financing costs (2,482 ) (2,681 ) Total fixed rate secured debt, net 754,489 756,151 4.53 % 4.4 17 Variable Rate Debt Tax-exempt secured notes payable (c) 94,700 94,700 1.42 % 5.9 2 Fannie Mae credit facilities (b) 182,606 280,946 2.05 % 1.3 5 Deferred financing costs (288 ) (939 ) Total variable rate secured debt, net 277,018 374,707 1.84 % 2.9 7 Total Secured Debt, net 1,031,507 1,130,858 3.80 % 4.0 24 Unsecured Debt: Variable Rate Debt Borrowings outstanding under unsecured credit facility due January 2020 (d) (h) — — — % 2.8 Borrowings outstanding under unsecured commercial paper program due April 2017 (e) (h) 220,000 — 1.24 % 0.0 Borrowings outstanding under unsecured working capital credit facility due January 2019 (f) 36,140 21,350 1.88 % 1.8 Term Loan Facility due January 2021 (d) (h) 35,000 35,000 1.73 % 3.8 Fixed Rate Debt 4.25% Medium-Term Notes due June 2018 (net of discounts of $501 and $608, respectively) (h) 299,499 299,392 4.25 % 1.2 3.70% Medium-Term Notes due October 2020 (net of discounts of $28 and $30, respectively) (h) 299,972 299,970 3.70 % 3.5 2.34% Term Loan Facility due January 2021 (d) (h) 315,000 315,000 2.34 % 3.8 4.63% Medium-Term Notes due January 2022 (net of discounts of $1,715 and $1,805 respectively) (h) 398,285 398,195 4.63 % 4.8 3.75% Medium-Term Notes due July 2024 (net of discounts of $756 and $782, respectively) (h) 299,244 299,218 3.75 % 7.3 8.50% Debentures due September 2024 15,644 15,644 8.50 % 7.5 4.00% Medium-Term Notes due October 2025 (net of discounts of $585 and $602, respectively) (g) (h) 299,415 299,398 4.00 % 8.5 2.95% Medium-Term Notes due September 2026 (h) 300,000 300,000 2.95 % 9.4 Other 21 21 Deferred financing costs (12,435 ) (12,568 ) Total Unsecured Debt, net 2,505,785 2,270,620 3.52 % 4.9 Total Debt, net $ 3,537,292 $ 3,401,478 3.67 % 4.6
Secured credit facilities	Further information related to these credit facilities is as follows (dollars in thousands) : March 31, December 31, 2016 Borrowings outstanding $ 538,442 $ 636,782 Weighted average borrowings during the period ended 604,002 737,802 Maximum daily borrowings during the period ended 636,782 813,544 Weighted average interest rate during the period ended 3.9 % 3.9 % Weighted average interest rate at the end of the period 4.0 % 3.8 %
Aggregate maturities of secured debt	The aggregate maturities, including amortizing principal payments of unsecured and secured debt, of total debt for the next ten calendar years subsequent to March 31, 2017 are as follows (dollars in thousands): Year Total Fixed Secured Debt Total Variable Secured Debt Total Secured Debt Total Unsecured Debt Total Debt 2017 $ 3,310 $ 46,568 $ 49,878 $ 220,000 $ 269,878 2018 74,637 136,038 210,675 300,000 510,675 2019 249,395 67,700 317,095 36,140 353,235 2020 198,076 — 198,076 300,000 498,076 2021 1,117 — 1,117 350,000 351,117 2022 1,157 — 1,157 400,000 401,157 2023 41,245 — 41,245 — 41,245 2024 — — — 315,644 315,644 2025 127,600 — 127,600 300,000 427,600 2026 50,000 — 50,000 300,000 350,000 Thereafter — 27,000 27,000 — 27,000 Subtotal 746,537 277,306 1,023,843 2,521,784 3,545,627 Non-cash (a) 7,952 (288 ) 7,664 (15,999 ) (8,335 ) Total $ 754,489 $ 277,018 $ 1,031,507 $ 2,505,785 $ 3,537,292
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
Secured debt instruments	Secured debt consists of the following as of March 31, 2017 and December 31, 2016 ( dollars in thousands ): Principal Outstanding For the Three Months Ended March 31, 2017 March 31, December 31, 2016 Weighted Average Interest Rate Weighted Average Years to Maturity Number of Communities Encumbered Fixed Rate Debt Fannie Mae credit facilities $ 228,870 $ 244,912 5.07 % 2.6 6 Deferred financing costs (718 ) (1,070 ) Total fixed rate secured debt, net 228,152 243,842 5.07 % 2.6 6 Variable Rate Debt Tax-exempt secured note payable 27,000 27,000 1.39 % 15.0 1 Fannie Mae credit facilities 81,339 163,637 2.34 % 1.7 2 Deferred financing costs (251 ) (505 ) Total variable rate secured debt, net 108,088 190,132 2.10 % 5.0 3 Total Secured Debt, net $ 336,240 $ 433,974 4.26 % 3.4 9
Secured credit facilities	The following information relates to the credit facilities owed by the Operating Partnership (dollars in thousands) : March 31, December 31, 2016 Borrowings outstanding $ 310,209 $ 408,549 Weighted average borrowings during the period ended 375,770 414,759 Maximum daily borrowings during the period ended 408,549 421,001 Weighted average interest rate during the period ended 4.1 % 3.9 % Interest rate at the end of the period 4.4 % 4.0 %
Aggregate maturities of secured debt	The aggregate maturities of the Operating Partnership’s secured debt due during each of the next ten calendar years subsequent to March 31, 2017 are as follows (dollars in thousands): Fixed Variable Year Secured Credit Facilities Tax-Exempt Secured Notes Payable Secured Credit Facilities Total 2017 $ — $ — $ — $ — 2018 41,854 — 81,339 123,193 2019 133,204 — — 133,204 2020 53,812 — — 53,812 2021 — — — — 2022 — — — — 2023 — — — — 2024 — — — — 2025 — — — — 2026 — — — — Thereafter — 27,000 — 27,000 Subtotal 228,870 27,000 81,339 337,209 Non-cash (a) (718 ) (84 ) (167 ) (969 ) Total $ 228,152 $ 26,916 $ 81,172 $ 336,240

Income_(Loss) Per Share (Tables

Income/(Loss) Per Share (Tables)	3 Months Ended
	Mar. 31, 2017
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 months ended March 31, 2017 and 2016 (shares in thousands) : Three Months Ended March 31, 2017 2016 OP/DownREIT Units 24,962 25,191 Convertible preferred stock 3,028 3,028 Stock options, unvested LTIP Units and unvested restricted stock 1,898 1,829
(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 March 31, 2017 2016 Numerator for income/(loss) per share: Income/(loss) from continuing operations $ 26,264 $ 8,534 Gain/(loss) on sale of real estate owned, net of tax 2,132 3,070 Net (income)/loss attributable to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (2,338 ) (905 ) Net (income)/loss attributable to noncontrolling interests (91 ) (306 ) Net income/(loss) attributable to UDR, Inc. 25,967 10,393 Distributions to preferred stockholders — Series E (Convertible) (929 ) (929 ) Income/(loss) attributable to common stockholders - basic and diluted $ 25,038 $ 9,464 Denominator for income/(loss) per share: Weighted average common shares outstanding 267,402 263,355 Non-vested restricted stock awards (612 ) (899 ) Denominator for basic income/(loss) per share 266,790 262,456 Incremental shares issuable from assumed conversion of stock options, unvested LTIP Units and unvested restricted stock 1,898 1,829 Denominator for diluted income/(loss) per share 268,688 264,285 Income/(loss) per weighted average common share: Basic $ 0.09 $ 0.04 Diluted $ 0.09 $ 0.04

Noncontrolling Interests (Table

Noncontrolling Interests (Tables)	3 Months Ended
	Mar. 31, 2017
Noncontrolling Interest [Abstract]
Redeemable noncontrolling interests in the Operating Partnership	The following table sets forth redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership for the following period ( dollars in thousands ): Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership, December 31, 2016 $ 909,482 Mark-to-market adjustment to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership 281 Conversion of OP Units/DownREIT Units to Common Stock (1,850 ) Net income/(loss) attributable to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership 2,338 Distributions to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (7,919 ) Vesting of Long-Term Incentive Plan Units 2,317 Allocation of other comprehensive income/(loss) 129 Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership, March 31, 2017 $ 904,778

Fair Value of Derivatives and51

Fair Value of Derivatives and Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2017
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 March 31, 2017 and December 31, 2016 are summarized as follows (dollars in thousands) : Fair Value at March 31, 2017, Using Total Carrying Amount in Statement of Financial Position at March 31, 2017 Fair Value Estimate at March 31, 2017 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) $ 19,790 $ 19,735 $ — $ — $ 19,735 Derivatives - Interest rate contracts (b) 5,067 5,067 — 5,067 — Total assets $ 24,857 $ 24,802 $ — $ 5,067 $ 19,735 Derivatives - Interest rate contracts (b) $ 9 $ 9 $ — $ 9 $ — Secured debt instruments - fixed rate: (c) Mortgage notes payable 401,135 395,504 — — 395,504 Fannie Mae credit facilities 355,836 365,391 — — 365,391 Secured debt instruments - variable rate: (c) Tax-exempt secured notes payable 94,700 94,700 — — 94,700 Fannie Mae credit facilities 182,606 182,606 — — 182,606 Unsecured debt instruments: (c) Working capital credit facility 36,140 36,140 — — 36,140 Commercial paper program 220,000 220,000 — — 220,000 Unsecured notes 2,262,059 2,302,863 — — 2,302,863 Total liabilities $ 3,552,485 $ 3,597,213 $ — $ 9 $ 3,597,204 Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (d) $ 904,778 $ 904,778 $ — $ 904,778 $ — Fair Value at December 31, 2016, Using Total Carrying Amount in Statement of Financial Position at December 31, 2016 Fair Value Estimate at December 31, 2016 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) $ 19,790 $ 19,645 $ — $ — $ 19,645 Derivatives - Interest rate contracts (b) 4,360 4,360 — 4,360 — Total assets $ 24,150 $ 24,005 $ — $ 4,360 $ 19,645 Derivatives- Interest rate contracts (b) $ 413 $ 413 $ — $ 413 $ — Secured debt instruments - fixed rate: (c) Mortgage notes payable 402,996 396,045 — — 396,045 Fannie Mae credit facilities 355,836 365,693 — — 365,693 Secured debt instruments - variable rate: (c) Tax-exempt secured notes payable 94,700 94,700 — — 94,700 Fannie Mae credit facilities 280,946 280,946 — — 280,946 Unsecured debt instruments: (c) Working capital credit facility 21,350 21,350 — — 21,350 Unsecured notes 2,261,838 2,304,492 — — 2,304,492 Total liabilities $ 3,418,079 $ 3,463,639 $ — $ 413 $ 3,463,226 Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (d) $ 909,482 $ 909,482 $ — $ 909,482 $ — (a) See Note 2, Significant Accounting Policies. (b) See Note 10, Derivatives and Hedging Activity. (c) See Note 6, Secured Debt and Unsecured Debt, Net. (d) See Note 8, Noncontrolling Interests.

Fair Value of Derivatives and52

Fair Value of Derivatives and Financial Instruments (UNITED DOMINION REALTY, L.P.) (Tables)	3 Months Ended
	Mar. 31, 2017
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 March 31, 2017 and December 31, 2016 are summarized as follows (dollars in thousands) : Fair Value at March 31, 2017, Using Total Carrying Amount in Statement of Financial Position at March 31, 2017 Fair Value Estimate at March 31, 2017 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) $ 19,790 $ 19,735 $ — $ — $ 19,735 Derivatives - Interest rate contracts (b) 5,067 5,067 — 5,067 — Total assets $ 24,857 $ 24,802 $ — $ 5,067 $ 19,735 Derivatives - Interest rate contracts (b) $ 9 $ 9 $ — $ 9 $ — Secured debt instruments - fixed rate: (c) Mortgage notes payable 401,135 395,504 — — 395,504 Fannie Mae credit facilities 355,836 365,391 — — 365,391 Secured debt instruments - variable rate: (c) Tax-exempt secured notes payable 94,700 94,700 — — 94,700 Fannie Mae credit facilities 182,606 182,606 — — 182,606 Unsecured debt instruments: (c) Working capital credit facility 36,140 36,140 — — 36,140 Commercial paper program 220,000 220,000 — — 220,000 Unsecured notes 2,262,059 2,302,863 — — 2,302,863 Total liabilities $ 3,552,485 $ 3,597,213 $ — $ 9 $ 3,597,204 Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (d) $ 904,778 $ 904,778 $ — $ 904,778 $ — Fair Value at December 31, 2016, Using Total Carrying Amount in Statement of Financial Position at December 31, 2016 Fair Value Estimate at December 31, 2016 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) $ 19,790 $ 19,645 $ — $ — $ 19,645 Derivatives - Interest rate contracts (b) 4,360 4,360 — 4,360 — Total assets $ 24,150 $ 24,005 $ — $ 4,360 $ 19,645 Derivatives- Interest rate contracts (b) $ 413 $ 413 $ — $ 413 $ — Secured debt instruments - fixed rate: (c) Mortgage notes payable 402,996 396,045 — — 396,045 Fannie Mae credit facilities 355,836 365,693 — — 365,693 Secured debt instruments - variable rate: (c) Tax-exempt secured notes payable 94,700 94,700 — — 94,700 Fannie Mae credit facilities 280,946 280,946 — — 280,946 Unsecured debt instruments: (c) Working capital credit facility 21,350 21,350 — — 21,350 Unsecured notes 2,261,838 2,304,492 — — 2,304,492 Total liabilities $ 3,418,079 $ 3,463,639 $ — $ 413 $ 3,463,226 Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (d) $ 909,482 $ 909,482 $ — $ 909,482 $ — (a) See Note 2, Significant Accounting Policies. (b) See Note 10, Derivatives and Hedging Activity. (c) See Note 6, Secured Debt and Unsecured Debt, Net. (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 March 31, 2017 and December 31, 2016 are summarized as follows (dollars in thousands) : Fair Value at March 31, 2017, Using Total Carrying Amount in Statement of Financial Position at March 31, 2017 Fair Value Estimate at March 31, 2017 Quoted Prices in Significant Significant Description: Secured debt instruments - fixed rate: (a) Fannie Mae credit facilities $ 228,870 $ 235,159 $ — $ — $ 235,159 Secured debt instruments - variable rate: (a) Tax-exempt secured notes payable 27,000 27,000 — — 27,000 Fannie Mae credit facilities 81,339 81,339 — — 81,339 Total liabilities $ 337,209 $ 343,498 $ — $ — $ 343,498 Fair Value at December 31, 2016, Using Total Carrying Amount in Statement of Financial Position at December 31, 2016 Fair Value Estimate at December 31, 2016 Quoted Prices in Significant Significant Description: Derivatives - Interest rate contracts (b) $ 1 $ 1 $ — $ 1 $ — Total assets $ 1 $ 1 $ — $ 1 $ — Secured debt instruments - fixed rate: (a) Fannie Mae credit facilities $ 244,912 $ 251,664 $ — $ — $ 251,664 Secured debt instruments - variable rate: (a) Tax-exempt secured notes payable 27,000 27,000 — — 27,000 Fannie Mae credit facilities 163,637 163,637 — — 163,637 Total liabilities $ 435,549 $ 442,301 $ — $ — $ 442,301 (a) See Note 5, Debt, Net.

