UDR (UDR) 10-Q 27 Jul 16 2016 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2016	Jul. 25, 2016
Entity Registrant Name	UDR, Inc.
Entity Central Index Key	74,208
Document Type	10-Q
Document Period End Date	Jun. 30, 2016
Amendment Flag	false
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q2
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		267,057,652
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	Jun. 30, 2016
Amendment Flag	false
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q2
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	Jun. 30, 2016	Dec. 31, 2015
Real estate owned:
Real estate held for investment	$ 9,073,474	$ 9,053,599
Less: accumulated depreciation	(2,842,273)	(2,646,044)
Real estate held for investment, net	6,231,201	6,407,555
Real estate under development (net of accumulated depreciation of $0 and $0, respectively)	238,938	124,072
Real estate held for disposition (net of accumulated depreciation of $0 and $830, respectively)	0	11,775
Total real estate owned, net of accumulated depreciation	6,470,139	6,543,402
Cash and cash equivalents	5,167	6,742
Restricted Cash	20,524	20,798
Funds held in escrow from Internal Revenue Code Section 1031 exchanges	34,732	0
Notes receivable, net	19,694	16,694
Investments in and advances to unconsolidated joint ventures, net	933,403	938,906
Other assets	126,423	137,302
Total assets	7,610,082	7,663,844
Liabilities:
Secured debt, net	1,256,119	1,376,945
Unsecured debt, net	2,209,058	2,193,850
Real estate taxes payable	23,168	18,786
Accrued interest payable	26,735	29,162
Security deposits and prepaid rent	37,916	36,330
Distributions payable	86,957	80,368
Accounts payable, accrued expenses, and other liabilities	91,275	81,356
Total liabilities	3,731,228	3,816,797
Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership	929,985	946,436
Equity:
Common stock, $0.01 par value; 350,000,000 shares authorized; 267,058,578 and 261,844,521 shares issued and outstanding at June 30, 2016 and December 31, 2015, respectively	2,671	2,618
Additional Paid in Capital	4,622,939	4,447,816
Distributions in excess of net income	(1,712,418)	(1,584,459)
Accumulated other comprehensive income/(loss), net	(12,974)	(12,678)
Total stockholders' equity	2,946,676	2,899,755
Noncontrolling interests	2,193	856
Total equity	2,948,869	2,900,611
Total liabilities and equity	7,610,082	7,663,844
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	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Real estate owned:
Real estate under development accumulated depreciation	$ 0	$ 0
Real estate held for disposition accumulated depreciation	$ 0	$ 830
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	267,058,578	261,844,521
Common stock, shares outstanding	267,058,578	261,844,521
Series F Preferred Stock [Member]
Equity:
Preferred stock, shares issued	16,452,496	16,452,496
Preferred stock, shares outstanding	16,452,496	16,452,496
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		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
REVENUES
Rental income	$ 236,168	$ 212,764	$ 468,125	$ 419,811
Joint venture management and other fees	2,618	3,098	5,476	15,804
Total revenues	238,786	215,862	473,601	435,615
OPERATING EXPENSES
Property operating and maintenance	38,574	37,194	78,020	74,444
Real estate taxes and insurance	30,279	25,138	58,656	51,360
Property management	6,494	5,851	12,873	11,545
Other operating expenses	1,892	1,769	3,644	3,535
Real estate depreciation and amortization	105,937	90,344	211,276	179,121
General and administrative	10,835	13,721	24,679	25,873
Casualty-related charges/(recoveries), net	1,629	843	1,629	1,839
Other Depreciation and Amortization	1,486	1,700	3,039	3,323
Total operating expenses	197,126	176,560	393,816	351,040
Operating income	41,660	39,302	79,785	84,575
Income/(loss) from unconsolidated entities	325	(573)	1,004	58,586
Interest expense	(30,678)	(29,673)	(61,782)	(58,473)
Interest income and other income/(expense), net	540	382	971	742
Income/(loss) before income taxes and gain/(loss) on sale of real estate owned	11,847	9,438	19,978	85,430
Tax benefit/(expense), net	402	1,404	805	1,829
Income/(loss) from continuing operations	12,249	10,842	20,783	87,259
Gain/(loss) on sale of real estate owned, net of tax	7,315	79,042	10,385	79,042
Net income/(loss)	19,564	89,884	31,168	166,301
Net (income)/loss attributable to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership	(1,610)	(3,029)	(2,515)	(5,617)
Net (income)/loss attributable to noncontrolling interests	(8)	0	(314)	(7)
Net income/(loss) attributable to UDR, Inc.	17,946	86,855	28,339	160,677
Distributions to preferred stockholders - Series E (Convertible)	(929)	(931)	(1,858)	(1,862)
Net (loss)/income attributable to common stockholders	$ 17,017	$ 85,924	$ 26,481	$ 158,815
Income/(loss) per weighted average common share - basic	$ 0.06	$ 0.33	$ 0.10	$ 0.62
Income/(loss) per weighted average common share - diluted	0.06	0.33	0.10	0.61
Common distributions declared per share	$ 0.30	$ 0.28	$ 0.5900	$ 0.5550
Weighted average number of common shares outstanding — basic	266,268	257,849	264,362	257,344
Weighted average number of common shares outstanding — diluted	268,174	262,806	266,227	259,267

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income / (Loss) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Net income/(loss)	$ 19,564	$ 89,884	$ 31,168	$ 166,301
Other comprehensive income/(loss), including portion attributable to noncontrolling interests:
Unrealized holding gain/(loss)	(1,963)	6,186	(2,774)	(1,366)
(Gain)/loss reclassified into earnings from other comprehensive income/(loss)	943	292	1,878	1,029
Other comprehensive income/(loss), including portion attributable to noncontrolling interests	(1,020)	6,478	(896)	(337)
Comprehensive income/(loss)	18,544	96,362	30,272	165,964
Comprehensive (income)/loss attributable to noncontrolling interests	(1,537)	(3,253)	(2,229)	(5,623)
Comprehensive income/(loss) attributable to UDR, Inc.	$ 17,007	$ 93,109	$ 28,043	$ 160,341

Consolidated Statements of Chan

Consolidated Statements of Changes in Equity (Unaudited) - 6 months ended Jun. 30, 2016 - 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]	Common Class A [Member]
Beginning Balance at Dec. 31, 2015	$ 2,900,611	$ 46,458	$ 2,618	$ 4,447,816	$ (1,584,459)	$ (12,678)	$ 856
Consolidted Statements of Changes in Equity
Net income/(loss) attributable to UDR, Inc.	28,339				28,339		0
Net income/(loss) attributable to noncontrolling interests	301					0	301
Disposition of noncontrolling interests in consolidated real estate	(1,155)						(1,155)
Contribution of noncontrolling interest in consolidated real estate	220						220
Long Term Incentive Plan Unit grants	1,971						1,971
Other comprehensive income/(loss)	(296)		0	0		(296)
Issuance/(forfeitures) of common and restricted shares, net	1,812		3	1,809
Issuance of common shares through public offering	173,283	0	50	173,233	0
Adjustment for conversion of noncontrolling interest of unitholders in the Operating Partnership	81		0	81				$ 81
Common stock distributions declared ($0.5900 per share)	(157,632)				(157,632)		0
Preferred stock distributions declared-Series E ($0.6644 per share)	(1,858)				(1,858)
Adjustment to reflect redemption value of redeemable noncontrolling interests	3,192				3,192
Ending Balance at Jun. 30, 2016	$ 2,948,869	$ 46,458	$ 2,671	$ 4,622,939	$ (1,712,418)	$ (12,974)	$ 2,193

Consolidated Statements of Cha7

Consolidated Statements of Changes in Equity (Unaudited) (Parenthetical)	6 Months Ended
	Jun. 30, 2016$ / shares
Common distributions declared per share	$ 0.5900
Series E Preferred Stock [Member]
Preferred Stock, Dividend Rate, Percentage	8.00%
Preferred stock distributions declared	$ 0.6644

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Operating Activities
Net income/(loss)	$ 31,168	$ 166,301
Adjustments to reconcile net income/(loss) to net cash provided by operating activities:
Depreciation and amortization	214,315	182,444
Gain/(loss) on sale of real estate owned, net of tax	(10,385)	(79,042)
Tax (benefit)/expense, net	(805)	(1,829)
(Income)/loss from unconsolidated entities	(1,004)	(58,586)
Amortization of share-base compensation	7,075	9,060
Other	7,515	5,933
Changes in operating assets and liabilities:
(Increase)/decrease in operating assets	(8,551)	7,431
Increase/(decrease) in operating liabilities	(12,858)	(14,709)
Net cash provided by/(used in) operating activities	226,470	217,003
Investing Activities
Acquisition of real estate assets	(17,235)	0
Proceeds from sale of real estate investments, net	21,943	90,543
Development of real estate assets	(66,138)	(66,083)
Capital expenditures and other major improvements - real estate assets, net of escrow reimbursement	(49,112)	(47,453)
Capital expenditures - non-real estate assets	(1,941)	(1,655)
Investment in unconsolidated joint ventures	(20,635)	(184,078)
Distributions received from unconsolidated joint venture	13,663	46,075
(Issuance)/repayment of notes receivable	(3,000)	(1,125)
Net cash provided by/(used in) investing activities	(122,455)	(163,776)
Financing Activities
Payments on secured debt	(145,499)	(4,549)
Proceeds from the issuance of secured debt	25,000	0
Payments on unsecured debt	(95,053)	(325,319)
Net proceeds/(repayment) of revolving bank debt	109,199	304,500
Proceeds from the issuance of common shares through public offering, net	173,283	108,739
Distributions paid to redeemable noncontrolling interests	(14,624)	(5,148)
Distributions paid to preferred stockholders	(1,858)	(1,862)
Distributions paid to common stockholders	(151,512)	(138,559)
Other	(4,526)	(3,263)
Net cash provided by/(used in) financing activities	(105,590)	(65,461)
Net increase/(decrease) in cash and cash equivalents	(1,575)	(12,234)
Cash and cash equivalents, beginning of period	6,742	15,224
Cash and cash equivalents, end of period	5,167	2,990
Supplemental Information:
Interest paid during the period, net of amounts capitalized	64,793	66,448
Non-cash transactions:
Fair value adjustment of debt acquired as part of acquisition of real estate	0	1,363
Development costs and capital expenditures incurred but not yet paid	42,940	23,523
Conversion of Operating Partnership noncontrolling interest to common stock (2,080 shares in 2016 and 102,784 shares in 2015)	81	3,498
1745 Shea [Member]
Non-cash transactions:
Acquisition of real estate	0	24,067
Wilshire LaJolla [Member]
Non-cash transactions:
Transfer of investment in and advances to unconsolidated joint venture to real estate owned	11,526
Common Class A [Member]
Non-cash transactions:
Conversion of Operating Partnership noncontrolling interest to common stock (2,080 shares in 2016 and 102,784 shares in 2015)	81	3,498
Continuing Operations [Member]
Adjustments to reconcile net income/(loss) to net cash provided by operating activities:
Tax (benefit)/expense, net	$ (805)	$ (1,829)

Consolidated Statements of Cas9

Consolidated Statements of Cash Flows (Unaudited) (Parenthetical) - shares shares in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Non-cash transactions:
Conversion of OP Units into common shares	2,080	102,784

Consolidated Balance Sheets (UN

Consolidated Balance Sheets (UNITED DOMINION REALTY, L.P) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Real estate owned:
Real estate held for investment	$ 9,073,474	$ 9,053,599
Less: accumulated depreciation	(2,842,273)	(2,646,044)
Total real estate owned, net of accumulated depreciation	6,470,139	6,543,402
Cash and cash equivalents	5,167	6,742
Restricted cash	20,524	20,798
Investment in unconsolidated entities	933,403	938,906
Other assets	126,423	137,302
Total assets	7,610,082	7,663,844
LIABILITIES AND CAPITAL
Secured debt, net	1,256,119	1,376,945
Real estate taxes payable	23,168	18,786
Accrued interest payable	26,735	29,162
Security deposits and prepaid rent	37,916	36,330
Distributions payable	86,957	80,368
Accounts payable, accrued expenses, and other liabilities	91,275	81,356
Total liabilities	3,731,228	3,816,797
Partners' Capital:
Accumulated other comprehensive income/(loss), net	(12,974)	(12,678)
Total liabilities and equity	7,610,082	7,663,844
United Dominion Reality L.P. [Member]
Real estate owned:
Real estate held for investment	3,664,728	3,630,905
Less: accumulated depreciation	(1,353,616)	(1,281,258)
Total real estate owned, net of accumulated depreciation	2,311,112	2,349,647
Cash and cash equivalents	1,535	3,103
Restricted cash	11,659	11,344
Investment in unconsolidated entities	134,823	166,186
Other assets	23,864	24,528
Total assets	2,482,993	2,554,808
LIABILITIES AND CAPITAL
Secured debt, net	446,009	475,964
Notes payable due to General Partner	273,334	273,334
Real estate taxes payable	5,232	2,775
Accrued interest payable	1,371	1,550
Security deposits and prepaid rent	16,616	15,929
Distributions payable	54,196	50,962
Accounts payable, accrued expenses, and other liabilities	16,639	12,964
Total liabilities	813,397	833,478
Commitments and contingencies (Note 10)
Partners' Capital:
General partner: 110,883 OP Units outstanding at June 30, 2016 and December 31, 2015	1,054	1,110
Limited partners: 183,167,815 OP Units outstanding at June 30, 2016 and December 31, 2015	1,619,927	1,712,415
Accumulated other comprehensive income/(loss), net	(113)	(113)
Total partners' capital	1,620,868	1,713,412
Advances (to)/from General Partner	(26,875)	11,270
Noncontrolling interests	21,853	19,188
Total capital	1,669,596	1,721,330
Total liabilities and equity	$ 2,482,993	$ 2,554,808

Consolidated Balance Sheets (11

Consolidated Balance Sheets (UNITED DOMINION REALTY, L.P) (Parenthetical) - United Dominion Reality L.P. [Member] - shares	Jun. 30, 2016	Dec. 31, 2015
Partners' Capital:
OP units outstanding related to general partner	110,883	110,883
OP units outstanding related to limited partner	183,167,815	183,167,815

Consolidated Statements of Op12

Consolidated Statements of Operations (Unaudited) (UNITED DOMINION REALTY, L.P) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
REVENUES
Rental income	$ 236,168	$ 212,764	$ 468,125	$ 419,811
OPERATING EXPENSES
Property operating and maintenance	38,574	37,194	78,020	74,444
Real estate taxes and insurance	30,279	25,138	58,656	51,360
Property management	6,494	5,851	12,873	11,545
Other operating expenses	1,892	1,769	3,644	3,535
Real estate depreciation and amortization	105,937	90,344	211,276	179,121
General and administrative	10,835	13,721	24,679	25,873
Casualty-related (recoveries)/charges, net	1,629	843	1,629	1,839
Total operating expenses	197,126	176,560	393,816	351,040
Operating income	41,660	39,302	79,785	84,575
Income/(loss) from unconsolidated entities	325	(573)	1,004	58,586
Interest expense	(30,678)	(29,673)	(61,782)	(58,473)
Income/(loss) from continuing operations	12,249	10,842	20,783	87,259
Gain/(loss) on sale of real estate owned	7,315	79,042	10,385	79,042
United Dominion Reality L.P. [Member]
REVENUES
Rental income	100,892	113,158	199,678	223,253
OPERATING EXPENSES
Property operating and maintenance	15,838	19,065	31,898	38,179
Real estate taxes and insurance	10,396	11,810	20,570	24,676
Property management	2,775	3,112	5,492	6,139
Other operating expenses	1,519	1,496	3,019	2,986
Real estate depreciation and amortization	37,053	44,100	73,844	88,578
General and administrative	3,844	7,032	9,265	12,671
Casualty-related (recoveries)/charges, net	465	280	465	873
Total operating expenses	71,890	86,895	144,553	174,102
Operating income	29,002	26,263	55,125	49,151
Income/(loss) from unconsolidated entities	(10,030)	0	(23,417)	0
Interest expense	(4,525)	(9,757)	(9,077)	(19,377)
Interest expense on note payable due to General Partner	(3,053)	(1,151)	(6,106)	(2,302)
Income/(loss) from continuing operations	11,394	15,355	16,525	27,472
Gain/(loss) on sale of real estate owned	0	32,375	0	56,998
Net income/(loss)	11,394	47,730	16,525	84,470
Net (income)/loss attributable to noncontrolling interest	(350)	(347)	(694)	(741)
Net income/(loss) attributable to OP unitholders	$ 11,044	$ 47,383	$ 15,831	$ 83,729
Income/(loss) per OP unit- basic and diluted:
Income/(loss) per weighted average OP unit - basic and diluted	$ 0.06	$ 0.26	$ 0.09	$ 0.46
Weighted average OP units outstanding - basic and diluted	183,279	183,279	183,279	183,279

Consolidated Statements of Co13

Consolidated Statements of Comprehensive Income / (Loss) (UNITED DOMINION REALTY, L.P.) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Other comprehensive income/(loss), including portion attributable to noncontrolling interests:
Unrealized holding gain/(loss)	$ (1,963)	$ 6,186	$ (2,774)	$ (1,366)
Other comprehensive income/(loss), including portion attributable to noncontrolling interests	(1,020)	6,478	(896)	(337)
Comprehensive income/(loss)	18,544	96,362	30,272	165,964
Comprehensive income/(loss) attributable to OP unitholders	17,007	93,109	28,043	160,341
United Dominion Reality L.P. [Member]
Net income/(loss)	11,394	47,730	16,525	84,470
Other comprehensive income/(loss), including portion attributable to noncontrolling interests:
Unrealized holding gain/(loss)	(1)	(26)	(3)	(77)
(Gain)/loss reclassified into earnings from other comprehensive income/(loss)	2	267	3	553
Other comprehensive income/(loss), including portion attributable to noncontrolling interests	1	241	0	476
Comprehensive income/(loss)	11,395	47,971	16,525	84,946
Comprehensive (income)/loss attributable to noncontrolling interests	(350)	(347)	(694)	(741)
Comprehensive income/(loss) attributable to OP unitholders	$ 11,045	$ 47,624	$ 15,831	$ 84,205

Consolidated Statements of Ch14

Consolidated Statements of Changes in Capital (UNITED DOMINION REALTY, L.P) (Unaudited) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2016
Long Term Incentive Plan Unit grants		$ 1,971
United Dominion Reality L.P. [Member]
Balance, December 31, 2015		1,721,330
Net income/(loss)	$ 11,394	16,525
Distributions		(108,375)
OP Units Redemptions for common shares of UDR		0
Adjustment to reflect limited partners' capital at redemption value		0
Long Term Incentive Plan Unit grants		1,971
Net change in amount due (to)/from General Partner		38,145
Balance, June 30, 2016	1,669,596	1,669,596
Payable/(Receivable) due to/(from) General Partner [Member] [Member] | United Dominion Reality L.P. [Member]
Net change in amount due (to)/from General Partner		38,145
Accumulated Other Comprehensive Income (Loss) [Member] | United Dominion Reality L.P. [Member]
Balance, December 31, 2015		(113)
Balance, June 30, 2016	(113)	(113)
Partnership Capital [Member] | United Dominion Reality L.P. [Member]
Balance, December 31, 2015		1,713,412
Net income/(loss)		15,831
Distributions		(108,375)
OP Units Redemptions for common shares of UDR		0
Adjustment to reflect limited partners' capital at redemption value		0
Long Term Incentive Plan Unit grants		0
Balance, June 30, 2016	1,620,868	1,620,868
Noncontrolling Interest [Member] | United Dominion Reality L.P. [Member]
Balance, December 31, 2015		19,188
Net income/(loss)		694
Adjustment to reflect limited partners' capital at redemption value		0
Balance, June 30, 2016	21,853	21,853
Class A Limited Partner [Member] | United Dominion Reality L.P. [Member]
Balance, December 31, 2015		64,409
Net income/(loss)		151
Distributions		(1,164)
OP Units Redemptions for common shares of UDR		0
Adjustment to reflect limited partners' capital at redemption value		1,276
Balance, June 30, 2016	64,672	64,672
Limited Partners [Member] | United Dominion Reality L.P. [Member]
Balance, December 31, 2015		268,481
Net income/(loss)		631
Distributions		(4,408)
OP Units Redemptions for common shares of UDR		81
Adjustment to reflect limited partners' capital at redemption value		4,875
Long Term Incentive Plan Unit grants		0
Balance, June 30, 2016	269,498	269,498
Limited Partner [Member] | United Dominion Reality L.P. [Member]
Balance, December 31, 2015		1,379,525
Net income/(loss)		15,039
Distributions		(102,737)
OP Units Redemptions for common shares of UDR		81
Adjustment to reflect limited partners' capital at redemption value		(6,151)
Balance, June 30, 2016	1,285,757	1,285,757
General Partner [Member] | United Dominion Reality L.P. [Member]
Balance, December 31, 2015		1,110
Net income/(loss)		10
Distributions		(66)
Adjustment to reflect limited partners' capital at redemption value		0
Balance, June 30, 2016	$ 1,054	1,054
Noncontrolling Interest [Member]
Long Term Incentive Plan Unit grants		$ 1,971

Consolidated Statements of Ca15

Consolidated Statements of Cash Flows (UNITED DOMINION REALTY, L.P) (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Adjustments to reconcile net income/(loss) to net cash provided by operating activities:
Depreciation and amortization	$ 211,276	$ 179,121
Gain/(loss) on sale of real estate owned	10,385	79,042
(Income)/loss from unconsolidated entities	(1,004)	(58,586)
Other	7,515	5,933
Changes in operating assets and liabilities:
(Increase)/decrease in operating assets	(8,551)	7,431
Increase/(decrease) in operating liabilities	(12,858)	(14,709)
Net cash provided by/(used in) operating activities	226,470	217,003
Investing Activities
Proceeds from sale of real estate investments, net	21,943	90,543
Development of real estate assets	(66,138)	(66,083)
Capital expenditures and other major improvements - real estate assets, net of escrow reimbursement	(49,112)	(47,453)
Distributions received from unconsolidated entities	13,663	46,075
Net cash provided by/(used in) investing activities	(122,455)	(163,776)
Financing Activities
Payments on secured debt	(145,499)	(4,549)
Net cash provided by/(used in) financing activities	(105,590)	(65,461)
Net increase/(decrease) in cash and cash equivalents	(1,575)	(12,234)
Cash and cash equivalents, beginning of period	6,742	15,224
Cash and cash equivalents, end of period	5,167	2,990
Supplemental Information:
Interest paid during the period, net of amounts capitalized	64,793	66,448
Non-cash transactions:
Development costs and capital expenditures incurred but not yet paid	42,940	23,523
LTIP Unit grants	1,971
United Dominion Reality L.P. [Member]
Operating Activities
Net income/(loss)	16,525	84,470
Adjustments to reconcile net income/(loss) to net cash provided by operating activities:
Depreciation and amortization	73,844	88,578
Gain/(loss) on sale of real estate owned	0	56,998
(Income)/loss from unconsolidated entities	23,417	0
Other	1,176	524
Changes in operating assets and liabilities:
(Increase)/decrease in operating assets	(1,521)	(341)
Increase/(decrease) in operating liabilities	2,509	(976)
Net cash provided by/(used in) operating activities	115,950	115,257
Investing Activities
Proceeds from sale of real estate investments, net	0	27,718
Development of real estate assets	0	(7,740)
Capital expenditures and other major improvements - real estate assets, net of escrow reimbursement	(30,117)	(25,487)
Distributions received from unconsolidated entities	7,946	0
Net cash provided by/(used in) investing activities	(22,171)	(5,509)
Financing Activities
Advances from/(to) General Partner, net	(59,922)	(102,378)
Payments on secured debt	(30,322)	(2,588)
Distributions paid to partnership unitholders	(5,103)	(5,120)
Net cash provided by/(used in) financing activities	(95,347)	(110,086)
Net increase/(decrease) in cash and cash equivalents	(1,568)	(338)
Cash and cash equivalents, beginning of period	3,103	502
Cash and cash equivalents, end of period	1,535	164
Supplemental Information:
Interest paid during the period, net of amounts capitalized	11,296	23,296
Non-cash transactions:
Development costs and capital expenditures incurred but not yet paid	7,020	5,200
LTIP Unit grants	$ 1,971	$ 0

Consolidation and Basis of Pres

Consolidation and Basis of Presentation	6 Months Ended
	Jun. 30, 2016
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 June 30, 2016 , there were 183,278,698 units in the Operating Partnership outstanding, of which 174,227,479 units, or 95.1% , were owned by UDR and 9,051,219 units, or 4.9% , were owned by limited partners. As of June 30, 2016 , there were 32,367,380 units in the DownREIT Partnership (“DownREIT Units”) outstanding, of which 16,229,407 , or 50.1% , were owned by UDR (of which, 13,470,651 , or 41.6% , were held by the Operating Partnership) and 16,137,973 , or 49.9% , 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 June 30, 2016 , and results of operations for the three and six months ended June 30, 2016 and 2015 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, 2015 appearing in UDR’s Annual Report on Form 10-K, filed with the Securities and Exchange Commission on February 23, 2016 . 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.)	6 Months Ended
	Jun. 30, 2016
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 June 30, 2016 , there were 183,278,698 units in the Operating Partnership outstanding, of which 174,227,479 units, or 95.1% , were owned by UDR and 9,051,219 units, or 4.9% , were owned by limited partners. As of June 30, 2016 , there were 32,367,380 units in the DownREIT Partnership (“DownREIT Units”) outstanding, of which 16,229,407 , or 50.1% , were owned by UDR (of which, 13,470,651 , or 41.6% , were held by the Operating Partnership) and 16,137,973 , or 49.9% , 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 June 30, 2016 , and results of operations for the three and six months ended June 30, 2016 and 2015 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, 2015 appearing in UDR’s Annual Report on Form 10-K, filed with the Securities and Exchange Commission on February 23, 2016 . 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 the three months ended June 30, 2016 and 2015 , rental revenues of the Operating Partnership represented 43% and 53% , respectively, and for the six months ended June 30, 2016 and 2015 , 43% and 53% , respectively, of the General Partner’s consolidated rental revenues. As of June 30, 2016 , the Operating Partnership’s apartment portfolio consisted of 56 communities located in 14 markets consisting of 16,974 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 June 30, 2016 , there were 183,278,698 OP Units outstanding, of which 174,227,479 or 95.1% were owned by UDR and affiliated entities and 9,051,219 or 4.9% 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 June 30, 2016 , and results of operations for the three and six months ended June 30, 2016 and 2015 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, 2015 included in the Annual Report on Form 10-K filed by UDR and the Operating Partnership with the SEC on February 23, 2016 . 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	6 Months Ended
	Jun. 30, 2016
Accounting Policies [Abstract]
SIGNIFICANT ACCOUNTING POLICIES	SIGNIFICANT ACCOUNTING POLICIES Recent Accounting Pronouncements In June 2016, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("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 will be effective for the Company on January 1, 2017, with early adoption permitted. The update requires a prospective, retrospective or modified retrospective approach, depending on the type of amendment. The Company 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 Company on January 1, 2019, with early adoption permitted. The Company is currently evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures. In February 2015, the FASB issued ASU 2015-02, Amendments to the Consolidation Analysis , which makes changes to both the variable interest model and the voting model of consolidation. Under ASU 2015-02, companies will need to re-evaluate whether an entity meets the criteria to be considered a variable interest entity (“VIE”) or whether the consolidation of an entity should be assessed under the voting model. The new standard specifically eliminates the presumption in the current voting model that a general partner controls a limited partnership or similar entity unless that presumption can be overcome. The new standard was effective for the Company beginning on January 1, 2016. The adoption of the new standard did not result in the consolidation of entities not previously consolidated or the deconsolidation of any entities previously consolidated. Upon adopting the new standard, the Operating Partnership and DownREIT Partnership became VIEs as the limited partners of these entities lack substantive kick-out rights and substantive participating rights. The Company is the primary beneficiary of, and continues to consolidate, the entities determined to be VIEs. 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 supersedes current revenue recognition guidance, including industry-specific revenue guidance. The updated standard will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. The standard specifically excludes lease contracts. The ASU allows for the use of either the full or modified retrospective transition method, and the standard will be effective for the Company on January 1, 2018; early adoption is permitted on January 1, 2017. The Company has not yet selected a transition method and we are currently evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures. 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 amended consolidation guidance. The Company first evaluates whether each entity is a 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 June 30, 2016 and December 31, 2015 ( dollars in thousands): Interest rate at Balance outstanding June 30, June 30, December 31, 2015 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 % 1,200 1,200 Note due April 2021 (d) 10.00 % 3,000 — Total notes receivable, net $ 19,694 $ 16,694 (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). In March 2016, the terms of this secured note receivable were amended to extend the maturity from the fifth anniversary of the date of the note (February 2017) to 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 . 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) In April 2016, the Company entered into a secured note receivable with an unaffiliated third party with an aggregate commitment of $15.0 million . During the six months ended June 30, 2016 , the Company loaned $3.0 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 $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 $0.3 million of interest income from notes receivable during the three months ended June 30, 2016 and 2015 , respectively, and $0.8 million and $0.7 million during the six months ended June 30, 2016 and 2015 , respectively, none of which was related party interest income. Interest income is included in Interest income and other income/(expense), net on the Consolidated Statements of Operations. Comprehensive Income/(Loss) Comprehensive income/(loss), which is defined as the change in equity during each period from transactions and other events and circumstances from nonowner sources, including all changes in equity during a period except for those resulting from investments by or distributions to stockholders, is displayed in the accompanying Consolidated Statements of Comprehensive Income/(Loss). For the three and six months ended June 30, 2016 and 2015 , 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 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”), primarily those engaged in development activities. 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 June 30, 2016 , UDR’s net deferred tax asset was $8.4 million (net of a valuation allowance of $0.1 million ), which is included in Other assets on the Consolidated Balance Sheets. GAAP defines a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. GAAP also provides guidance on derecognition, classification, interest and penalties, accounting for interim periods, disclosure and transition. The Company recognizes its tax positions and evaluates them using a two-step process. First, UDR determines whether a tax position is more likely than not (greater than 50 percent probability) to be sustained upon examination, including resolution of any related appeals or litigation processes, based on the technical merits of the position. Second, the Company will determine the amount of benefit to recognize and record the amount that is more likely than not to be realized upon ultimate settlement. UDR had no material unrecognized tax benefit, accrued interest or penalties at June 30, 2016 . UDR and its subsidiaries are subject to federal income tax as well as income tax of various state and local jurisdictions. The tax years 2011 through 2014 remain open to examination by tax jurisdictions to which we are subject. When applicable, UDR recognizes interest and/or penalties related to uncertain tax positions in Tax benefit/(provision), net on the Consolidated Statements of Operations.

Significant Accounting Polici19

Significant Accounting Policies (UNITED DOMINION REALTY, L.P.)	6 Months Ended
	Jun. 30, 2016
Entity Information [Line Items]
SIGNIFICANT ACCOUNTING POLICIES	SIGNIFICANT ACCOUNTING POLICIES Recent Accounting Pronouncements In June 2016, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("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 will be effective for the Company on January 1, 2017, with early adoption permitted. The update requires a prospective, retrospective or modified retrospective approach, depending on the type of amendment. The Company 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 Company on January 1, 2019, with early adoption permitted. The Company is currently evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures. In February 2015, the FASB issued ASU 2015-02, Amendments to the Consolidation Analysis , which makes changes to both the variable interest model and the voting model of consolidation. Under ASU 2015-02, companies will need to re-evaluate whether an entity meets the criteria to be considered a variable interest entity (“VIE”) or whether the consolidation of an entity should be assessed under the voting model. The new standard specifically eliminates the presumption in the current voting model that a general partner controls a limited partnership or similar entity unless that presumption can be overcome. The new standard was effective for the Company beginning on January 1, 2016. The adoption of the new standard did not result in the consolidation of entities not previously consolidated or the deconsolidation of any entities previously consolidated. Upon adopting the new standard, the Operating Partnership and DownREIT Partnership became VIEs as the limited partners of these entities lack substantive kick-out rights and substantive participating rights. The Company is the primary beneficiary of, and continues to consolidate, the entities determined to be VIEs. 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 supersedes current revenue recognition guidance, including industry-specific revenue guidance. The updated standard will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. The standard specifically excludes lease contracts. The ASU allows for the use of either the full or modified retrospective transition method, and the standard will be effective for the Company on January 1, 2018; early adoption is permitted on January 1, 2017. The Company has not yet selected a transition method and we are currently evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures. 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 amended consolidation guidance. The Company first evaluates whether each entity is a 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 June 30, 2016 and December 31, 2015 ( dollars in thousands): Interest rate at Balance outstanding June 30, June 30, December 31, 2015 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 % 1,200 1,200 Note due April 2021 (d) 10.00 % 3,000 — Total notes receivable, net $ 19,694 $ 16,694 (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). In March 2016, the terms of this secured note receivable were amended to extend the maturity from the fifth anniversary of the date of the note (February 2017) to 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 . 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) In April 2016, the Company entered into a secured note receivable with an unaffiliated third party with an aggregate commitment of $15.0 million . During the six months ended June 30, 2016 , the Company loaned $3.0 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 $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 $0.3 million of interest income from notes receivable during the three months ended June 30, 2016 and 2015 , respectively, and $0.8 million and $0.7 million during the six months ended June 30, 2016 and 2015 , respectively, none of which was related party interest income. Interest income is included in Interest income and other income/(expense), net on the Consolidated Statements of Operations. Comprehensive Income/(Loss) Comprehensive income/(loss), which is defined as the change in equity during each period from transactions and other events and circumstances from nonowner sources, including all changes in equity during a period except for those resulting from investments by or distributions to stockholders, is displayed in the accompanying Consolidated Statements of Comprehensive Income/(Loss). For the three and six months ended June 30, 2016 and 2015 , 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 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”), primarily those engaged in development activities. 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 June 30, 2016 , UDR’s net deferred tax asset was $8.4 million (net of a valuation allowance of $0.1 million ), which is included in Other assets on the Consolidated Balance Sheets. GAAP defines a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. GAAP also provides guidance on derecognition, classification, interest and penalties, accounting for interim periods, disclosure and transition. The Company recognizes its tax positions and evaluates them using a two-step process. First, UDR determines whether a tax position is more likely than not (greater than 50 percent probability) to be sustained upon examination, including resolution of any related appeals or litigation processes, based on the technical merits of the position. Second, the Company will determine the amount of benefit to recognize and record the amount that is more likely than not to be realized upon ultimate settlement. UDR had no material unrecognized tax benefit, accrued interest or penalties at June 30, 2016 . UDR and its subsidiaries are subject to federal income tax as well as income tax of various state and local jurisdictions. The tax years 2011 through 2014 remain open to examination by tax jurisdictions to which we are subject. When applicable, UDR recognizes interest and/or penalties related to uncertain tax positions in Tax benefit/(provision), 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 June 2016, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("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 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 will be effective for the Operating Partnership on January 1, 2017, with early adoption permitted. The update requires a prospective, retrospective or modified retrospective approach, depending on the type of amendment. 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. The Operating Partnership is currently evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures. In February 2015, the FASB issued ASU 2015-02, Amendments to the Consolidation Analysis , which makes changes to both the variable interest model and the voting model of consolidation. Under ASU 2015-02, companies will need to re-evaluate whether an entity meets the criteria to be considered a variable interest entity (“VIE”) or whether the consolidation of an entity should be assessed under the voting model. The new standard specifically eliminates the presumption in the current voting model that a general partner controls a limited partnership or similar entity unless that presumption can be overcome. The new standard was effective for the Operating Partnership beginning on January 1, 2016. The adoption of the new standard did not result in the consolidation of entities not previously consolidated or the deconsolidation of any entities previously consolidated. Upon adopting the new standard, UDR Lighthouse DownREIT L.P. (the “DownREIT Partnership”) became 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 and will continue to account for its interest as an equity method investment. 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 supersedes current revenue recognition guidance, including industry-specific revenue guidance. The updated standard will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. The standard specifically excludes lease contracts. The ASU allows for the use of either the full or modified retrospective transition method, and the standard will be effective for the Operating Partnership on January 1, 2018; early adoption is permitted on January 1, 2017. The Operating Partnership has not yet selected a transition method and we are currently evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures. 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 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 and six months ended June 30, 2016 and 2015 , 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 ( 2011 through 2014 ) of tax jurisdictions and concluded there is no tax liability resulting from unrecognized tax benefits relating to uncertain income tax positions taken or expected to be taken in future tax returns.

Real Estate Owned

Real Estate Owned	6 Months Ended
	Jun. 30, 2016
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 June 30, 2016 , the Company owned and consolidated 132 communities in 10 states plus the District of Columbia totaling 40,728 apartment homes. The following table summarizes the carrying amounts for our real estate owned (at cost) as of June 30, 2016 and December 31, 2015 (dollars in thousands): June 30, December 31, 2015 Land $ 1,794,615 $ 1,833,156 Depreciable property — held and used: Land Improvements 178,355 173,821 Building, improvements, and furniture, fixtures and equipment 7,100,504 7,046,622 Under development: Land and land improvements 111,028 78,085 Building, improvements, and furniture, fixtures and equipment 127,910 45,987 Real estate held for disposition: Land — 9,963 Building, improvements, and furniture, fixtures and equipment — 2,642 Real estate owned 9,312,412 9,190,276 Accumulated depreciation (2,842,273 ) (2,646,874 ) Real estate owned, net $ 6,470,139 $ 6,543,402 In June 2016, the Company increased its ownership interest from 50% to 100% in a parcel of land in Los Angeles, California for a purchase price of approximately $20.1 million , including closing costs. As a result, the Company consolidated the parcel of land. UDR had previously accounted for its 50% interest in the parcel of land as an unconsolidated joint venture (see Note 5, Joint Ventures and Partnerships ). We accounted for the consolidation as an asset acquisition resulting in no gain or loss upon consolidation and increased our real estate owned by $31.1 million . Subsequent to the acquisition, the Company entered into a triple-net operating ground lease for the parcel of land at market terms with a third-party developer. The lessee plans to construct a multi-family community on the parcel of land. The ground lease provides the ground lessee with options to buy the fee interest in the parcel of land. The lease term is 49 years plus two 25 -year extension options, does not transfer ownership to the lessee, and does not include a bargain purchase option. During the six months ended June 30, 2016 , the Company sold a retail center in Bellevue, Washington and its 95% ownership interest in two parcels of land in Santa Monica, California for total gross proceeds of $69.4 million , resulting in total net proceeds of $66.1 million and a total gain, net of tax, of $10.4 million . A portion of the proceeds related to the sale of the retail center in Bellevue, Washington were designated for Internal Revenue Code ("IRC") Section 1031 exchanges. As of June 30, 2016 , $34.7 million of these proceeds were included in Funds held in escrow from Internal Revenue Code Section 1031 exchanges on the Consolidated Balance Sheet. 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 $2.7 million and $1.6 million for the three months ended June 30, 2016 and 2015 , respectively, and $4.7 million and $3.8 million for the six months ended June 30, 2016 and 2015 , respectively. Total interest capitalized was $3.8 million and $3.8 million for the three months ended June 30, 2016 and 2015 , respectively, and $8.0 million and $8.6 million for the six months ended June 30, 2016 and 2015 , 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.)	6 Months Ended
	Jun. 30, 2016
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 June 30, 2016 , the Company owned and consolidated 132 communities in 10 states plus the District of Columbia totaling 40,728 apartment homes. The following table summarizes the carrying amounts for our real estate owned (at cost) as of June 30, 2016 and December 31, 2015 (dollars in thousands): June 30, December 31, 2015 Land $ 1,794,615 $ 1,833,156 Depreciable property — held and used: Land Improvements 178,355 173,821 Building, improvements, and furniture, fixtures and equipment 7,100,504 7,046,622 Under development: Land and land improvements 111,028 78,085 Building, improvements, and furniture, fixtures and equipment 127,910 45,987 Real estate held for disposition: Land — 9,963 Building, improvements, and furniture, fixtures and equipment — 2,642 Real estate owned 9,312,412 9,190,276 Accumulated depreciation (2,842,273 ) (2,646,874 ) Real estate owned, net $ 6,470,139 $ 6,543,402 In June 2016, the Company increased its ownership interest from 50% to 100% in a parcel of land in Los Angeles, California for a purchase price of approximately $20.1 million , including closing costs. As a result, the Company consolidated the parcel of land. UDR had previously accounted for its 50% interest in the parcel of land as an unconsolidated joint venture (see Note 5, Joint Ventures and Partnerships ). We accounted for the consolidation as an asset acquisition resulting in no gain or loss upon consolidation and increased our real estate owned by $31.1 million . Subsequent to the acquisition, the Company entered into a triple-net operating ground lease for the parcel of land at market terms with a third-party developer. The lessee plans to construct a multi-family community on the parcel of land. The ground lease provides the ground lessee with options to buy the fee interest in the parcel of land. The lease term is 49 years plus two 25 -year extension options, does not transfer ownership to the lessee, and does not include a bargain purchase option. During the six months ended June 30, 2016 , the Company sold a retail center in Bellevue, Washington and its 95% ownership interest in two parcels of land in Santa Monica, California for total gross proceeds of $69.4 million , resulting in total net proceeds of $66.1 million and a total gain, net of tax, of $10.4 million . A portion of the proceeds related to the sale of the retail center in Bellevue, Washington were designated for Internal Revenue Code ("IRC") Section 1031 exchanges. As of June 30, 2016 , $34.7 million of these proceeds were included in Funds held in escrow from Internal Revenue Code Section 1031 exchanges on the Consolidated Balance Sheet. 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 $2.7 million and $1.6 million for the three months ended June 30, 2016 and 2015 , respectively, and $4.7 million and $3.8 million for the six months ended June 30, 2016 and 2015 , respectively. Total interest capitalized was $3.8 million and $3.8 million for the three months ended June 30, 2016 and 2015 , respectively, and $8.0 million and $8.6 million for the six months ended June 30, 2016 and 2015 , 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. As of June 30, 2016 , the Operating Partnership owned and consolidated 56 communities in eight states plus the District of Columbia totaling 16,974 apartment homes. The following table summarizes the carrying amounts for our real estate owned (at cost) as of June 30, 2016 and December 31, 2015 (dollars in thousands) : June 30, December 31, 2015 Land $ 835,686 $ 833,300 Depreciable property — held and used: Buildings, improvements, and furniture, fixture and equipment 2,829,042 2,797,605 Real estate owned 3,664,728 3,630,905 Accumulated depreciation (1,353,616 ) (1,281,258 ) Real estate owned, net $ 2,311,112 $ 2,349,647 The Operating Partnership did not have any acquisitions or sales of real estate during the six months ended June 30, 2016 . 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 $0.2 million for the three months ended June 30, 2016 and 2015 , respectively, and $0.6 million and $0.3 million for the six months ended June 30, 2016 and 2015 , respectively. Total interest capitalized was less than $0.1 million for the three months ended June 30, 2016 and 2015 , and $0.2 million and less than $0.1 million for the six months ended June 30, 2016 and 2015 , 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)	6 Months Ended
	Jun. 30, 2016
Equity Method Investments and Joint Ventures [Abstract]
Variable Interest Entity Disclosure [Text Block]	VARIABLE INTEREST ENTITIES As of January 1, 2016, the Company adopted ASU 2015-02. See discussion in Note 2, Significant Accounting Policies for further details. As a result of the adoption, the Operating Partnership and DownREIT Partnership were determined to be VIEs. As the Company was determined to be the primary beneficiary, we will continue to consolidate these 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 continues to consolidate, the Operating Partnership and DownREIT Partnership based on its role as the manager of the communities and its direct ownership interests, including all general partner interests. 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	6 Months Ended
	Jun. 30, 2016
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 June 30, 2016 and December 31, 2015 (dollars in thousands) : Joint Venture Location of Properties Number of Properties Number of Apartment Homes Investment at UDR’s Ownership Interest June 30, June 30, June 30, December 31, June 30, December 31, Operating and development: UDR/MetLife I 1 development community (a); Various 3 land parcels 150 $ 21,319 $ 15,894 19.6 % 17.2 % UDR/MetLife II (b) Various 21 operating communities 4,642 418,701 425,230 50.0 % 50.0 % Other UDR/MetLife Development Joint Ventures (c) 1 operating community; Various 4 development communities (a) 1,437 164,870 171,659 50.6 % 50.6 % UDR/MetLife Vitruvian Park® Addison, TX 3 operating communities; 6 land parcels 1,130 71,984 73,469 50.0 % 50.0 % UDR/KFH Washington, D.C. 3 operating communities 660 15,126 17,211 30.0 % 30.0 % Investment in and advances to unconsolidated joint ventures, net, before participating loan investment and preferred equity investment 692,000 703,463 Income from Investment Investment at Three Months Ended June 30, Six Months Ended June 30, Location Rate Years To Maturity June 30, December 31, 2016 2015 2016 2015 Participating loan investment: Steele Creek Denver, CO 6.5% 1.1 93,902 90,747 $1,560 $1,352 $3,079 $2,506 Preferred equity investment: West Coast Development Joint Venture Various 6.5% N/A 147,501 144,696 $1,409 $(548) $3,198 $(548) Total investment in and advances to unconsolidated joint ventures, net $ 933,403 $ 938,906 (a) The number of apartment homes for the communities under development presented in the table above is based on the projected number of total homes. As of June 30, 2016 , 447 apartment homes had been completed in Other UDR/MetLife Development Joint Ventures, and no apartment homes had been completed in UDR/MetLife I. (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 and six months ended June 30, 2016 , the Company recorded losses of $0 and $1.1 million , respectively, its proportionate share of the total losses incurred. (c) In June 2016, the Company increased its ownership interest from 50% to 100% in a parcel of land in Los Angeles, California for a purchase price of approximately $20.1 million , including closing costs. As a result, the Company consolidated the parcel of land and it is no longer accounted for as an unconsolidated joint venture (see Note 3, Real Estate Owned ). The parcel of land was previously held in Other/UDR MetLife Development Joint Ventures. As of June 30, 2016 and December 31, 2015 , the Company had deferred fees and deferred profit from the sale of properties to joint ventures or partnerships of $8.3 million and $6.8 million , respectively, which will be recognized through income over the weighted average life of the related properties, upon the disposition of the properties to a third party, or upon completion of certain development obligations. The Company recognized management fees for our management of the joint ventures and partnerships of $2.6 million and $2.6 million for the three months ended June 30, 2016 and 2015 , respectively, and $5.4 million and $5.2 million for the six months ended June 30, 2016 and 2015 , respectively. The management fees are included in Joint venture management and other fees on the Consolidated Statements of Operations. The Company may, in the future, make additional capital contributions to certain of our joint ventures and partnerships should additional capital contributions be necessary to fund acquisitions or operations. We evaluate our investments in unconsolidated joint ventures and partnerships when events or changes in circumstances indicate that there may be an other-than-temporary decline in value. We consider various factors to determine if a decrease in the value of the investment is other-than-temporary. The Company did not recognize any other-than-temporary decreases in the value of its investments in unconsolidated joint ventures or partnerships during the three and six months ended June 30, 2016 and 2015 . Combined summary balance sheets relating to the unconsolidated joint ventures and partnerships (not just our proportionate share) are presented below as of June 30, 2016 and December 31, 2015 ( dollars in thousands ): June 30, December 31, 2015 Total real estate, net $ 3,169,088 $ 3,135,757 Cash and cash equivalents 27,961 36,480 Amount due from UDR 1,069 — Other assets 20,634 29,891 Total assets $ 3,218,752 $ 3,202,128 Amount due to UDR $ — $ 7,266 Third party debt 1,707,406 1,614,463 Accounts payable and accrued liabilities 74,563 95,523 Total liabilities 1,781,969 1,717,252 Total equity 1,436,783 1,484,876 Total liabilities and equity $ 3,218,752 $ 3,202,128 Investment in and advances to unconsolidated joint ventures, net $ 933,403 $ 938,906 Combined summary financial information relating to the unconsolidated joint ventures’ and partnerships’ operations (not just our proportionate share), is presented below for the three and six months ended June 30, 2016 and 2015 ( dollars in thousands ) : Three Months Ended Six Months Ended June 30, June 30, 2016 2015 2016 2015 Total revenues $ 58,153 $ 55,450 $ 113,190 $ 109,996 Property operating expenses (22,981 ) (21,557 ) (46,394 ) (41,724 ) Real estate depreciation and amortization (21,770 ) (19,402 ) (40,713 ) (38,754 ) Operating income/(loss) 13,402 14,491 26,083 29,518 Interest expense (17,005 ) (16,169 ) (33,184 ) (32,230 ) Other income/(expense) (2 ) (7 ) (4 ) (7 ) Income/(loss) from discontinued operations — — — 182,488 Net income/(loss) $ (3,605 ) $ (1,685 ) $ (7,105 ) $ 179,769 UDR income/(loss) from unconsolidated entities $ 325 $ (573 ) $ 1,004 $ 58,586

Unconsolidated Entities (UNITED

Unconsolidated Entities (UNITED DOMINION REALTY, L.P.) Unconsolidated Entities (UNITED DOMINION REALTY, L.P.)	6 Months Ended
	Jun. 30, 2016
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 June 30, 2016 and December 31, 2015 (dollars in thousands) : Joint Venture Location of Properties Number of Properties Number of Apartment Homes Investment at UDR’s Ownership Interest June 30, June 30, June 30, December 31, June 30, December 31, Operating and development: UDR/MetLife I 1 development community (a); Various 3 land parcels 150 $ 21,319 $ 15,894 19.6 % 17.2 % UDR/MetLife II (b) Various 21 operating communities 4,642 418,701 425,230 50.0 % 50.0 % Other UDR/MetLife Development Joint Ventures (c) 1 operating community; Various 4 development communities (a) 1,437 164,870 171,659 50.6 % 50.6 % UDR/MetLife Vitruvian Park® Addison, TX 3 operating communities; 6 land parcels 1,130 71,984 73,469 50.0 % 50.0 % UDR/KFH Washington, D.C. 3 operating communities 660 15,126 17,211 30.0 % 30.0 % Investment in and advances to unconsolidated joint ventures, net, before participating loan investment and preferred equity investment 692,000 703,463 Income from Investment Investment at Three Months Ended June 30, Six Months Ended June 30, Location Rate Years To Maturity June 30, December 31, 2016 2015 2016 2015 Participating loan investment: Steele Creek Denver, CO 6.5% 1.1 93,902 90,747 $1,560 $1,352 $3,079 $2,506 Preferred equity investment: West Coast Development Joint Venture Various 6.5% N/A 147,501 144,696 $1,409 $(548) $3,198 $(548) Total investment in and advances to unconsolidated joint ventures, net $ 933,403 $ 938,906 (a) The number of apartment homes for the communities under development presented in the table above is based on the projected number of total homes. As of June 30, 2016 , 447 apartment homes had been completed in Other UDR/MetLife Development Joint Ventures, and no apartment homes had been completed in UDR/MetLife I. (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 and six months ended June 30, 2016 , the Company recorded losses of $0 and $1.1 million , respectively, its proportionate share of the total losses incurred. (c) In June 2016, the Company increased its ownership interest from 50% to 100% in a parcel of land in Los Angeles, California for a purchase price of approximately $20.1 million , including closing costs. As a result, the Company consolidated the parcel of land and it is no longer accounted for as an unconsolidated joint venture (see Note 3, Real Estate Owned ). The parcel of land was previously held in Other/UDR MetLife Development Joint Ventures. As of June 30, 2016 and December 31, 2015 , the Company had deferred fees and deferred profit from the sale of properties to joint ventures or partnerships of $8.3 million and $6.8 million , respectively, which will be recognized through income over the weighted average life of the related properties, upon the disposition of the properties to a third party, or upon completion of certain development obligations. The Company recognized management fees for our management of the joint ventures and partnerships of $2.6 million and $2.6 million for the three months ended June 30, 2016 and 2015 , respectively, and $5.4 million and $5.2 million for the six months ended June 30, 2016 and 2015 , respectively. The management fees are included in Joint venture management and other fees on the Consolidated Statements of Operations. The Company may, in the future, make additional capital contributions to certain of our joint ventures and partnerships should additional capital contributions be necessary to fund acquisitions or operations. We evaluate our investments in unconsolidated joint ventures and partnerships when events or changes in circumstances indicate that there may be an other-than-temporary decline in value. We consider various factors to determine if a decrease in the value of the investment is other-than-temporary. The Company did not recognize any other-than-temporary decreases in the value of its investments in unconsolidated joint ventures or partnerships during the three and six months ended June 30, 2016 and 2015 . Combined summary balance sheets relating to the unconsolidated joint ventures and partnerships (not just our proportionate share) are presented below as of June 30, 2016 and December 31, 2015 ( dollars in thousands ): June 30, December 31, 2015 Total real estate, net $ 3,169,088 $ 3,135,757 Cash and cash equivalents 27,961 36,480 Amount due from UDR 1,069 — Other assets 20,634 29,891 Total assets $ 3,218,752 $ 3,202,128 Amount due to UDR $ — $ 7,266 Third party debt 1,707,406 1,614,463 Accounts payable and accrued liabilities 74,563 95,523 Total liabilities 1,781,969 1,717,252 Total equity 1,436,783 1,484,876 Total liabilities and equity $ 3,218,752 $ 3,202,128 Investment in and advances to unconsolidated joint ventures, net $ 933,403 $ 938,906 Combined summary financial information relating to the unconsolidated joint ventures’ and partnerships’ operations (not just our proportionate share), is presented below for the three and six months ended June 30, 2016 and 2015 ( dollars in thousands ) : Three Months Ended Six Months Ended June 30, June 30, 2016 2015 2016 2015 Total revenues $ 58,153 $ 55,450 $ 113,190 $ 109,996 Property operating expenses (22,981 ) (21,557 ) (46,394 ) (41,724 ) Real estate depreciation and amortization (21,770 ) (19,402 ) (40,713 ) (38,754 ) Operating income/(loss) 13,402 14,491 26,083 29,518 Interest expense (17,005 ) (16,169 ) (33,184 ) (32,230 ) Other income/(expense) (2 ) (7 ) (4 ) (7 ) Income/(loss) from discontinued operations — — — 182,488 Net income/(loss) $ (3,605 ) $ (1,685 ) $ (7,105 ) $ 179,769 UDR income/(loss) from unconsolidated entities $ 325 $ (573 ) $ 1,004 $ 58,586
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 Operating Partnership's investment in the DownREIT Partnership is accounted for 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 share of the net earnings or losses of the partnership in accordance with the partnership agreement. Upon adopting ASU 2015-02, the DownREIT Partnership became 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 June 30, 2016 , the DownREIT Partnership operated 13 communities with 6,261 apartment homes. The Operating Partnership’s investment in the DownREIT Partnership was $134.8 million and $166.2 million as of June 30, 2016 and December 31, 2015 , respectively. Combined summary balance sheets relating to all of the DownREIT Partnership (not just our proportionate share) are presented below as of June 30, 2016 and December 31, 2015 ( dollars in thousands ): June 30, December 31, 2015 Total real estate, net $ 1,432,291 $ 1,457,244 Cash and cash equivalents — 89 Other assets 15,334 37,228 Note receivable from affiliate 126,500 126,500 Amount due from UDR — 35,293 Total assets $ 1,574,125 $ 1,656,354 Secured debt, net 443,639 524,052 Amount due to UDR 45,348 — Accounts payable and accrued liabilities 26,315 25,487 Total liabilities 515,302 549,539 Total equity 1,058,823 1,106,815 Total liabilities and equity $ 1,574,125 $ 1,656,354 OP’s investment in the DownREIT Partnership $ 134,823 $ 166,186 Combined summary financial information relating to all of the DownREIT Partnership (not just our proportionate share) is presented below for the three and six months ended June 30, 2016 ( dollars in thousands ) : Three Months Ended Six Months Ended June 30, June 30, 2016 2016 Rental income $ 32,646 $ 64,263 Property operating and maintenance (11,084 ) (22,441 ) Real estate depreciation and amortization (30,308 ) (60,361 ) Operating income/(loss) (8,746 ) (18,539 ) Interest expense (3,524 ) (7,265 ) Other income/(expense) (1,358 ) (3,090 ) Net income/(loss) $ (13,628 ) $ (28,894 ) OP's income/(loss) from unconsolidated entities $ (10,030 ) $ (23,417 ) There is no financial information presented for the three and six months ended June 30, 2015 as the DownREIT Partnership was formed in the fourth quarter of 2015.