Derivatives and Hedging Activ53

Derivatives and Hedging Activity (Tables)	3 Months Ended
	Mar. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Outstanding interest rate derivatives	As of March 31, 2017 , 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 (a) 4 $ 315,000 Interest rate caps 2 $ 203,166 (a) Of the four interest rate swaps noted in the table above, two swaps with an aggregate notional value of $215.0 million mature in April 2017 and two swaps with an aggregate notional value of $100.0 million mature in January 2020. The Company has entered into two forward starting interest rate swaps with an aggregate notional value of $215.0 million and a maturity in January 2020, which are effective upon the expiration of the swaps maturing in April 2017. 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. Changes in the fair value of derivatives not designated in hedging relationships are recorded directly in earnings and resulted in a loss of less than $0.1 million for the three months ended March 31, 2017 and 2016 . As of March 31, 2017 , 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 table below presents the fair value of the Company’s derivative financial instruments as well as their classification on the Consolidated Balance Sheets as of March 31, 2017 and December 31, 2016 ( dollars in thousands ): Asset Derivatives (included in Other assets ) Liability Derivatives (included in Other liabilities ) Fair Value at: Fair Value at: March 31, December 31, March 31, December 31, Derivatives designated as hedging instruments: Interest rate products $ 5,067 $ 4,359 $ 9 $ 413 Derivatives not designated as hedging instruments: Interest rate products $ — $ 1 $ — $ —
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 months ended March 31, 2017 and 2016 ( 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) 2017 2016 2017 2016 2017 2016 Three Months Ended March 31, Interest rate products $ 632 $ (811 ) $ (764 ) $ (935 ) $ (54 ) $ —
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 2017 2016 Three Months Ended March 31, Interest rate products $ (1 ) $ —
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 March 31, 2017 $ 5,067 $ — $ 5,067 $ (5 ) $ — $ 5,062 December 31, 2016 $ 4,360 $ — $ 4,360 $ (221 ) $ — $ 4,139 (a) Amounts reconcile to the aggregate fair value of derivative assets in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Consolidated Balance Sheets” 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 (a) Gross Amounts Not Offset in the Consolidated Balance Sheets Financial Instruments Cash Collateral Posted Net Amount March 31, 2017 $ 9 $ — $ 9 $ (5 ) $ — $ 4 December 31, 2016 $ 413 $ — $ 413 $ (221 ) $ — $ 192 (a) Amounts reconcile to the aggregate fair value of derivative liabilities in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Consolidated Balance Sheets” located in this footnote.

Derivatives and Hedging Activ54

Derivatives and Hedging Activity (UNITED DOMINION REALTY, L.P.) (Tables)	3 Months Ended
	Mar. 31, 2017
Entity Information [Line Items]
Outstanding interest rate derivatives	As of March 31, 2017 , 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 (a) 4 $ 315,000 Interest rate caps 2 $ 203,166 (a) Of the four interest rate swaps noted in the table above, two swaps with an aggregate notional value of $215.0 million mature in April 2017 and two swaps with an aggregate notional value of $100.0 million mature in January 2020. The Company has entered into two forward starting interest rate swaps with an aggregate notional value of $215.0 million and a maturity in January 2020, which are effective upon the expiration of the swaps maturing in April 2017. 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. Changes in the fair value of derivatives not designated in hedging relationships are recorded directly in earnings and resulted in a loss of less than $0.1 million for the three months ended March 31, 2017 and 2016 . As of March 31, 2017 , 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 table below presents the fair value of the Company’s derivative financial instruments as well as their classification on the Consolidated Balance Sheets as of March 31, 2017 and December 31, 2016 ( dollars in thousands ): Asset Derivatives (included in Other assets ) Liability Derivatives (included in Other liabilities ) Fair Value at: Fair Value at: March 31, December 31, March 31, December 31, Derivatives designated as hedging instruments: Interest rate products $ 5,067 $ 4,359 $ 9 $ 413 Derivatives not designated as hedging instruments: Interest rate products $ — $ 1 $ — $ —
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 months ended March 31, 2017 and 2016 ( 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) 2017 2016 2017 2016 2017 2016 Three Months Ended March 31, Interest rate products $ 632 $ (811 ) $ (764 ) $ (935 ) $ (54 ) $ —
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 2017 2016 Three Months Ended March 31, Interest rate products $ (1 ) $ —
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 March 31, 2017 $ 5,067 $ — $ 5,067 $ (5 ) $ — $ 5,062 December 31, 2016 $ 4,360 $ — $ 4,360 $ (221 ) $ — $ 4,139 (a) Amounts reconcile to the aggregate fair value of derivative assets in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Consolidated Balance Sheets” 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 (a) Gross Amounts Not Offset in the Consolidated Balance Sheets Financial Instruments Cash Collateral Posted Net Amount March 31, 2017 $ 9 $ — $ 9 $ (5 ) $ — $ 4 December 31, 2016 $ 413 $ — $ 413 $ (221 ) $ — $ 192 (a) Amounts reconcile to the aggregate fair value of derivative liabilities in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Consolidated Balance Sheets” located in this footnote.
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
Outstanding interest rate derivatives	As of March 31, 2017 , 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 caps 1 $ 82,494 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. Changes in the fair value of derivatives not designated in hedging relationships are recorded directly in earnings and resulted in an adjustment to earnings of less than $0.1 million for the three months ended March 31, 2017 and 2016 . As of March 31, 2017 , we 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 $ 87,580 As of March 31, 2017 , 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 caps 1 $ 82,494 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. Changes in the fair value of derivatives not designated in hedging relationships are recorded directly in earnings and resulted in an adjustment to earnings of less than $0.1 million for the three months ended March 31, 2017 and 2016 . As of March 31, 2017 , we 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 $ 87,580
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 March 31, 2017 and December 31, 2016 ( dollars in thousands ): Asset Derivatives (included in Other assets ) Liability Derivatives (included in Other liabilities ) Fair Value at: Fair Value at: March 31, December 31, March 31, December 31, Derivatives designated as hedging instruments: Interest rate products $ — $ — $ — $ — Derivatives not designated as hedging instruments: Interest rate products $ — $ 1 $ — $ —
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 months ended March 31, 2017 and 2016 ( 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 2017 2016 2017 2016 2017 2016 Three Months Ended March 31, Interest rate products $ — $ (2 ) $ — $ (1 ) $ (54 ) $ —
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 2017 2016 Three Months Ended March 31, Interest rate products $ (1 ) $ —
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 March 31, 2017 and December 31, 2016 : 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 March 31, 2017 $ — $ — $ — $ — $ — $ — December 31, 2016 $ 1 $ — $ 1 $ — $ — $ 1 (a) Amounts reconcile to the aggregate fair value of derivative assets in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Consolidated Balance Sheets” 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 (a) Gross Amounts Not Offset in the Consolidated Balance Sheets Financial Instruments Cash Collateral Posted Net Amount March 31, 2017 $ — $ — $ — $ — $ — $ — December 31, 2016 $ — $ — $ — $ — $ — $ — (a) Amounts reconcile to the aggregate fair value of derivative liabilities in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Consolidated Balance Sheets” located in this footnote.

Capital Structure (UNITED DOM55

Capital Structure (UNITED DOMINION REALTY, L.P.) Capital Structure (UNITED DOMINION REALTY, L.P.) (Tables)	3 Months Ended
	Mar. 31, 2017
United Dominion Reality L.P. [Member]
Limited Partners' Capital Account [Line Items]
Schedule of Limited Partners' Capital Account by Class [Table Text Block]	The following table shows OP Units outstanding and OP Unit activity as of and for the three months ended March 31, 2017 : Class A Limited Partners UDR, Inc. Limited Partners Limited Partner Class A Limited Partner General Partner Total Ending balance at December 31, 2016 1,751,671 7,296,943 173,997,540 121,661 110,883 183,278,698 Vesting of LTIP Units — 72,226 — — 72,226 OP redemptions for UDR stock — (3,607 ) 3,607 — — — Ending balance at March 31, 2017 1,751,671 7,365,562 174,001,147 121,661 110,883 183,350,924

Commitments and Contingencies56

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Real estate commitments	The following summarizes the Company’s real estate commitments at March 31, 2017 ( dollars in thousands ): Number of Properties Costs Incurred to Date (a) Expected Costs to Complete Average Ownership Stake Wholly-owned — under development 2 $ 393,837 (b) $ 314,663 100 % Wholly-owned — redevelopment 1 3,699 (b) 5,801 100 % Joint ventures: Unconsolidated joint ventures 6 721,462 66,525 (c) 50 % Participating loan investments 1 94,002 (d) — (e) 0 % Preferred equity investments 2 42,013 (f) — 49 % Total $ 1,255,013 $ 386,989 (a) Represents 100% of project costs incurred as of March 31, 2017 . (b) Costs incurred as of March 31, 2017 include $25.3 million and $0.7 million of accrued fixed assets for development and redevelopment, respectively. (c) Represents UDR’s proportionate share of expected remaining costs to complete the developments. (d) Represents the participating loan balance funded as of March 31, 2017 . (e) Represents UDR's remaining participating loan commitment for Steele Creek. (f) Represents UDR's investment in the West Coast Development Joint Ventures for the properties under development as of March 31, 2017 .

Reportable Segment (Tables)

Reportable Segment (Tables)	3 Months Ended
	Mar. 31, 2017
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 for UDR’s reportable segments for the three months ended March 31, 2017 and 2016 , and reconciles NOI to Net Income/(Loss) Attributable to UDR, Inc . in the Consolidated Statements of Operations (dollars in thousands) : Three Months Ended March 31, (a) 2017 2016 Reportable apartment home segment rental income Same-Store Communities West Region $ 82,220 $ 78,409 Mid-Atlantic Region 52,109 50,154 Northeast Region 37,921 36,460 Southeast Region 28,657 27,137 Southwest Region 10,679 10,125 Non-Mature Communities/Other 29,685 29,672 Total segment and consolidated rental income $ 241,271 $ 231,957 Reportable apartment home segment NOI Same-Store Communities West Region $ 61,895 $ 59,146 Mid-Atlantic Region 36,315 33,729 Northeast Region 26,901 26,360 Southeast Region 19,661 18,797 Southwest Region 6,678 6,331 Non-Mature Communities/Other 20,033 19,771 Total segment and consolidated NOI 171,483 164,134 Reconciling items: Joint venture management and other fees 2,570 2,858 Property management (6,635 ) (6,379 ) Other operating expenses (1,691 ) (1,752 ) Real estate depreciation and amortization (105,032 ) (105,339 ) General and administrative (13,075 ) (13,844 ) Casualty-related (charges)/recoveries, net (502 ) — Other depreciation and amortization (1,608 ) (1,553 ) Income/(loss) from unconsolidated entities 11,198 679 Interest expense (30,539 ) (31,104 ) Interest income and other income/(expense), net 427 431 Tax (provision)/benefit, net (332 ) 403 Gain/(loss) on sale of real estate owned, net of tax 2,132 3,070 Net (income)/loss attributable to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (2,338 ) (905 ) Net (income)/loss attributable to noncontrolling interests (91 ) (306 ) Net income/(loss) attributable to UDR, Inc. $ 25,967 $ 10,393 (a) Same-Store Community population consisted of 35,689 apartment homes.
Details of assets of UDR's reportable segments	The following table details the assets of UDR’s reportable segments as of March 31, 2017 and December 31, 2016 (dollars in thousands) : March 31, December 31, Reportable apartment home segment assets: Same-Store Communities: West Region $ 2,944,437 $ 2,938,073 Mid-Atlantic Region 2,221,312 2,216,067 Northeast Region 1,858,432 1,857,193 Southeast Region 750,147 746,762 Southwest Region 283,979 283,260 Non-Mature Communities/Other 1,729,262 1,574,398 Total segment assets 9,787,569 9,615,753 Accumulated depreciation (3,026,660 ) (2,923,625 ) Total segment assets — net book value 6,760,909 6,692,128 Reconciling items: Cash and cash equivalents 2,460 2,112 Restricted cash 19,757 19,994 Notes receivable, net 19,790 19,790 Investment in and advances to unconsolidated joint ventures, net 818,990 827,025 Other assets 114,005 118,535 Total consolidated assets $ 7,735,911 $ 7,679,584

Reportable Segments (UNITED D58

Reportable Segments (UNITED DOMINION REALTY, L.P.) (Tables)	3 Months Ended
	Mar. 31, 2017
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
Reportable segments information	The following table details rental income and NOI for the Operating Partnership’s reportable segments for the three months ended March 31, 2017 and 2016 , and reconciles NOI to Net income/(loss) attributable to OP unitholders in the Consolidated Statements of Operations (dollars in thousands) : Three Months Ended March 31, (a) 2017 2016 Reportable apartment home segment rental income Same-Store Communities West Region $ 50,482 $ 47,636 Mid-Atlantic Region 14,748 14,167 Northeast Region 13,559 13,006 Southeast Region 12,271 11,696 Non-Mature Communities/Other 11,545 12,281 Total segment and consolidated rental income $ 102,605 $ 98,786 Reportable apartment home segment NOI Same-Store Communities West Region $ 38,445 $ 36,159 Mid-Atlantic Region 10,095 9,362 Northeast Region 10,131 10,057 Southeast Region 8,283 8,043 Non-Mature Communities/Other 8,109 8,931 Total segment and consolidated NOI 75,063 72,552 Reconciling items: Property management (2,822 ) (2,717 ) Other operating expenses (1,548 ) (1,500 ) Real estate depreciation and amortization (36,879 ) (36,791 ) General and administrative (5,219 ) (5,421 ) Casualty-related recoveries/(charges), net (553 ) — Income/(loss) from unconsolidated entities (5,424 ) (13,387 ) Interest expense (8,611 ) (7,605 ) Net (income)/loss attributable to noncontrolling interests (350 ) (344 ) Net income/(loss) attributable to OP unitholders $ 13,657 $ 4,787 (a) Same-Store Community population consisted of 15,058 apartment homes. The following table details the assets of the Operating Partnership’s reportable segments as of March 31, 2017 and December 31, 2016 (dollars in thousands) : March 31, December 31, 2016 Reportable apartment home segment assets Same-Store Communities West Region $ 1,601,136 $ 1,596,815 Mid-Atlantic Region 656,850 655,693 Northeast Region 675,407 674,928 Southeast Region 330,214 328,729 Non-Mature Communities/Other 422,727 418,539 Total segment assets 3,686,334 3,674,704 Accumulated depreciation (1,445,528 ) (1,408,815 ) Total segment assets - net book value 2,240,806 2,265,889 Reconciling items: Cash and cash equivalents 864 756 Restricted cash 12,141 11,694 Investment in unconsolidated entities 103,267 112,867 Other assets 21,475 24,329 Total consolidated assets $ 2,378,553 $ 2,415,535

Consolidation and Basis of Pr59

Consolidation and Basis of Presentation (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Other Interest and Dividend Income	$ 0.5	$ 0.4
Limited partnership units owned	183,350,924		183,278,698
Deferred Tax Assets, Net	$ 0.4		$ 0.6
UDR Lighthouse DownREIT L.P. [Member]
Operating Partnership outstanding units	32,367,380
United Dominion Reality L.P. [Member] | UDR Lighthouse DownREIT L.P. [Member]
Operating Partnership outstanding units	13,470,651
Percentage of units outstanding in Heritage OP	41.60%
Limited Partner [Member] | UDR Lighthouse DownREIT L.P. [Member]
Operating Partnership outstanding units	15,835,284
Percentage of units outstanding in Heritage OP	48.92359%
General Partner [Member] | UDR Lighthouse DownREIT L.P. [Member]
Operating Partnership outstanding units	16,532,096
General Partners Capital Account Units Owned Percentage	51.07641%
Non-affiliated Partners [Member]
Limited partnership units owned	7,365,562		7,296,943