Secured and Unsecured Debt

Secured and Unsecured Debt	6 Months Ended
	Jun. 30, 2016
Debt Disclosure [Abstract]
Debt Disclosure [Text Block]	SECURED AND UNSECURED DEBT, NET The following is a summary of our secured and unsecured debt at June 30, 2016 and December 31, 2015 ( dollars in thousands ): Six Months Ended Principal Outstanding June 30, 2016 June 30, December 31, 2015 Weighted Average Weighted Average Number of Communities Secured Debt: Fixed Rate Debt Mortgage notes payable (a) $ 322,689 $ 442,617 4.30 % 6.3 5 Fannie Mae credit facilities (b) 512,584 514,462 5.23 % 2.6 18 Deferred financing costs (3,482 ) (4,278 ) Total fixed rate secured debt, net 831,791 952,801 4.87 % 4.0 23 Variable Rate Debt Mortgage notes payable (c) 31,337 31,337 2.25 % 0.6 1 Tax-exempt secured notes payable (d) 94,700 94,700 1.18 % 6.7 2 Fannie Mae credit facilities (b) 299,378 299,378 1.92 % 3.6 8 Deferred financing costs (1,087 ) (1,271 ) Total variable rate secured debt, net 424,328 424,144 1.78 % 4.0 11 Total Secured Debt, net 1,256,119 1,376,945 3.82 % 4.0 34 Unsecured Debt: Variable Rate Debt Borrowings outstanding under an unsecured credit facility due January 2020 (e) (i) 255,000 150,000 1.36 % 3.6 Borrowings outstanding under an unsecured working capital credit facility due January 2019 (f) 4,199 — 1.37 % 2.5 1.40% Term Loan Facility due January 2021 (e) (i) 35,000 35,000 1.40 % 4.6 Fixed Rate Debt 5.25% Medium-Term Notes due January 2016 (g) — 83,260 — % — 6.21% Term Notes due July 2016 (g) — 12,091 — % — 4.25% Medium-Term Notes due June 2018 (net of discounts of $822 and $1,037, respectively) (i) 299,178 298,963 4.25 % 1.9 3.70% Medium-Term Notes due October 2020 (net of discounts of $34 and $38, respectively) (i) 299,966 299,962 3.70 % 4.3 2.23% Term Loan Facility due January 2021 (e) (i) 315,000 315,000 2.23 % 4.6 4.63% Medium-Term Notes due January 2022 (net of discounts of $1,985 and $2,164, respectively) (i) 398,015 397,836 4.63 % 5.5 3.75% Medium-Term Notes due July 2024 (net of discounts of $834 and $886, respectively) (i) 299,166 299,114 3.75 % 8.0 8.50% Debentures due September 2024 15,644 15,644 8.50 % 8.2 4.00% Medium-Term Notes due October 2025 (net of discounts of $637 and $671, respectively) (h) (i) 299,363 299,329 4.00 % 9.3 Other 23 24 N/A N/A Deferred financing costs (11,496 ) (12,373 ) N/A N/A Total Unsecured Debt, net 2,209,058 2,193,850 3.58 % 5.4 Total Debt, net $ 3,465,177 $ 3,570,795 3.76 % 4.9 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 June 30, 2016 , secured debt encumbered $2.1 billion or 22.5% of UDR’s total real estate owned based upon gross book value ( $7.2 billion or 77.5% of UDR’s real estate owned based on gross book value is unencumbered). (a) At June 30, 2016 , fixed rate mortgage notes payable are generally due in monthly installments of principal and interest and mature at various dates from February 2017 through June 2026 and carry interest rates ranging from 3.35% to 5.86% . On June 1, 2016, the Company entered into a $25.0 million fixed rate mortgage note due June 5, 2026 with an interest rate of 3.35% . Interest is payable monthly beginning on July 5, 2016. The Company will from time to time acquire properties subject to fixed rate debt instruments. In those situations, the Company records the debt at its estimated fair value and amortizes any difference between the fair value and par to interest expense over the life of the underlying debt instrument. The Company had a reduction to interest expense based on the amortization of the fair market adjustment of debt assumed in the acquisition of properties of $0.7 million and $1.3 million during the three months ended June 30, 2016 and 2015 , respectively, and $1.5 million and $2.4 million during the six months ended June 30, 2016 and 2015 , respectively. The unamortized fair market adjustment was a net premium of $8.4 million and $10.0 million at June 30, 2016 and December 31, 2015 , respectively. (b) UDR has three secured credit facilities with Fannie Mae with an aggregate commitment of $812.0 million at June 30, 2016 . The Fannie Mae credit facilities mature at various dates from May 2017 through July 2023 and bear interest at floating and fixed rates. At June 30, 2016 , $512.6 million of the outstanding balance was fixed and had a weighted average interest rate of 5.23% and the remaining balance of $299.4 million had a weighted average variable interest rate of 1.92% . Further information related to these credit facilities is as follows (dollars in thousands) : June 30, December 31, 2015 Borrowings outstanding $ 811,962 $ 813,840 Weighted average borrowings during the period ended 812,752 822,521 Maximum daily borrowings during the period ended 813,544 834,003 Weighted average interest rate during the period ended 4.0 % 4.0 % Weighted average interest rate at the end of the period 4.0 % 3.9 % (c) In July 2016, the Company paid off the $31.3 million variable rate mortgage note payable with borrowings under its $1.1 billion unsecured revolving credit facility. (d) 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 an interest rate of 1.18% as of June 30, 2016 . (e) As of June 30, 2016 , the Company has a $1.1 billion senior unsecured revolving credit facility (the “Revolving Credit Facility”) and a $350.0 million senior unsecured term loan facility (the “Term Loan Facility”). The credit agreement 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 June 30, 2016 and December 31, 2015 (dollars in thousands): June 30, December 31, 2015 Total revolving credit facility $ 1,100,000 $ 1,100,000 Borrowings outstanding at end of period (1) 255,000 150,000 Weighted average daily borrowings during the period ended 155,780 353,647 Maximum daily borrowings during the period ended 260,000 541,500 Weighted average interest rate during the period ended 1.3 % 1.1 % Interest rate at end of the period 1.4 % 1.2 % (1) Excludes $2.8 million and $2.3 million of letters of credit at June 30, 2016 and December 31, 2015 , respectively. (f) As of June 30, 2016 , the Company has a working capital credit facility, which provides for a $30 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. In July 2016, the Company amended the working capital credit facility to increase the maximum borrowing capacity from $30 million to $75 million . The scheduled maturity date and interest rate were unchanged by the amendment. The following is a summary of short-term bank borrowings under UDR’s working capital credit facility at June 30, 2016 and December 31, 2015 (dollars in thousands): June 30, December 31, 2015 Total revolving working capital credit facility $ 30,000 $ 30,000 Borrowings outstanding at end of period 4,199 — Weighted average daily borrowings during the period ended 12,601 — Maximum daily borrowings during the period ended 29,361 — Weighted average interest rate during the period ended 1.3 % — % Interest rate at end of the period 1.4 % — % (g) Paid off at maturity with borrowings under the Company's $1.1 billion unsecured revolving credit facility. (h) 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% . (i) 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 June 30, 2016 are as follows (dollars in thousands): Year Total Fixed Secured Debt Total Variable Secured Debt Total Secured Debt Total Unsecured Debt Total Debt 2016 $ 3,559 $ — $ 3,559 $ — $ 3,559 2017 179,189 96,337 275,526 — 275,526 2018 73,096 137,969 211,065 300,000 511,065 2019 247,796 67,700 315,496 4,199 319,695 2020 170,664 — 170,664 555,000 725,664 2021 — — — 350,000 350,000 2022 — — — 400,000 400,000 2023 — 96,409 96,409 — 96,409 2024 — — — 315,644 315,644 2025 127,600 — 127,600 300,000 427,600 Thereafter 25,000 27,000 52,000 — 52,000 Subtotal 826,904 425,415 1,252,319 2,224,843 3,477,162 Non-cash (a) 4,887 (1,087 ) 3,800 (15,785 ) (11,985 ) Total $ 831,791 $ 424,328 $ 1,256,119 $ 2,209,058 $ 3,465,177 (a) Includes the unamortized balance of fair market value adjustments, premiums/discounts, deferred hedge gains, and deferred financing costs. For the three months ended June 30, 2016 and 2015 , the Company amortized $1.2 million and $1.5 million , respectively, of deferred financing costs into Interest expense . For the six months ended June 30, 2016 and 2015 , the Company amortized $2.4 million and $3.0 million , respectively, of deferred financing costs into Interest expense We were in compliance with the covenants of our debt instruments at June 30, 2016 .

Debt (UNITED DOMINION REALTY, L

Debt (UNITED DOMINION REALTY, L.P.)	6 Months Ended
	Jun. 30, 2016
Entity Information [Line Items]
DEBT	SECURED AND UNSECURED DEBT, NET The following is a summary of our secured and unsecured debt at June 30, 2016 and December 31, 2015 ( dollars in thousands ): Six Months Ended Principal Outstanding June 30, 2016 June 30, December 31, 2015 Weighted Average Weighted Average Number of Communities Secured Debt: Fixed Rate Debt Mortgage notes payable (a) $ 322,689 $ 442,617 4.30 % 6.3 5 Fannie Mae credit facilities (b) 512,584 514,462 5.23 % 2.6 18 Deferred financing costs (3,482 ) (4,278 ) Total fixed rate secured debt, net 831,791 952,801 4.87 % 4.0 23 Variable Rate Debt Mortgage notes payable (c) 31,337 31,337 2.25 % 0.6 1 Tax-exempt secured notes payable (d) 94,700 94,700 1.18 % 6.7 2 Fannie Mae credit facilities (b) 299,378 299,378 1.92 % 3.6 8 Deferred financing costs (1,087 ) (1,271 ) Total variable rate secured debt, net 424,328 424,144 1.78 % 4.0 11 Total Secured Debt, net 1,256,119 1,376,945 3.82 % 4.0 34 Unsecured Debt: Variable Rate Debt Borrowings outstanding under an unsecured credit facility due January 2020 (e) (i) 255,000 150,000 1.36 % 3.6 Borrowings outstanding under an unsecured working capital credit facility due January 2019 (f) 4,199 — 1.37 % 2.5 1.40% Term Loan Facility due January 2021 (e) (i) 35,000 35,000 1.40 % 4.6 Fixed Rate Debt 5.25% Medium-Term Notes due January 2016 (g) — 83,260 — % — 6.21% Term Notes due July 2016 (g) — 12,091 — % — 4.25% Medium-Term Notes due June 2018 (net of discounts of $822 and $1,037, respectively) (i) 299,178 298,963 4.25 % 1.9 3.70% Medium-Term Notes due October 2020 (net of discounts of $34 and $38, respectively) (i) 299,966 299,962 3.70 % 4.3 2.23% Term Loan Facility due January 2021 (e) (i) 315,000 315,000 2.23 % 4.6 4.63% Medium-Term Notes due January 2022 (net of discounts of $1,985 and $2,164, respectively) (i) 398,015 397,836 4.63 % 5.5 3.75% Medium-Term Notes due July 2024 (net of discounts of $834 and $886, respectively) (i) 299,166 299,114 3.75 % 8.0 8.50% Debentures due September 2024 15,644 15,644 8.50 % 8.2 4.00% Medium-Term Notes due October 2025 (net of discounts of $637 and $671, respectively) (h) (i) 299,363 299,329 4.00 % 9.3 Other 23 24 N/A N/A Deferred financing costs (11,496 ) (12,373 ) N/A N/A Total Unsecured Debt, net 2,209,058 2,193,850 3.58 % 5.4 Total Debt, net $ 3,465,177 $ 3,570,795 3.76 % 4.9 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 June 30, 2016 , secured debt encumbered $2.1 billion or 22.5% of UDR’s total real estate owned based upon gross book value ( $7.2 billion or 77.5% of UDR’s real estate owned based on gross book value is unencumbered). (a) At June 30, 2016 , fixed rate mortgage notes payable are generally due in monthly installments of principal and interest and mature at various dates from February 2017 through June 2026 and carry interest rates ranging from 3.35% to 5.86% . On June 1, 2016, the Company entered into a $25.0 million fixed rate mortgage note due June 5, 2026 with an interest rate of 3.35% . Interest is payable monthly beginning on July 5, 2016. The Company will from time to time acquire properties subject to fixed rate debt instruments. In those situations, the Company records the debt at its estimated fair value and amortizes any difference between the fair value and par to interest expense over the life of the underlying debt instrument. The Company had a reduction to interest expense based on the amortization of the fair market adjustment of debt assumed in the acquisition of properties of $0.7 million and $1.3 million during the three months ended June 30, 2016 and 2015 , respectively, and $1.5 million and $2.4 million during the six months ended June 30, 2016 and 2015 , respectively. The unamortized fair market adjustment was a net premium of $8.4 million and $10.0 million at June 30, 2016 and December 31, 2015 , respectively. (b) UDR has three secured credit facilities with Fannie Mae with an aggregate commitment of $812.0 million at June 30, 2016 . The Fannie Mae credit facilities mature at various dates from May 2017 through July 2023 and bear interest at floating and fixed rates. At June 30, 2016 , $512.6 million of the outstanding balance was fixed and had a weighted average interest rate of 5.23% and the remaining balance of $299.4 million had a weighted average variable interest rate of 1.92% . Further information related to these credit facilities is as follows (dollars in thousands) : June 30, December 31, 2015 Borrowings outstanding $ 811,962 $ 813,840 Weighted average borrowings during the period ended 812,752 822,521 Maximum daily borrowings during the period ended 813,544 834,003 Weighted average interest rate during the period ended 4.0 % 4.0 % Weighted average interest rate at the end of the period 4.0 % 3.9 % (c) In July 2016, the Company paid off the $31.3 million variable rate mortgage note payable with borrowings under its $1.1 billion unsecured revolving credit facility. (d) 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 an interest rate of 1.18% as of June 30, 2016 . (e) As of June 30, 2016 , the Company has a $1.1 billion senior unsecured revolving credit facility (the “Revolving Credit Facility”) and a $350.0 million senior unsecured term loan facility (the “Term Loan Facility”). The credit agreement 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 June 30, 2016 and December 31, 2015 (dollars in thousands): June 30, December 31, 2015 Total revolving credit facility $ 1,100,000 $ 1,100,000 Borrowings outstanding at end of period (1) 255,000 150,000 Weighted average daily borrowings during the period ended 155,780 353,647 Maximum daily borrowings during the period ended 260,000 541,500 Weighted average interest rate during the period ended 1.3 % 1.1 % Interest rate at end of the period 1.4 % 1.2 % (1) Excludes $2.8 million and $2.3 million of letters of credit at June 30, 2016 and December 31, 2015 , respectively. (f) As of June 30, 2016 , the Company has a working capital credit facility, which provides for a $30 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. In July 2016, the Company amended the working capital credit facility to increase the maximum borrowing capacity from $30 million to $75 million . The scheduled maturity date and interest rate were unchanged by the amendment. The following is a summary of short-term bank borrowings under UDR’s working capital credit facility at June 30, 2016 and December 31, 2015 (dollars in thousands): June 30, December 31, 2015 Total revolving working capital credit facility $ 30,000 $ 30,000 Borrowings outstanding at end of period 4,199 — Weighted average daily borrowings during the period ended 12,601 — Maximum daily borrowings during the period ended 29,361 — Weighted average interest rate during the period ended 1.3 % — % Interest rate at end of the period 1.4 % — % (g) Paid off at maturity with borrowings under the Company's $1.1 billion unsecured revolving credit facility. (h) 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% . (i) 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 June 30, 2016 are as follows (dollars in thousands): Year Total Fixed Secured Debt Total Variable Secured Debt Total Secured Debt Total Unsecured Debt Total Debt 2016 $ 3,559 $ — $ 3,559 $ — $ 3,559 2017 179,189 96,337 275,526 — 275,526 2018 73,096 137,969 211,065 300,000 511,065 2019 247,796 67,700 315,496 4,199 319,695 2020 170,664 — 170,664 555,000 725,664 2021 — — — 350,000 350,000 2022 — — — 400,000 400,000 2023 — 96,409 96,409 — 96,409 2024 — — — 315,644 315,644 2025 127,600 — 127,600 300,000 427,600 Thereafter 25,000 27,000 52,000 — 52,000 Subtotal 826,904 425,415 1,252,319 2,224,843 3,477,162 Non-cash (a) 4,887 (1,087 ) 3,800 (15,785 ) (11,985 ) Total $ 831,791 $ 424,328 $ 1,256,119 $ 2,209,058 $ 3,465,177 (a) Includes the unamortized balance of fair market value adjustments, premiums/discounts, deferred hedge gains, and deferred financing costs. For the three months ended June 30, 2016 and 2015 , the Company amortized $1.2 million and $1.5 million , respectively, of deferred financing costs into Interest expense . For the six months ended June 30, 2016 and 2015 , the Company amortized $2.4 million and $3.0 million , respectively, of deferred financing costs into Interest expense We were in compliance with the covenants of our debt instruments at June 30, 2016 .
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 June 30, 2016 and December 31, 2015 ( dollars in thousands ): Six Months Ended Principal Outstanding June 30, 2016 June 30, December 31, 2015 Weighted Average Interest Rate Weighted Average Years to Maturity Number of Communities Encumbered Fixed Rate Debt Mortgage notes payable $ — $ 30,132 N/A — — Fannie Mae credit facilities 250,638 250,828 5.08 % 3.2 8 Deferred financing costs (1,296 ) (1,627 ) Total fixed rate secured debt, net 249,342 279,333 5.08 % 3.2 8 Variable Rate Debt Tax-exempt secured note payable 27,000 27,000 1.18 % 15.7 1 Fannie Mae credit facilities 170,203 170,203 2.12 % 4.2 6 Deferred financing costs (536 ) (572 ) Total variable rate secured debt, net 196,667 196,631 1.99 % 5.8 7 Total Secured Debt, net $ 446,009 $ 475,964 3.86 % 4.3 15 As of June 30, 2016 , an aggregate commitment of $420.8 million of the General Partner's secured credit facilities with Fannie Mae was allocated to the Operating Partnership based on the ownership of the assets securing the debt. The entire commitment was outstanding at June 30, 2016 . The Fannie Mae credit facilities mature at various dates from May 2017 through July 2023 and bear interest at floating and fixed rates. At June 30, 2016 , $250.6 million of the outstanding balance was fixed and had a weighted average interest rate of 5.08% and the remaining balance of $170.2 million on these facilities had a weighted average variable interest rate of 2.12% . The following information relates to the credit facilities allocated to the Operating Partnership (dollars in thousands) : June 30, December 31, 2015 Borrowings outstanding $ 420,841 $ 421,031 Weighted average borrowings during the period ended 421,251 425,522 Maximum daily borrowings during the period 421,661 431,462 Weighted average interest rate during the period ended 3.8 % 3.8 % Interest rate at the end of the period 3.9 % 3.8 % 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 Secured credit facilities. At June 30, 2016 , the General Partner had borrowings against its fixed rate facilities of $512.6 million , of which $250.6 million was allocated to the Operating Partnership based on the ownership of the assets securing the debt. As of June 30, 2016 , the fixed rate Fannie Mae credit facilities allocated to the Operating Partnership had a weighted average fixed interest rate of 5.08% . 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 1.18% as of June 30, 2016 . Secured credit facilities. At June 30, 2016 , the General Partner had borrowings against its variable rate facilities of $299.4 million , of which $170.2 million was allocated to the Operating Partnership based on the ownership of the assets securing the debt. As of June 30, 2016 , the variable rate borrowings under the Fannie Mae credit facilities allocated to the Operating Partnership had a weighted average floating interest rate of 2.12% . The aggregate maturities of the Operating Partnership’s secured debt due during each of the next ten calendar years subsequent to June 30, 2016 are as follows (dollars in thousands): Fixed Variable Year Secured Credit Facilities Tax-Exempt Secured Notes Payable Secured Credit Facilities Total 2016 $ 195 $ — $ — $ 195 2017 15,640 — 6,566 22,206 2018 48,872 — 96,327 145,199 2019 123,095 — — 123,095 2020 62,836 — — 62,836 2021 — — — — 2022 — — — — 2023 — — 67,310 67,310 2024 — — — — 2025 — — — — Thereafter — 27,000 — 27,000 Subtotal 250,638 27,000 170,203 447,841 Non-cash (a) (1,296 ) (89 ) (447 ) (1,832 ) Total $ 249,342 $ 26,911 $ 169,756 $ 446,009 (a) Includes the unamortized balance of fair market value adjustments, premiums/discounts, deferred hedge gains, and deferred financing costs. For the three months ended June 30, 2016 and 2015 , the Operating Partnership amortized $0.1 million and $0.4 million , respectively, and $0.3 million and $0.7 million for the six months ended June 30, 2016 and 2015 , 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 , $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 and $300 million of medium-term notes due October 2025 . As of June 30, 2016 and December 31, 2015 , the outstanding balance under the unsecured revolving credit facility was $255.0 million and $150.0 million , respectively.

Income_(Loss) Per Share

Income/(Loss) Per Share	6 Months Ended
	Jun. 30, 2016
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 Six Months Ended June 30, June 30, 2016 2015 2016 2015 Numerator for income/(loss) per share: Income/(loss) from continuing operations $ 12,249 $ 10,842 $ 20,783 $ 87,259 Gain/(loss) on sale of real estate owned, net of tax 7,315 79,042 10,385 79,042 Net (income)/loss attributable to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (1,610 ) (3,029 ) (2,515 ) (5,617 ) Net (income)/loss attributable to noncontrolling interests (8 ) — (314 ) (7 ) Net income/(loss) attributable to UDR, Inc. 17,946 86,855 28,339 160,677 Distributions to preferred stockholders — Series E (Convertible) (929 ) (931 ) (1,858 ) (1,862 ) Income/(loss) attributable to common stockholders - basic $ 17,017 $ 85,924 $ 26,481 $ 158,815 Dilutive distributions to preferred stockholders - Series E (Convertible) — 931 — — Income/(loss) attributable to common stockholders - diluted $ 17,017 $ 86,855 $ 26,481 $ 158,815 Denominator for income/(loss) per share: Weighted average common shares outstanding 267,113 259,028 265,234 258,567 Non-vested restricted stock awards (845 ) (1,179 ) (872 ) (1,223 ) Denominator for basic income/(loss) per share 266,268 257,849 264,362 257,344 Incremental shares issuable from assumed conversion of stock options, unvested LTIP Units, and unvested restricted stock 1,906 4,957 1,865 1,923 Denominator for diluted income/(loss) per share 268,174 262,806 266,227 259,267 Income/(loss) per weighted average common share: Basic $ 0.06 $ 0.33 $ 0.10 $ 0.62 Diluted $ 0.06 $ 0.33 $ 0.10 $ 0.61 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 and six months ended June 30, 2016 and the six months ended June 30, 2015 , the Company's Series E preferred stock was anti-dilutive. For the three months ended June 30, 2015 , the Company's Series E preferred stock was dilutive for purposes of calculating earnings per share. The following table sets forth the additional shares of common stock outstanding by equity instrument if converted to common stock for each of the three and six months ended June 30, 2016 and 2015 (shares in thousands) : Three Months Ended Six Months Ended June 30, June 30, 2016 2015 2016 2015 OP/DownREIT Units 25,190 9,125 25,191 9,145 Preferred stock 3,028 3,036 3,028 3,036 Stock options, unvested LTIP Units and unvested restricted stock 1,906 1,921 1,865 1,923

Noncontrolling Interests

Noncontrolling Interests	6 Months Ended
	Jun. 30, 2016
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 and DownREIT Units outside of permanent equity and reports the OP Units and 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, 2015 $ 946,436 Mark-to-market adjustment to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (3,192 ) Conversion of OP Units to Common Stock (81 ) Net income/(loss) attributable to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership 2,515 Distributions to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (15,093 ) Allocation of other comprehensive income/(loss) (600 ) Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership, June 30, 2016 $ 929,985 The following sets forth net income/(loss) attributable to common stockholders and transfers from redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership for the following periods (dollars in thousands) : Three Months Ended Six Months Ended June 30, June 30, 2016 2015 2016 2015 Net income/(loss) attributable to common stockholders $ 17,017 $ 85,924 $ 26,481 $ 158,815 Conversion of OP Units and DownREIT Units to UDR Common stock 81 3,479 81 3,498 Change in equity from net income/(loss) attributable to common stockholders and conversion of OP Units and DownREIT Units to UDR Common Stock $ 17,098 $ 89,403 $ 26,562 $ 162,313 Noncontrolling Interests Noncontrolling interests represent interests of unrelated partners and unvested LTIP Units in certain consolidated affiliates. Net (income)/loss attributable to noncontrolling interests was less than $(0.1) million and zero during the three months ended June 30, 2016 and 2015 , respectively, and $(0.3) million and less than $(0.1) million during the six months ended June 30, 2016 and 2015 , respectively

Related Party Transactions (UNI

Related Party Transactions (UNITED DOMINION REALTY, L.P.)	6 Months Ended
	Jun. 30, 2016
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
RELATED PARTY TRANSACTIONS	RELATED PARTY TRANSACTIONS Advances (To)/From the General Partner The Operating Partnership participates in the General Partner’s central cash management program, wherein all the Operating Partnership’s cash receipts are remitted to the General Partner and all cash disbursements are funded by the General Partner. In addition, other miscellaneous costs such as administrative expenses are incurred by the General Partner on behalf of the Operating Partnership. As a result of these various transactions between the Operating Partnership and the General Partner, the Operating Partnership had net Advances (to)/from General Partner of $26.9 million and $(11.3) million at June 30, 2016 and December 31, 2015 , respectively, which are reflected as decreases of capital on the Consolidated Balance Sheets. Allocation of General and Administrative Expenses The General Partner provides various general and administrative and other overhead services for the Operating Partnership including legal assistance, acquisitions analysis, marketing and advertising, and allocates these expenses to the Operating Partnership first on the basis of direct usage when identifiable, with the remainder allocated based on its pro-rata portion of UDR’s total apartment homes. The general and administrative expenses allocated to the Operating Partnership by UDR were $2.9 million and $5.7 million during the three months ended June 30, 2016 and 2015 , respectively, and $7.5 million and $9.9 million during the six months ended June 30, 2016 and 2015 , 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 June 30, 2016 and 2015 , the Operating Partnership incurred $3.7 million and $4.3 million , respectively, and during the six months ended June 30, 2016 and 2015 , the Operating Partnership incurred $7.3 million and $8.6 million , respectively, of related party management fees related to a management agreement entered into in 2011 with wholly-owned subsidiaries of UDR's taxable REIT subsidiaries ("TRS") (See further discussion in paragraph below). These related party management fees are initially recorded in General and administrative on the Consolidated Statements of Operations, and a portion related to management fees charged by UDR's TRS is reclassified to Property management on the Consolidated Statements of Operations. (See further discussion below.) Management Fee In 2011, the Operating Partnership entered into a management agreement with wholly owned subsidiaries of UDR's TRSs. Under the management agreement, the Operating Partnership is charged a management fee equal to 2.75% of gross rental revenues, which is classified in Property management on the Consolidated Statements of Operations. Notes Payable to General Partner As of June 30, 2016 and December 31, 2015 , 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 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 $1.2 million during the three months ended June 30, 2016 and 2015 , respectively, and $6.1 million and $2.3 million during the six months ended June 30, 2016 and 2015 , respectively.