Consolidation and Basis of Pr60

Consolidation and Basis of Presentation (UNITED DOMINION REALTY, L.P.) (Details)	3 Months Ended
	Mar. 31, 2017CommunitiesApartment_HomesMarketsshares	Mar. 31, 2016	Dec. 31, 2016shares
Entity Information [Line Items]
Number of Real Estate Properties | Communities	128
Number of apartments owned (in apartments homes) | Apartment_Homes	39,698
OP units outstanding related to limited partner	183,350,924		183,278,698
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
Rental revenues percent of General Partner's consolidated rental revenues	43.00%	42.60%
Number of Real Estate Properties | Communities	54
Number of markets operating within (in markets) | Markets	14
Number of apartments owned (in apartments homes) | Apartment_Homes	16,698
Operating Partnership outstanding units	183,350,924
OP units outstanding related to general partner	110,883		110,883
OP units outstanding related to limited partner	183,240,041		183,167,815
Limited Partner [Member] | United Dominion Reality L.P. [Member]
Entity Information [Line Items]
OP units outstanding related to limited partner	174,233,691
Percentage of units outstanding in Heritage OP	95.00%
Non-affiliated Partners [Member]
Entity Information [Line Items]
OP units outstanding related to limited partner	7,365,562		7,296,943
Non-affiliated Partners [Member] | United Dominion Reality L.P. [Member]
Entity Information [Line Items]
OP units outstanding related to limited partner	9,117,233		9,048,614
Percentage of units outstanding in Heritage OP	5.00%		4.90%

Significant Accounting Polici61

Significant Accounting Policies (Details) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Accounting Policies [Line Items]
Return on investment in unconsolidated joint ventures	$ 1,455,000	$ 272,000
Distributions received from unconsolidated entities	(9,711,000)	(7,711,000)
Notes receivable, net	19,790,000		$ 19,790,000
Current Income Tax Expense (Benefit)	0
Deferred Tax Assets, Net	400,000		600,000
Significant Accounting Policies (Textual) [Abstract]
Note maturity public capital threshold	5,000,000
Note receivable interest income	$ 500,000	400,000
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
Interest Income, Related Party	$ 0
Note due February 2017 [Member]
Accounting Policies [Line Items]
Note Receivable Interest Rate	10.00%
Notes receivable, net			12,994,000
Significant Accounting Policies (Textual) [Abstract]
Notes receivable	$ 12,994,000
Note maturity public capital threshold	$ 5,000,000
Other [Member]
Accounting Policies [Line Items]
Note Receivable Interest Rate	8.00%
Notes receivable, net	$ 2,500,000		2,500,000
Significant Accounting Policies (Textual) [Abstract]
Notes receivable	$ 2,500,000
Note due October 2020 [Member]
Accounting Policies [Line Items]
Note Receivable Interest Rate	8.00%
Notes receivable, net	$ 1,296,000		1,296,000
Significant Accounting Policies (Textual) [Abstract]
Notes receivable	2,000,000
Note maturity public capital threshold	$ 10,000,000
Note Due April 2021 [Member]
Accounting Policies [Line Items]
Note Receivable Interest Rate	10.00%
Notes receivable, net	$ 3,000,000		3,000,000
Significant Accounting Policies (Textual) [Abstract]
Notes receivable	15,000,000
Note maturity public capital threshold	25,000,000
RedeemableNoncontrollingInterest [Member]
Accounting Policies [Line Items]
Comprehensive (loss)/income attributable to non-controlling interests	129,000	(500,000)
Accounting Standards Update 2016-09 [Member]
Accounting Policies [Line Items]
Cumulative effect upon adoption of ASU 2016-09	0
Accumulated Distributions in Excess of Net Income [Member] | Accounting Standards Update 2016-09 [Member]
Accounting Policies [Line Items]
Cumulative effect upon adoption of ASU 2016-09	(558,000)
Fair Value, Measurements, Recurring [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
Accounting Policies [Line Items]
Notes receivable, net	$ 19,790,000		$ 19,790,000
Scenario, Previously Reported [Member]
Accounting Policies [Line Items]
Return on investment in unconsolidated joint ventures		0
Distributions received from unconsolidated entities		(7,983,000)
Adjustments for New Accounting Principle, Early Adoption [Member]
Accounting Policies [Line Items]
Distributions received from unconsolidated entities		$ (272,000)

Real Estate Owned (Details)

Real Estate Owned (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Land	$ 1,812,797	$ 1,801,576
Land Improvements	180,837	178,701
Depreciable property - held and used:
Building, Improvements, and Furniture, Fixtures and Equipment	7,400,098	7,291,570
Under development:
Real estate under development (net of accumulated depreciation of $0 and $0, respectively)	393,837	342,282
Real estate owned	9,787,569	9,615,753
Real Estates Owned Accumulated Depreciation	3,026,660	2,923,625
Real Estate Investments, Net	6,760,909	6,692,128
Land [Member]
Under development:
Real estate under development (net of accumulated depreciation of $0 and $0, respectively)	111,028	111,028
Real Estate Held-for-sale	0	1,104
Construction in progress [Member]
Under development:
Real estate under development (net of accumulated depreciation of $0 and $0, respectively)	282,809	231,254
Building and Building Improvements [Member]
Under development:
Real Estate Held-for-sale	$ 0	$ 520

Real Estate Owned (Details Text

Real Estate Owned (Details Textual) $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)CommunitiesApartment_HomesStates	Mar. 31, 2016USD ($)	Dec. 31, 2016
Real Estate Properties [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	$ 97,000
Number of Apartment Homes Acquired	155
Investment in unconsolidated joint ventures	$ 24,193	$ 13,262
Real Estate Owned (Textual) [Abstract]
Number of states in which there are owned and consolidated communities	10
Number of apartment homes owned and consolidated by the Company | Apartment_Homes	39,698
Number of Real Estate Properties | Communities	128
Development costs excluding direct costs and capitlized interest	$ 2,800	2,000
Interest capitalized during period	4,700	4,200
Other Cost and Expense, Operating	1,691	1,752
Proceeds from Sale of Property, Plant, and Equipment	3,500
Payments for (Proceeds from) Investments	3,300
Gain/(loss) on sale of real estate owned, net of tax	2,132	3,070
Casualty-related (recoveries)/charges, net	$ 502	0
CityLine [Member]
Real Estate Properties [Line Items]
Number of Apartment Homes Acquired	244
Investment in unconsolidated joint ventures	$ 66,000
United Dominion Reality L.P. [Member]
Real Estate Owned (Textual) [Abstract]
Number of states in which there are owned and consolidated communities | States	8
Number of apartment homes owned and consolidated by the Company | Apartment_Homes	16,698
Number of Real Estate Properties | Communities	54
Development costs excluding direct costs and capitlized interest	$ 300	300
Interest capitalized during period	100	100
Other Cost and Expense, Operating	1,548	1,500
Casualty-related (recoveries)/charges, net	$ 553	$ 0
Operating Community [Member] | Unconsolidated Joint Venture Vitruvian Park [Member]
Real Estate Properties [Line Items]
Equity Method Investment, Ownership Percentage	50.00%		50.00%
Real Estate Owned (Textual) [Abstract]
Number of Real Estate Properties	3
Operating Community [Member] | Unconsolidated Joint Venture UDR MetLife II Partnership [Member]
Real Estate Properties [Line Items]
Equity Method Investment, Ownership Percentage	50.00%		50.00%
Real Estate Owned (Textual) [Abstract]
Number of Real Estate Properties	18
Development Community [Member] | Unconsolidated Joint Venture Vitruvian Park [Member]
Real Estate Owned (Textual) [Abstract]
Number of Real Estate Properties	1
Land, Buildings and Improvements [Member] | Unconsolidated Joint Venture UDR MetLife II Partnership [Member]
Real Estate Properties [Line Items]
Property, Plant and Equipment, Additions	$ 12,200
Subsequent Investment [Member] | CityLine [Member]
Real Estate Properties [Line Items]
Equity Method Investment, Ownership Percentage	100.00%
Initial Investment [Member] | CityLine [Member]
Real Estate Properties [Line Items]
Equity Method Investment, Ownership Percentage	49.00%

Real Estate Owned (UNITED DOM64

Real Estate Owned (UNITED DOMINION REALTY, L.P.) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Land	$ 1,812,797	$ 1,801,576
Under development:
Real estate under development (net of accumulated depreciation of $0 and $0, respectively)	393,837	342,282
Real estate owned	9,787,569	9,615,753
Real Estates Owned Accumulated Depreciation	(3,026,660)	(2,923,625)
Real estate owned, net	6,760,909	6,692,128
Land [Member]
Under development:
Real estate under development (net of accumulated depreciation of $0 and $0, respectively)	111,028	111,028
Real Estate Held-for-sale	0	1,104
Construction in progress [Member]
Under development:
Real estate under development (net of accumulated depreciation of $0 and $0, respectively)	282,809	231,254
Building and Building Improvements [Member]
Under development:
Real Estate Held-for-sale	0	520
United Dominion Reality L.P. [Member]
Property, Plant and Equipment [Line Items]
Land	837,945	836,644
Depreciable property - held and used:
Building, improvements, and furniture, fixture and equipment	2,848,389	2,838,060
Under development:
Real estate owned	3,686,334	3,674,704
Real Estates Owned Accumulated Depreciation	(1,445,528)
Real estate owned, net	$ 2,240,806	$ 2,265,889

Real Estate Owned (UNITED DOM65

Real Estate Owned (UNITED DOMINION REALTY, L.P.) (Details Textual) $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)CommunitiesApartment_HomesStates	Mar. 31, 2016USD ($)	Dec. 31, 2016USD ($)
Real Estate Owned (Textual) [Abstract]
Number of communities owned (in communities) | Communities	128
Number of states operating within (in states)	10
Number of apartments owned (in apartments homes) | Apartment_Homes	39,698
Number of communities acquired apartment homes are within | Communities	0
Development costs excluding direct costs and capitlized interest	$ 2,800	$ 2,000
Interest capitalized during period	4,700	4,200
Other Cost and Expense, Operating	1,691	1,752
Proceeds from Sale of Property, Plant, and Equipment	3,500
Deferred profit from the sale of properties	9,700		$ 9,500
Casualty-related (recoveries)/charges, net	502	0
Payments for (Proceeds from) Investments	$ 3,300
United Dominion Reality L.P. [Member]
Real Estate Owned (Textual) [Abstract]
Number of communities owned (in communities) | Communities	54
Number of states operating within (in states) | States	8
Number of apartments owned (in apartments homes) | Apartment_Homes	16,698
Development costs excluding direct costs and capitlized interest	$ 300	300
Interest capitalized during period	100	100
Other Cost and Expense, Operating	1,548	1,500
Casualty-related (recoveries)/charges, net	$ 553	$ 0

Joint Ventures (Details)

Joint Ventures (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)Communities	Mar. 31, 2016USD ($)	Dec. 31, 2016USD ($)
Financial information relating to unconsolidated joint ventures operations
Income/(loss) from unconsolidated entities	$ 11,198	$ 679
Combined summary of balance sheets relating to unconsolidated joint ventures
Investment in unconsolidated entities	818,990		$ 827,025
Deferred gains on the sale of depreciable property	$ 9,700		9,500
Number of Real Estate Properties | Communities	128
Investments in and advances to unconsolidated joint ventures, net	$ 818,990		827,025
Unconsolidated Joint Ventures [Member]
Financial information relating to unconsolidated joint ventures operations
Total revenues	58,524	55,037
Equity Method Investment Summarized Financial Information Property Operating Expense	(21,834)	(23,413)
Real estate depreciation and amortization	(23,333)	(18,943)
Net income /(loss)	(4,333)	(3,500)
Combined summary of balance sheets relating to unconsolidated joint ventures
Total real estate, net	2,904,183		2,901,067
Equity Method Investment Summarized Financial Information Cash and cash equivalents	28,676		32,503
Equity Method Investment Summarized Financial Information Other assets	17,288		19,047
Total assets	2,950,147		2,952,617
Amount due to UDR	2,746		521
Third party debt	1,811,490		1,794,379
Equity Method Investment Summarized Financial Information Accounts payable and accrued liabilities	55,471		66,391
Total liabilities	1,869,707		1,861,291
Total equity	1,080,440		1,091,326
Investment in unconsolidated entities	579,642		582,719
Equity Method of Investment Summarized Financial Information Operating income/(loss)	13,357	12,681
Equity Method Investment Summarized Financial Information Interest expense	$ (17,690)	(16,181)
Preferred Equity Investment West Coast Development JV [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Equity Method Investment, Ownership Percentage	48.00%
Equity Method Investment, Preferred Return		12,766
Number of Real Estate Properties	5
Operating Community [Member] | Unconsolidated Joint Venture UDR Met Life I Partnership [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Investment in unconsolidated entities	$ 29,182		$ 25,209
Equity Method Investment, Ownership Percentage	50.00%		50.00%
Number of apartment homes	150
Operating Community [Member] | Unconsolidated Joint Venture UDR MetLife II Partnership [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Investment in unconsolidated entities	$ 309,409		$ 311,282
Equity Method Investment, Ownership Percentage	50.00%		50.00%
Number of apartment homes	4,059
Number of Real Estate Properties	18
Operating Community [Member] | Unconsolidated Joint Venture Vitruvian Park [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Investment in unconsolidated entities	$ 73,154		$ 72,414
Equity Method Investment, Ownership Percentage	50.00%		50.00%
Number of apartment homes	1,513
Number of Real Estate Properties	3
Operating Community [Member] | Unconsolidated Joint Venture Three [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Investment in unconsolidated entities	$ 11,801		$ 12,835
Equity Method Investment, Ownership Percentage	30.00%		30.00%
Number of apartment homes	660
Number of Real Estate Properties	3
Operating Community [Member] | Unconsolidated Joint Venture Other MetLife [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Investment in unconsolidated entities	$ 156,096		$ 160,979
Equity Method Investment, Ownership Percentage	50.60%		50.60%
Number of apartment homes	1,437
Number of Real Estate Properties	1
Land Parcel [Member] | Unconsolidated Joint Venture UDR Met Life I Partnership [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Number of Real Estate Properties	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	5
Development Community [Member] | Unconsolidated Joint Venture Vitruvian Park [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Number of Real Estate Properties	1
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
Development Community [Member] | Participating Loan Investment Steele Creek Denver Colorado [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Investment in unconsolidated entities	$ 94,002		$ 94,003
Income from Participating Loan	$ 1,533	1,519
Participating Loan, Interest Rate, Stated Percentage	6.50%
Participating Loan Years to Maturity	4 months
Development Community [Member] | Preferred Equity Investment West Coast Development JV [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Investment in unconsolidated entities	$ 145,346		$ 150,303
Equity Method Investment, Preferred Return		$ 1,427
Participating Loan, Interest Rate, Stated Percentage	6.50%