Fair Value of Derivatives and F

Fair Value of Derivatives and Financial Instruments	6 Months Ended
	Jun. 30, 2016
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 June 30, 2016 and December 31, 2015 are summarized as follows (dollars in thousands) : Fair Value at June 30, 2016, Using Total Carrying Amount in Statement of Financial Position at June 30, 2016 Fair Value Estimate at June 30, 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) $ 19,694 $ 19,501 $ — $ — $ 19,501 Derivatives - Interest rate contracts (b) 3 3 — 3 — Total assets $ 19,697 $ 19,504 $ — $ 3 $ 19,501 Derivatives - Interest rate contracts (b) $ 3,554 $ 3,554 $ — $ 3,554 $ — Secured debt instruments - fixed rate: (c) Mortgage notes payable 322,689 340,060 — — 340,060 Fannie Mae credit facilities 512,584 542,250 — — 542,250 Secured debt instruments - variable rate: (c) Mortgage notes payable 31,337 31,337 — — 31,337 Tax-exempt secured notes payable 94,700 94,700 — — 94,700 Fannie Mae credit facilities 299,378 299,378 — — 299,378 Unsecured debt instruments: (c) Commercial bank 259,199 259,199 — — 259,199 Senior unsecured notes 1,961,355 2,096,376 — — 2,096,376 Total liabilities $ 3,484,796 $ 3,666,854 $ — $ 3,554 $ 3,663,300 Redeemable noncontrolling interests in the Operating Partnership and DownREIT Parthership (d) $ 929,985 $ 929,985 $ — $ 929,985 $ — Fair Value at December 31, 2015, Using Total Carrying Amount in Statement of Financial Position at December 31, 2015 Fair Value Estimate at December 31, 2015 Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Description: Notes receivable (a) $ 16,694 $ 16,938 $ — $ — $ 16,938 Derivatives - Interest rate contracts (b) 13 13 — 13 — Total assets $ 16,707 $ 16,951 $ — $ 13 $ 16,938 Derivatives- Interest rate contracts (b) $ 2,112 $ 2,112 $ — $ 2,112 $ — Secured debt instruments - fixed rate: (c) Mortgage notes payable 442,617 448,019 — — 448,019 Fannie Mae credit facilities 514,462 539,050 — — 539,050 Secured debt instruments - variable rate: (c) Mortgage notes payable 31,337 31,337 — — 31,337 Tax-exempt secured notes payable 94,700 94,700 — — 94,700 Fannie Mae credit facilities 299,378 299,378 — — 299,378 Unsecured debt instruments: (c) Commercial bank 150,000 150,000 — — 150,000 Senior unsecured notes 2,056,223 2,108,687 — — 2,108,687 Total liabilities $ 3,590,829 $ 3,673,283 $ — $ 2,112 $ 3,671,171 Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (d) $ 946,436 $ 946,436 $ — $ 946,436 $ — (a) See Note 2, Significant Accounting Policies. (b) See Note 10, Derivatives and Hedging Activity. (c) See Note 6, Secured and Unsecured Debt, Net. (d) See Note 8, Noncontrolling Interests. There were no transfers into or out of each of the levels of the fair value hierarchy. Financial Instruments Carried at Fair Value The fair values of interest rate swaps are determined using the market standard methodology of netting the discounted future fixed cash receipts (or payments) and the discounted expected variable cash payments (or receipts). The variable cash payments (or receipts) are based on an expectation of future interest rates (forward curves) derived from observable market interest rate curves. The fair values of interest rate options are determined using the market standard methodology of discounting the future expected cash receipts that would occur if variable interest rates rise above the strike rate of the caps. The variable interest rates used in the calculation of projected receipts on the cap are based on an expectation of future interest rates derived from observable market interest rate curves and volatilities. The Company incorporates credit valuation adjustments to appropriately reflect both its own nonperformance risk and the respective counterparty’s nonperformance risk in the fair value measurements. In adjusting the fair value of its derivative contracts for the effect of nonperformance risk, the Company has considered the impact of netting and any applicable credit enhancements, such as collateral postings, thresholds, mutual puts, and guarantees. Although the Company has determined that the majority of the inputs used to value its derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with its derivatives utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by itself and its counterparties. However, as of June 30, 2016 and December 31, 2015 , 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 June 30, 2016 and December 31, 2015 , the fair values of cash and cash equivalents, restricted cash, accounts receivable, prepaids, real estate taxes payable, accrued interest payable, security deposits and prepaid rent, distributions payable and accounts payable approximated their carrying values because of the short term nature of these instruments. The estimated fair values of other financial instruments were determined by the Company using available market information and appropriate valuation methodologies. Considerable judgment is necessary to interpret market data and develop estimated fair values. Accordingly, the estimates presented herein are not necessarily indicative of the amounts the Company would realize on the disposition of the financial instruments. The use of different market assumptions or estimation methodologies may have a material effect on the estimated fair value amounts. We estimate the fair value of our notes receivable and debt instruments by discounting the remaining cash flows of the debt instrument at a discount rate equal to the replacement market credit spread plus the corresponding treasury yields. Factors considered in determining a replacement market credit spread include general market conditions, borrower specific credit spreads, time remaining to maturity, loan-to-value ratios and collateral quality, where applicable (Level 3). We record impairment losses on long-lived assets used in operations when events and circumstances indicate that the assets might be impaired and the undiscounted cash flows estimated to be generated by the future operation and disposition of those assets are less than the net book value of those assets. Our cash flow estimates are based upon historical results adjusted to reflect our best estimate of future market and operating conditions and our estimated holding periods. The net book value of impaired assets is reduced to fair value. Our estimates of fair value represent our best estimate based upon Level 3 inputs such as industry trends and reference to market rates and transactions. We consider various factors to determine if a decrease in the value of our investment in and advances to unconsolidated joint ventures, net is other-than-temporary. These factors include, but are not limited to, age of the venture, our intent and ability to retain our investment in the entity, the financial condition and long-term prospects of the entity, and the relationships with the other joint venture partners and its lenders. Based on the significance of the unobservable inputs, we classify these fair value measurements within Level 3 of the valuation hierarchy. The Company did not incur any other-than-temporary decrease in the value of its investments in unconsolidated joint ventures during the three and six months ended June 30, 2016 and 2015 . 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.)	6 Months Ended
	Jun. 30, 2016
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 June 30, 2016 and December 31, 2015 are summarized as follows (dollars in thousands) : Fair Value at June 30, 2016, Using Total Carrying Amount in Statement of Financial Position at June 30, 2016 Fair Value Estimate at June 30, 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) $ 19,694 $ 19,501 $ — $ — $ 19,501 Derivatives - Interest rate contracts (b) 3 3 — 3 — Total assets $ 19,697 $ 19,504 $ — $ 3 $ 19,501 Derivatives - Interest rate contracts (b) $ 3,554 $ 3,554 $ — $ 3,554 $ — Secured debt instruments - fixed rate: (c) Mortgage notes payable 322,689 340,060 — — 340,060 Fannie Mae credit facilities 512,584 542,250 — — 542,250 Secured debt instruments - variable rate: (c) Mortgage notes payable 31,337 31,337 — — 31,337 Tax-exempt secured notes payable 94,700 94,700 — — 94,700 Fannie Mae credit facilities 299,378 299,378 — — 299,378 Unsecured debt instruments: (c) Commercial bank 259,199 259,199 — — 259,199 Senior unsecured notes 1,961,355 2,096,376 — — 2,096,376 Total liabilities $ 3,484,796 $ 3,666,854 $ — $ 3,554 $ 3,663,300 Redeemable noncontrolling interests in the Operating Partnership and DownREIT Parthership (d) $ 929,985 $ 929,985 $ — $ 929,985 $ — Fair Value at December 31, 2015, Using Total Carrying Amount in Statement of Financial Position at December 31, 2015 Fair Value Estimate at December 31, 2015 Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Description: Notes receivable (a) $ 16,694 $ 16,938 $ — $ — $ 16,938 Derivatives - Interest rate contracts (b) 13 13 — 13 — Total assets $ 16,707 $ 16,951 $ — $ 13 $ 16,938 Derivatives- Interest rate contracts (b) $ 2,112 $ 2,112 $ — $ 2,112 $ — Secured debt instruments - fixed rate: (c) Mortgage notes payable 442,617 448,019 — — 448,019 Fannie Mae credit facilities 514,462 539,050 — — 539,050 Secured debt instruments - variable rate: (c) Mortgage notes payable 31,337 31,337 — — 31,337 Tax-exempt secured notes payable 94,700 94,700 — — 94,700 Fannie Mae credit facilities 299,378 299,378 — — 299,378 Unsecured debt instruments: (c) Commercial bank 150,000 150,000 — — 150,000 Senior unsecured notes 2,056,223 2,108,687 — — 2,108,687 Total liabilities $ 3,590,829 $ 3,673,283 $ — $ 2,112 $ 3,671,171 Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (d) $ 946,436 $ 946,436 $ — $ 946,436 $ — (a) See Note 2, Significant Accounting Policies. (b) See Note 10, Derivatives and Hedging Activity. (c) See Note 6, Secured and Unsecured Debt, Net. (d) See Note 8, Noncontrolling Interests. There were no transfers into or out of each of the levels of the fair value hierarchy. Financial Instruments Carried at Fair Value The fair values of interest rate swaps are determined using the market standard methodology of netting the discounted future fixed cash receipts (or payments) and the discounted expected variable cash payments (or receipts). The variable cash payments (or receipts) are based on an expectation of future interest rates (forward curves) derived from observable market interest rate curves. The fair values of interest rate options are determined using the market standard methodology of discounting the future expected cash receipts that would occur if variable interest rates rise above the strike rate of the caps. The variable interest rates used in the calculation of projected receipts on the cap are based on an expectation of future interest rates derived from observable market interest rate curves and volatilities. The Company incorporates credit valuation adjustments to appropriately reflect both its own nonperformance risk and the respective counterparty’s nonperformance risk in the fair value measurements. In adjusting the fair value of its derivative contracts for the effect of nonperformance risk, the Company has considered the impact of netting and any applicable credit enhancements, such as collateral postings, thresholds, mutual puts, and guarantees. Although the Company has determined that the majority of the inputs used to value its derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with its derivatives utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by itself and its counterparties. However, as of June 30, 2016 and December 31, 2015 , 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 June 30, 2016 and December 31, 2015 , the fair values of cash and cash equivalents, restricted cash, accounts receivable, prepaids, real estate taxes payable, accrued interest payable, security deposits and prepaid rent, distributions payable and accounts payable approximated their carrying values because of the short term nature of these instruments. The estimated fair values of other financial instruments were determined by the Company using available market information and appropriate valuation methodologies. Considerable judgment is necessary to interpret market data and develop estimated fair values. Accordingly, the estimates presented herein are not necessarily indicative of the amounts the Company would realize on the disposition of the financial instruments. The use of different market assumptions or estimation methodologies may have a material effect on the estimated fair value amounts. We estimate the fair value of our notes receivable and debt instruments by discounting the remaining cash flows of the debt instrument at a discount rate equal to the replacement market credit spread plus the corresponding treasury yields. Factors considered in determining a replacement market credit spread include general market conditions, borrower specific credit spreads, time remaining to maturity, loan-to-value ratios and collateral quality, where applicable (Level 3). We record impairment losses on long-lived assets used in operations when events and circumstances indicate that the assets might be impaired and the undiscounted cash flows estimated to be generated by the future operation and disposition of those assets are less than the net book value of those assets. Our cash flow estimates are based upon historical results adjusted to reflect our best estimate of future market and operating conditions and our estimated holding periods. The net book value of impaired assets is reduced to fair value. Our estimates of fair value represent our best estimate based upon Level 3 inputs such as industry trends and reference to market rates and transactions. We consider various factors to determine if a decrease in the value of our investment in and advances to unconsolidated joint ventures, net is other-than-temporary. These factors include, but are not limited to, age of the venture, our intent and ability to retain our investment in the entity, the financial condition and long-term prospects of the entity, and the relationships with the other joint venture partners and its lenders. Based on the significance of the unobservable inputs, we classify these fair value measurements within Level 3 of the valuation hierarchy. The Company did not incur any other-than-temporary decrease in the value of its investments in unconsolidated joint ventures during the three and six months ended June 30, 2016 and 2015 . 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 June 30, 2016 and December 31, 2015 are summarized as follows (dollars in thousands) : Fair Value at June 30, 2016, Using Total Carrying Amount in Statement of Financial Position at June 30, 2016 Fair Value Estimate at June 30, 2016 Quoted Prices in Significant Significant Description: Derivatives - Interest rate contracts (a) $ 2 $ 2 $ — $ 2 $ — Total assets $ 2 $ 2 $ — $ 2 $ — Secured debt instruments - fixed rate: (b) Fannie Mae credit facilities $ 250,638 $ 267,526 $ — $ — $ 267,526 Secured debt instruments - variable rate: (b) Tax-exempt secured notes payable 27,000 27,000 — — 27,000 Fannie Mae credit facilities 170,203 170,203 — — 170,203 Total liabilities $ 447,841 $ 464,729 $ — $ — $ 464,729 Fair Value at December 31, 2015, Using Total Carrying Amount in Statement of Financial Position at December 31, 2015 Fair Value Estimate at December 31, 2015 Quoted Prices in Significant Significant Description: Derivatives - Interest rate contracts (a) $ 8 $ 8 $ — $ 8 $ — Total assets $ 8 $ 8 $ — $ 8 $ — Secured debt instruments - fixed rate: (b) Mortgage notes payable $ 30,132 $ 30,308 $ — $ — $ 30,308 Fannie Mae credit facilities 250,828 263,070 — — 263,070 Secured debt instruments - variable rate: (b) Tax-exempt secured notes payable 27,000 27,000 — — 27,000 Fannie Mae credit facilities 170,203 170,203 — — 170,203 Total liabilities $ 478,163 $ 490,581 $ — $ — $ 490,581 (a) See Note 8, Derivatives and Hedging Activity. (b) See Note 5, Debt, Net. 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 June 30, 2016 and December 31, 2015 , 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 June 30, 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 Operating Partnership using available market information and appropriate valuation methodologies. Considerable judgment is necessary to interpret market data and develop estimated fair values. Accordingly, the estimates presented herein are not necessarily indicative of the amounts the Operating Partnership would realize on the disposition of the financial instruments. The use of different market assumptions or estimation methodologies may have a material effect on the estimated fair value amounts. Fair value of our debt instruments is estimated by discounting the remaining cash flows of the debt instrument at a discount rate equal to the replacement market credit spread plus the corresponding treasury yields. Factors considered in determining a replacement market credit spread include general market conditions, borrower specific credit spreads, time remaining to maturity, loan-to-value ratios and collateral quality (Level 3). The Operating Partnership records impairment losses on long-lived assets used in operations when events and circumstances indicate that the assets might be impaired and the undiscounted cash flows estimated to be generated by the future operation and disposition of those assets are less than the net book value of those assets. Cash flow estimates are based upon historical results adjusted to reflect management’s best estimate of future market and operating conditions and our estimated holding periods. The net book value of impaired assets is reduced to fair value. The General Partner’s estimates of fair value represent management’s estimates based upon Level 3 inputs such as industry trends and reference to market rates and transactions.

Derivatives and Hedging Activit

Derivatives and Hedging Activity	6 Months Ended
	Jun. 30, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities Disclosure [Text Block]	DERIVATIVES AND HEDGING ACTIVITY Risk Management Objective of Using Derivatives The Company is exposed to certain risks arising from both its business operations and economic conditions. The Company principally manages its exposures to a wide variety of business and operational risks through management of its core business activities. The Company manages economic risks, including interest rate, liquidity, and credit risk primarily by managing the amount, sources, and duration of its debt funding and through the use of derivative financial instruments. Specifically, the Company may enter into derivative financial instruments to manage exposures that arise from business activities that result in the receipt or payment of future known and uncertain cash amounts, the value of which are determined by interest rates. The Company’s derivative financial instruments are used to manage differences in the amount, timing, and duration of the Company’s known or expected cash receipts and its known or expected cash payments principally related to the Company’s investments and borrowings. Cash Flow Hedges of Interest Rate Risk The Company’s objectives in using interest rate derivatives are to add stability to interest expense and to manage its exposure to interest rate movements. To accomplish this objective, the Company primarily uses interest rate swaps and caps as part of its interest rate risk management strategy. Interest rate swaps designated as cash flow hedges involve the receipt of variable-rate amounts from a counterparty in exchange for the Company making fixed-rate payments over the life of the agreements without exchange of the underlying notional amount. Interest rate caps designated as cash flow hedges involve the receipt of variable-rate amounts from a counterparty if interest rates rise above the strike rate on the contract in exchange for an up-front premium. The effective portion of changes in the fair value of derivatives designated and that qualify as cash flow hedges is recorded in Accumulated other comprehensive income/(loss), net in the Consolidated Balance Sheets and is subsequently reclassified into earnings in the period that the hedged forecasted transaction affects earnings. During the three and six months ended June 30, 2016 and 2015 , 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 and six months ended June 30, 2016 and 2015 , 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 June 30, 2017 , the Company estimates that an additional $3.6 million will be reclassified as an increase to interest expense. As of June 30, 2016 , the Company had the following outstanding interest rate derivatives that were designated as cash flow hedges of interest rate risk ( dollars in thousands ): Interest Rate Derivative Number of Instruments Notional Interest rate swaps (a) 3 $ 315,000 Interest rate caps 2 $ 203,166 (a) The three interest rate swaps noted in the table above mature in January and April 2017. During the second quarter of 2016, the Company entered into four forward starting interest rate swaps, with an aggregate notional amount of $315.0 million , which are effective in January and April 2017 and mature in January 2020. 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 an adjustment to earnings of less than $0.1 million for the three and six months ended June 30, 2016 and 2015 . As of June 30, 2016 , 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 Balance Sheet The tables below present the fair value of the Company’s derivative financial instruments as well as their classification on the Consolidated Balance Sheets as of June 30, 2016 and December 31, 2015 ( dollars in thousands ): Asset Derivatives (included in Other assets ) Liability Derivatives (included in Other liabilities ) Fair Value at: Fair Value at: June 30, December 31, June 30, December 31, Derivatives designated as hedging instruments: Interest rate products $ 2 $ 9 $ 3,554 $ 2,112 Derivatives not designated as hedging instruments: Interest rate products $ 1 $ 4 $ — $ — Tabular Disclosure of the Effect of Derivative Instruments on the Consolidated Statements of Operations The tables below present the effect of the Company’s derivative financial instruments on the Consolidated Statements of Operations for the three and six months ended June 30, 2016 and 2015 ( 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) 2016 2015 2016 2015 2016 2015 Three Months Ended June 30, Interest rate products $ (1,963 ) $ 6,186 $ (943 ) $ (292 ) $ — $ — Six Months Ended June 30, Interest rate products $ (2,774 ) $ (1,366 ) $ (1,878 ) $ (1,029 ) $ — $ — Gain/(Loss) Recognized in Interest income and other income/(expense), net Derivatives Not Designated as Hedging Instruments 2016 2015 Three Months Ended June 30, Interest rate products $ (3 ) $ (22 ) Six Months Ended June 30, Interest rate products $ (3 ) $ (24 ) Credit-risk-related Contingent Features The Company has agreements with some of its derivative counterparties that contain a provision where (1) if the Company defaults on any of its indebtedness, including default where repayment of the indebtedness has not been accelerated by the lender, then the Company could also be declared in default on its derivative obligations; or (2) the Company could be declared in default on its derivative obligations if repayment of the underlying indebtedness is accelerated by the lender due to the Company’s default on the indebtedness. Certain of the Company’s agreements with its derivative counterparties contain provisions where, if there is a change in the Company’s financial condition that materially changes the Company’s creditworthiness in an adverse manner, the Company may be required to fully collateralize its obligations under the derivative instrument. The Company also has an agreement with a derivative counterparty that incorporates the loan and financial covenant provisions of the Company’s indebtedness with a lender affiliate of the derivative counterparty. Failure to comply with these covenant provisions would result in the Company being in default on any derivative instrument obligations covered by the agreement. 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 June 30, 2016 , the fair value of derivatives in a net liability position, which includes accrued interest but excludes any adjustment for nonperformance risk, related to these agreements was $3.8 million . As of June 30, 2016 , the Company has not posted any collateral related to these agreements. If the Company had breached any of these provisions at June 30, 2016 , it may have been required to settle its obligations under the agreements at their termination value of $3.8 million . Tabular Disclosure of Offsetting Derivatives Company has elected not to offset derivative positions in the consolidated financial statements. The tables below present the effect on its financial position had the Company made the election to offset its derivative positions as of June 30, 2016 and December 31, 2015 (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 June 30, 2016 $ 3 $ — $ 3 $ — $ — $ 3 December 31, 2015 $ 13 $ — $ 13 $ — $ — $ 13 (a) Amounts reconcile to the aggregate fair value of derivative assets in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Balance Sheet” located in this footnote. Offsetting of Derivative Liabilities Gross Amounts of Recognized Liabilities Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts of Liabilities Presented in the Consolidated Balance Sheets (a) Gross Amounts Not Offset in the Consolidated Balance Sheets Financial Instruments Cash Collateral Posted Net Amount June 30, 2016 $ 3,554 $ — $ 3,554 $ — $ — $ 3,554 December 31, 2015 $ 2,112 $ — $ 2,112 $ — $ — $ 2,112 (a) Amounts reconcile to the aggregate fair value of derivative liabilities in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Balance Sheet” located in this footnote.

Derivatives and Hedging Activ33

Derivatives and Hedging Activity (UNITED DOMINION REALTY, L.P.)	6 Months Ended
	Jun. 30, 2016
Entity Information [Line Items]
DERIVATIVES AND HEDGING ACTIVITY	DERIVATIVES AND HEDGING ACTIVITY Risk Management Objective of Using Derivatives The Company is exposed to certain risks arising from both its business operations and economic conditions. The Company principally manages its exposures to a wide variety of business and operational risks through management of its core business activities. The Company manages economic risks, including interest rate, liquidity, and credit risk primarily by managing the amount, sources, and duration of its debt funding and through the use of derivative financial instruments. Specifically, the Company may enter into derivative financial instruments to manage exposures that arise from business activities that result in the receipt or payment of future known and uncertain cash amounts, the value of which are determined by interest rates. The Company’s derivative financial instruments are used to manage differences in the amount, timing, and duration of the Company’s known or expected cash receipts and its known or expected cash payments principally related to the Company’s investments and borrowings. Cash Flow Hedges of Interest Rate Risk The Company’s objectives in using interest rate derivatives are to add stability to interest expense and to manage its exposure to interest rate movements. To accomplish this objective, the Company primarily uses interest rate swaps and caps as part of its interest rate risk management strategy. Interest rate swaps designated as cash flow hedges involve the receipt of variable-rate amounts from a counterparty in exchange for the Company making fixed-rate payments over the life of the agreements without exchange of the underlying notional amount. Interest rate caps designated as cash flow hedges involve the receipt of variable-rate amounts from a counterparty if interest rates rise above the strike rate on the contract in exchange for an up-front premium. The effective portion of changes in the fair value of derivatives designated and that qualify as cash flow hedges is recorded in Accumulated other comprehensive income/(loss), net in the Consolidated Balance Sheets and is subsequently reclassified into earnings in the period that the hedged forecasted transaction affects earnings. During the three and six months ended June 30, 2016 and 2015 , 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 and six months ended June 30, 2016 and 2015 , 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 June 30, 2017 , the Company estimates that an additional $3.6 million will be reclassified as an increase to interest expense. As of June 30, 2016 , the Company had the following outstanding interest rate derivatives that were designated as cash flow hedges of interest rate risk ( dollars in thousands ): Interest Rate Derivative Number of Instruments Notional Interest rate swaps (a) 3 $ 315,000 Interest rate caps 2 $ 203,166 (a) The three interest rate swaps noted in the table above mature in January and April 2017. During the second quarter of 2016, the Company entered into four forward starting interest rate swaps, with an aggregate notional amount of $315.0 million , which are effective in January and April 2017 and mature in January 2020. 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 an adjustment to earnings of less than $0.1 million for the three and six months ended June 30, 2016 and 2015 . As of June 30, 2016 , 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 Balance Sheet The tables below present the fair value of the Company’s derivative financial instruments as well as their classification on the Consolidated Balance Sheets as of June 30, 2016 and December 31, 2015 ( dollars in thousands ): Asset Derivatives (included in Other assets ) Liability Derivatives (included in Other liabilities ) Fair Value at: Fair Value at: June 30, December 31, June 30, December 31, Derivatives designated as hedging instruments: Interest rate products $ 2 $ 9 $ 3,554 $ 2,112 Derivatives not designated as hedging instruments: Interest rate products $ 1 $ 4 $ — $ — Tabular Disclosure of the Effect of Derivative Instruments on the Consolidated Statements of Operations The tables below present the effect of the Company’s derivative financial instruments on the Consolidated Statements of Operations for the three and six months ended June 30, 2016 and 2015 ( 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) 2016 2015 2016 2015 2016 2015 Three Months Ended June 30, Interest rate products $ (1,963 ) $ 6,186 $ (943 ) $ (292 ) $ — $ — Six Months Ended June 30, Interest rate products $ (2,774 ) $ (1,366 ) $ (1,878 ) $ (1,029 ) $ — $ — Gain/(Loss) Recognized in Interest income and other income/(expense), net Derivatives Not Designated as Hedging Instruments 2016 2015 Three Months Ended June 30, Interest rate products $ (3 ) $ (22 ) Six Months Ended June 30, Interest rate products $ (3 ) $ (24 ) Credit-risk-related Contingent Features The Company has agreements with some of its derivative counterparties that contain a provision where (1) if the Company defaults on any of its indebtedness, including default where repayment of the indebtedness has not been accelerated by the lender, then the Company could also be declared in default on its derivative obligations; or (2) the Company could be declared in default on its derivative obligations if repayment of the underlying indebtedness is accelerated by the lender due to the Company’s default on the indebtedness. Certain of the Company’s agreements with its derivative counterparties contain provisions where, if there is a change in the Company’s financial condition that materially changes the Company’s creditworthiness in an adverse manner, the Company may be required to fully collateralize its obligations under the derivative instrument. The Company also has an agreement with a derivative counterparty that incorporates the loan and financial covenant provisions of the Company’s indebtedness with a lender affiliate of the derivative counterparty. Failure to comply with these covenant provisions would result in the Company being in default on any derivative instrument obligations covered by the agreement. 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 June 30, 2016 , the fair value of derivatives in a net liability position, which includes accrued interest but excludes any adjustment for nonperformance risk, related to these agreements was $3.8 million . As of June 30, 2016 , the Company has not posted any collateral related to these agreements. If the Company had breached any of these provisions at June 30, 2016 , it may have been required to settle its obligations under the agreements at their termination value of $3.8 million . Tabular Disclosure of Offsetting Derivatives Company has elected not to offset derivative positions in the consolidated financial statements. The tables below present the effect on its financial position had the Company made the election to offset its derivative positions as of June 30, 2016 and December 31, 2015 (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 June 30, 2016 $ 3 $ — $ 3 $ — $ — $ 3 December 31, 2015 $ 13 $ — $ 13 $ — $ — $ 13 (a) Amounts reconcile to the aggregate fair value of derivative assets in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Balance Sheet” located in this footnote. Offsetting of Derivative Liabilities Gross Amounts of Recognized Liabilities Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts of Liabilities Presented in the Consolidated Balance Sheets (a) Gross Amounts Not Offset in the Consolidated Balance Sheets Financial Instruments Cash Collateral Posted Net Amount June 30, 2016 $ 3,554 $ — $ 3,554 $ — $ — $ 3,554 December 31, 2015 $ 2,112 $ — $ 2,112 $ — $ — $ 2,112 (a) Amounts reconcile to the aggregate fair value of derivative liabilities in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Balance Sheet” located in this footnote.
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
DERIVATIVES AND HEDGING ACTIVITY	DERIVATIVES AND HEDGING ACTIVITY Risk Management Objective of Using Derivatives The Operating Partnership is exposed to certain risks arising from both its business operations and economic conditions. The General Partner principally manages its exposures to a wide variety of business and operational risks through management of its core business activities. The General Partner manages economic risks, including interest rate, liquidity, and credit risk primarily by managing the amount, sources, and duration of its debt funding and through the use of derivative financial instruments. Specifically, the General Partner enters into derivative financial instruments to manage exposures that arise from business activities that result in the receipt or payment of future known and uncertain cash amounts, the value of which are determined by interest rates. The General Partner’s and the Operating Partnership’s derivative financial instruments are used to manage differences in the amount, timing, and duration of the General Partner’s known or expected cash payments principally related to the General Partner’s borrowings. Cash Flow Hedges of Interest Rate Risk The General Partner’s objectives in using interest rate derivatives are to add stability to interest expense and to manage its exposure to interest rate movements. To accomplish this objective, the General Partner primarily uses interest rate swaps and caps as part of its interest rate risk management strategy. Interest rate swaps designated as cash flow hedges involve the receipt of variable-rate amounts from a counterparty in exchange for the General Partner making fixed-rate payments over the life of the agreements without exchange of the underlying notional amount. Interest rate caps designated as cash flow hedges involve the receipt of variable-rate amounts from a counterparty if interest rates rise above the strike rate on the contract in exchange for an up front premium. A portion of the General Partner’s interest rate derivatives have been allocated to the Operating Partnership based on the General Partner’s underlying debt instruments allocated to the Operating Partnership. (See Note 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 and six months ended June 30, 2016 and 2015 , 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. The Operating Partnership recorded no gain or loss from ineffectiveness during the three and six months ended June 30, 2016 and 2015 . Amounts reported in Accumulated other comprehensive income/(loss), net related to derivatives will be reclassified to interest expense as interest payments are made on the General Partner’s variable-rate debt that is allocated to the Operating Partnership. Through June 30, 2017 , we estimate that less than $0.1 million will be reclassified as an increase to interest expense. As of June 30, 2016 , the Operating Partnership had the following outstanding interest rate derivatives designated as cash flow hedges of interest rate risk ( dollars in thousands ): Interest Rate Derivative Number of Instruments Notional Interest rate caps 1 $ 96,327 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 and six months ended June 30, 2016 and 2015 . As of June 30, 2016 , 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 $ 98,932 Tabular Disclosure of Fair Values of Derivative Instruments on the Balance Sheet The table below presents the fair value of the Operating Partnership’s derivative financial instruments as well as their classification on the Consolidated Balance Sheets as of June 30, 2016 and December 31, 2015 ( dollars in thousands ): Asset Derivatives (included in Other assets ) Liability Derivatives (included in Other liabilities ) Fair Value at: Fair Value at: June 30, December 31, June 30, December 31, Derivatives designated as hedging instruments: Interest rate products $ 1 $ 4 $ — $ — Derivatives not designated as hedging instruments: Interest rate products $ 1 $ 4 $ — $ — Tabular Disclosure of the Effect of Derivative Instruments on the Consolidated Statements of Operations The tables below present the effect of the derivative financial instruments on the Consolidated Statements of Operations for the three and six months ended June 30, 2016 and 2015 ( 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 2016 2015 2016 2015 2016 2015 Three Months Ended June 30, Interest rate products $ (1 ) $ (26 ) $ (2 ) $ (267 ) $ — $ — Six Months Ended June 30, Interest rate products $ (3 ) $ (77 ) $ (3 ) $ (553 ) $ — $ — Gain/(Loss) Recognized in Interest income and other income/(expense), net Derivatives Not Designated as Hedging Instruments 2016 2015 Three Months Ended June 30, Interest rate products $ (3 ) $ (22 ) Six Months Ended June 30, Interest rate products $ (3 ) $ (23 ) 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 June 30, 2016 and December 31, 2015 , 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 June 30, 2016 , the fair value of derivatives in a net liability position that were allocated to the Operating Partnership, which includes accrued interest but excludes any adjustment for nonperformance risk, related to these agreements was 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 June 30, 2016 and December 31, 2015 : 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 June 30, 2016 $ 2 $ — $ 2 $ — $ — $ 2 December 31, 2015 $ 8 $ — $ 8 $ — $ — $ 8 (a) Amounts reconcile to the aggregate fair value of derivative assets in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Balance Sheet” located in this footnote. Offsetting of Derivative Liabilities Gross Amounts of Recognized Liabilities Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts of Liabilities Presented in the Consolidated Balance Sheets (b) Gross Amounts Not Offset in the Consolidated Balance Sheets Financial Instruments Cash Collateral Posted Net Amount June 30, 2016 $ — $ — $ — $ — $ — $ — December 31, 2015 $ — $ — $ — $ — $ — $ — (b) Amounts reconcile to the aggregate fair value of derivative liabilities in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Balance Sheet” located in this footnote.

Stock Based Compensation

Stock Based Compensation	6 Months Ended
	Jun. 30, 2016
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 $3.2 million and $4.8 million for the three months ended June 30, 2016 and 2015 , respectively, and $7.1 million and $9.1 million during the six months ended June 30, 2016 and 2015 , respectively.

Capital Structure (UNITED DOMIN

Capital Structure (UNITED DOMINION REALTY, L.P.)	6 Months Ended
	Jun. 30, 2016
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 June 30, 2016 and December 31, 2015 , all of which were held by UDR. Limited Partnership Units As of June 30, 2016 and December 31, 2015 , there were 183,167,815 limited partnership units outstanding, of which 1,873,332 were Class A Limited Partnership Units. UDR owned 174,116,596 , or 95.1% , of OP Units outstanding at June 30, 2016 and December 31, 2015 , of which 121,661 were Class A Limited Partnership Units. The remaining 9,051,219 , or 4.9% , of OP Units outstanding were held by non-affiliated partners at June 30, 2016 and December 31, 2015 , 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 $334.2 million and $340.1 million as of June 30, 2016 and December 31, 2015 , respectively, based on the value of UDR’s common stock at each period end. A limited partner has no right to receive any distributions from the Operating Partnership on or after the date of redemption of its OP Units. Class A Limited Partnership Units Class A Limited Partnership Units have a cumulative, annual, non-compounded preferred return, which is equal to 8% based on a value of $16.61 per Class A Limited Partnership Unit. Holders of the Class A Limited Partnership Units exclusively possess certain voting rights. The Operating Partnership may not do the following without approval of the holders of the Class A Limited Partnership Units: (i) increase the authorized or issued amount of Class A Limited Partnership Units, (ii) reclassify any other partnership interest into Class A Limited Partnership Units, (iii) create, authorize or issue any obligations or security convertible into or the right to purchase any Class A Limited Partnership units, (iv) enter into a merger or acquisition, or (v) amend or modify the Operating Partnership Agreement in a manner that adversely affects the relative rights, preferences or privileges of the Class A Limited Partnership Units. 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	6 Months Ended
	Jun. 30, 2016
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 June 30, 2016 ( dollars in thousands ): Number of Properties Costs Incurred to Date (a) Expected Costs to Complete Average Ownership Stake Wholly-owned — under development 2 $ 238,938 (b) $ 469,562 100 % Wholly-owned — redevelopment 4 20,752 (b) 24,648 100 % Joint ventures: Unconsolidated joint ventures 5 614,300 88,086 (c) 50 % Participating loan investments 1 93,902 (d) — 0 % Preferred equity investments 2 57,874 (e) — 48 % $ 1,025,766 $ 582,296 (a) Represents 100% of project costs incurred as of June 30, 2016 . (b) Costs incurred to date include $28.4 million and $5.1 million of accrued fixed assets for development and redevelopment, respectively. (c) Represents UDR’s proportionate share of expected remaining costs to complete. (d) Represents the participating loan balance funded as of June 30, 2016 . (e) Represents UDR's upfront investment contributed to the West Coast Development Joint Venture for the properties under development as of June 30, 2016 . 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.)	6 Months Ended
	Jun. 30, 2016
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 June 30, 2016 ( dollars in thousands ): Number of Properties Costs Incurred to Date (a) Expected Costs to Complete Average Ownership Stake Wholly-owned — under development 2 $ 238,938 (b) $ 469,562 100 % Wholly-owned — redevelopment 4 20,752 (b) 24,648 100 % Joint ventures: Unconsolidated joint ventures 5 614,300 88,086 (c) 50 % Participating loan investments 1 93,902 (d) — 0 % Preferred equity investments 2 57,874 (e) — 48 % $ 1,025,766 $ 582,296 (a) Represents 100% of project costs incurred as of June 30, 2016 . (b) Costs incurred to date include $28.4 million and $5.1 million of accrued fixed assets for development and redevelopment, respectively. (c) Represents UDR’s proportionate share of expected remaining costs to complete. (d) Represents the participating loan balance funded as of June 30, 2016 . (e) Represents UDR's upfront investment contributed to the West Coast Development Joint Venture for the properties under development as of June 30, 2016 . Contingencies Litigation and Legal Matters The Company is subject to various legal proceedings and claims arising in the ordinary course of business. The Company cannot determine the ultimate liability with respect to such legal proceedings and claims at this time. The Company believes that such liability, to the extent not provided for through insurance or otherwise, will not have a material adverse effect on our financial condition, results of operations or cash flow.
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Commitments Real Estate Under Development The following summarizes the Operating Partnership’s real estate commitments at June 30, 2016 ( dollars in thousands ): Number of Properties Costs Incurred to Date (a) Expected Costs to Complete (unaudited) Real estate communities — redevelopment 2 $ 14,351 $ 18,649 (a) Costs incurred to date include $3.3 million of accrued fixed assets for redevelopment. Contingencies Litigation and Legal Matters The Operating Partnership is subject to various legal proceedings and claims arising in the ordinary course of business. The Operating Partnership cannot determine the ultimate liability with respect to such legal proceedings and claims at this time. The General Partner believes that such liability, to the extent not provided for through insurance or otherwise, will not have a material adverse effect on the Operating Partnership’s financial condition, results of operations or cash flow.

Reportable Segments

Reportable Segments	6 Months Ended
	Jun. 30, 2016
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 April 1, 2015 for quarter-to-date comparison and January 1, 2015 for year-to-date comparison and held as of June 30, 2016 . A comparison of operating results from the prior year is meaningful as these communities were owned and had stabilized occupancy and operating expenses as of the beginning of the prior period, there is no plan to conduct substantial redevelopment activities, and the community is not held for disposition within the current year. A community is considered to have stabilized occupancy once it achieves 90% occupancy for at least three consecutive months. • Non-Mature Communities/Other represent those communities that do not meet the criteria to be included in Same-Store Communities , including, but not limited to, recently acquired, developed and redeveloped properties, and the non-apartment components of mixed use properties. Management evaluates the performance of each of our apartment communities on a Same-Store Community and Non-Mature Community/Other basis, as well as individually and geographically. This is consistent with the aggregation criteria under GAAP as each of our apartment communities generally has similar economic characteristics, facilities, services, and tenants. Therefore, the Company’s reportable segments have been aggregated by geography in a manner identical to that which is provided to the chief operating decision maker. All revenues are from external customers and no single tenant or related group of tenants contributed 10% or more of UDR’s total revenues during the three and six months ended June 30, 2016 and 2015 . The following table details rental income and NOI for UDR’s reportable segments for the three and six months ended June 30, 2016 and 2015 , and reconciles NOI to Net Income/(Loss) Attributable to UDR, Inc . in the Consolidated Statements of Operations (dollars in thousands) : Three Months Ended Six Months Ended June 30, (a) June 30, (b) 2016 2015 2016 2015 Reportable apartment home segment rental income Same-Store Communities West Region $ 75,060 $ 69,510 $ 147,423 $ 135,777 Mid-Atlantic Region 41,706 41,041 82,910 81,418 Northeast Region 32,490 30,935 64,560 61,230 Southeast Region 27,702 25,844 54,839 51,126 Southwest Region 13,285 12,697 26,428 25,171 Non-Mature Communities/Other 45,925 32,737 91,965 65,089 Total consolidated rental income $ 236,168 $ 212,764 $ 468,125 $ 419,811 Reportable apartment home segment NOI Same-Store Communities West Region $ 55,265 $ 51,781 $ 109,541 $ 100,718 Mid-Atlantic Region 29,301 28,456 57,357 55,989 Northeast Region 23,677 22,408 46,609 43,941 Southeast Region 19,081 17,426 37,877 34,312 Southwest Region 8,187 8,078 16,415 15,702 Non-Mature Communities/Other 31,804 22,283 63,650 43,345 Total consolidated NOI 167,315 150,432 331,449 294,007 Reconciling items: Joint venture management and other fees 2,618 3,098 5,476 15,804 Property management (6,494 ) (5,851 ) (12,873 ) (11,545 ) Other operating expenses (1,892 ) (1,769 ) (3,644 ) (3,535 ) Real estate depreciation and amortization (105,937 ) (90,344 ) (211,276 ) (179,121 ) General and administrative (10,835 ) (13,721 ) (24,679 ) (25,873 ) Casualty-related recoveries/(charges), net (1,629 ) (843 ) (1,629 ) (1,839 ) Other depreciation and amortization (1,486 ) (1,700 ) (3,039 ) (3,323 ) Income/(loss) from unconsolidated entities 325 (573 ) 1,004 58,586 Interest expense (30,678 ) (29,673 ) (61,782 ) (58,473 ) Interest income and other income/(expense), net 540 382 971 742 Tax benefit/(provision), net 402 1,404 805 1,829 Gain/(loss) on sale of real estate owned, net of tax 7,315 79,042 10,385 79,042 Net (income)/loss attributable to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (1,610 ) (3,029 ) (2,515 ) (5,617 ) Net (income)/loss attributable to noncontrolling interests (8 ) — (314 ) (7 ) Net income/(loss) attributable to UDR, Inc. $ 17,946 $ 86,855 $ 28,339 $ 160,677 (a) Same-Store Community population consisted of 34,179 apartment homes. (b) Same-Store Community population consisted of 34,017 apartment homes. The following table details the assets of UDR’s reportable segments as of June 30, 2016 and December 31, 2015 (dollars in thousands) : June 30, December 31, Reportable apartment home segment assets: Same-Store Communities: West Region $ 2,778,642 $ 2,766,939 Mid-Atlantic Region 1,532,799 1,522,868 Northeast Region 1,629,365 1,621,555 Southeast Region 737,292 730,060 Southwest Region 387,874 384,487 Non-Mature Communities/Other 2,246,440 2,164,367 Total segment assets 9,312,412 9,190,276 Accumulated depreciation (2,842,273 ) (2,646,874 ) Total segment assets — net book value 6,470,139 6,543,402 Reconciling items: Cash and cash equivalents 5,167 6,742 Restricted cash 20,524 20,798 Funds held in escrow from Internal Revenue Code Section 1031 exchanges 34,732 — Notes receivable, net 19,694 16,694 Investment in and advances to unconsolidated joint ventures, net 933,403 938,906 Other assets 126,423 137,302 Total consolidated assets $ 7,610,082 $ 7,663,844 Capital expenditures related to our Same-Store Communities totaled $24.3 million and $18.7 million for the three months ended June 30, 2016 and 2015 , respectively, and $37.5 million and $30.6 million for the six months ended June 30, 2016 and 2015 , respectively. Capital expenditures related to our Non-Mature Communities/Other totaled $1.7 million and $3.2 million for the three months ended June 30, 2016 and 2015 , respectively, and $4.1 million and $7.1 million for the six months ended June 30, 2016 and 2015 , respectively. Markets included in the above geographic segments are as follows: i. West Region — Orange County, San Francisco, Seattle, Los Angeles, Monterey Peninsula, Other Southern California, and Portland ii. Mid-Atlantic Region — Metropolitan D.C., Baltimore, and Richmond 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.)	6 Months Ended
	Jun. 30, 2016
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 April 1, 2015 for quarter-to-date comparison and January 1, 2015 for year-to-date comparison and held as of June 30, 2016 . A comparison of operating results from the prior year is meaningful as these communities were owned and had stabilized occupancy and operating expenses as of the beginning of the prior period, there is no plan to conduct substantial redevelopment activities, and the community is not held for disposition within the current year. A community is considered to have stabilized occupancy once it achieves 90% occupancy for at least three consecutive months. • Non-Mature Communities/Other represent those communities that do not meet the criteria to be included in Same-Store Communities , including, but not limited to, recently acquired, developed and redeveloped properties, and the non-apartment components of mixed use properties. Management evaluates the performance of each of our apartment communities on a Same-Store Community and Non-Mature Community/Other basis, as well as individually and geographically. This is consistent with the aggregation criteria under GAAP as each of our apartment communities generally has similar economic characteristics, facilities, services, and tenants. Therefore, the Company’s reportable segments have been aggregated by geography in a manner identical to that which is provided to the chief operating decision maker. All revenues are from external customers and no single tenant or related group of tenants contributed 10% or more of UDR’s total revenues during the three and six months ended June 30, 2016 and 2015 . The following table details rental income and NOI for UDR’s reportable segments for the three and six months ended June 30, 2016 and 2015 , and reconciles NOI to Net Income/(Loss) Attributable to UDR, Inc . in the Consolidated Statements of Operations (dollars in thousands) : Three Months Ended Six Months Ended June 30, (a) June 30, (b) 2016 2015 2016 2015 Reportable apartment home segment rental income Same-Store Communities West Region $ 75,060 $ 69,510 $ 147,423 $ 135,777 Mid-Atlantic Region 41,706 41,041 82,910 81,418 Northeast Region 32,490 30,935 64,560 61,230 Southeast Region 27,702 25,844 54,839 51,126 Southwest Region 13,285 12,697 26,428 25,171 Non-Mature Communities/Other 45,925 32,737 91,965 65,089 Total consolidated rental income $ 236,168 $ 212,764 $ 468,125 $ 419,811 Reportable apartment home segment NOI Same-Store Communities West Region $ 55,265 $ 51,781 $ 109,541 $ 100,718 Mid-Atlantic Region 29,301 28,456 57,357 55,989 Northeast Region 23,677 22,408 46,609 43,941 Southeast Region 19,081 17,426 37,877 34,312 Southwest Region 8,187 8,078 16,415 15,702 Non-Mature Communities/Other 31,804 22,283 63,650 43,345 Total consolidated NOI 167,315 150,432 331,449 294,007 Reconciling items: Joint venture management and other fees 2,618 3,098 5,476 15,804 Property management (6,494 ) (5,851 ) (12,873 ) (11,545 ) Other operating expenses (1,892 ) (1,769 ) (3,644 ) (3,535 ) Real estate depreciation and amortization (105,937 ) (90,344 ) (211,276 ) (179,121 ) General and administrative (10,835 ) (13,721 ) (24,679 ) (25,873 ) Casualty-related recoveries/(charges), net (1,629 ) (843 ) (1,629 ) (1,839 ) Other depreciation and amortization (1,486 ) (1,700 ) (3,039 ) (3,323 ) Income/(loss) from unconsolidated entities 325 (573 ) 1,004 58,586 Interest expense (30,678 ) (29,673 ) (61,782 ) (58,473 ) Interest income and other income/(expense), net 540 382 971 742 Tax benefit/(provision), net 402 1,404 805 1,829 Gain/(loss) on sale of real estate owned, net of tax 7,315 79,042 10,385 79,042 Net (income)/loss attributable to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (1,610 ) (3,029 ) (2,515 ) (5,617 ) Net (income)/loss attributable to noncontrolling interests (8 ) — (314 ) (7 ) Net income/(loss) attributable to UDR, Inc. $ 17,946 $ 86,855 $ 28,339 $ 160,677 (a) Same-Store Community population consisted of 34,179 apartment homes. (b) Same-Store Community population consisted of 34,017 apartment homes. The following table details the assets of UDR’s reportable segments as of June 30, 2016 and December 31, 2015 (dollars in thousands) : June 30, December 31, Reportable apartment home segment assets: Same-Store Communities: West Region $ 2,778,642 $ 2,766,939 Mid-Atlantic Region 1,532,799 1,522,868 Northeast Region 1,629,365 1,621,555 Southeast Region 737,292 730,060 Southwest Region 387,874 384,487 Non-Mature Communities/Other 2,246,440 2,164,367 Total segment assets 9,312,412 9,190,276 Accumulated depreciation (2,842,273 ) (2,646,874 ) Total segment assets — net book value 6,470,139 6,543,402 Reconciling items: Cash and cash equivalents 5,167 6,742 Restricted cash 20,524 20,798 Funds held in escrow from Internal Revenue Code Section 1031 exchanges 34,732 — Notes receivable, net 19,694 16,694 Investment in and advances to unconsolidated joint ventures, net 933,403 938,906 Other assets 126,423 137,302 Total consolidated assets $ 7,610,082 $ 7,663,844 Capital expenditures related to our Same-Store Communities totaled $24.3 million and $18.7 million for the three months ended June 30, 2016 and 2015 , respectively, and $37.5 million and $30.6 million for the six months ended June 30, 2016 and 2015 , respectively. Capital expenditures related to our Non-Mature Communities/Other totaled $1.7 million and $3.2 million for the three months ended June 30, 2016 and 2015 , respectively, and $4.1 million and $7.1 million for the six months ended June 30, 2016 and 2015 , respectively. Markets included in the above geographic segments are as follows: i. West Region — Orange County, San Francisco, Seattle, Los Angeles, Monterey Peninsula, Other Southern California, and Portland ii. Mid-Atlantic Region — Metropolitan D.C., Baltimore, and Richmond 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 is property management expense which is calculated as 2.75% of property revenue to cover the regional supervision and accounting costs related to consolidated property operations, and land rent. The chief operating decision maker of the General Partner utilizes NOI as the key measure of segment profit or loss. The Operating Partnership’s two reportable segments are Same-Store Communities and Non-Mature Communities/Other: • Same-Store Communities represent those communities acquired, developed, and stabilized prior to April 1, 2015 for quarter-to-date comparison and January 1, 2015 for the year-to-date comparison and held as of June 30, 2016 . A comparison of operating results from the prior year is meaningful as these communities were owned and had stabilized occupancy and operating expenses as of the beginning of the prior period, there is no plan to conduct substantial redevelopment activities, and the community is not held for disposition within the current year. A community is considered to have stabilized occupancy once it achieves 90% occupancy for at least three consecutive months. • Non-Mature Communities/Other represent those communities that do not meet the criteria to be included in Same-Store Communities , including, but not limited to, recently acquired, developed and redeveloped properties, and the non-apartment components of mixed use properties. Management of the General Partner evaluates the performance of each of the Operating Partnership’s apartment communities on a Same-Store Community and Non-Mature Community/Other basis, as well as individually and geographically. This is consistent with the aggregation criteria under GAAP as each of the apartment communities generally has similar economic characteristics, facilities, services, and tenants. Therefore, the Operating Partnership’s reportable segments have been aggregated by geography in a manner identical to that which is provided to the chief operating decision maker. All revenues are from external customers and no single tenant or related group of tenants contributed 10% or more of the Operating Partnership’s total revenues during the three and six months ended June 30, 2016 and 2015 . The following table details rental income and NOI for the Operating Partnership’s reportable segments for the three and six months ended June 30, 2016 and 2015 , and reconciles NOI to Net income/(loss) attributable to OP unitholders in the Consolidated Statements of Operations (dollars in thousands) : Three Months Ended Six Months Ended June 30, (a) June 30, (b) 2016 2015 2016 2015 Reportable apartment home segment rental income Same-Store Communities West Region $ 45,493 $ 41,715 $ 90,095 $ 82,451 Mid-Atlantic Region 10,805 10,554 21,455 20,882 Northeast Region 13,203 12,784 26,209 25,173 Southeast Region 11,918 11,175 23,615 22,172 Non-Mature Communities/Other 19,473 36,930 38,304 72,575 Total consolidated rental income $ 100,892 $ 113,158 $ 199,678 $ 223,253 Reportable apartment home segment NOI Same-Store Communities West Region $ 34,203 $ 31,481 $ 67,830 $ 61,598 Mid-Atlantic Region 7,479 7,294 14,704 14,310 Northeast Region 10,406 9,972 20,463 19,657 Southeast Region 8,165 7,488 16,208 14,755 Non-Mature Communities/Other 14,405 26,048 28,005 50,078 Total consolidated NOI 74,658 82,283 147,210 160,398 Reconciling items: Property management (2,775 ) (3,112 ) (5,492 ) (6,139 ) Other operating expenses (1,519 ) (1,496 ) (3,019 ) (2,986 ) Real estate depreciation and amortization (37,053 ) (44,100 ) (73,844 ) (88,578 ) General and administrative (3,844 ) (7,032 ) (9,265 ) (12,671 ) Casualty-related recoveries/(charges), net (465 ) (280 ) (465 ) (873 ) Income/(loss) from unconsolidated entities (10,030 ) — (23,417 ) — Interest expense (7,578 ) (10,908 ) (15,183 ) (21,679 ) Gain/(loss) on sale of real estate owned — 32,375 — 56,998 Net (income)/loss attributable to noncontrolling interests (350 ) (347 ) (694 ) (741 ) Net income/(loss) attributable to OP unitholders $ 11,044 $ 47,383 $ 15,831 $ 83,729 (a) Same-Store Community population consisted of 14,277 apartment homes. (b) Same-Store Community population consisted of 14,277 apartment homes. The following table details the assets of the Operating Partnership’s reportable segments as of June 30, 2016 and December 31, 2015 (dollars in thousands) : June 30, December 31, 2015 Reportable apartment home segment assets Same-Store Communities West Region $ 1,506,255 $ 1,497,867 Mid-Atlantic Region 413,093 410,710 Northeast Region 672,588 669,082 Southeast Region 324,514 321,787 Non-Mature Communities/Other 748,278 731,459 Total assets 3,664,728 3,630,905 Accumulated depreciation (1,353,616 ) (1,281,258 ) Total assets - net book value 2,311,112 2,349,647 Reconciling items: Cash and cash equivalents 1,535 3,103 Restricted cash 11,659 11,344 Investment in unconsolidated entities 134,823 166,186 Other assets 23,864 24,528 Total consolidated assets $ 2,482,993 $ 2,554,808 Capital expenditures related to the Operating Partnership’s Same-Store Communities totaled $11.6 million and $9.1 million for the three months ended June 30, 2016 and 2015 , respectively, and $16.7 million and $14.4 million for the six months ended June 30, 2016 and 2015 , respectively. Capital expenditures related to the Operating Partnership’s Non-Mature Communities/Other totaled $0.5 million and $4.1 million for the three months ended June 30, 2016 and 2015 , respectively, and $0.9 million and $7.1 million for the six months ended June 30, 2016 and 2015 , respectively. Markets included in the above geographic segments are as follows: i. West Region — Orange County, San Francisco, Seattle, Los Angeles, Monterey Peninsula, Other Southern California, and Portland ii. Mid-Atlantic Region — Metropolitan D.C. and Baltimore iii. Northeast Region — New York and Boston iv. Southeast Region — Tampa, Nashville, and Other Florida