Joint Ventures (Details Textual

Joint Ventures (Details Textual) $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)Communities	Mar. 31, 2016USD ($)	Dec. 31, 2016USD ($)
Schedule of Equity Method Investments [Line Items]
Casualty-related (recoveries)/charges, net	$ 502	$ 0
Proceeds from Sale of Property, Plant, and Equipment	3,500
Gain/(loss) on sale of real estate owned	$ 2,132	$ 3,070
Number of Real Estate Properties | Communities	128
Community Threshold, Period Above Occupancy Threshold	3 months	3 months
Secured Debt	$ 1,031,507		$ 1,130,858
Joint Ventures
Real Estate Owned Gross	9,787,569		9,615,753
Unamortized discount	10,400		11,200
First installment of payable incurred in partial consideration for acquisition of ownership interest in joint venture	269,878
Second installment of payable incurred in partial consideration for acquisition of ownership interest in joint venture	510,675
Interest expense	(30,539)	$ (31,104)
Investment in unconsolidated entities	818,990		827,025
Deferred profit from the sale of properties	9,700		9,500
Investment in unconsolidated joint ventures	24,193	13,262
Management fees for our involvement in the joint ventures	$ 2,600	2,800
Condition for Community considered to have stabilized occupancy	0.9
Number of Apartment Homes Acquired	155
717 Olympic [Member]
Schedule of Equity Method Investments [Line Items]
Casualty-related (recoveries)/charges, net	$ 900	(1,100)
Unconsolidated Joint Venture UDR Met Life I Partnership [Member]
Schedule of Equity Method Investments [Line Items]
Number of apartments of development community	0
Unconsolidated Joint Venture 399 Fremont [Member]
Schedule of Equity Method Investments [Line Items]
Number of apartments of development community	1,018
Preferred Equity Investment West Coast Development JV [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment Cost of Ownership Interest	$ 136,300
Number of Real Estate Properties	5
Total Fixed Price Option Sales Price	$ 597,400
Community Threshold, Period Above Occupancy Threshold	90 days
Joint Ventures
Equity Method Investment, Preferred Return		12,766
Equity Method Investment, Ownership Percentage	48.00%
Number of Completed Communities	3
Number of Remaining Communities	4
Number of Stabilized Communities	2
Number of Non Stabilized Communities	2
Condition for Community considered to have stabilized occupancy	0.8
CityLine [Member]
Joint Ventures
Investment in unconsolidated joint ventures	$ 66,000
Number of Apartment Homes Acquired	244
Preferred Equity Method Investment West Coast Development JV Cityline II [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment Cost of Ownership Interest	$ 15,500
Total Fixed Price Option Sales Price	$ 61,300
Joint Ventures
Equity Method Investment, Ownership Percentage	49.00%
Hold Period	1 year
Operating Community [Member] | Unconsolidated Joint Venture Vitruvian Park [Member]
Schedule of Equity Method Investments [Line Items]
Number of Real Estate Properties	3
Number of apartment homes	1,513
Joint Ventures
Investment in unconsolidated entities	$ 73,154		$ 72,414
Equity Method Investment, Ownership Percentage	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 apartment homes	150
Joint Ventures
Investment in unconsolidated entities	$ 29,182		$ 25,209
Equity Method Investment, Ownership Percentage	50.00%		50.00%
Operating Community [Member] | Unconsolidated Joint Venture UDR MetLife II Partnership [Member]
Schedule of Equity Method Investments [Line Items]
Number of Real Estate Properties	18
Number of apartment homes	4,059
Joint Ventures
Investment in unconsolidated entities	$ 309,409		$ 311,282
Equity Method Investment, Ownership Percentage	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
Number of apartment homes	660
Joint Ventures
Investment in unconsolidated entities	$ 11,801		$ 12,835
Equity Method Investment, Ownership Percentage	30.00%		30.00%
Operating Community [Member] | Unconsolidated Joint Venture Other MetLife [Member]
Schedule of Equity Method Investments [Line Items]
Number of Real Estate Properties	1
Number of apartment homes	1,437
Joint Ventures
Investment in unconsolidated entities	$ 156,096		$ 160,979
Equity Method Investment, Ownership Percentage	50.60%		50.60%
Development Community [Member] | Unconsolidated Joint Venture Vitruvian Park [Member]
Schedule of Equity Method Investments [Line Items]
Number of Real Estate Properties	1
Development Community [Member] | Unconsolidated Joint Venture Other MetLife [Member]
Schedule of Equity Method Investments [Line Items]
Number of Real Estate Properties	4
Development Community [Member] | Preferred Equity Investment West Coast Development JV [Member]
Joint Ventures
Investment in unconsolidated entities	$ 145,346		$ 150,303
Equity Method Investment, Preferred Return		$ 1,427
Participating Loan, Interest Rate, Stated Percentage	6.50%
Development Community [Member] | Preferred Equity Method Investment West Coast Development JV Cityline II [Member]
Joint Ventures
Participating Loan, Interest Rate, Stated Percentage	6.50%
Subsequent Investment [Member] | CityLine [Member]
Joint Ventures
Equity Method Investment, Ownership Percentage	100.00%
Initial Investment [Member] | CityLine [Member]
Joint Ventures
Equity Method Investment, Ownership Percentage	49.00%

Unconsolidated Entities (UNIT68

Unconsolidated Entities (UNITED DOMINION REALTY, L.P.) Unconsolidated Entities (UNITED DOMINION REALTY, L.P.) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Equity Method Investments	$ 818,990		$ 827,025
Income/(loss) from unconsolidated entities	11,198	$ 679
United Dominion Reality L.P. [Member]
Equity Method Investment Summarized Financial Information Real Estate, Net	1,400,046		1,413,983
Equity Method Investment Summarized Financial Information Cash and cash equivalents	35		66
Equity Method Investment Summarized Financial Information Other assets	4,498		4,843
Equity Method Investment, Summarized Financial Information, Assets	1,531,079		1,545,392
Equity Method Investment Summarized Financial Information Accounts payable and accrued liabilities	23,976		27,571
Equity Method Investment, Summarized Financial Information, Liabilities	466,148		471,178
Equity Method Investment Summarized Financial Information, Equity	1,064,931		1,074,214
Equity Method Investment, Summarized Financial Information, Liabilities and Equity	1,531,079		1,545,392
Equity Method Investments	103,267		112,867
Income/(loss) from unconsolidated entities	(5,424)	(13,387)
UDR Lighthouse DownREIT L.P. [Member] | United Dominion Reality L.P. [Member]
Equity Method Investment Summarized Financial Instrument, Note Receivable	126,500		126,500
Equity Method Investment Summarized Financial Information, Secured Debt, Net	442,172		$ 443,607
Equity Method Investment, Summarized Financial Information, Revenue	33,298	31,617
Equity Method Investment Summarized Financial Information Property Operating Expense	(13,976)	(14,269)
Equity Method Investment Summarized Financial Information Depreciation Amortization	(20,608)	(30,053)
Equity Method of Investment Summarized Financial Information Operating income/(loss)	(1,286)	(12,705)
Equity Method Investment Summarized Financial Information Interest expense	(3,860)	(3,741)
Equity Method Investment Summarized Financial Information Other income/(expense)	1,166	1,180
Net income /(loss)	$ (3,980)	$ (15,266)

Unconsolidated Entities (UNIT69

Unconsolidated Entities (UNITED DOMINION REALTY, L.P.) Unconsolidated Entities (UNITED DOMINION REALTY, L.P.) (Details Textual) $ in Thousands	Mar. 31, 2017USD ($)CommunitiesApartment_Homes	Dec. 31, 2016USD ($)
Schedule of Equity Method Investments [Line Items]
Number of Real Estate Properties | Communities	128
Number of apartment homes owned and consolidated by the Company | Apartment_Homes	39,698
Equity Method Investments | $	$ 818,990	$ 827,025
United Dominion Reality L.P. [Member]
Schedule of Equity Method Investments [Line Items]
Number of Real Estate Properties | Communities	54
Number of apartment homes owned and consolidated by the Company | Apartment_Homes	16,698
Equity Method Investments | $	$ 103,267	$ 112,867
United Dominion Reality L.P. [Member] | UDR Lighthouse DownREIT L.P. [Member]
Schedule of Equity Method Investments [Line Items]
Number of Real Estate Properties | Communities	13
Number of apartment homes owned and consolidated by the Company | Apartment_Homes	6,261

Secured and Unsecured Debt (Det

Secured and Unsecured Debt (Details)	3 Months Ended
	Mar. 31, 2017USD ($)	Mar. 31, 2016	Dec. 31, 2016USD ($)
Secured debt instruments
Weighted average interest rate	3.67%
Long-term Debt	$ 3,537,292,000		$ 3,401,478,000
Unsecured Debt	$ 2,505,785,000		2,270,620,000
Weighted Average Years to Maturity	4 years 7 months 23 days
Commercial Paper, at Carrying Value	$ 220,000,000		0
Line of Credit Facility, Amount Outstanding	$ 2,900,000		2,900,000
Commercial Paper [Member]
Secured debt instruments
Weighted average interest rate	1.24%	0.00%
Weighted Average Years to Maturity	18 days
Fixed Rate Debt [Member]
Secured debt instruments
Principal outstanding	$ 754,489,000		756,151,000
Weighted average interest rate	4.53%
Weighted Average Years to Maturity	4 years 4 months 24 days
Number of Communities Encumbered	17
Variable Rate Debt [Member]
Secured debt instruments
Principal outstanding	$ 277,018,000		374,707,000
Weighted average interest rate	1.84%
Weighted Average Years to Maturity	2 years 10 months 9 days
Number of Communities Encumbered	7
Mortgages Notes Payable [Member] | Fixed Rate Debt [Member]
Secured debt instruments
Weighted average interest rate	4.04%
Weighted Average Years to Maturity	6 years 21 days
Number of Communities Encumbered	7
Tax-exempt secured notes payable [Member] | Variable Rate Debt [Member]
Secured debt instruments
Weighted average interest rate	1.42%
Weighted Average Years to Maturity	5 years 11 months 8 days
Number of Communities Encumbered	2
Fannie Mae credit facilities [Member] | Fixed Rate Debt [Member]
Secured debt instruments
Weighted average interest rate	5.06%
Weighted Average Years to Maturity	2 years 6 months 25 days
Number of Communities Encumbered	10
Fannie Mae credit facilities [Member] | Variable Rate Debt [Member]
Secured debt instruments
Weighted average interest rate	2.05%
Weighted Average Years to Maturity	1 year 3 months 5 days
Number of Communities Encumbered	5
Secured Debt [Member]
Secured debt instruments
Principal outstanding	$ 1,031,507,000		1,130,858,000
Weighted average interest rate	3.80%
Long-term Debt	$ 1,031,507,000
Weighted Average Years to Maturity	3 years 11 months 24 days
Number of Communities Encumbered	24
Secured Debt [Member] | Fixed Rate Debt [Member]
Secured debt instruments
Long-term Debt	$ 754,489,000
Secured Debt [Member] | Variable Rate Debt [Member]
Secured debt instruments
Long-term Debt	$ 277,018,000
Unsecured Revolving Credit Facility due October 2015 [Member]
Secured debt instruments
Weighted average interest rate	0.00%
Weighted Average Years to Maturity	2 years 10 months
Line of Credit Facility, Amount Outstanding	$ 0		0
Unsecured Working Capital Credit Facility due January 2019 [Member]
Secured debt instruments
Weighted average interest rate	1.88%
Weighted Average Years to Maturity	1 year 9 months 1 day
Line of Credit Facility, Amount Outstanding	$ 36,140,000		21,350,000
1.21% Term Loan Facility due January 2021 [Member]
Secured debt instruments
Weighted average interest rate	1.73%
Senior Notes	$ 35,000,000		35,000,000
Weighted Average Years to Maturity	3 years 9 months 29 days
ThreePointSevenTermNotesDueOctober2020 [Member]
Secured debt instruments
Senior Notes	$ 299,972,000		299,970,000
Weighted Average Years to Maturity	3 years 6 months 1 day
2.23% Term Loan Facility due January 2021 [Member]
Secured debt instruments
Weighted average interest rate	2.34%
Senior Notes	$ 315,000,000		315,000,000
Weighted Average Years to Maturity	3 years 9 months 29 days
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	$ 398,285,000		398,195,000
Weighted Average Years to Maturity	4 years 9 months 10 days
3.75 MTN Due July 2024 [Member]
Secured debt instruments
Weighted average interest rate	3.75%
Senior Notes	$ 299,244,000		299,218,000
Weighted Average Years to Maturity	7 years 3 months 1 day
Three point seven percent medium term note due October 2020 [Member]
Secured debt instruments
Weighted average interest rate	3.70%
Eight Point Five Zero Percent, Debentures, Due September 2024 [Member]
Secured debt instruments
Weighted average interest rate	8.50%
Senior Notes	$ 15,644,000		15,644,000
Weighted Average Years to Maturity	7 years 5 months 15 days
4.00% Medium-Term Note due October 2025 [Member]
Secured debt instruments
Weighted average interest rate	4.00%
Senior Notes	$ 299,415,000		299,398,000
Weighted Average Years to Maturity	8 years 6 months 1 day
2.95% Medium-Term Note due September 2026 [Member]
Secured debt instruments
Weighted average interest rate	2.95%
Senior Notes	$ 300,000,000		300,000,000
Weighted Average Years to Maturity	9 years 5 months 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	$ 299,499,000		299,392,000
Weighted Average Years to Maturity	1 year 2 months 1 day
Other [Member]
Secured debt instruments
Senior Notes	$ 21,000		21,000
Unsecured Debt [Member]
Secured debt instruments
Weighted average interest rate	3.52%
Long-term Debt	$ 2,505,785,000
Unsecured Debt	$ 2,505,785,000		2,270,620,000
Weighted Average Years to Maturity	4 years 11 months 1 day
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	$ 401,135,000		402,996,000
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	355,836,000		355,836,000
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	182,606,000		280,946,000
Unsecured Debt [Member]
Secured debt instruments
Deferred Finance Costs, Net	(12,435,000)		(12,568,000)
Secured Debt [Member] | Variable Rate Debt [Member]
Secured debt instruments
Deferred Finance Costs, Net	(288,000)		(939,000)
Secured Debt [Member] | Fixed Rate Debt [Member]
Secured debt instruments
Deferred Finance Costs, Net	$ (2,482,000)		$ (2,681,000)

Secured and Unsecured Debt (D71

Secured and Unsecured Debt (Details 1) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Line of Credit Facility [Line Items]
Unamortized discount	$ 10,400		$ 11,200
Secured credit facilities
Borrowings outstanding	$ 2,900		2,900
Debt Instrument Weighted Average Years to Maturity	4 years 7 months 23 days
Fannie Mae [Member]
Secured credit facilities
Borrowings outstanding	$ 538,442		$ 636,782
Weighted average daily borrowings during the period ended	604,002	$ 737,802
Maximum daily borrowings during the period ended	$ 636,782	$ 813,544
Weighted average interest rate during the period ended	3.89%	3.90%
Interest rate at the end of the period	4.04%		3.80%
Four Point Two Five Percentage Medium-Term Notes due June 2018 [Member]
Line of Credit Facility [Line Items]
Unamortized discount	$ 501		$ 608
Secured credit facilities
Debt Instrument Weighted Average Years to Maturity	1 year 2 months 1 day
Three point seven percent medium term note due October 2020 [Member]
Line of Credit Facility [Line Items]
Unamortized discount	$ 28		30
Four Point Six Three Percent Term Medium Notes Due January Two Thousand Twenty-Two [Member]
Line of Credit Facility [Line Items]
Unamortized discount	$ 1,715		1,805
Secured credit facilities
Debt Instrument Weighted Average Years to Maturity	4 years 9 months 10 days
3.75 MTN Due July 2024 [Member]
Line of Credit Facility [Line Items]
Unamortized discount	$ 756		$ 782
Secured credit facilities
Debt Instrument Weighted Average Years to Maturity	7 years 3 months 1 day
Variable Rate Debt [Member]
Secured credit facilities
Debt Instrument Weighted Average Years to Maturity	2 years 10 months 9 days

Secured and Unsecured Debt (D72

Secured and Unsecured Debt (Details 2) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Secured Debt, Encumbers Real Estate Owned, Amount	$ 1,900,000
Secured Debt, Encumbers Real Estate Owned, Percent	19.70%
Debt Instrument Weighted Average Years to Maturity	4 years 7 months 23 days
Unamortized discount	$ 10,400	$ 11,200
Aggregate maturities of secured debt
2,014	269,878
2,015	510,675
2,016	353,235
2,017	498,076
2,018	351,117
Total	1,031,507	1,130,858
Secured Debt, Unencumbered Real Estate Owned, Amount	$ 7,900,000
Secured Debt, Unencumbered Real Estate Owned, Percent	80.30%
Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	4 years 4 months 24 days
Variable Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	2 years 10 months 9 days
ThreePointSevenTermNotesDueOctober2020 [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	3 years 6 months 1 day
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	4 years 9 months 10 days
Unamortized discount	$ 1,715	1,805
Mortgages Notes Payable [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	6 years 21 days
Tax Exempt Notes Payable [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	5 years 11 months 8 days
Fannie Mae credit facilities [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	2 years 6 months 25 days
Fannie Mae credit facilities [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	1 year 3 months 5 days
3.75 MTN Due July 2024 [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	7 years 3 months 1 day
Unamortized discount	$ 756	$ 782

Secured and Unsecured Debt (D73

Secured and Unsecured Debt (Details 3) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Summary of unsecured debt
Unsecured Debt, Total	$ 2,505,785	$ 2,270,620
Unamortized discount	10,400	11,200
4.63% Medium-Term Notes due January 2022 [Member]
Summary of unsecured debt
Senior Unsecured Notes	398,285	398,195
Unamortized discount	1,715	1,805
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	299,499	299,392
Unamortized discount	501	608
Other [Member]
Summary of unsecured debt
Senior Unsecured Notes	$ 21	$ 21

Secured and Unsecured Debt (D74

Secured and Unsecured Debt (Details 4) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Summary of short-term bank borrowings under unsecured commercial bank credit facility
Borrowings outstanding at end of period	$ 2,900
Unsecured Commercial Bank Credit Facility [Member]
Summary of short-term bank borrowings under unsecured commercial bank credit facility
Total revolving credit facility	2,000,000		$ 1,100,000
Weighted average daily borrowings during the period ended	9,222	$ 161,505
Maximum daily borrowings during the period ended	$ 120,000	$ 340,000
Weighted average interest rate during the period ended	1.60%	1.40%
Interest rate at the end of the period	0.00%		0.00%
Unsecured Working Capital Credit Facility due January 2019 [Member]
Summary of short-term bank borrowings under unsecured commercial bank credit facility
Total revolving credit facility	$ 75,000		$ 75,000
Borrowings outstanding at end of period	36,140
Weighted average daily borrowings during the period ended	26,714	$ 21,936
Maximum daily borrowings during the period ended	$ 67,799	$ 69,633
Weighted average interest rate during the period ended	1.70%	1.40%
Interest rate at the end of the period	1.90%		1.70%

Secured and Unsecured Debt Secu

Secured and Unsecured Debt Secured and Unsecured Debt (Details 5) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Short-term Debt [Line Items]
Commercial Paper, Maximum Borrowing Amount	$ 500,000,000		$ 0
Commercial Paper, at Carrying Value	$ 220,000,000		$ 0
Weighted average interest rate	3.67%
Commercial Paper [Member]
Short-term Debt [Line Items]
Short-term Debt, Average Outstanding Amount	$ 80,228,000	$ 0
Short-term Debt, Maximum Amount Outstanding During Period	$ 220,000,000	$ 0
Short-term Debt, Weighted Average Interest Rate	1.153%		0.00%
Weighted average interest rate	1.24%	0.00%

Secured and Unsecured Debt (D76

Secured and Unsecured Debt (Details 6) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 3,545,627
Debt Instrument, Unamortized Discount (Premium), Net	(8,335)
Aggregate maturities of unsecured debt
2,014	269,878
2,015	510,675
2,016	353,235
2,017	498,076
2,018	351,117
Unsecured Debt, Total	2,505,785	$ 2,270,620
Long-term Debt	3,537,292	3,401,478
Long-Term Debt, Maturities, Repayment of Principle in Year Six	401,157
Long-Term Debt, Maturities, Repayment of Principle in Year Seven	41,245
Long-Term Debt, Maturities, Repayment of Principle in Year Eight	315,644
Long-Term Debt, Maturities, Repayment of Principle in Year Nine	427,600
Long-Term Debt, Maturities, Repayment of Principle in Year Ten	350,000
Long-Term Debt, Maturities, Repayments of Principal after Year Ten	27,000
Secured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	1,023,843
Debt Instrument, Unamortized Discount (Premium), Net	7,664
Aggregate maturities of unsecured debt
2,014	49,878
2,015	210,675
2,016	317,095
2,017	198,076
2,018	1,117
Long-term Debt	1,031,507
Long-Term Debt, Maturities, Repayment of Principle in Year Six	1,157
Long-Term Debt, Maturities, Repayment of Principle in Year Seven	41,245
Long-Term Debt, Maturities, Repayment of Principle in Year Eight	0
Long-Term Debt, Maturities, Repayment of Principle in Year Nine	127,600
Long-Term Debt, Maturities, Repayment of Principle in Year Ten	50,000
Long-Term Debt, Maturities, Repayments of Principal after Year Ten	27,000
Unsecured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	2,521,784
Debt Instrument, Unamortized Discount (Premium), Net	(15,999)
Aggregate maturities of unsecured debt
2,014	220,000
2,015	300,000
2,016	36,140
2,017	300,000
2,018	350,000
Unsecured Debt, Total	2,505,785	$ 2,270,620
Long-term Debt	2,505,785
Long-Term Debt, Maturities, Repayment of Principle in Year Six	400,000
Long-Term Debt, Maturities, Repayment of Principle in Year Seven	0
Long-Term Debt, Maturities, Repayment of Principle in Year Eight	315,644
Long-Term Debt, Maturities, Repayment of Principle in Year Nine	300,000
Long-Term Debt, Maturities, Repayment of Principle in Year Ten	300,000
Long-Term Debt, Maturities, Repayments of Principal after Year Ten	0
Fixed Rate Debt [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	746,537
Debt Instrument, Unamortized Discount (Premium), Net	7,952
Aggregate maturities of unsecured debt
2,014	3,310
2,015	74,637
2,016	249,395
2,017	198,076
2,018	1,117
Long-term Debt	754,489
Long-Term Debt, Maturities, Repayment of Principle in Year Six	1,157
Long-Term Debt, Maturities, Repayment of Principle in Year Seven	41,245
Long-Term Debt, Maturities, Repayment of Principle in Year Eight	0
Long-Term Debt, Maturities, Repayment of Principle in Year Nine	127,600
Long-Term Debt, Maturities, Repayment of Principle in Year Ten	50,000
Long-Term Debt, Maturities, Repayments of Principal after Year Ten	0
Variable Rate Debt [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	277,306
Debt Instrument, Unamortized Discount (Premium), Net	(288)
Aggregate maturities of unsecured debt
2,014	46,568
2,015	136,038
2,016	67,700
2,017	0
2,018	0
Long-term Debt	277,018
Long-Term Debt, Maturities, Repayment of Principle in Year Six	0
Long-Term Debt, Maturities, Repayment of Principle in Year Seven	0
Long-Term Debt, Maturities, Repayment of Principle in Year Eight	0
Long-Term Debt, Maturities, Repayment of Principle in Year Nine	0
Long-Term Debt, Maturities, Repayment of Principle in Year Ten	0
Long-Term Debt, Maturities, Repayments of Principal after Year Ten	$ 27,000

Secured and Unsecured Debt (D77

Secured and Unsecured Debt (Details Textual) $ in Thousands	Jun. 27, 2014	Mar. 31, 2017USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2016USD ($)
Debt Instrument [Line Items]
Amortization of Financing Costs		$ 1,100	$ 1,300
Secured Debt (Textual) [Abstract]
Secured debt amount which encumbers real estate owned based upon book value		$ 1,900,000
Percentage of secured debt which encumbers real estate owned based upon book value		19.70%
Secured debt amount of real estate owned which is unencumbered		$ 7,900,000
Percentage of secured debt of real estate owned which is unencumbered		80.30%
Weighted average interest rate		3.67%
Unamortized fair market adjustment		$ 10,400		$ 11,200
Borrowings outstanding		2,900		2,900
Long-term Commercial Paper		500,000
Secured Debt		1,031,507		1,130,858
Repayments of Secured Debt		99,463	2,205
Fixed Rate Debt [Member]
Secured Debt (Textual) [Abstract]
Secured debt including debt on real estate held for sale		$ 754,489		756,151
Weighted average interest rate		4.53%
Variable Rate Debt [Member]
Secured Debt (Textual) [Abstract]
Secured debt including debt on real estate held for sale		$ 277,018		374,707
Weighted average interest rate		1.84%
Repayments of Secured Debt		$ 98,300
Unsecured Debt [Member]
Secured Debt (Textual) [Abstract]
Weighted average interest rate		3.52%
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 Working Capital Credit Facility due January 2019 [Member]
Secured Debt (Textual) [Abstract]
Credit facilities with aggregate commitment		$ 75,000		75,000
Weighted average interest rate		1.88%
Borrowings outstanding		$ 36,140		21,350
Line of Credit Facility, Interest Rate Description		90
Line of Credit Facility, Description Range Low		85
Line of Credit Facility, Description Range High		155
3.75 MTN Due July 2024 [Member]
Secured Debt (Textual) [Abstract]
Weighted average interest rate		3.75%
Unamortized fair market adjustment		$ 756		782
Debt Instrument, Maturity Date	Jul. 1, 2024
Senior Notes		$ 299,244		299,218
Mortgages Notes Payable [Member] | Fixed Rate Debt [Member]
Secured Debt (Textual) [Abstract]
Weighted average interest rate		4.04%
Debt Instrument, Maturity Date Range, Start		May 1, 2019
Debt instrument, maturity date range, end		Nov. 5, 2026
Notes payable minimum interest rates range		3.15%
Notes payable maximum interest rates range		5.86%
Debt Assumed As Part of Acquisition [Member]
Secured Debt (Textual) [Abstract]
Amortization of Debt Discount (Premium)		$ 700	$ 800
Tax Exempt Notes Payable [Member] | Variable Rate Debt [Member]
Secured Debt (Textual) [Abstract]
Weighted average interest rate		1.42%
Fannie Mae credit facilities [Member] | Fixed Rate Debt [Member]
Secured Debt (Textual) [Abstract]
Weighted average interest rate		5.06%
Debt Instrument, Maturity Date Range, Start		May 1, 2017
Debt instrument, maturity date range, end		Jul. 1, 2020
Fannie Mae credit facilities [Member] | Variable Rate Debt [Member]
Secured Debt (Textual) [Abstract]
Weighted average interest rate		2.05%
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		1.39%
Notes payable maximum interest rates range		1.44%
Fannie Mae [Member]
Secured Debt (Textual) [Abstract]
Borrowings outstanding		$ 538,442		636,782
Revolving Credit Facility [Member]
Secured Debt (Textual) [Abstract]
Line of Credit Facility, Interest Rate Description		90
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
Line of Credit Facility, Commitment Fee Description		15
4.00% Medium-Term Note due October 2025 [Member]
Secured Debt (Textual) [Abstract]
Weighted average interest rate		4.00%
Portion of Medium Term Note subject to Interest Rate Swaps		$ 200,000
Long-term Debt, Weighted Average Interest Rate		4.55%
Senior Notes		$ 299,415		299,398
2.95% Medium-Term Note due September 2026 [Member]
Secured Debt (Textual) [Abstract]
Weighted average interest rate		2.95%
Senior Notes		$ 300,000		300,000
UDR Bank Credit Facility [Member]
Secured Debt (Textual) [Abstract]
Credit facilities with aggregate commitment		$ 2,000,000		1,100,000
Number of Extensions of loan		2
Extension period of option on loan		6 months
Debt Instrument, Maturity Date		Jan. 31, 2020
UDR Bank Credit Facility [Member] | Unsecured Debt [Member]
Secured Debt (Textual) [Abstract]
Credit facilities with aggregate commitment		$ 350,000
Debt Instrument, Maturity Date		Jan. 29, 2021
UDR Bank Credit Facility [Member] | Revolving Credit Facility [Member]
Secured Debt (Textual) [Abstract]
Credit facilities with aggregate commitment		$ 1,100,000
Unsecured Working Capital Credit Facility due January 2019 [Member]
Secured Debt (Textual) [Abstract]
Credit facilities with aggregate commitment		75,000
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		355,836		355,836
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		182,606		280,946
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		$ 401,135		$ 402,996

Secured and Unsecured Debt (D78

Secured and Unsecured Debt (Details Textual 1) - USD ($) $ in Thousands	Sep. 26, 2013	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Debt Instrument [Line Items]
Amortization of Financing Costs		$ 1,100	$ 1,300
Unsecured Debt (Textual) [Abstract]
Line of Credit Facility, Amount Outstanding		2,900		$ 2,900
Unamortized discount		$ 10,400		11,200
Debt Instrument, Interest Rate During Period		3.67%
ThreePointSevenTermNotesDueOctober2020 [Member]
Unsecured Debt (Textual) [Abstract]
Debt Instrument, Maturity Date	Oct. 31, 2020
Senior Notes		$ 299,972		299,970
4.63% Medium-Term Notes due January 2022 [Member]
Unsecured Debt (Textual) [Abstract]
Unamortized discount		1,715		1,805
Senior Notes		$ 398,285		398,195
Debt Instrument, Interest Rate During Period		4.63%
UDR Bank Credit Facility [Member]
Unsecured Debt (Textual) [Abstract]
Total revolving credit facility		$ 2,000,000		$ 1,100,000
Interest rate		0.00%		0.00%
Debt Instrument, Maturity Date		Jan. 31, 2020