Significant Accounting Polici40

Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2016
Accounting Policies [Abstract]
Comprehensive Income, Policy [Policy Text Block]	Comprehensive Income/(Loss) Comprehensive income/(loss), which is defined as the change in equity during each period from transactions and other events and circumstances from nonowner sources, including all changes in equity during a period except for those resulting from investments by or distributions to stockholders, is displayed in the accompanying Consolidated Statements of Comprehensive Income/(Loss). For the three and six months ended June 30, 2016 and 2015 , 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 June 2016, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("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 will be effective for the Company on January 1, 2017, with early adoption permitted. The update requires a prospective, retrospective or modified retrospective approach, depending on the type of amendment. The Company 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 Company on January 1, 2019, with early adoption permitted. The Company is currently evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures. In February 2015, the FASB issued ASU 2015-02, Amendments to the Consolidation Analysis , which makes changes to both the variable interest model and the voting model of consolidation. Under ASU 2015-02, companies will need to re-evaluate whether an entity meets the criteria to be considered a variable interest entity (“VIE”) or whether the consolidation of an entity should be assessed under the voting model. The new standard specifically eliminates the presumption in the current voting model that a general partner controls a limited partnership or similar entity unless that presumption can be overcome. The new standard was effective for the Company beginning on January 1, 2016. The adoption of the new standard did not result in the consolidation of entities not previously consolidated or the deconsolidation of any entities previously consolidated. Upon adopting the new standard, the Operating Partnership and DownREIT Partnership became VIEs as the limited partners of these entities lack substantive kick-out rights and substantive participating rights. The Company is the primary beneficiary of, and continues to consolidate, the entities determined to be VIEs. 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 supersedes current revenue recognition guidance, including industry-specific revenue guidance. The updated standard will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. The standard specifically excludes lease contracts. The ASU allows for the use of either the full or modified retrospective transition method, and the standard will be effective for the Company on January 1, 2018; early adoption is permitted on January 1, 2017. The Company has not yet selected a transition method and we are currently evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures. 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 amended consolidation guidance. The Company first evaluates whether each entity is a 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”), primarily those engaged in development activities. 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 June 30, 2016 , UDR’s net deferred tax asset was $8.4 million (net of a valuation allowance of $0.1 million ), which is included in Other assets on the Consolidated Balance Sheets. GAAP defines a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. GAAP also provides guidance on derecognition, classification, interest and penalties, accounting for interim periods, disclosure and transition. The Company recognizes its tax positions and evaluates them using a two-step process. First, UDR determines whether a tax position is more likely than not (greater than 50 percent probability) to be sustained upon examination, including resolution of any related appeals or litigation processes, based on the technical merits of the position. Second, the Company will determine the amount of benefit to recognize and record the amount that is more likely than not to be realized upon ultimate settlement. UDR had no material unrecognized tax benefit, accrued interest or penalties at June 30, 2016 . UDR and its subsidiaries are subject to federal income tax as well as income tax of various state and local jurisdictions. The tax years 2011 through 2014 remain open to examination by tax jurisdictions to which we are subject. When applicable, UDR recognizes interest and/or penalties related to uncertain tax positions in Tax benefit/(provision), 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 June 30, 2016 and December 31, 2015 ( dollars in thousands): Interest rate at Balance outstanding June 30, June 30, December 31, 2015 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 % 1,200 1,200 Note due April 2021 (d) 10.00 % 3,000 — Total notes receivable, net $ 19,694 $ 16,694 (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). In March 2016, the terms of this secured note receivable were amended to extend the maturity from the fifth anniversary of the date of the note (February 2017) to 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 . 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) In April 2016, the Company entered into a secured note receivable with an unaffiliated third party with an aggregate commitment of $15.0 million . During the six months ended June 30, 2016 , the Company loaned $3.0 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 $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 $0.3 million of interest income from notes receivable during the three months ended June 30, 2016 and 2015 , respectively, and $0.8 million and $0.7 million during the six months ended June 30, 2016 and 2015 , 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)	6 Months Ended
	Jun. 30, 2016
Entity Information [Line Items]
New Accounting Pronouncements, Policy [Policy Text Block]	Recent Accounting Pronouncements In June 2016, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("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 will be effective for the Company on January 1, 2017, with early adoption permitted. The update requires a prospective, retrospective or modified retrospective approach, depending on the type of amendment. The Company 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 Company on January 1, 2019, with early adoption permitted. The Company is currently evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures. In February 2015, the FASB issued ASU 2015-02, Amendments to the Consolidation Analysis , which makes changes to both the variable interest model and the voting model of consolidation. Under ASU 2015-02, companies will need to re-evaluate whether an entity meets the criteria to be considered a variable interest entity (“VIE”) or whether the consolidation of an entity should be assessed under the voting model. The new standard specifically eliminates the presumption in the current voting model that a general partner controls a limited partnership or similar entity unless that presumption can be overcome. The new standard was effective for the Company beginning on January 1, 2016. The adoption of the new standard did not result in the consolidation of entities not previously consolidated or the deconsolidation of any entities previously consolidated. Upon adopting the new standard, the Operating Partnership and DownREIT Partnership became VIEs as the limited partners of these entities lack substantive kick-out rights and substantive participating rights. The Company is the primary beneficiary of, and continues to consolidate, the entities determined to be VIEs. 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 supersedes current revenue recognition guidance, including industry-specific revenue guidance. The updated standard will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. The standard specifically excludes lease contracts. The ASU allows for the use of either the full or modified retrospective transition method, and the standard will be effective for the Company on January 1, 2018; early adoption is permitted on January 1, 2017. The Company has not yet selected a transition method and we are currently evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures. 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 amended consolidation guidance. The Company first evaluates whether each entity is a 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 and six months ended June 30, 2016 and 2015 , 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”), primarily those engaged in development activities. 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 June 30, 2016 , UDR’s net deferred tax asset was $8.4 million (net of a valuation allowance of $0.1 million ), which is included in Other assets on the Consolidated Balance Sheets. GAAP defines a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. GAAP also provides guidance on derecognition, classification, interest and penalties, accounting for interim periods, disclosure and transition. The Company recognizes its tax positions and evaluates them using a two-step process. First, UDR determines whether a tax position is more likely than not (greater than 50 percent probability) to be sustained upon examination, including resolution of any related appeals or litigation processes, based on the technical merits of the position. Second, the Company will determine the amount of benefit to recognize and record the amount that is more likely than not to be realized upon ultimate settlement. UDR had no material unrecognized tax benefit, accrued interest or penalties at June 30, 2016 . UDR and its subsidiaries are subject to federal income tax as well as income tax of various state and local jurisdictions. The tax years 2011 through 2014 remain open to examination by tax jurisdictions to which we are subject. When applicable, UDR recognizes interest and/or penalties related to uncertain tax positions in Tax benefit/(provision), 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 June 2016, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("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 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 will be effective for the Operating Partnership on January 1, 2017, with early adoption permitted. The update requires a prospective, retrospective or modified retrospective approach, depending on the type of amendment. 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. The Operating Partnership is currently evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures. In February 2015, the FASB issued ASU 2015-02, Amendments to the Consolidation Analysis , which makes changes to both the variable interest model and the voting model of consolidation. Under ASU 2015-02, companies will need to re-evaluate whether an entity meets the criteria to be considered a variable interest entity (“VIE”) or whether the consolidation of an entity should be assessed under the voting model. The new standard specifically eliminates the presumption in the current voting model that a general partner controls a limited partnership or similar entity unless that presumption can be overcome. The new standard was effective for the Operating Partnership beginning on January 1, 2016. The adoption of the new standard did not result in the consolidation of entities not previously consolidated or the deconsolidation of any entities previously consolidated. Upon adopting the new standard, UDR Lighthouse DownREIT L.P. (the “DownREIT Partnership”) became 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 and will continue to account for its interest as an equity method investment. 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 supersedes current revenue recognition guidance, including industry-specific revenue guidance. The updated standard will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. The standard specifically excludes lease contracts. The ASU allows for the use of either the full or modified retrospective transition method, and the standard will be effective for the Operating Partnership on January 1, 2018; early adoption is permitted on January 1, 2017. The Operating Partnership has not yet selected a transition method and we are currently evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures. 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 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 and six months ended June 30, 2016 and 2015 , 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 ( 2011 through 2014 ) of tax jurisdictions and concluded there is no tax liability resulting from unrecognized tax benefits relating to uncertain income tax positions taken or expected to be taken in future tax returns.

Significant Accounting Polici42

Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2016
Accounting Policies [Abstract]
Notes receivable	The following table summarizes our notes receivable, net as of June 30, 2016 and December 31, 2015 ( dollars in thousands): Interest rate at Balance outstanding June 30, June 30, December 31, 2015 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 % 1,200 1,200 Note due April 2021 (d) 10.00 % 3,000 — Total notes receivable, net $ 19,694 $ 16,694

Real Estate Owned (Tables)

Real Estate Owned (Tables)	6 Months Ended
	Jun. 30, 2016
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 June 30, 2016 and December 31, 2015 (dollars in thousands): June 30, December 31, 2015 Land $ 1,794,615 $ 1,833,156 Depreciable property — held and used: Land Improvements 178,355 173,821 Building, improvements, and furniture, fixtures and equipment 7,100,504 7,046,622 Under development: Land and land improvements 111,028 78,085 Building, improvements, and furniture, fixtures and equipment 127,910 45,987 Real estate held for disposition: Land — 9,963 Building, improvements, and furniture, fixtures and equipment — 2,642 Real estate owned 9,312,412 9,190,276 Accumulated depreciation (2,842,273 ) (2,646,874 ) Real estate owned, net $ 6,470,139 $ 6,543,402

Real Estate Owned (UNITED DOM44

Real Estate Owned (UNITED DOMINION REALTY, L.P.) (Tables)	6 Months Ended
	Jun. 30, 2016
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 June 30, 2016 and December 31, 2015 (dollars in thousands): June 30, December 31, 2015 Land $ 1,794,615 $ 1,833,156 Depreciable property — held and used: Land Improvements 178,355 173,821 Building, improvements, and furniture, fixtures and equipment 7,100,504 7,046,622 Under development: Land and land improvements 111,028 78,085 Building, improvements, and furniture, fixtures and equipment 127,910 45,987 Real estate held for disposition: Land — 9,963 Building, improvements, and furniture, fixtures and equipment — 2,642 Real estate owned 9,312,412 9,190,276 Accumulated depreciation (2,842,273 ) (2,646,874 ) Real estate owned, net $ 6,470,139 $ 6,543,402
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 June 30, 2016 and December 31, 2015 (dollars in thousands) : June 30, December 31, 2015 Land $ 835,686 $ 833,300 Depreciable property — held and used: Buildings, improvements, and furniture, fixture and equipment 2,829,042 2,797,605 Real estate owned 3,664,728 3,630,905 Accumulated depreciation (1,353,616 ) (1,281,258 ) Real estate owned, net $ 2,311,112 $ 2,349,647

Joint Ventures (Tables)

Joint Ventures (Tables)	6 Months Ended
	Jun. 30, 2016
Equity Method Investments and Joint Ventures [Abstract]
Combined Summary of Balance Sheets Relating to Unconsolidated Joint Ventures [Table Text Block]	We evaluate our investments in unconsolidated joint ventures and partnerships when events or changes in circumstances indicate that there may be an other-than-temporary decline in value. We consider various factors to determine if a decrease in the value of the investment is other-than-temporary. The Company did not recognize any other-than-temporary decreases in the value of its investments in unconsolidated joint ventures or partnerships during the three and six months ended June 30, 2016 and 2015 . Combined summary balance sheets relating to the unconsolidated joint ventures and partnerships (not just our proportionate share) are presented below as of June 30, 2016 and December 31, 2015 ( dollars in thousands ): June 30, December 31, 2015 Total real estate, net $ 3,169,088 $ 3,135,757 Cash and cash equivalents 27,961 36,480 Amount due from UDR 1,069 — Other assets 20,634 29,891 Total assets $ 3,218,752 $ 3,202,128 Amount due to UDR $ — $ 7,266 Third party debt 1,707,406 1,614,463 Accounts payable and accrued liabilities 74,563 95,523 Total liabilities 1,781,969 1,717,252 Total equity 1,436,783 1,484,876 Total liabilities and equity $ 3,218,752 $ 3,202,128 Investment in and advances to unconsolidated joint ventures, net $ 933,403 $ 938,906
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 June 30, 2016 and December 31, 2015 (dollars in thousands) : Joint Venture Location of Properties Number of Properties Number of Apartment Homes Investment at UDR’s Ownership Interest June 30, June 30, June 30, December 31, June 30, December 31, Operating and development: UDR/MetLife I 1 development community (a); Various 3 land parcels 150 $ 21,319 $ 15,894 19.6 % 17.2 % UDR/MetLife II (b) Various 21 operating communities 4,642 418,701 425,230 50.0 % 50.0 % Other UDR/MetLife Development Joint Ventures (c) 1 operating community; Various 4 development communities (a) 1,437 164,870 171,659 50.6 % 50.6 % UDR/MetLife Vitruvian Park® Addison, TX 3 operating communities; 6 land parcels 1,130 71,984 73,469 50.0 % 50.0 % UDR/KFH Washington, D.C. 3 operating communities 660 15,126 17,211 30.0 % 30.0 % Investment in and advances to unconsolidated joint ventures, net, before participating loan investment and preferred equity investment 692,000 703,463 Income from Investment Investment at Three Months Ended June 30, Six Months Ended June 30, Location Rate Years To Maturity June 30, December 31, 2016 2015 2016 2015 Participating loan investment: Steele Creek Denver, CO 6.5% 1.1 93,902 90,747 $1,560 $1,352 $3,079 $2,506 Preferred equity investment: West Coast Development Joint Venture Various 6.5% N/A 147,501 144,696 $1,409 $(548) $3,198 $(548) Total investment in and advances to unconsolidated joint ventures, net $ 933,403 $ 938,906 (a) The number of apartment homes for the communities under development presented in the table above is based on the projected number of total homes. As of June 30, 2016 , 447 apartment homes had been completed in Other UDR/MetLife Development Joint Ventures, and no apartment homes had been completed in UDR/MetLife I. (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 and six months ended June 30, 2016 , the Company recorded losses of $0 and $1.1 million , respectively, its proportionate share of the total losses incurred. (c) In June 2016, the Company increased its ownership interest from 50% to 100% in a parcel of land in Los Angeles, California for a purchase price of approximately $20.1 million , including closing costs. As a result, the Company consolidated the parcel of land and it is no longer accounted for as an unconsolidated joint venture (see Note 3, Real Estate Owned ). The parcel of land was previously held in Other/UDR MetLife Development Joint Ventures.
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 and six months ended June 30, 2016 and 2015 ( dollars in thousands ) : Three Months Ended Six Months Ended June 30, June 30, 2016 2015 2016 2015 Total revenues $ 58,153 $ 55,450 $ 113,190 $ 109,996 Property operating expenses (22,981 ) (21,557 ) (46,394 ) (41,724 ) Real estate depreciation and amortization (21,770 ) (19,402 ) (40,713 ) (38,754 ) Operating income/(loss) 13,402 14,491 26,083 29,518 Interest expense (17,005 ) (16,169 ) (33,184 ) (32,230 ) Other income/(expense) (2 ) (7 ) (4 ) (7 ) Income/(loss) from discontinued operations — — — 182,488 Net income/(loss) $ (3,605 ) $ (1,685 ) $ (7,105 ) $ 179,769 UDR income/(loss) from unconsolidated entities $ 325 $ (573 ) $ 1,004 $ 58,586
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 June 30, 2016 and December 31, 2015 (dollars in thousands) : Joint Venture Location of Properties Number of Properties Number of Apartment Homes Investment at UDR’s Ownership Interest June 30, June 30, June 30, December 31, June 30, December 31, Operating and development: UDR/MetLife I 1 development community (a); Various 3 land parcels 150 $ 21,319 $ 15,894 19.6 % 17.2 % UDR/MetLife II (b) Various 21 operating communities 4,642 418,701 425,230 50.0 % 50.0 % Other UDR/MetLife Development Joint Ventures (c) 1 operating community; Various 4 development communities (a) 1,437 164,870 171,659 50.6 % 50.6 % UDR/MetLife Vitruvian Park® Addison, TX 3 operating communities; 6 land parcels 1,130 71,984 73,469 50.0 % 50.0 % UDR/KFH Washington, D.C. 3 operating communities 660 15,126 17,211 30.0 % 30.0 % Investment in and advances to unconsolidated joint ventures, net, before participating loan investment and preferred equity investment 692,000 703,463 Income from Investment Investment at Three Months Ended June 30, Six Months Ended June 30, Location Rate Years To Maturity June 30, December 31, 2016 2015 2016 2015 Participating loan investment: Steele Creek Denver, CO 6.5% 1.1 93,902 90,747 $1,560 $1,352 $3,079 $2,506 Preferred equity investment: West Coast Development Joint Venture Various 6.5% N/A 147,501 144,696 $1,409 $(548) $3,198 $(548) Total investment in and advances to unconsolidated joint ventures, net $ 933,403 $ 938,906 (a) The number of apartment homes for the communities under development presented in the table above is based on the projected number of total homes. As of June 30, 2016 , 447 apartment homes had been completed in Other UDR/MetLife Development Joint Ventures, and no apartment homes had been completed in UDR/MetLife I. (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 and six months ended June 30, 2016 , the Company recorded losses of $0 and $1.1 million , respectively, its proportionate share of the total losses incurred. (c) In June 2016, the Company increased its ownership interest from 50% to 100% in a parcel of land in Los Angeles, California for a purchase price of approximately $20.1 million , including closing costs. As a result, the Company consolidated the parcel of land and it is no longer accounted for as an unconsolidated joint venture (see Note 3, Real Estate Owned ). The parcel of land was previously held in Other/UDR MetLife Development Joint Ventures. As of June 30, 2016 and December 31, 2015 , the Company had deferred fees and deferred profit from the sale of properties to joint ventures or partnerships of $8.3 million and $6.8 million , respectively, which will be recognized through income over the weighted average life of the related properties, upon the disposition of the properties to a third party, or upon completion of certain development obligations. The Company recognized management fees for our management of the joint ventures and partnerships of $2.6 million and $2.6 million for the three months ended June 30, 2016 and 2015 , respectively, and $5.4 million and $5.2 million for the six months ended June 30, 2016 and 2015 , respectively. The management fees are included in Joint venture management and other fees on the Consolidated Statements of Operations. The Company may, in the future, make additional capital contributions to certain of our joint ventures and partnerships should additional capital contributions be necessary to fund acquisitions or operations. We evaluate our investments in unconsolidated joint ventures and partnerships when events or changes in circumstances indicate that there may be an other-than-temporary decline in value. We consider various factors to determine if a decrease in the value of the investment is other-than-temporary. The Company did not recognize any other-than-temporary decreases in the value of its investments in unconsolidated joint ventures or partnerships during the three and six months ended June 30, 2016 and 2015 . Combined summary balance sheets relating to the unconsolidated joint ventures and partnerships (not just our proportionate share) are presented below as of June 30, 2016 and December 31, 2015 ( dollars in thousands ): June 30, December 31, 2015 Total real estate, net $ 3,169,088 $ 3,135,757 Cash and cash equivalents 27,961 36,480 Amount due from UDR 1,069 — Other assets 20,634 29,891 Total assets $ 3,218,752 $ 3,202,128 Amount due to UDR $ — $ 7,266 Third party debt 1,707,406 1,614,463 Accounts payable and accrued liabilities 74,563 95,523 Total liabilities 1,781,969 1,717,252 Total equity 1,436,783 1,484,876 Total liabilities and equity $ 3,218,752 $ 3,202,128 Investment in and advances to unconsolidated joint ventures, net $ 933,403 $ 938,906 Combined summary financial information relating to the unconsolidated joint ventures’ and partnerships’ operations (not just our proportionate share), is presented below for the three and six months ended June 30, 2016 and 2015 ( dollars in thousands ) : Three Months Ended Six Months Ended June 30, June 30, 2016 2015 2016 2015 Total revenues $ 58,153 $ 55,450 $ 113,190 $ 109,996 Property operating expenses (22,981 ) (21,557 ) (46,394 ) (41,724 ) Real estate depreciation and amortization (21,770 ) (19,402 ) (40,713 ) (38,754 ) Operating income/(loss) 13,402 14,491 26,083 29,518 Interest expense (17,005 ) (16,169 ) (33,184 ) (32,230 ) Other income/(expense) (2 ) (7 ) (4 ) (7 ) Income/(loss) from discontinued operations — — — 182,488 Net income/(loss) $ (3,605 ) $ (1,685 ) $ (7,105 ) $ 179,769 UDR income/(loss) from unconsolidated entities $ 325 $ (573 ) $ 1,004 $ 58,586

Unconsolidated Entities (UNIT46

Unconsolidated Entities (UNITED DOMINION REALTY, L.P.) Unconsolidated Entities (UNITED DOMINION REALTY, L.P.) (Tables)	6 Months Ended
	Jun. 30, 2016
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 and six months ended June 30, 2016 and 2015 ( dollars in thousands ) : Three Months Ended Six Months Ended June 30, June 30, 2016 2015 2016 2015 Total revenues $ 58,153 $ 55,450 $ 113,190 $ 109,996 Property operating expenses (22,981 ) (21,557 ) (46,394 ) (41,724 ) Real estate depreciation and amortization (21,770 ) (19,402 ) (40,713 ) (38,754 ) Operating income/(loss) 13,402 14,491 26,083 29,518 Interest expense (17,005 ) (16,169 ) (33,184 ) (32,230 ) Other income/(expense) (2 ) (7 ) (4 ) (7 ) Income/(loss) from discontinued operations — — — 182,488 Net income/(loss) $ (3,605 ) $ (1,685 ) $ (7,105 ) $ 179,769 UDR income/(loss) from unconsolidated entities $ 325 $ (573 ) $ 1,004 $ 58,586
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 June 30, 2016 and December 31, 2015 ( dollars in thousands ): June 30, December 31, 2015 Total real estate, net $ 1,432,291 $ 1,457,244 Cash and cash equivalents — 89 Other assets 15,334 37,228 Note receivable from affiliate 126,500 126,500 Amount due from UDR — 35,293 Total assets $ 1,574,125 $ 1,656,354 Secured debt, net 443,639 524,052 Amount due to UDR 45,348 — Accounts payable and accrued liabilities 26,315 25,487 Total liabilities 515,302 549,539 Total equity 1,058,823 1,106,815 Total liabilities and equity $ 1,574,125 $ 1,656,354 OP’s investment in the DownREIT Partnership $ 134,823 $ 166,186 Combined summary financial information relating to all of the DownREIT Partnership (not just our proportionate share) is presented below for the three and six months ended June 30, 2016 ( dollars in thousands ) : Three Months Ended Six Months Ended June 30, June 30, 2016 2016 Rental income $ 32,646 $ 64,263 Property operating and maintenance (11,084 ) (22,441 ) Real estate depreciation and amortization (30,308 ) (60,361 ) Operating income/(loss) (8,746 ) (18,539 ) Interest expense (3,524 ) (7,265 ) Other income/(expense) (1,358 ) (3,090 ) Net income/(loss) $ (13,628 ) $ (28,894 ) OP's income/(loss) from unconsolidated entities $ (10,030 ) $ (23,417 )