Debt (UNITED DOMINION REALTY,79

Debt (UNITED DOMINION REALTY, L.P.) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)Communities	Dec. 31, 2016USD ($)
Debt Instrument [Line Items]
Weighted average interest rate	3.67%
Debt Instrument Weighted Average Years to Maturity	4 years 7 months 23 days
Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Principal outstanding	$ 754,489	$ 756,151
Weighted average interest rate	4.53%
Debt Instrument Weighted Average Years to Maturity	4 years 4 months 24 days
Number of Communities Encumbered (in communities)	17
Fixed Rate Debt [Member] | Mortgages Notes Payable [Member]
Debt Instrument [Line Items]
Weighted average interest rate	4.04%
Debt Instrument Weighted Average Years to Maturity	6 years 21 days
Number of Communities Encumbered (in communities)	7
Fixed Rate Debt [Member] | Fannie Mae credit facilities [Member]
Debt Instrument [Line Items]
Weighted average interest rate	5.06%
Debt Instrument Weighted Average Years to Maturity	2 years 6 months 25 days
Number of Communities Encumbered (in communities)	10
Variable Rate Debt [Member]
Debt Instrument [Line Items]
Principal outstanding	$ 277,018	374,707
Weighted average interest rate	1.84%
Debt Instrument Weighted Average Years to Maturity	2 years 10 months 9 days
Number of Communities Encumbered (in communities)	7
Variable Rate Debt [Member] | Fannie Mae credit facilities [Member]
Debt Instrument [Line Items]
Weighted average interest rate	2.05%
Debt Instrument Weighted Average Years to Maturity	1 year 3 months 5 days
Number of Communities Encumbered (in communities)	5
Variable Rate Debt [Member] | Tax Exempt Notes Payable [Member]
Debt Instrument [Line Items]
Weighted average interest rate	1.42%
Debt Instrument Weighted Average Years to Maturity	5 years 11 months 8 days
Number of Communities Encumbered (in communities)	2
United Dominion Reality L.P. [Member]
Debt Instrument [Line Items]
Principal outstanding	$ 336,240	433,974
Weighted average interest rate	4.26%
Debt Instrument Weighted Average Years to Maturity	3 years 4 months 14 days
Number of Communities Encumbered (in communities) | Communities	9
United Dominion Reality L.P. [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Principal outstanding	$ 228,152	243,842
Weighted average interest rate	5.07%
Debt Instrument Weighted Average Years to Maturity	2 years 6 months 27 days
Number of Communities Encumbered (in communities) | Communities	6
United Dominion Reality L.P. [Member] | Fixed Rate Debt [Member] | Fannie Mae credit facilities [Member]
Debt Instrument [Line Items]
Weighted average interest rate	5.07%
Debt Instrument Weighted Average Years to Maturity	2 years 6 months 27 days
Number of Communities Encumbered (in communities) | Communities	6
United Dominion Reality L.P. [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Principal outstanding	$ 108,088	190,132
Weighted average interest rate	2.10%
Debt Instrument Weighted Average Years to Maturity	5 years
Number of Communities Encumbered (in communities) | Communities	3
United Dominion Reality L.P. [Member] | Variable Rate Debt [Member] | Fannie Mae credit facilities [Member]
Debt Instrument [Line Items]
Weighted average interest rate	2.34%
Debt Instrument Weighted Average Years to Maturity	1 year 8 months 1 day
Number of Communities Encumbered (in communities) | Communities	2
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
Weighted average interest rate	1.39%
Debt Instrument Weighted Average Years to Maturity	14 years 11 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	$ 355,836	355,836
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	182,606	280,946
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	228,870	244,912
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	81,339	163,637
Secured Debt [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Deferred Finance Costs, Net	(288)	(939)
Secured Debt [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Deferred Finance Costs, Net	(2,482)	(2,681)
Secured Debt [Member] | United Dominion Reality L.P. [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Deferred Finance Costs, Net	(251)	(505)
Secured Debt [Member] | United Dominion Reality L.P. [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Deferred Finance Costs, Net	$ (718)	$ (1,070)

Debt (UNITED DOMINION REALTY,80

Debt (UNITED DOMINION REALTY, L.P.) (Details 1) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	4 years 7 months 23 days
Borrowings outstanding	$ 2,900		$ 2,900
Fannie Mae [Member]
Debt Instrument [Line Items]
Borrowings outstanding	538,442		$ 636,782
Weighted average daily borrowings during the period ended	604,002	$ 737,802
Maximum daily borrowings during the period ended	$ 636,782	$ 813,544
Weighted average interest rate during the period ended	3.89%	3.90%
Interest rate at the end of the period	4.04%		3.80%
United Dominion Reality L.P. [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	3 years 4 months 14 days
United Dominion Reality L.P. [Member] | Fannie Mae [Member]
Debt Instrument [Line Items]
Borrowings outstanding	$ 310,209		$ 408,549
Weighted average daily borrowings during the period ended	375,770	$ 414,759
Maximum daily borrowings during the period ended	$ 408,549	$ 421,001
Weighted average interest rate during the period ended	4.10%	3.90%
Interest rate at the end of the period	4.40%		4.00%
Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	4 years 4 months 24 days
Fixed Rate Debt [Member] | Mortgages [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	6 years 21 days
Fixed Rate Debt [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	2 years 6 months 25 days
Fixed Rate Debt [Member] | United Dominion Reality L.P. [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	2 years 6 months 27 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	2 years 6 months 27 days
Variable Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	2 years 10 months 9 days
Variable Rate Debt [Member] | Tax Exempt Notes Payable [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	5 years 11 months 8 days
Variable Rate Debt [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	1 year 3 months 5 days
Variable Rate Debt [Member] | United Dominion Reality L.P. [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	5 years
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	14 years 11 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	1 year 8 months 1 day

Debt (UNITED DOMINION REALTY,81

Debt (UNITED DOMINION REALTY, L.P.) (Details 2) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
2,014	$ 269,878
2,015	510,675
2,016	353,235
2,017	498,076
2,018	351,117
Long-term Debt, Gross	3,545,627
Debt Instrument, Unamortized Discount (Premium), Net	(8,335)
Total	1,031,507	$ 1,130,858
Long-Term Debt, Maturities, Repayment of Principle in Year Six	401,157
Long-Term Debt, Maturities, Repayment of Principle in Year Seven	41,245
Long-Term Debt, Maturities, Repayment of Principle in Year Eight	315,644
Long-Term Debt, Maturities, Repayment of Principle in Year Nine	427,600
Long-Term Debt, Maturities, Repayment of Principle in Year Ten	350,000
Long-Term Debt, Maturities, Repayments of Principal after Year Ten	27,000
United Dominion Reality L.P. [Member]
Debt Instrument [Line Items]
2,014	0
2,015	123,193
2,016	133,204
2,017	53,812
2,018	0
Thereafter	27,000
Long-term Debt, Gross	337,209
Debt Instrument, Unamortized Discount (Premium), Net	(969)
Total	336,240	$ 433,974
Long-Term Debt, Maturities, Repayment of Principle in Year Six	0
Long-Term Debt, Maturities, Repayment of Principle in Year Seven	0
Long-Term Debt, Maturities, Repayment of Principle in Year Eight	0
Long-Term Debt, Maturities, Repayment of Principle in Year Nine	0
Long-Term Debt, Maturities, Repayment of Principle in Year Ten	0
United Dominion Reality L.P. [Member] | Fannie Mae credit facilities [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
2,014	0
2,015	41,854
2,016	133,204
2,017	53,812
2,018	0
Long-term Debt, Gross	228,870
Debt Instrument, Unamortized Discount (Premium), Net	(718)
Total	228,152
Long-Term Debt, Maturities, Repayment of Principle in Year Six	0
Long-Term Debt, Maturities, Repayment of Principle in Year Seven	0
Long-Term Debt, Maturities, Repayment of Principle in Year Eight	0
Long-Term Debt, Maturities, Repayment of Principle in Year Nine	0
Long-Term Debt, Maturities, Repayment of Principle in Year Ten	0
Long-Term Debt, Maturities, Repayments of Principal after Year Ten	0
United Dominion Reality L.P. [Member] | Fannie Mae credit facilities [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
2,014	0
2,015	81,339
2,016	0
2,017	0
2,018	0
Long-term Debt, Gross	81,339
Debt Instrument, Unamortized Discount (Premium), Net	(167)
Total	81,172
Long-Term Debt, Maturities, Repayment of Principle in Year Six	0
Long-Term Debt, Maturities, Repayment of Principle in Year Seven	0
Long-Term Debt, Maturities, Repayment of Principle in Year Eight	0
Long-Term Debt, Maturities, Repayment of Principle in Year Nine	0
Long-Term Debt, Maturities, Repayment of Principle in Year Ten	0
Long-Term Debt, Maturities, Repayments of Principal after Year Ten	0
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
Long-term Debt, Gross	27,000
Debt Instrument, Unamortized Discount (Premium), Net	(84)
Total	26,916
Long-Term Debt, Maturities, Repayment of Principle in Year Six	0
Long-Term Debt, Maturities, Repayment of Principle in Year Seven	0
Long-Term Debt, Maturities, Repayment of Principle in Year Eight	0
Long-Term Debt, Maturities, Repayment of Principle in Year Nine	0
Long-Term Debt, Maturities, Repayment of Principle in Year Ten	0
Long-Term Debt, Maturities, Repayments of Principal after Year Ten	$ 27,000

Debt (UNITED DOMINION REALTY,82

Debt (UNITED DOMINION REALTY, L.P.) (Details Textual) - USD ($)	Jun. 27, 2014	Sep. 26, 2013	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity			4 years 7 months 23 days
Amortization of Financing Costs			$ 1,100,000	$ 1,300,000
Long-term Commercial Paper			500,000,000
Borrowings outstanding			$ 2,900,000		$ 2,900,000
Weighted average interest rate			3.67%
Unamortized fair market adjustment			$ 10,400,000		11,200,000
Commercial Paper, at Carrying Value			220,000,000		0
UDR Bank Credit Facility [Member]
Debt Instrument [Line Items]
Total revolving credit facility			$ 2,000,000,000		1,100,000,000
Debt Instrument, Maturity Date			Jan. 31, 2020
Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity			4 years 4 months 24 days
Secured debt including debt on real estate held for sale			$ 754,489,000		756,151,000
Weighted average interest rate			4.53%
Variable Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity			2 years 10 months 9 days
Secured debt including debt on real estate held for sale			$ 277,018,000		374,707,000
Weighted average interest rate			1.84%
Fannie Mae [Member]
Debt Instrument [Line Items]
Borrowings outstanding			$ 538,442,000		636,782,000
Fannie Mae credit facilities [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity			2 years 6 months 25 days
Debt Instrument, Maturity Date Range, Start			May 1, 2017
Weighted average interest rate			5.06%
Debt Instrument, Maturity Date Range, End			Jul. 1, 2020
Fannie Mae credit facilities [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity			1 year 3 months 5 days
Weighted average interest rate			2.05%
Mortgages [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity			6 years 21 days
Debt Instrument, Maturity Date Range, Start			May 1, 2019
Weighted average interest rate			4.04%
Notes payable minimum interest rates range			3.15%
Notes payable maximum interest rates range			5.86%
Debt Instrument, Maturity Date Range, End			Nov. 5, 2026
Tax Exempt Notes Payable [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity			5 years 11 months 8 days
Weighted average interest rate			1.42%
Unsecured Revolving Credit Facility due October 2015 [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity			2 years 10 months
Borrowings outstanding			$ 0		0
Weighted average interest rate			0.00%
4.25% Medium-Term Notes due June 2018 [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity			1 year 2 months 1 day
Weighted average interest rate			4.25%
Unamortized fair market adjustment			$ 501,000		608,000
Debt Instrument, Maturity Date		Jun. 1, 2018
Three point seven percent medium term note due October 2020 [Member]
Debt Instrument [Line Items]
Weighted average interest rate			3.70%
Unamortized fair market adjustment			$ 28,000		30,000
ThreePointSevenTermNotesDueOctober2020 [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity			3 years 6 months 1 day
Debt Instrument, Maturity Date		Oct. 31, 2020
2.23% Term Loan Facility due January 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity			3 years 9 months 29 days
Weighted average interest rate			2.34%
4.63% Medium-Term Notes due January 2022 [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity			4 years 9 months 10 days
Weighted average interest rate			4.63%
Unamortized fair market adjustment			$ 1,715,000		1,805,000
3.75 MTN Due July 2024 [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity			7 years 3 months 1 day
Weighted average interest rate			3.75%
Unamortized fair market adjustment			$ 756,000		782,000
Debt Instrument, Maturity Date	Jul. 1, 2024
4.00% Medium-Term Note due October 2025 [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity			8 years 6 months 1 day
Weighted average interest rate			4.00%
2.95% Medium-Term Note due September 2026 [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity			9 years 5 months 1 day
Weighted average interest rate			2.95%
United Dominion Reality L.P. [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity			3 years 4 months 14 days
Amortization of Financing Costs			$ 100,000	$ 200,000
Secured debt including debt on real estate held for sale			$ 336,240,000		433,974,000
Weighted average interest rate			4.26%
United Dominion Reality L.P. [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity			2 years 6 months 27 days
Secured debt including debt on real estate held for sale			$ 228,152,000		243,842,000
Weighted average interest rate			5.07%
United Dominion Reality L.P. [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity			5 years
Secured debt including debt on real estate held for sale			$ 108,088,000		190,132,000
Weighted average interest rate			2.10%
United Dominion Reality L.P. [Member] | Fannie Mae [Member]
Debt Instrument [Line Items]
Borrowings outstanding			$ 310,209,000		408,549,000
United Dominion Reality L.P. [Member] | Fannie Mae credit facilities [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity			2 years 6 months 27 days
Debt Instrument, Maturity Date Range, Start			Dec. 1, 2018
Weighted average interest rate			5.07%
United Dominion Reality L.P. [Member] | Fannie Mae credit facilities [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity			1 year 8 months 1 day
Weighted average interest rate			2.34%
United Dominion Reality L.P. [Member] | Tax Exempt Notes Payable [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity			14 years 11 months 19 days
Secured debt including debt on real estate held for sale			$ 27,000,000		27,000,000
Weighted average interest rate			1.39%
Debt Instrument, Maturity Date Range, End			Mar. 1, 2032
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
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
United Dominion Reality L.P. [Member] | 2.23% Term Loan Facility due January 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date Range, End			Jan. 1, 2021
United Dominion Reality L.P. [Member] | 2.23% Term Loan Facility due January 2021 [Member] | Financial Guarantee [Member]
Debt Instrument [Line Items]
Guarantor borrowing capacity			$ 350,000,000
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
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
United Dominion Reality L.P. [Member] | 4.00% Medium-Term Note due October 2025 [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date Range, End			Oct. 1, 2025
United Dominion Reality L.P. [Member] | 4.00% Medium-Term Note due October 2025 [Member] | Financial Guarantee [Member]
Debt Instrument [Line Items]
Guarantor borrowing capacity			$ 300,000,000
United Dominion Reality L.P. [Member] | 2.95% Medium-Term Note due September 2026 [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date Range, End			Sep. 1, 2026
United Dominion Reality L.P. [Member] | 2.95% Medium-Term Note due September 2026 [Member] | Financial Guarantee [Member]
Debt Instrument [Line Items]
Guarantor borrowing capacity			$ 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			401,135,000		402,996,000
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			355,836,000		355,836,000
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			182,606,000		280,946,000
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			81,339,000		163,637,000
Fixed Rate Secured Debt Instruments Fair Value			228,870,000		244,912,000
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			228,870,000		244,912,000
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			$ 81,339,000		$ 163,637,000

Income_(Loss) Per Share (Detail

Income/(Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Income/(loss) from continuing operations	$ 26,264	$ 8,534
Net Income (Loss) Attributable to Noncontrolling Interest	91	306
Income/(loss) from continuing operations attributable to UDR, Inc.	25,967	10,393
Distributions to preferred stockholders - Series E (Convertible)	(929)	(929)
Income/(loss) from continuing operations operations attributable to common stockholders	25,038	9,464
Net income/(loss)	28,396	11,604
Net (income)/loss attributable to noncontrolling interests	(101)
Net (income)/loss attributable to redeemable non-controlling interests in Operating Partnership	2,338	905
Net income/(loss) attributable to common stockholders	$ 25,038	$ 9,464
Denominator for earnings per share - basic and diluted:
Weighted average common shares outstanding	267,402	263,355
Incremental Common Shares Attributable to Participating Nonvested Shares with Non-forfeitable Dividend Rights	(612)	(899)
Weighted average number of common shares outstanding — basic	266,790	262,456
Incremental shares issuable for assumed conversion of: Stock options and unvested restricted stock	(1,898)	(1,829)
Weighted average number of common shares outstanding — diluted	268,688	264,285
Net income/(loss) attributable to common stockholders	$ 0.09	$ 0.04
Net income/(loss) attributable to common stockholders	$ 0.09	$ 0.04
OP Units [Member]
Denominator for earnings per share - basic and diluted:
Antidilutive securities	24,962	25,191
Convertible Preferred Stock [Member]
Denominator for earnings per share - basic and diluted:
Antidilutive securities	3,028	3,028
Stock options and unvested restricted stock [Member]
Denominator for earnings per share - basic and diluted:
Antidilutive securities	1,898	1,829
RedeemableNoncontrollingInterest [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
(Income)/loss from continuing operations attributable to noncontrolling interest	$ (2,338)	$ (905)

Noncontrolling Interests (Detai

Noncontrolling Interests (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Noncontrolling Interest [Line Items]
Net Income (Loss) Attributable to Noncontrolling Interest	$ 91	$ 306
Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership	904,778		$ 909,482
Net Income (Loss) Available to Common Stockholders, Basic	25,038	9,464
Long Term Incentive Plan Operating Partnership Unit Vesting, Value	2,317
Redeemable noncontrolling interests in the Operating Partnership
Mark to market adjustment to redeemable noncontrolling interests in the Operating Partnership	281
Conversion of Stock, Amount Issued	1,850
Adjustment for conversion of noncontrolling interest of unitholders in Operating Partnership	(1,850)	0
Net (income)/loss attributable to redeemable non-controlling interests in Operating Partnership	2,338	$ 905
Distributions to redeemable noncontrolling interests in the Operating Partnership	(7,919)
Redeemable non-controlling interests in operating partnership	904,778
Net income attributable to non-controlling interests	$ 101

Related Party Transactions (U85

Related Party Transactions (UNITED DOMINION REALTY, L.P.) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Related Party Transaction [Line Items]
Limited partnership units owned	183,350,924		183,278,698
Related party management fees	$ 3,600	$ 3,600
United Dominion Reality L.P. [Member]
Related Party Transaction [Line Items]
Limited partnership units owned	183,240,041		183,167,815
Interest Expense, Related Party	$ 3,053	3,053
Notes payable due to General Partner	$ 273,334		$ 273,334
United Dominion Reality L.P. [Member] | Taxable REIT Subsidiaries [Member]
Related Party Transaction [Line Items]
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	$ 4,500	$ 4,600
United Dominion Reality L.P. [Member] | UDR, Inc. [Member] | Bottom Dollar Guaranty [Member]
Related Party Transaction [Line Items]
Notes payable due to General Partner			$ 273,300
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	4.12%
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%
Debt Instrument, Maturity Date Range, End	Dec. 31, 2023
Note for 184.6 million [Member] | United Dominion Reality L.P. [Member] | UDR, Inc. [Member] | Guaranty Related To Community Acquisition [Member]
Related Party Transaction [Line Items]
Debt Instrument, Maturity Date Range, End	Apr. 1, 2026

Fair Value of Derivatives and86

Fair Value of Derivatives and Financial Instruments (Details) - USD ($)	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes receivable, net	$ 19,790,000	$ 19,790,000
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	5,067,000	4,360,000
Derivative Liability	9,000	413,000
Secured debt instruments - variable rate
Borrowings outstanding	2,900,000	2,900,000
Unsecured debt instruments
Redeemable Noncontrolling Interest, Equity, Carrying Amount	904,778,000
Redeemable noncontrolling interests in the Operating Partnership (d)	904,778,000	909,482,000
Commercial Paper, at Carrying Value	220,000,000	0
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	19,790,000	19,790,000
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Total assets	24,857,000	24,150,000
Unsecured debt instruments
Total liabilities	3,552,485,000	3,418,079,000
Carrying (Reported) Amount, 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
Derivative Liability		413,000
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Senior Unsecured Notes [Member] | Fair Value, Measurements, Recurring [Member]
Unsecured debt instruments
Unsecured debt instruments (c)	2,262,059,000	2,261,838,000
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)	19,735,000	19,645,000
Total assets	24,802,000	24,005,000
Unsecured debt instruments
Total liabilities	3,597,213,000	3,463,639,000
Redeemable noncontrolling interests in the Operating Partnership (d)	904,778,000	909,482,000
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	5,067,000	4,360,000
Derivatives - Interest rate contracts (b)	9,000	413,000
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	395,504,000	396,045,000
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	94,700,000	94,700,000
Estimate of Fair Value, Fair Value Disclosure [Member] | Line of Credit [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial Paper Instruments Fair Value	220,000,000
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	365,391,000	365,693,000
Secured debt instruments - variable rate
Secured debt instruments - variable rate	182,606,000	280,946,000
Unsecured debt instruments
Unsecured debt instruments (c)	36,140,000	21,350,000
Estimate of Fair Value, Fair Value Disclosure [Member] | Senior Unsecured Notes [Member] | Fair Value, Measurements, Recurring [Member]
Unsecured debt instruments
Unsecured debt instruments (c)	2,302,863,000	2,304,492,000
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
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]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial Paper Instruments Fair Value	0
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	5,067,000	4,360,000
Unsecured debt instruments
Total liabilities	9,000	413,000
Redeemable noncontrolling interests in the Operating Partnership (d)	904,778,000	909,482,000
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	5,067,000	4,360,000
Derivatives - Interest rate contracts (b)	9,000	413,000
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
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]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial Paper Instruments Fair Value	0
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)	19,735,000	19,645,000
Total assets	19,735,000	19,645,000
Unsecured debt instruments
Total liabilities	3,597,204,000	3,463,226,000
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	395,504,000	396,045,000
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	94,700,000	94,700,000
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	365,391,000	365,693,000
Secured debt instruments - variable rate
Secured debt instruments - variable rate	182,606,000	280,946,000
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 3 [Member] | Commercial bank [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial Paper Instruments Fair Value	220,000,000
Unsecured debt instruments
Unsecured debt instruments (c)	36,140,000	21,350,000
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)	2,302,863,000	2,304,492,000
Unsecured Revolving Credit Facility due October 2015 [Member]
Secured debt instruments - variable rate
Borrowings outstanding	0	0
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	277,018,000	374,707,000
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	94,700,000	94,700,000
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	182,606,000	280,946,000
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	754,489,000	756,151,000
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	355,836,000	355,836,000
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	$ 401,135,000	$ 402,996,000

Fair Value of Derivatives and87

Fair Value of Derivatives and Financial Instruments (UNITED DOMINION REALTY, L.P.) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
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	$ 0	$ 1
Derivative Liability Designated as Hedging Instrument, Fair Value	0	0
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	24,857	24,150
Secured debt instruments - variable rate
Total liabilities	3,552,485	3,418,079
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		1
Secured debt instruments - variable rate
Total liabilities	337,209	435,549
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		1
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	228,870	244,912
Secured debt instruments - variable rate
Secured debt instruments - variable rate	81,339	163,637
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	24,802	24,005
Secured debt instruments - variable rate
Total liabilities	3,597,213	3,463,639
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	5,067	4,360
Derivative Liability Designated as Hedging Instrument, Fair Value	9	413
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	395,504	396,045
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	365,391	365,693
Secured debt instruments - variable rate
Secured debt instruments - variable rate	182,606	280,946
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
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	5,067	4,360
Secured debt instruments - variable rate
Total liabilities	9	413
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	5,067	4,360
Derivative Liability Designated as Hedging Instrument, Fair Value	9	413
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
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	19,735	19,645
Secured debt instruments - variable rate
Total liabilities	3,597,204	3,463,226
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	395,504	396,045
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	365,391	365,693
Secured debt instruments - variable rate
Secured debt instruments - variable rate	182,606	280,946
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		1
Secured debt instruments - variable rate
Total liabilities	343,498	442,301
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		1
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	235,159	251,664
Secured debt instruments - variable rate
Secured debt instruments - variable rate	81,339	163,637
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
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
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		1
Secured debt instruments - variable rate
Total liabilities	0	0
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		1
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
Secured debt instruments - variable rate
Total liabilities	343,498	442,301
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
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	235,159	251,664
Secured debt instruments - variable rate
Secured debt instruments - variable rate	$ 81,339	$ 163,637

Derivatives and Hedging Activ88

Derivatives and Hedging Activity (Details) $ in Thousands	Mar. 31, 2017USD ($)instruments
Designated as Hedging Instrument [Member] | Interest rate swaps [Member]
Derivative [Line Items]
Number instruments	4
Notional	$ 315,000
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 Activ89

Derivatives and Hedging Activity (Details 1) $ in Thousands	Mar. 31, 2017USD ($)instruments	Dec. 31, 2016USD ($)
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	$ 5,067	$ 4,359
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	0	1
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	9	413
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 Activ90

Derivatives and Hedging Activity (Details 2) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Effect of derivative instruments on the Consolidated Statements of Operations
Unrealized holding gain/(loss)	$ 632	$ (811)
Amount of Gain or (Loss) Recognized in Income on Derivative	(1)	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)	(764)	(935)
Amount of Gain or (Loss) Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness Testing)	$ (54)	$ 0

Derivatives and Hedging Activ91

Derivatives and Hedging Activity (Details 3) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
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)	5,067	4,360
Gross Amounts Not Offset in the Consolidated Balance Sheets, Financial Instruments	(5)	(221)
Gross Amounts Not Offset in the Consolidated Balance Sheets, Cash Collateral Received	0	0
Net Amount	5,062	4,139
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)	9	413
Gross Amounts Not Offset in the Consolidated Balance Sheets, Financial Instruments	(5)	(221)
Gross Amounts Not Offset in the Consolidated Balance Sheets, Cash Collateral Received	0	0
Net Amount	$ 4	192
Fair Value, Measurements, Recurring [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Interest Rate Contracts [Member]
Offsetting Derivative Liabilities [Abstract]
Net Amounts of Liabilities Presented in the Consolidated Balance Sheets (b)		$ 413

Derivatives and Hedging Activ92

Derivatives and Hedging Activity (Details Textual) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Derivative, Collateral, Obligation to Return Cash	$ 0		$ 0
Derivatives And Hedging Activity (Textual) [Abstract]
Ineffectiveness on Interest Rate Fair Value Hedges is Immaterial	0
Estimated additional accumulated other comprehensive Income/(Loss) transferred to interest expense	$ 500,000
Derivative instruments not designated as hedging instruments, gain (loss), net	(1,000)	$ 0
Payment required to pay for contract termination	4,900,000
Other Income Expense [Member] | Interest Rate Contracts [Member]
Derivatives And Hedging Activity (Textual) [Abstract]
Derivative instruments not designated as hedging instruments, gain (loss), net	100,000	100,000
Cash Flow Hedging [Member] | Interest Expense [Member] | Interest Rate Contracts [Member]
Derivatives And Hedging Activity (Textual) [Abstract]
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net	54,000	0
Interest rate swaps [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Notional	315,000,000
United Dominion Reality L.P. [Member]
Derivatives, Fair Value [Line Items]
Derivative, Collateral, Obligation to Return Cash	$ 0		$ 0
Derivatives And Hedging Activity (Textual) [Abstract]
Ineffectiveness on Interest Rate Fair Value Hedges is Immaterial	0
Estimated additional accumulated other comprehensive Income/(Loss) transferred to interest expense	$ 100,000
Derivative instruments not designated as hedging instruments, gain (loss), net	100,000	0
Fair value of derivatives in a net liability position	0
United Dominion Reality L.P. [Member] | 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
United Dominion Reality L.P. [Member] | Cash Flow Hedging [Member] | Interest Expense [Member] | Interest Rate Contracts [Member]
Derivatives And Hedging Activity (Textual) [Abstract]
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net	$ 54,000	$ 0

Derivatives and Hedging Activ93

Derivatives and Hedging Activity (UNITED DOMINION REALTY, L.P.) (Details) $ in Thousands	Mar. 31, 2017USD ($)instruments
Designated as Hedging Instrument [Member] | Interest rate swaps [Member]
Derivative [Line Items]
Number instruments	4
Outstanding interest rate derivatives not designated as hedging instrument
Notional	$ 315,000
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 caps [Member]
Derivative [Line Items]
Number instruments	1
Outstanding interest rate derivatives not designated as hedging instrument
Notional	$ 82,494
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	$ 87,580

Derivatives and Hedging Activ94

Derivatives and Hedging Activity (UNITED DOMINION REALTY, L.P.) (Details 1) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
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	$ 5,067	$ 4,359
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	0	1
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	9	413
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	0	1
Derivative Liability Designated as Hedging Instrument, Fair Value	0	0
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	0	0
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	0	1
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	0	0
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 Activ95

Derivatives and Hedging Activity (UNITED DOMINION REALTY, L.P.) (Details 2) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized holding gain/(loss)	$ 632,000	$ (811,000)
Amount of Gain or (Loss) Recognized in Income on Derivative	(1,000)	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	100,000	100,000
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)	(764,000)	(935,000)
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net	(54,000)	0
United Dominion Reality L.P. [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized holding gain/(loss)	0	(2,000)
Amount of Gain or (Loss) Recognized in Income on Derivative	100,000	0
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	(1,000)	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)	0	(1,000)
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net	$ (54,000)	$ 0

Derivatives and Hedging Activ96

Derivatives and Hedging Activity (UNITED DOMINION REALTY, L.P.) (Details 3) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
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)	5,067	4,360
Gross Amounts Not Offset in the Consolidated Balance Sheets, Financial Instruments	5	221
Gross Amounts Not Offset in the Consolidated Balance Sheets, Cash Collateral Received	0	0
Net Amount	5,062	4,139
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)	9	413
Gross Amounts Not Offset in the Consolidated Balance Sheets, Financial Instruments	5	221
Gross Amounts Not Offset in the Consolidated Balance Sheets, Cash Collateral Received	0	0
Net Amount	4	192
United Dominion Reality L.P. [Member]
Offsetting Derivative Assets [Abstract]
Derivative Asset Designated as Hedging Instrument, Fair Value	0	1
Gross Amounts Offset in the Consolidated Balance Sheets	0	0
Net Amounts of Assets Presented in the Consolidated Balance Sheets (a)	0	1
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	0	1
Offsetting Derivative Liabilities [Abstract]
Derivative Liability Designated as Hedging Instrument, Fair Value	0	0
Gross Amounts Offset in the Consolidated Balance Sheets	0	0
Net Amounts of Liabilities Presented in the Consolidated Balance Sheets (b)	0	0
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	$ 0	$ 0

Derivatives and Hedging Activ97

Derivatives and Hedging Activity (UNITED DOMINION REALTY, L.P.) (Details Textual) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Entity Information [Line Items]
Ineffectiveness on Interest Rate Fair Value Hedges is Immaterial	0
Estimated additional accumulated other comprehensive Income/(Loss) transferred to interest expense	$ 500,000
Losses in the fair value of derivatives not designated in hedging relationships	1,000	$ 0
Payment required to pay for contract termination	4,900,000
Derivative, Collateral, Obligation to Return Cash	$ 0		$ 0
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
Ineffectiveness on Interest Rate Fair Value Hedges is Immaterial	0
Estimated additional accumulated other comprehensive Income/(Loss) transferred to interest expense	$ 100,000
Losses in the fair value of derivatives not designated in hedging relationships	(100,000)	0
Fair value of derivatives in a net liability position	0
Derivative, Collateral, Obligation to Return Cash	0		$ 0
Interest Expense [Member] | Interest Rate Contracts [Member] | Cash Flow Hedging [Member]
Entity Information [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net	54,000	0
Interest Expense [Member] | Interest Rate Contracts [Member] | Cash Flow Hedging [Member] | United Dominion Reality L.P. [Member]
Entity Information [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net	$ 54,000	$ 0

Stock Based Compensation (Detai

Stock Based Compensation (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Stock Based Compensation (Textual) [Abstract]
Stock based compensation expense	$ 3.4	$ 3.9