Secured and Unsecured Debt (Tab

Secured and Unsecured Debt (Tables)	6 Months Ended
	Jun. 30, 2016
Debt Disclosure [Abstract]
Secured debt instruments	The following is a summary of our secured and unsecured debt at June 30, 2016 and December 31, 2015 ( dollars in thousands ): Six Months Ended Principal Outstanding June 30, 2016 June 30, December 31, 2015 Weighted Average Weighted Average Number of Communities Secured Debt: Fixed Rate Debt Mortgage notes payable (a) $ 322,689 $ 442,617 4.30 % 6.3 5 Fannie Mae credit facilities (b) 512,584 514,462 5.23 % 2.6 18 Deferred financing costs (3,482 ) (4,278 ) Total fixed rate secured debt, net 831,791 952,801 4.87 % 4.0 23 Variable Rate Debt Mortgage notes payable (c) 31,337 31,337 2.25 % 0.6 1 Tax-exempt secured notes payable (d) 94,700 94,700 1.18 % 6.7 2 Fannie Mae credit facilities (b) 299,378 299,378 1.92 % 3.6 8 Deferred financing costs (1,087 ) (1,271 ) Total variable rate secured debt, net 424,328 424,144 1.78 % 4.0 11 Total Secured Debt, net 1,256,119 1,376,945 3.82 % 4.0 34 Unsecured Debt: Variable Rate Debt Borrowings outstanding under an unsecured credit facility due January 2020 (e) (i) 255,000 150,000 1.36 % 3.6 Borrowings outstanding under an unsecured working capital credit facility due January 2019 (f) 4,199 — 1.37 % 2.5 1.40% Term Loan Facility due January 2021 (e) (i) 35,000 35,000 1.40 % 4.6 Fixed Rate Debt 5.25% Medium-Term Notes due January 2016 (g) — 83,260 — % — 6.21% Term Notes due July 2016 (g) — 12,091 — % — 4.25% Medium-Term Notes due June 2018 (net of discounts of $822 and $1,037, respectively) (i) 299,178 298,963 4.25 % 1.9 3.70% Medium-Term Notes due October 2020 (net of discounts of $34 and $38, respectively) (i) 299,966 299,962 3.70 % 4.3 2.23% Term Loan Facility due January 2021 (e) (i) 315,000 315,000 2.23 % 4.6 4.63% Medium-Term Notes due January 2022 (net of discounts of $1,985 and $2,164, respectively) (i) 398,015 397,836 4.63 % 5.5 3.75% Medium-Term Notes due July 2024 (net of discounts of $834 and $886, respectively) (i) 299,166 299,114 3.75 % 8.0 8.50% Debentures due September 2024 15,644 15,644 8.50 % 8.2 4.00% Medium-Term Notes due October 2025 (net of discounts of $637 and $671, respectively) (h) (i) 299,363 299,329 4.00 % 9.3 Other 23 24 N/A N/A Deferred financing costs (11,496 ) (12,373 ) N/A N/A Total Unsecured Debt, net 2,209,058 2,193,850 3.58 % 5.4 Total Debt, net $ 3,465,177 $ 3,570,795 3.76 % 4.9
Secured credit facilities	Further information related to these credit facilities is as follows (dollars in thousands) : June 30, December 31, 2015 Borrowings outstanding $ 811,962 $ 813,840 Weighted average borrowings during the period ended 812,752 822,521 Maximum daily borrowings during the period ended 813,544 834,003 Weighted average interest rate during the period ended 4.0 % 4.0 % Weighted average interest rate at the end of the period 4.0 % 3.9 %
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 June 30, 2016 are as follows (dollars in thousands): Year Total Fixed Secured Debt Total Variable Secured Debt Total Secured Debt Total Unsecured Debt Total Debt 2016 $ 3,559 $ — $ 3,559 $ — $ 3,559 2017 179,189 96,337 275,526 — 275,526 2018 73,096 137,969 211,065 300,000 511,065 2019 247,796 67,700 315,496 4,199 319,695 2020 170,664 — 170,664 555,000 725,664 2021 — — — 350,000 350,000 2022 — — — 400,000 400,000 2023 — 96,409 96,409 — 96,409 2024 — — — 315,644 315,644 2025 127,600 — 127,600 300,000 427,600 Thereafter 25,000 27,000 52,000 — 52,000 Subtotal 826,904 425,415 1,252,319 2,224,843 3,477,162 Non-cash (a) 4,887 (1,087 ) 3,800 (15,785 ) (11,985 ) Total $ 831,791 $ 424,328 $ 1,256,119 $ 2,209,058 $ 3,465,177

Debt (UNITED DOMINION REALTY,48

Debt (UNITED DOMINION REALTY, L.P.) (Tables)	6 Months Ended
	Jun. 30, 2016
Entity Information [Line Items]
Secured debt instruments	The following is a summary of our secured and unsecured debt at June 30, 2016 and December 31, 2015 ( dollars in thousands ): Six Months Ended Principal Outstanding June 30, 2016 June 30, December 31, 2015 Weighted Average Weighted Average Number of Communities Secured Debt: Fixed Rate Debt Mortgage notes payable (a) $ 322,689 $ 442,617 4.30 % 6.3 5 Fannie Mae credit facilities (b) 512,584 514,462 5.23 % 2.6 18 Deferred financing costs (3,482 ) (4,278 ) Total fixed rate secured debt, net 831,791 952,801 4.87 % 4.0 23 Variable Rate Debt Mortgage notes payable (c) 31,337 31,337 2.25 % 0.6 1 Tax-exempt secured notes payable (d) 94,700 94,700 1.18 % 6.7 2 Fannie Mae credit facilities (b) 299,378 299,378 1.92 % 3.6 8 Deferred financing costs (1,087 ) (1,271 ) Total variable rate secured debt, net 424,328 424,144 1.78 % 4.0 11 Total Secured Debt, net 1,256,119 1,376,945 3.82 % 4.0 34 Unsecured Debt: Variable Rate Debt Borrowings outstanding under an unsecured credit facility due January 2020 (e) (i) 255,000 150,000 1.36 % 3.6 Borrowings outstanding under an unsecured working capital credit facility due January 2019 (f) 4,199 — 1.37 % 2.5 1.40% Term Loan Facility due January 2021 (e) (i) 35,000 35,000 1.40 % 4.6 Fixed Rate Debt 5.25% Medium-Term Notes due January 2016 (g) — 83,260 — % — 6.21% Term Notes due July 2016 (g) — 12,091 — % — 4.25% Medium-Term Notes due June 2018 (net of discounts of $822 and $1,037, respectively) (i) 299,178 298,963 4.25 % 1.9 3.70% Medium-Term Notes due October 2020 (net of discounts of $34 and $38, respectively) (i) 299,966 299,962 3.70 % 4.3 2.23% Term Loan Facility due January 2021 (e) (i) 315,000 315,000 2.23 % 4.6 4.63% Medium-Term Notes due January 2022 (net of discounts of $1,985 and $2,164, respectively) (i) 398,015 397,836 4.63 % 5.5 3.75% Medium-Term Notes due July 2024 (net of discounts of $834 and $886, respectively) (i) 299,166 299,114 3.75 % 8.0 8.50% Debentures due September 2024 15,644 15,644 8.50 % 8.2 4.00% Medium-Term Notes due October 2025 (net of discounts of $637 and $671, respectively) (h) (i) 299,363 299,329 4.00 % 9.3 Other 23 24 N/A N/A Deferred financing costs (11,496 ) (12,373 ) N/A N/A Total Unsecured Debt, net 2,209,058 2,193,850 3.58 % 5.4 Total Debt, net $ 3,465,177 $ 3,570,795 3.76 % 4.9
Secured credit facilities	Further information related to these credit facilities is as follows (dollars in thousands) : June 30, December 31, 2015 Borrowings outstanding $ 811,962 $ 813,840 Weighted average borrowings during the period ended 812,752 822,521 Maximum daily borrowings during the period ended 813,544 834,003 Weighted average interest rate during the period ended 4.0 % 4.0 % Weighted average interest rate at the end of the period 4.0 % 3.9 %
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 June 30, 2016 are as follows (dollars in thousands): Year Total Fixed Secured Debt Total Variable Secured Debt Total Secured Debt Total Unsecured Debt Total Debt 2016 $ 3,559 $ — $ 3,559 $ — $ 3,559 2017 179,189 96,337 275,526 — 275,526 2018 73,096 137,969 211,065 300,000 511,065 2019 247,796 67,700 315,496 4,199 319,695 2020 170,664 — 170,664 555,000 725,664 2021 — — — 350,000 350,000 2022 — — — 400,000 400,000 2023 — 96,409 96,409 — 96,409 2024 — — — 315,644 315,644 2025 127,600 — 127,600 300,000 427,600 Thereafter 25,000 27,000 52,000 — 52,000 Subtotal 826,904 425,415 1,252,319 2,224,843 3,477,162 Non-cash (a) 4,887 (1,087 ) 3,800 (15,785 ) (11,985 ) Total $ 831,791 $ 424,328 $ 1,256,119 $ 2,209,058 $ 3,465,177
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
Secured debt instruments	Secured debt consists of the following as of June 30, 2016 and December 31, 2015 ( dollars in thousands ): Six Months Ended Principal Outstanding June 30, 2016 June 30, December 31, 2015 Weighted Average Interest Rate Weighted Average Years to Maturity Number of Communities Encumbered Fixed Rate Debt Mortgage notes payable $ — $ 30,132 N/A — — Fannie Mae credit facilities 250,638 250,828 5.08 % 3.2 8 Deferred financing costs (1,296 ) (1,627 ) Total fixed rate secured debt, net 249,342 279,333 5.08 % 3.2 8 Variable Rate Debt Tax-exempt secured note payable 27,000 27,000 1.18 % 15.7 1 Fannie Mae credit facilities 170,203 170,203 2.12 % 4.2 6 Deferred financing costs (536 ) (572 ) Total variable rate secured debt, net 196,667 196,631 1.99 % 5.8 7 Total Secured Debt, net $ 446,009 $ 475,964 3.86 % 4.3 15
Secured credit facilities	The following information relates to the credit facilities allocated to the Operating Partnership (dollars in thousands) : June 30, December 31, 2015 Borrowings outstanding $ 420,841 $ 421,031 Weighted average borrowings during the period ended 421,251 425,522 Maximum daily borrowings during the period 421,661 431,462 Weighted average interest rate during the period ended 3.8 % 3.8 % Interest rate at the end of the period 3.9 % 3.8 %
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 June 30, 2016 are as follows (dollars in thousands): Fixed Variable Year Secured Credit Facilities Tax-Exempt Secured Notes Payable Secured Credit Facilities Total 2016 $ 195 $ — $ — $ 195 2017 15,640 — 6,566 22,206 2018 48,872 — 96,327 145,199 2019 123,095 — — 123,095 2020 62,836 — — 62,836 2021 — — — — 2022 — — — — 2023 — — 67,310 67,310 2024 — — — — 2025 — — — — Thereafter — 27,000 — 27,000 Subtotal 250,638 27,000 170,203 447,841 Non-cash (a) (1,296 ) (89 ) (447 ) (1,832 ) Total $ 249,342 $ 26,911 $ 169,756 $ 446,009

Income_(Loss) Per Share (Tables

Income/(Loss) Per Share (Tables)	6 Months Ended
	Jun. 30, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]	The following table sets forth the additional shares of common stock outstanding by equity instrument if converted to common stock for each of the three and six months ended June 30, 2016 and 2015 (shares in thousands) : Three Months Ended Six Months Ended June 30, June 30, 2016 2015 2016 2015 OP/DownREIT Units 25,190 9,125 25,191 9,145 Preferred stock 3,028 3,036 3,028 3,036 Stock options, unvested LTIP Units and unvested restricted stock 1,906 1,921 1,865 1,923
(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 Six Months Ended June 30, June 30, 2016 2015 2016 2015 Numerator for income/(loss) per share: Income/(loss) from continuing operations $ 12,249 $ 10,842 $ 20,783 $ 87,259 Gain/(loss) on sale of real estate owned, net of tax 7,315 79,042 10,385 79,042 Net (income)/loss attributable to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (1,610 ) (3,029 ) (2,515 ) (5,617 ) Net (income)/loss attributable to noncontrolling interests (8 ) — (314 ) (7 ) Net income/(loss) attributable to UDR, Inc. 17,946 86,855 28,339 160,677 Distributions to preferred stockholders — Series E (Convertible) (929 ) (931 ) (1,858 ) (1,862 ) Income/(loss) attributable to common stockholders - basic $ 17,017 $ 85,924 $ 26,481 $ 158,815 Dilutive distributions to preferred stockholders - Series E (Convertible) — 931 — — Income/(loss) attributable to common stockholders - diluted $ 17,017 $ 86,855 $ 26,481 $ 158,815 Denominator for income/(loss) per share: Weighted average common shares outstanding 267,113 259,028 265,234 258,567 Non-vested restricted stock awards (845 ) (1,179 ) (872 ) (1,223 ) Denominator for basic income/(loss) per share 266,268 257,849 264,362 257,344 Incremental shares issuable from assumed conversion of stock options, unvested LTIP Units, and unvested restricted stock 1,906 4,957 1,865 1,923 Denominator for diluted income/(loss) per share 268,174 262,806 266,227 259,267 Income/(loss) per weighted average common share: Basic $ 0.06 $ 0.33 $ 0.10 $ 0.62 Diluted $ 0.06 $ 0.33 $ 0.10 $ 0.61

Noncontrolling Interests (Table

Noncontrolling Interests (Tables)	6 Months Ended
	Jun. 30, 2016
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, 2015 $ 946,436 Mark-to-market adjustment to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (3,192 ) Conversion of OP Units to Common Stock (81 ) Net income/(loss) attributable to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership 2,515 Distributions to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (15,093 ) Allocation of other comprehensive income/(loss) (600 ) Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership, June 30, 2016 $ 929,985 The following sets forth net income/(loss) attributable to common stockholders and transfers from redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership for the following periods (dollars in thousands) : Three Months Ended Six Months Ended June 30, June 30, 2016 2015 2016 2015 Net income/(loss) attributable to common stockholders $ 17,017 $ 85,924 $ 26,481 $ 158,815 Conversion of OP Units and DownREIT Units to UDR Common stock 81 3,479 81 3,498 Change in equity from net income/(loss) attributable to common stockholders and conversion of OP Units and DownREIT Units to UDR Common Stock $ 17,098 $ 89,403 $ 26,562 $ 162,313

Fair Value of Derivatives and51

Fair Value of Derivatives and Financial Instruments (Tables)	6 Months Ended
	Jun. 30, 2016
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 June 30, 2016 and December 31, 2015 are summarized as follows (dollars in thousands) : Fair Value at June 30, 2016, Using Total Carrying Amount in Statement of Financial Position at June 30, 2016 Fair Value Estimate at June 30, 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) $ 19,694 $ 19,501 $ — $ — $ 19,501 Derivatives - Interest rate contracts (b) 3 3 — 3 — Total assets $ 19,697 $ 19,504 $ — $ 3 $ 19,501 Derivatives - Interest rate contracts (b) $ 3,554 $ 3,554 $ — $ 3,554 $ — Secured debt instruments - fixed rate: (c) Mortgage notes payable 322,689 340,060 — — 340,060 Fannie Mae credit facilities 512,584 542,250 — — 542,250 Secured debt instruments - variable rate: (c) Mortgage notes payable 31,337 31,337 — — 31,337 Tax-exempt secured notes payable 94,700 94,700 — — 94,700 Fannie Mae credit facilities 299,378 299,378 — — 299,378 Unsecured debt instruments: (c) Commercial bank 259,199 259,199 — — 259,199 Senior unsecured notes 1,961,355 2,096,376 — — 2,096,376 Total liabilities $ 3,484,796 $ 3,666,854 $ — $ 3,554 $ 3,663,300 Redeemable noncontrolling interests in the Operating Partnership and DownREIT Parthership (d) $ 929,985 $ 929,985 $ — $ 929,985 $ — Fair Value at December 31, 2015, Using Total Carrying Amount in Statement of Financial Position at December 31, 2015 Fair Value Estimate at December 31, 2015 Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Description: Notes receivable (a) $ 16,694 $ 16,938 $ — $ — $ 16,938 Derivatives - Interest rate contracts (b) 13 13 — 13 — Total assets $ 16,707 $ 16,951 $ — $ 13 $ 16,938 Derivatives- Interest rate contracts (b) $ 2,112 $ 2,112 $ — $ 2,112 $ — Secured debt instruments - fixed rate: (c) Mortgage notes payable 442,617 448,019 — — 448,019 Fannie Mae credit facilities 514,462 539,050 — — 539,050 Secured debt instruments - variable rate: (c) Mortgage notes payable 31,337 31,337 — — 31,337 Tax-exempt secured notes payable 94,700 94,700 — — 94,700 Fannie Mae credit facilities 299,378 299,378 — — 299,378 Unsecured debt instruments: (c) Commercial bank 150,000 150,000 — — 150,000 Senior unsecured notes 2,056,223 2,108,687 — — 2,108,687 Total liabilities $ 3,590,829 $ 3,673,283 $ — $ 2,112 $ 3,671,171 Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (d) $ 946,436 $ 946,436 $ — $ 946,436 $ — (a) See Note 2, Significant Accounting Policies. (b) See Note 10, Derivatives and Hedging Activity. (c) See Note 6, Secured 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)	6 Months Ended
	Jun. 30, 2016
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 June 30, 2016 and December 31, 2015 are summarized as follows (dollars in thousands) : Fair Value at June 30, 2016, Using Total Carrying Amount in Statement of Financial Position at June 30, 2016 Fair Value Estimate at June 30, 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) $ 19,694 $ 19,501 $ — $ — $ 19,501 Derivatives - Interest rate contracts (b) 3 3 — 3 — Total assets $ 19,697 $ 19,504 $ — $ 3 $ 19,501 Derivatives - Interest rate contracts (b) $ 3,554 $ 3,554 $ — $ 3,554 $ — Secured debt instruments - fixed rate: (c) Mortgage notes payable 322,689 340,060 — — 340,060 Fannie Mae credit facilities 512,584 542,250 — — 542,250 Secured debt instruments - variable rate: (c) Mortgage notes payable 31,337 31,337 — — 31,337 Tax-exempt secured notes payable 94,700 94,700 — — 94,700 Fannie Mae credit facilities 299,378 299,378 — — 299,378 Unsecured debt instruments: (c) Commercial bank 259,199 259,199 — — 259,199 Senior unsecured notes 1,961,355 2,096,376 — — 2,096,376 Total liabilities $ 3,484,796 $ 3,666,854 $ — $ 3,554 $ 3,663,300 Redeemable noncontrolling interests in the Operating Partnership and DownREIT Parthership (d) $ 929,985 $ 929,985 $ — $ 929,985 $ — Fair Value at December 31, 2015, Using Total Carrying Amount in Statement of Financial Position at December 31, 2015 Fair Value Estimate at December 31, 2015 Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Description: Notes receivable (a) $ 16,694 $ 16,938 $ — $ — $ 16,938 Derivatives - Interest rate contracts (b) 13 13 — 13 — Total assets $ 16,707 $ 16,951 $ — $ 13 $ 16,938 Derivatives- Interest rate contracts (b) $ 2,112 $ 2,112 $ — $ 2,112 $ — Secured debt instruments - fixed rate: (c) Mortgage notes payable 442,617 448,019 — — 448,019 Fannie Mae credit facilities 514,462 539,050 — — 539,050 Secured debt instruments - variable rate: (c) Mortgage notes payable 31,337 31,337 — — 31,337 Tax-exempt secured notes payable 94,700 94,700 — — 94,700 Fannie Mae credit facilities 299,378 299,378 — — 299,378 Unsecured debt instruments: (c) Commercial bank 150,000 150,000 — — 150,000 Senior unsecured notes 2,056,223 2,108,687 — — 2,108,687 Total liabilities $ 3,590,829 $ 3,673,283 $ — $ 2,112 $ 3,671,171 Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (d) $ 946,436 $ 946,436 $ — $ 946,436 $ — (a) See Note 2, Significant Accounting Policies. (b) See Note 10, Derivatives and Hedging Activity. (c) See Note 6, Secured 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 June 30, 2016 and December 31, 2015 are summarized as follows (dollars in thousands) : Fair Value at June 30, 2016, Using Total Carrying Amount in Statement of Financial Position at June 30, 2016 Fair Value Estimate at June 30, 2016 Quoted Prices in Significant Significant Description: Derivatives - Interest rate contracts (a) $ 2 $ 2 $ — $ 2 $ — Total assets $ 2 $ 2 $ — $ 2 $ — Secured debt instruments - fixed rate: (b) Fannie Mae credit facilities $ 250,638 $ 267,526 $ — $ — $ 267,526 Secured debt instruments - variable rate: (b) Tax-exempt secured notes payable 27,000 27,000 — — 27,000 Fannie Mae credit facilities 170,203 170,203 — — 170,203 Total liabilities $ 447,841 $ 464,729 $ — $ — $ 464,729 Fair Value at December 31, 2015, Using Total Carrying Amount in Statement of Financial Position at December 31, 2015 Fair Value Estimate at December 31, 2015 Quoted Prices in Significant Significant Description: Derivatives - Interest rate contracts (a) $ 8 $ 8 $ — $ 8 $ — Total assets $ 8 $ 8 $ — $ 8 $ — Secured debt instruments - fixed rate: (b) Mortgage notes payable $ 30,132 $ 30,308 $ — $ — $ 30,308 Fannie Mae credit facilities 250,828 263,070 — — 263,070 Secured debt instruments - variable rate: (b) Tax-exempt secured notes payable 27,000 27,000 — — 27,000 Fannie Mae credit facilities 170,203 170,203 — — 170,203 Total liabilities $ 478,163 $ 490,581 $ — $ — $ 490,581 (a) See Note 8, Derivatives and Hedging Activity. (b) See Note 5, Debt, Net.

Derivatives and Hedging Activ53

Derivatives and Hedging Activity (Tables)	6 Months Ended
	Jun. 30, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Outstanding interest rate derivatives	As of June 30, 2016 , the Company had the following outstanding interest rate derivatives that were designated as cash flow hedges of interest rate risk ( dollars in thousands ): Interest Rate Derivative Number of Instruments Notional Interest rate swaps (a) 3 $ 315,000 Interest rate caps 2 $ 203,166 (a) The three interest rate swaps noted in the table above mature in January and April 2017. During the second quarter of 2016, the Company entered into four forward starting interest rate swaps, with an aggregate notional amount of $315.0 million , which are effective in January and April 2017 and mature in January 2020. 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 an adjustment to earnings of less than $0.1 million for the three and six months ended June 30, 2016 and 2015 . As of June 30, 2016 , the Company had the following outstanding derivatives that were not designated as hedges in qualifying hedging relationships ( dollars in thousands ): Product Number of Instruments Notional Interest rate caps 3 $ 133,107
Fair value of Company's derivative financial instruments and their classification on Consolidated Balance Sheet	The tables below present the fair value of the Company’s derivative financial instruments as well as their classification on the Consolidated Balance Sheets as of June 30, 2016 and December 31, 2015 ( dollars in thousands ): Asset Derivatives (included in Other assets ) Liability Derivatives (included in Other liabilities ) Fair Value at: Fair Value at: June 30, December 31, June 30, December 31, Derivatives designated as hedging instruments: Interest rate products $ 2 $ 9 $ 3,554 $ 2,112 Derivatives not designated as hedging instruments: Interest rate products $ 1 $ 4 $ — $ —
Effect of Company's derivative financial instruments on Consolidated Statements of Operation	The tables below present the effect of the Company’s derivative financial instruments on the Consolidated Statements of Operations for the three and six months ended June 30, 2016 and 2015 ( 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) 2016 2015 2016 2015 2016 2015 Three Months Ended June 30, Interest rate products $ (1,963 ) $ 6,186 $ (943 ) $ (292 ) $ — $ — Six Months Ended June 30, Interest rate products $ (2,774 ) $ (1,366 ) $ (1,878 ) $ (1,029 ) $ — $ —
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 2016 2015 Three Months Ended June 30, Interest rate products $ (3 ) $ (22 ) Six Months Ended June 30, Interest rate products $ (3 ) $ (24 )
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 June 30, 2016 $ 3 $ — $ 3 $ — $ — $ 3 December 31, 2015 $ 13 $ — $ 13 $ — $ — $ 13 (a) Amounts reconcile to the aggregate fair value of derivative assets in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Balance Sheet” located in this footnote.
Offsetting Liabilities [Table Text Block]	Offsetting of Derivative Liabilities Gross Amounts of Recognized Liabilities Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts of Liabilities Presented in the Consolidated Balance Sheets (a) Gross Amounts Not Offset in the Consolidated Balance Sheets Financial Instruments Cash Collateral Posted Net Amount June 30, 2016 $ 3,554 $ — $ 3,554 $ — $ — $ 3,554 December 31, 2015 $ 2,112 $ — $ 2,112 $ — $ — $ 2,112 (a) Amounts reconcile to the aggregate fair value of derivative liabilities in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Balance Sheet” located in this footnote.