Capital Structure (UNITED DOM99

Capital Structure (UNITED DOMINION REALTY, L.P.) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)$ / Unitsshares	Dec. 31, 2016USD ($)shares	Dec. 31, 2014shares
Limited Partners' Capital Account [Line Items]
Limited partnership units owned	183,350,924	183,278,698
Long Term Incentive Plan Operating Partnership Units Vesting, Shares	72,226
Partners' Capital Account, Units, Redeemed	0
Redeemable Noncontrolling Interest, Equity, Carrying Amount | $	$ 904,778
Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership | $	$ 904,778	$ 909,482
United Dominion Reality L.P. [Member]
Limited Partners' Capital Account [Line Items]
General Partnership units outstanding	110,883	110,883
Limited partnership units owned	183,240,041	183,167,815
Limited Partners' Capital Account, Required Period To Be Outstanding Before Unit is Redeemable	1 year
Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership | $	$ 330,600	$ 330,100
UDR, Inc. [Member]
Limited Partners' Capital Account [Line Items]
Limited partnership units owned	174,122,808	174,119,201
Percentage of units	95.00%	95.10%
Class A Limited Partner [Member]
Limited Partners' Capital Account [Line Items]
Limited partnership units owned	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
Class A Limited Partner [Member] | UDR, Inc. [Member]
Limited Partners' Capital Account [Line Items]
Limited partnership units owned	121,661	121,661	121,661
Non-affiliated Partners [Member]
Limited Partners' Capital Account [Line Items]
Limited partnership units owned	7,365,562	7,296,943
Long Term Incentive Plan Operating Partnership Units Vesting, Shares	72,226
Partners' Capital Account, Units, Redeemed	(3,607)
Non-affiliated Partners [Member] | United Dominion Reality L.P. [Member]
Limited Partners' Capital Account [Line Items]
Limited partnership units owned	9,117,233	9,048,614
Percentage of units	5.00%	4.90%
Non-affiliated Partners [Member] | Class A Limited Partner [Member]
Limited Partners' Capital Account [Line Items]
Limited partnership units owned	1,751,671	1,751,671
Long Term Incentive Plan Operating Partnership Units Vesting, Shares	0
Partners' Capital Account, Units, Redeemed	0
Limited Partner [Member] | United Dominion Reality L.P. [Member]
Limited Partners' Capital Account [Line Items]
Limited partnership units owned	174,233,691
Percentage of units	95.00%
Limited Partner [Member] | UDR, Inc. [Member]
Limited Partners' Capital Account [Line Items]
Limited partnership units owned	174,001,147	173,997,540
Long Term Incentive Plan Operating Partnership Units Vesting, Shares	0
Partners' Capital Account, Units, Redeemed	3,607
General Partner [Member] | UDR, Inc. [Member]
Limited Partners' Capital Account [Line Items]
Limited partnership units owned	110,883	110,883
Long Term Incentive Plan Operating Partnership Units Vesting, Shares	0
Partners' Capital Account, Units, Redeemed	0
Class A Limited Partner [Member] | UDR, Inc. [Member]
Limited Partners' Capital Account [Line Items]
Partners' Capital Account, Units, Redeemed	0

Commitments and Contingencie100

Commitments and Contingencies (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)Communities	Mar. 31, 2016USD ($)
Real Estate Properties [Line Items]
Development costs and capital expenditures incurred but not yet paid	$ 34,336	$ 21,220
Number of communities owned (in communities) | Communities	128
Costs Incurred to Date	$ 1,255,013
Expected Costs to Complete	386,989
Wholly owned — under development [Member]
Real Estate Properties [Line Items]
Development costs and capital expenditures incurred but not yet paid	$ 25,300
Number of communities owned (in communities)	2
Costs Incurred to Date	$ 393,837
Expected Costs to Complete	$ 314,663
Average Ownership Stake	100.00%
Wholly owned — redevelopment [Member]
Real Estate Properties [Line Items]
Development costs and capital expenditures incurred but not yet paid	$ 700
Number of communities owned (in communities)	1
Costs Incurred to Date	$ 3,699
Expected Costs to Complete	$ 5,801
Average Ownership Stake	100.00%
Unconsolidated joint ventures [Member]
Real Estate Properties [Line Items]
Number of communities owned (in communities)	6
Costs Incurred to Date	$ 721,462
Expected Costs to Complete	$ 66,525
Average Ownership Stake	50.00%
Participating Loan Investment Steele Creek Denver Colorado [Member]
Real Estate Properties [Line Items]
Number of communities owned (in communities)	1
Costs Incurred to Date	$ 94,002
Expected Costs to Complete	$ 0
Average Ownership Stake	0.00%
Preferred Equity Investment West Coast Development JV [Member]
Real Estate Properties [Line Items]
Number of communities owned (in communities)	2
Costs Incurred to Date	$ 42,013
Expected Costs to Complete	$ 0
Average Ownership Stake	49.00%

Commitments and Contingencie101

Commitments and Contingencies (UNITED DOMINION REALTY, L.P.) Commitments and Contingencies (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)Communities	Mar. 31, 2016USD ($)
Loss Contingencies [Line Items]
Development costs and capital expenditures incurred but not yet paid	$ 34,336	$ 21,220
Number of communities owned (in communities) | Communities	128
Cost Incurred to Date	$ 1,255,013
Expected Costs to Complete	386,989
United Dominion Reality L.P. [Member]
Loss Contingencies [Line Items]
Development costs and capital expenditures incurred but not yet paid	$ 4,816	$ 4,505
Number of communities owned (in communities) | Communities	54
Wholly owned — redevelopment [Member]
Loss Contingencies [Line Items]
Development costs and capital expenditures incurred but not yet paid	$ 700
Number of communities owned (in communities)	1
Cost Incurred to Date	$ 3,699
Expected Costs to Complete	5,801
Wholly owned — under development [Member]
Loss Contingencies [Line Items]
Development costs and capital expenditures incurred but not yet paid	$ 25,300
Number of communities owned (in communities)	2
Cost Incurred to Date	$ 393,837
Expected Costs to Complete	$ 314,663

Reportable Segments (Details)

Reportable Segments (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)Segments	Mar. 31, 2016USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Segment Reporting Information [Line Items]
Same Store Communities	35,689
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment NOI	$ 171,483	$ 164,134
Reconciling items:
Joint venture management and other fees	2,570	2,858
Property management	(6,635)	(6,379)
Other operating expenses	(1,691)	(1,752)
Segment Reporting Reconciling Items Cost of Services Depreciation and Amortization	(105,032)	(105,339)
General and administrative	(13,075)	(13,844)
Casualty-related (recoveries)/charges, net	(502)	0
Other depreciation and amortization	(1,608)	(1,553)
Income/(loss) from unconsolidated entities	11,198	679
Interest expense	30,539	31,104
Interest and other income/(expense), net	427	431
Tax benefit, net	(332)	403
Gain Loss on the Sale of Real Estate, Including Discontinued Operations	2,132	3,070
Net (income)/loss attributable to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership	(2,338)	(905)
Net (income)/loss attributable to noncontrolling interests	(91)	(306)
Net income/(loss) attributable to UDR, Inc.	25,967	10,393
Reportable apartment home segment assets:
Total segment assets	9,787,569		$ 9,615,753
Accumulated depreciation	(3,026,660)		(2,923,625)
Total segment asset - net book value	6,760,909		6,692,128
Reconciling items:
Cash and cash equivalents	2,460	$ 3,668	2,112	$ 6,742
Restricted cash	19,757		19,994
Notes receivable, net	19,790		19,790
Investments in and advances to unconsolidated joint ventures, net	818,990		827,025
Other assets	114,005		118,535
Total consolidated assets	$ 7,735,911		7,679,584
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
Same Communities [Member]
Reportable Segment (Textual) [Abstract]
SEC Schedule III, Real Estate, Improvements	$ 15,300	$ 12,900
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	82,220	78,409
Reportable apartment home segment NOI	61,895	59,146
Reportable apartment home segment assets:
Total segment assets	2,944,437		2,938,073
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	52,109	50,154
Reportable apartment home segment NOI	36,315	33,729
Reportable apartment home segment assets:
Total segment assets	2,221,312		2,216,067
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	37,921	36,460
Reportable apartment home segment NOI	26,901	26,360
Reportable apartment home segment assets:
Total segment assets	1,858,432		1,857,193
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	28,657	27,137
Reportable apartment home segment NOI	19,661	18,797
Reportable apartment home segment assets:
Total segment assets	750,147		746,762
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	10,679	10,125
Reportable apartment home segment NOI	6,678	6,331
Reportable apartment home segment assets:
Total segment assets	283,979		283,260
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	29,685	29,672
Reportable apartment home segment NOI	20,033	19,771
Reportable apartment home segment assets:
Total segment assets	1,729,262		1,574,398
Reportable Segment (Textual) [Abstract]
SEC Schedule III, Real Estate, Improvements	800	2,700
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	$ 241,271	231,957
United Dominion Reality L.P. [Member]
Segment Reporting Information [Line Items]
Same Store Communities	15,058
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment NOI	$ 75,063	72,552
Reconciling items:
Property management	(2,822)	(2,717)
Other operating expenses	(1,548)	(1,500)
Segment Reporting Reconciling Items Cost of Services Depreciation and Amortization	(36,879)	(36,791)
General and administrative	(5,219)	(5,421)
Casualty-related (recoveries)/charges, net	(553)	0
Income/(loss) from unconsolidated entities	(5,424)	(13,387)
Interest expense	8,611	7,605
Net (income)/loss attributable to noncontrolling interests	(350)	(344)
Net income/(loss) attributable to UDR, Inc.	13,657	4,787
Reportable apartment home segment assets:
Total segment assets	3,686,334		3,674,704
Accumulated depreciation	(1,445,528)
Total segment asset - net book value	2,240,806		2,265,889
Reconciling items:
Cash and cash equivalents	864	$ 1,102	756	$ 3,103
Restricted cash	12,141		11,694
Other assets	21,475		24,329
Total consolidated assets	$ 2,378,553		2,415,535
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
United Dominion Reality L.P. [Member] | Same-Store [Member]
Reportable Segment (Textual) [Abstract]
SEC Schedule III, Real Estate, Improvements	$ 8,000	$ 5,300
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	50,482	47,636
Reportable apartment home segment NOI	38,445	36,159
Reportable apartment home segment assets:
Total segment assets	1,601,136		1,596,815
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	14,748	14,167
Reportable apartment home segment NOI	10,095	9,362
Reportable apartment home segment assets:
Total segment assets	656,850		655,693
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	13,559	13,006
Reportable apartment home segment NOI	10,131	10,057
Reportable apartment home segment assets:
Total segment assets	675,407		674,928
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	12,271	11,696
Reportable apartment home segment NOI	8,283	8,043
Reportable apartment home segment assets:
Total segment assets	330,214		328,729
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	11,545	12,281
Reportable apartment home segment NOI	8,109	8,931
Reportable apartment home segment assets:
Total segment assets	422,727		$ 418,539
Reportable Segment (Textual) [Abstract]
SEC Schedule III, Real Estate, Improvements	400	300
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	$ 102,605	$ 98,786
Taxable REIT Subsidiaries [Member] | United Dominion Reality L.P. [Member]
Reportable Segment (Textual) [Abstract]
Related Party Transaction, Management Fee Percentage	2.75%

Reportable Segments (UNITED 103

Reportable Segments (UNITED DOMINION REALTY, L.P.) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)Segments	Mar. 31, 2016USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Segment Reporting Information [Line Items]
Equity Method Investments	$ 818,990		$ 827,025
Same Store Communities	35,689
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment NOI	$ (171,483)	$ (164,134)
Reconciling items:
Property management	(6,635)	(6,379)
Other operating expenses	(1,691)	(1,752)
General and administrative	(13,075)	(13,844)
Casualty-related (recoveries)/charges, net	(502)	0
Income/(loss) from unconsolidated entities	11,198	679
Interest expense	30,539	31,104
Net (income)/loss attributable to noncontrolling interests	(91)	(306)
Net income/(loss) attributable to OP unitholders	25,967	10,393
Reportable apartment home segment assets:
Total segment assets	9,787,569		9,615,753
Real Estate Investment Property, Accumulated Depreciation	3,026,660		2,923,072
Accumulated depreciation	(3,026,660)		(2,923,625)
Total segment asset - net book value	6,760,909		6,692,128
Reconciling items:
Cash and cash equivalents	2,460	$ 3,668	2,112	$ 6,742
Restricted cash	19,757		19,994
Other assets	114,005		118,535
Total assets	$ 7,735,911		7,679,584
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	3 months
Number of Tenants or related group of tenants that contributed 10% or more of company total revenue	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	$ 82,220	$ 78,409
Reportable apartment home segment NOI	(61,895)	(59,146)
Reportable apartment home segment assets:
Total segment assets	2,944,437		2,938,073
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	52,109	50,154
Reportable apartment home segment NOI	(36,315)	(33,729)
Reportable apartment home segment assets:
Total segment assets	2,221,312		2,216,067
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	37,921	36,460
Reportable apartment home segment NOI	(26,901)	(26,360)
Reportable apartment home segment assets:
Total segment assets	1,858,432		1,857,193
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	28,657	27,137
Reportable apartment home segment NOI	(19,661)	(18,797)
Reportable apartment home segment assets:
Total segment assets	750,147		746,762
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	10,679	10,125
Reportable apartment home segment NOI	(6,678)	(6,331)
Reportable apartment home segment assets:
Total segment assets	283,979		283,260
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	29,685	29,672
Reportable apartment home segment NOI	(20,033)	(19,771)
Reportable apartment home segment assets:
Total segment assets	1,729,262		1,574,398
Reportable Segment (Textual) [Abstract]
SEC Schedule III, Real Estate, Improvements	800	2,700
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	241,271	231,957
United Dominion Reality L.P. [Member]
Segment Reporting Information [Line Items]
Equity Method Investments	$ 103,267		112,867
Same Store Communities	15,058
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment NOI	$ (75,063)	(72,552)
Reconciling items:
Property management	(2,822)	(2,717)
Other operating expenses	(1,548)	(1,500)
General and administrative	(5,219)	(5,421)
Casualty-related (recoveries)/charges, net	(553)	0
Income/(loss) from unconsolidated entities	(5,424)	(13,387)
Interest expense	8,611	7,605
Net (income)/loss attributable to noncontrolling interests	(350)	(344)
Net income/(loss) attributable to OP unitholders	13,657	4,787
Reportable apartment home segment assets:
Total segment assets	3,686,334		3,674,704
Real Estate Investment Property, Accumulated Depreciation	1,445,528		1,408,815
Accumulated depreciation	(1,445,528)
Total segment asset - net book value	2,240,806		2,265,889
Reconciling items:
Cash and cash equivalents	864	$ 1,102	756	$ 3,103
Restricted cash	12,141		11,694
Other assets	21,475		24,329
Total assets	$ 2,378,553		2,415,535
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
United Dominion Reality L.P. [Member] | Same-Store [Member]
Reportable Segment (Textual) [Abstract]
SEC Schedule III, Real Estate, Improvements	$ 8,000	$ 5,300
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	50,482	47,636
Reportable apartment home segment NOI	(38,445)	(36,159)
Reportable apartment home segment assets:
Total segment assets	1,601,136		1,596,815
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	14,748	14,167
Reportable apartment home segment NOI	(10,095)	(9,362)
Reportable apartment home segment assets:
Total segment assets	656,850		655,693
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	13,559	13,006
Reportable apartment home segment NOI	(10,131)	(10,057)
Reportable apartment home segment assets:
Total segment assets	675,407		674,928
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	12,271	11,696
Reportable apartment home segment NOI	(8,283)	(8,043)
Reportable apartment home segment assets:
Total segment assets	330,214		328,729
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	11,545	12,281
Reportable apartment home segment NOI	(8,109)	(8,931)
Reportable apartment home segment assets:
Total segment assets	422,727		$ 418,539
Reportable Segment (Textual) [Abstract]
SEC Schedule III, Real Estate, Improvements	400	300
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	$ 102,605	$ 98,786