Derivatives and Hedging Activ54

Derivatives and Hedging Activity (UNITED DOMINION REALTY, L.P.) (Tables)	6 Months Ended
	Jun. 30, 2016
Entity Information [Line Items]
Outstanding interest rate derivatives	As of June 30, 2016 , the Company had the following outstanding interest rate derivatives that were designated as cash flow hedges of interest rate risk ( dollars in thousands ): Interest Rate Derivative Number of Instruments Notional Interest rate swaps (a) 3 $ 315,000 Interest rate caps 2 $ 203,166 (a) The three interest rate swaps noted in the table above mature in January and April 2017. During the second quarter of 2016, the Company entered into four forward starting interest rate swaps, with an aggregate notional amount of $315.0 million , which are effective in January and April 2017 and mature in January 2020. 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 an adjustment to earnings of less than $0.1 million for the three and six months ended June 30, 2016 and 2015 . As of June 30, 2016 , the Company had the following outstanding derivatives that were not designated as hedges in qualifying hedging relationships ( dollars in thousands ): Product Number of Instruments Notional Interest rate caps 3 $ 133,107
Fair value of Company's derivative financial instruments and their classification on Consolidated Balance Sheet	The tables below present the fair value of the Company’s derivative financial instruments as well as their classification on the Consolidated Balance Sheets as of June 30, 2016 and December 31, 2015 ( dollars in thousands ): Asset Derivatives (included in Other assets ) Liability Derivatives (included in Other liabilities ) Fair Value at: Fair Value at: June 30, December 31, June 30, December 31, Derivatives designated as hedging instruments: Interest rate products $ 2 $ 9 $ 3,554 $ 2,112 Derivatives not designated as hedging instruments: Interest rate products $ 1 $ 4 $ — $ —
Effect of Company's derivative financial instruments on Consolidated Statements of Operation	The tables below present the effect of the Company’s derivative financial instruments on the Consolidated Statements of Operations for the three and six months ended June 30, 2016 and 2015 ( 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) 2016 2015 2016 2015 2016 2015 Three Months Ended June 30, Interest rate products $ (1,963 ) $ 6,186 $ (943 ) $ (292 ) $ — $ — Six Months Ended June 30, Interest rate products $ (2,774 ) $ (1,366 ) $ (1,878 ) $ (1,029 ) $ — $ —
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 2016 2015 Three Months Ended June 30, Interest rate products $ (3 ) $ (22 ) Six Months Ended June 30, Interest rate products $ (3 ) $ (24 )
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 June 30, 2016 $ 3 $ — $ 3 $ — $ — $ 3 December 31, 2015 $ 13 $ — $ 13 $ — $ — $ 13 (a) Amounts reconcile to the aggregate fair value of derivative assets in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Balance Sheet” located in this footnote.
Offsetting Liabilities [Table Text Block]	Offsetting of Derivative Liabilities Gross Amounts of Recognized Liabilities Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts of Liabilities Presented in the Consolidated Balance Sheets (a) Gross Amounts Not Offset in the Consolidated Balance Sheets Financial Instruments Cash Collateral Posted Net Amount June 30, 2016 $ 3,554 $ — $ 3,554 $ — $ — $ 3,554 December 31, 2015 $ 2,112 $ — $ 2,112 $ — $ — $ 2,112 (a) Amounts reconcile to the aggregate fair value of derivative liabilities in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Balance Sheet” located in this footnote.
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
Outstanding interest rate derivatives	As of June 30, 2016 , the Operating Partnership had the following outstanding interest rate derivatives designated as cash flow hedges of interest rate risk ( dollars in thousands ): Interest Rate Derivative Number of Instruments Notional Interest rate caps 1 $ 96,327 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 and six months ended June 30, 2016 and 2015 . As of June 30, 2016 , 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 $ 98,932 As of June 30, 2016 , the Operating Partnership had the following outstanding interest rate derivatives designated as cash flow hedges of interest rate risk ( dollars in thousands ): Interest Rate Derivative Number of Instruments Notional Interest rate caps 1 $ 96,327 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 and six months ended June 30, 2016 and 2015 . As of June 30, 2016 , 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 $ 98,932
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 June 30, 2016 and December 31, 2015 ( dollars in thousands ): Asset Derivatives (included in Other assets ) Liability Derivatives (included in Other liabilities ) Fair Value at: Fair Value at: June 30, December 31, June 30, December 31, Derivatives designated as hedging instruments: Interest rate products $ 1 $ 4 $ — $ — Derivatives not designated as hedging instruments: Interest rate products $ 1 $ 4 $ — $ —
Effect of Company's derivative financial instruments on Consolidated Statements of Operation	The tables below present the effect of the derivative financial instruments on the Consolidated Statements of Operations for the three and six months ended June 30, 2016 and 2015 ( 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 2016 2015 2016 2015 2016 2015 Three Months Ended June 30, Interest rate products $ (1 ) $ (26 ) $ (2 ) $ (267 ) $ — $ — Six Months Ended June 30, Interest rate products $ (3 ) $ (77 ) $ (3 ) $ (553 ) $ — $ —
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 2016 2015 Three Months Ended June 30, Interest rate products $ (3 ) $ (22 ) Six Months Ended June 30, Interest rate products $ (3 ) $ (23 )
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 June 30, 2016 and December 31, 2015 : 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 June 30, 2016 $ 2 $ — $ 2 $ — $ — $ 2 December 31, 2015 $ 8 $ — $ 8 $ — $ — $ 8 (a) Amounts reconcile to the aggregate fair value of derivative assets in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Balance Sheet” located in this footnote.
Offsetting Liabilities [Table Text Block]	Offsetting of Derivative Liabilities Gross Amounts of Recognized Liabilities Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts of Liabilities Presented in the Consolidated Balance Sheets (b) Gross Amounts Not Offset in the Consolidated Balance Sheets Financial Instruments Cash Collateral Posted Net Amount June 30, 2016 $ — $ — $ — $ — $ — $ — December 31, 2015 $ — $ — $ — $ — $ — $ — (b) Amounts reconcile to the aggregate fair value of derivative liabilities in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Balance Sheet” located in this footnote.

Commitments and Contingencies55

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Real estate commitments	The following summarizes the Company’s real estate commitments at June 30, 2016 ( dollars in thousands ): Number of Properties Costs Incurred to Date (a) Expected Costs to Complete Average Ownership Stake Wholly-owned — under development 2 $ 238,938 (b) $ 469,562 100 % Wholly-owned — redevelopment 4 20,752 (b) 24,648 100 % Joint ventures: Unconsolidated joint ventures 5 614,300 88,086 (c) 50 % Participating loan investments 1 93,902 (d) — 0 % Preferred equity investments 2 57,874 (e) — 48 % $ 1,025,766 $ 582,296 (a) Represents 100% of project costs incurred as of June 30, 2016 . (b) Costs incurred to date include $28.4 million and $5.1 million of accrued fixed assets for development and redevelopment, respectively. (c) Represents UDR’s proportionate share of expected remaining costs to complete. (d) Represents the participating loan balance funded as of June 30, 2016 . (e) Represents UDR's upfront investment contributed to the West Coast Development Joint Venture for the properties under development as of June 30, 2016 .

Reportable Segment (Tables)

Reportable Segment (Tables)	6 Months Ended
	Jun. 30, 2016
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 and six months ended June 30, 2016 and 2015 , and reconciles NOI to Net Income/(Loss) Attributable to UDR, Inc . in the Consolidated Statements of Operations (dollars in thousands) : Three Months Ended Six Months Ended June 30, (a) June 30, (b) 2016 2015 2016 2015 Reportable apartment home segment rental income Same-Store Communities West Region $ 75,060 $ 69,510 $ 147,423 $ 135,777 Mid-Atlantic Region 41,706 41,041 82,910 81,418 Northeast Region 32,490 30,935 64,560 61,230 Southeast Region 27,702 25,844 54,839 51,126 Southwest Region 13,285 12,697 26,428 25,171 Non-Mature Communities/Other 45,925 32,737 91,965 65,089 Total consolidated rental income $ 236,168 $ 212,764 $ 468,125 $ 419,811 Reportable apartment home segment NOI Same-Store Communities West Region $ 55,265 $ 51,781 $ 109,541 $ 100,718 Mid-Atlantic Region 29,301 28,456 57,357 55,989 Northeast Region 23,677 22,408 46,609 43,941 Southeast Region 19,081 17,426 37,877 34,312 Southwest Region 8,187 8,078 16,415 15,702 Non-Mature Communities/Other 31,804 22,283 63,650 43,345 Total consolidated NOI 167,315 150,432 331,449 294,007 Reconciling items: Joint venture management and other fees 2,618 3,098 5,476 15,804 Property management (6,494 ) (5,851 ) (12,873 ) (11,545 ) Other operating expenses (1,892 ) (1,769 ) (3,644 ) (3,535 ) Real estate depreciation and amortization (105,937 ) (90,344 ) (211,276 ) (179,121 ) General and administrative (10,835 ) (13,721 ) (24,679 ) (25,873 ) Casualty-related recoveries/(charges), net (1,629 ) (843 ) (1,629 ) (1,839 ) Other depreciation and amortization (1,486 ) (1,700 ) (3,039 ) (3,323 ) Income/(loss) from unconsolidated entities 325 (573 ) 1,004 58,586 Interest expense (30,678 ) (29,673 ) (61,782 ) (58,473 ) Interest income and other income/(expense), net 540 382 971 742 Tax benefit/(provision), net 402 1,404 805 1,829 Gain/(loss) on sale of real estate owned, net of tax 7,315 79,042 10,385 79,042 Net (income)/loss attributable to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (1,610 ) (3,029 ) (2,515 ) (5,617 ) Net (income)/loss attributable to noncontrolling interests (8 ) — (314 ) (7 ) Net income/(loss) attributable to UDR, Inc. $ 17,946 $ 86,855 $ 28,339 $ 160,677 (a) Same-Store Community population consisted of 34,179 apartment homes. (b) Same-Store Community population consisted of 34,017 apartment homes.
Details of assets of UDR's reportable segments	The following table details the assets of UDR’s reportable segments as of June 30, 2016 and December 31, 2015 (dollars in thousands) : June 30, December 31, Reportable apartment home segment assets: Same-Store Communities: West Region $ 2,778,642 $ 2,766,939 Mid-Atlantic Region 1,532,799 1,522,868 Northeast Region 1,629,365 1,621,555 Southeast Region 737,292 730,060 Southwest Region 387,874 384,487 Non-Mature Communities/Other 2,246,440 2,164,367 Total segment assets 9,312,412 9,190,276 Accumulated depreciation (2,842,273 ) (2,646,874 ) Total segment assets — net book value 6,470,139 6,543,402 Reconciling items: Cash and cash equivalents 5,167 6,742 Restricted cash 20,524 20,798 Funds held in escrow from Internal Revenue Code Section 1031 exchanges 34,732 — Notes receivable, net 19,694 16,694 Investment in and advances to unconsolidated joint ventures, net 933,403 938,906 Other assets 126,423 137,302 Total consolidated assets $ 7,610,082 $ 7,663,844

Reportable Segments (UNITED D57

Reportable Segments (UNITED DOMINION REALTY, L.P.) (Tables)	6 Months Ended
	Jun. 30, 2016
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 and six months ended June 30, 2016 and 2015 , and reconciles NOI to Net income/(loss) attributable to OP unitholders in the Consolidated Statements of Operations (dollars in thousands) : Three Months Ended Six Months Ended June 30, (a) June 30, (b) 2016 2015 2016 2015 Reportable apartment home segment rental income Same-Store Communities West Region $ 45,493 $ 41,715 $ 90,095 $ 82,451 Mid-Atlantic Region 10,805 10,554 21,455 20,882 Northeast Region 13,203 12,784 26,209 25,173 Southeast Region 11,918 11,175 23,615 22,172 Non-Mature Communities/Other 19,473 36,930 38,304 72,575 Total consolidated rental income $ 100,892 $ 113,158 $ 199,678 $ 223,253 Reportable apartment home segment NOI Same-Store Communities West Region $ 34,203 $ 31,481 $ 67,830 $ 61,598 Mid-Atlantic Region 7,479 7,294 14,704 14,310 Northeast Region 10,406 9,972 20,463 19,657 Southeast Region 8,165 7,488 16,208 14,755 Non-Mature Communities/Other 14,405 26,048 28,005 50,078 Total consolidated NOI 74,658 82,283 147,210 160,398 Reconciling items: Property management (2,775 ) (3,112 ) (5,492 ) (6,139 ) Other operating expenses (1,519 ) (1,496 ) (3,019 ) (2,986 ) Real estate depreciation and amortization (37,053 ) (44,100 ) (73,844 ) (88,578 ) General and administrative (3,844 ) (7,032 ) (9,265 ) (12,671 ) Casualty-related recoveries/(charges), net (465 ) (280 ) (465 ) (873 ) Income/(loss) from unconsolidated entities (10,030 ) — (23,417 ) — Interest expense (7,578 ) (10,908 ) (15,183 ) (21,679 ) Gain/(loss) on sale of real estate owned — 32,375 — 56,998 Net (income)/loss attributable to noncontrolling interests (350 ) (347 ) (694 ) (741 ) Net income/(loss) attributable to OP unitholders $ 11,044 $ 47,383 $ 15,831 $ 83,729 (a) Same-Store Community population consisted of 14,277 apartment homes. (b) Same-Store Community population consisted of 14,277 apartment homes. The following table details the assets of the Operating Partnership’s reportable segments as of June 30, 2016 and December 31, 2015 (dollars in thousands) : June 30, December 31, 2015 Reportable apartment home segment assets Same-Store Communities West Region $ 1,506,255 $ 1,497,867 Mid-Atlantic Region 413,093 410,710 Northeast Region 672,588 669,082 Southeast Region 324,514 321,787 Non-Mature Communities/Other 748,278 731,459 Total assets 3,664,728 3,630,905 Accumulated depreciation (1,353,616 ) (1,281,258 ) Total assets - net book value 2,311,112 2,349,647 Reconciling items: Cash and cash equivalents 1,535 3,103 Restricted cash 11,659 11,344 Investment in unconsolidated entities 134,823 166,186 Other assets 23,864 24,528 Total consolidated assets $ 2,482,993 $ 2,554,808

Consolidation and Basis of Pr58

Consolidation and Basis of Presentation (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Other Interest and Dividend Income	$ 0.5	$ 0.3	$ 0.8	$ 0.7
Operating Partnership outstanding units	183,278,698		183,278,698
Deferred Tax Assets, Net	$ 8.4		$ 8.4
UDR Lighthouse DownREIT L.P. [Member]
Operating Partnership outstanding units	32,367,380		32,367,380
United Dominion Reality L.P. [Member] | UDR Lighthouse DownREIT L.P. [Member]
Operating Partnership outstanding units	13,470,651		13,470,651
Percentage of units outstanding in Heritage OP	41.61798%		41.61798%
Limited Partner [Member]
Percentage of units outstanding in Heritage OP	95.10%		95.10%
Limited Partner [Member] | UDR Lighthouse DownREIT L.P. [Member]
Operating Partnership outstanding units	16,137,973		16,137,973
Percentage of units outstanding in Heritage OP	49.85876%		49.85876%
General Partner [Member]
Limited partnership units owned	174,227,479		174,227,479
General Partner [Member] | UDR Lighthouse DownREIT L.P. [Member]
Operating Partnership outstanding units	16,229,407		16,229,407
General Partners Capital Account Units Owned Percentage	50.14124%		50.14124%
Non-affiliated Partners [Member]
Limited partnership units owned	9,051,219		9,051,219
Percentage of units outstanding in Heritage OP	4.90%		4.90%

Consolidation and Basis of Pr59

Consolidation and Basis of Presentation (UNITED DOMINION REALTY, L.P.) (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2016CommunitiesApartment_HomesMarketsshares	Jun. 30, 2015	Jun. 30, 2016CommunitiesApartment_HomesMarketsshares	Jun. 30, 2015	Dec. 31, 2015shares
Entity Information [Line Items]
Number of Real Estate Properties | Communities	132		132
Number of apartments owned (in apartments homes) | Apartment_Homes	40,728		40,728
Operating Partnership outstanding units	183,278,698		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%	53.00%	43.00%	53.00%
Number of Real Estate Properties | Communities	56		56
Number of markets operating within (in markets) | Markets	14		14
Number of apartments owned (in apartments homes) | Apartment_Homes	16,974		16,974
OP units outstanding related to general partner	110,883		110,883		110,883
OP units outstanding related to limited partner	183,167,815		183,167,815		183,167,815
Limited Partner [Member]
Entity Information [Line Items]
Percentage of units outstanding in Heritage OP	95.10%		95.10%
General Partner [Member]
Entity Information [Line Items]
OP units outstanding related to limited partner	174,227,479		174,227,479
Non-affiliated Partners [Member]
Entity Information [Line Items]
OP units outstanding related to limited partner	9,051,219		9,051,219
Percentage of units outstanding in Heritage OP	4.90%		4.90%

Significant Accounting Polici60

Significant Accounting Policies (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Accounting Policies [Line Items]
Notes receivable, net	$ 19,694,000		$ 19,694,000		$ 16,694,000
Current Income Tax Expense (Benefit)			0
Deferred Tax Assets, Net	8,400,000		8,400,000
Significant Accounting Policies (Textual) [Abstract]
Note maturity public capital threshold			5,000,000
Note receivable interest income	500,000	$ 300,000	800,000	$ 700,000
Net of a valuation allowance	100,000		100,000
Tax benefit/(expense), net	402,000	$ 1,404,000	$ 805,000	$ 1,829,000
Recognition and evaluation of tax position, whether a tax position is more likely			not (greater than 50 percent probability)
Unrecognized tax benefit, accrued interest or penalties due to examination	$ 0		$ 0
Interest Income, Related Party			$ 0
Note due February 2017 [Member]
Accounting Policies [Line Items]
Note Receivable Interest Rate	10.00%		10.00%
Notes receivable, net					12,994,000
Significant Accounting Policies (Textual) [Abstract]
Notes receivable	$ 13,000,000		$ 13,000,000
Note maturity public capital threshold			$ 5,000,000
Other [Member]
Accounting Policies [Line Items]
Note Receivable Interest Rate	8.00%		8.00%
Notes receivable, net	$ 2,500,000		$ 2,500,000		2,500,000
Significant Accounting Policies (Textual) [Abstract]
Notes receivable	$ 2,500,000		$ 2,500,000
Note due October 2020 [Member]
Accounting Policies [Line Items]
Note Receivable Interest Rate	8.00%		8.00%
Notes receivable, net	$ 1,200,000		$ 1,200,000		1,200,000
Significant Accounting Policies (Textual) [Abstract]
Notes receivable	$ 2,000,000		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%		10.00%
Notes receivable, net	$ 3,000,000		$ 3,000,000		$ 0
Significant Accounting Policies (Textual) [Abstract]
Notes receivable	$ 15,000,000		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			$ (600,000)

Real Estate Owned (Details)

Real Estate Owned (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Land	$ 1,794,615	$ 1,833,156
Land Improvements	178,355	173,821
Depreciable property - held and used:
Building, Improvements, and Furniture, Fixtures and Equipment	7,100,504	7,046,622
Under development:
Real estate under development (net of accumulated depreciation of $0 and $0, respectively)	238,938	124,072
Real estate owned	9,312,412	9,190,276
Real Estates Owned Accumulated Depreciation	2,842,273	2,646,874
Real Estate Investments, Net	6,470,139	6,543,402
Land [Member]
Under development:
Real estate under development (net of accumulated depreciation of $0 and $0, respectively)	111,028	78,085
Real Estate Held-for-sale	0	9,963
Construction in progress [Member]
Under development:
Real estate under development (net of accumulated depreciation of $0 and $0, respectively)	127,910	45,987
Building and Building Improvements [Member]
Under development:
Real Estate Held-for-sale	$ 0	$ 2,642

Real Estate Owned (Details Text

Real Estate Owned (Details Textual) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016USD ($)CommunitiesApartment_HomesStates	Jun. 30, 2015USD ($)	Jun. 30, 2016USD ($)CommunitiesApartment_HomesStates	Jun. 30, 2015USD ($)	Dec. 31, 2015USD ($)
Real Estate Properties [Line Items]
Investment in unconsolidated joint ventures			$ 20,635	$ 184,078
Lessor Leasing Arrangements, Operating Leases, Term of Contract			49 years
Number of Extensions of Ground Lease			2
Lessee Leasing Arrangements, Operating Leases, Renewal Term			25 years
Noncontrolling Interest Held in Joint Venture	95.00%		95.00%
Real Estate Owned (Textual) [Abstract]
Number of states in which there are owned and consolidated communities	10		10
Number of apartment homes owned and consolidated by the Company | Apartment_Homes	40,728		40,728
Number of Real Estate Properties | Communities	132		132
Development costs excluding direct costs and capitlized interest	$ 2,700	$ 1,600	$ 4,700	3,800
Interest capitalized during period	3,800	3,800	8,000	8,600
Other Cost and Expense, Operating	1,892	1,769	3,644	3,535
Proceeds from Sale of Property, Plant, and Equipment			69,400
Payments for (Proceeds from) Investments			66,071
Gain/(loss) on sale of real estate owned, net of tax	7,315	79,042	10,385	79,042
Funds held in escrow from Internal Revenue Code Section 1031 exchanges	34,732		34,732		$ 0
Casualty-related (recoveries)/charges, net	$ (1,629)	(843)	$ (1,629)	(1,839)
Communities Sold | Communities			2
Wilshire LaJolla [Member]
Real Estate Properties [Line Items]
Investment in unconsolidated joint ventures			$ 20,100
1745 Shea [Member]
Real Estate Owned (Textual) [Abstract]
Acquisition of real estate			$ 0	24,067
United Dominion Reality L.P. [Member]
Real Estate Owned (Textual) [Abstract]
Number of states in which there are owned and consolidated communities | States	8		8
Number of apartment homes owned and consolidated by the Company | Apartment_Homes	16,974		16,974
Number of Real Estate Properties | Communities	56		56
Development costs excluding direct costs and capitlized interest	$ 300	200	$ 600	300
Interest capitalized during period	100	100	200	100
Other Cost and Expense, Operating	1,519	1,496	3,019	2,986
Gain/(loss) on sale of real estate owned, net of tax	0	32,375	0	56,998
Casualty-related (recoveries)/charges, net	$ 465	$ 280	$ (465)	$ (873)
Operating Community [Member] | Unconsolidated Joint Venture Vitruvian Park [Member]
Real Estate Properties [Line Items]
Equity Method Investment, Ownership Percentage	50.00%		50.00%		50.00%
Real Estate Owned (Textual) [Abstract]
Number of Real Estate Properties	3		3
Land [Member] | Wilshire LaJolla [Member]
Real Estate Properties [Line Items]
Property, Plant and Equipment, Additions			$ 31,100
Subsequent Investment [Member] | Wilshire LaJolla [Member]
Real Estate Properties [Line Items]
Equity Method Investment, Ownership Percentage	100.00%		100.00%
Initial Investment [Member] | Wilshire LaJolla [Member]
Real Estate Properties [Line Items]
Equity Method Investment, Ownership Percentage	50.00%		50.00%

Real Estate Owned (UNITED DOM63

Real Estate Owned (UNITED DOMINION REALTY, L.P.) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Land	$ 1,794,615	$ 1,833,156
Under development:
Real estate under development (net of accumulated depreciation of $0 and $0, respectively)	238,938	124,072
Real estate owned	9,312,412	9,190,276
Less: accumulated depreciation	(2,842,273)	(2,646,044)
Real estate owned, net	6,470,139	6,543,402
Land [Member]
Under development:
Real estate under development (net of accumulated depreciation of $0 and $0, respectively)	111,028	78,085
Construction in progress [Member]
Under development:
Real estate under development (net of accumulated depreciation of $0 and $0, respectively)	127,910	45,987
United Dominion Reality L.P. [Member]
Property, Plant and Equipment [Line Items]
Land	835,686	833,300
Depreciable property - held and used:
Building, improvements, and furniture, fixture and equipment	2,829,042	2,797,605
Under development:
Real estate owned	3,664,728	3,630,905
Less: accumulated depreciation	(1,353,616)	(1,281,258)
Real estate owned, net	$ 2,311,112	$ 2,349,647

Real Estate Owned (UNITED DOM64

Real Estate Owned (UNITED DOMINION REALTY, L.P.) (Details Textual) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016USD ($)CommunitiesApartment_HomesStates	Jun. 30, 2015USD ($)	Jun. 30, 2016USD ($)CommunitiesApartment_HomesStates	Jun. 30, 2015USD ($)	Dec. 31, 2015USD ($)
Real Estate Owned (Textual) [Abstract]
Number of communities owned (in communities) | Communities	132		132
Number of states operating within (in states)	10		10
Number of apartments owned (in apartments homes) | Apartment_Homes	40,728		40,728
Number of communities acquired apartment homes are within | Communities	0
Development costs excluding direct costs and capitlized interest	$ 2,700	$ 1,600	$ 4,700	$ 3,800
Interest capitalized during period	3,800	3,800	8,000	8,600
Other Cost and Expense, Operating	1,892	1,769	3,644	3,535
Proceeds from Sale of Property, Plant, and Equipment			69,400
Deferred profit from the sale of properties	8,300		8,300		$ 6,800
Casualty-related (recoveries)/charges, net	$ (1,629)	(843)	(1,629)	(1,839)
Payments for (Proceeds from) Investments			$ 66,071
Communities Sold | Communities			2
United Dominion Reality L.P. [Member]
Real Estate Owned (Textual) [Abstract]
Number of communities owned (in communities) | Communities	56		56
Number of states operating within (in states) | States	8		8
Number of apartments owned (in apartments homes) | Apartment_Homes	16,974		16,974
Development costs excluding direct costs and capitlized interest	$ 300	200	$ 600	300
Interest capitalized during period	100	100	200	100
Other Cost and Expense, Operating	1,519	1,496	3,019	2,986
Casualty-related (recoveries)/charges, net	$ 465	$ 280	$ (465)	$ (873)

Joint Ventures (Details)

Joint Ventures (Details) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2016USD ($)Communities	Jun. 30, 2015USD ($)	Mar. 31, 2014USD ($)	Jun. 30, 2016USD ($)Communities	Jun. 30, 2015USD ($)	Dec. 31, 2015USD ($)
Financial information relating to unconsolidated joint ventures operations
Income/(loss) from unconsolidated entities	$ 325	$ (573)		$ 1,004	$ 58,586
Combined summary of balance sheets relating to unconsolidated joint ventures
Investment in unconsolidated entities	933,403			933,403		$ 938,906
Deferred gains on the sale of depreciable property	$ 8,300			$ 8,300		6,800
Number of Real Estate Properties | Communities	132			132
Investments in and advances to unconsolidated joint ventures, net	$ 933,403			$ 933,403		938,906
Unconsolidated Joint Ventures [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment Summarized Financial Information Income/(loss) from discontinued operations	0	0		0	182,488
Financial information relating to unconsolidated joint ventures operations
Total revenues	58,153	55,450	$ 109,996	113,190
Equity Method Investment Summarized Financial Information Property Operating Expense	(22,981)	(21,557)		(46,394)	(41,724)
Real estate depreciation and amortization	(21,770)	(19,402)	(38,754)	(40,713)
Net income /(loss)	(3,605)	(1,685)	$ 179,769	(7,105)
Combined summary of balance sheets relating to unconsolidated joint ventures
Total real estate, net	3,169,088			3,169,088		3,135,757
Equity Method Investment Summarized Financial Information Cash and cash equivalents	27,961			27,961		36,480
Equity Method Investment Summarized Financial Information Amount Due From Related Party	1,069			1,069		0
Equity Method Investment Summarized Financial Information Other assets	20,634			20,634		29,891
Total assets	3,218,752			3,218,752		3,202,128
Amount due to UDR	0			0		7,266
Third party debt	1,707,406			1,707,406		1,614,463
Equity Method Investment Summarized Financial Information Accounts payable and accrued liabilities	74,563			74,563		95,523
Total liabilities	1,781,969			1,781,969		1,717,252
Total equity	1,436,783			1,436,783		1,484,876
Equity Method Investment, Summarized Financial Information, Liabilities and Equity	3,218,752			3,218,752		3,202,128
Investment in unconsolidated entities	692,000			692,000		703,463
Equity Method of Investment Summarized Financial Information Operating income/(loss)	13,402	14,491		26,083	29,518
Equity Method Investment Summarized Financial Information Interest expense	(17,005)	(16,169)		(33,184)	(32,230)
Equity Method Investment Summarized Financial Information Other income/(expense)	(2)	(7)		(4)	(7)
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	$ 21,319			$ 21,319		$ 15,894
Equity Method Investment, Ownership Percentage	19.60%			19.60%		17.20%
Number of apartment homes	150			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	$ 418,701			$ 418,701		$ 425,230
Equity Method Investment, Ownership Percentage	50.00%			50.00%		50.00%
Number of apartment homes	4,642			4,642
Number of Real Estate Properties	21			21
Operating Community [Member] | Unconsolidated Joint Venture Vitruvian Park [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Investment in unconsolidated entities	$ 71,984			$ 71,984		$ 73,469
Equity Method Investment, Ownership Percentage	50.00%			50.00%		50.00%
Number of apartment homes	1,130			1,130
Number of Real Estate Properties	3			3
Operating Community [Member] | Unconsolidated Joint Venture Three [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Investment in unconsolidated entities	$ 15,126			$ 15,126		$ 17,211
Equity Method Investment, Ownership Percentage	30.00%			30.00%		30.00%
Number of apartment homes	660			660
Number of Real Estate Properties	3			3
Operating Community [Member] | Unconsolidated Joint Venture Other MetLife [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Investment in unconsolidated entities	$ 164,870			$ 164,870		$ 171,659
Equity Method Investment, Ownership Percentage	50.60%			50.60%		50.60%
Number of apartment homes	1,437			1,437
Number of Real Estate Properties	1			1
Land Parcel [Member] | Unconsolidated Joint Venture UDR Met Life I Partnership [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Number of Real Estate Properties	3			3
Land Parcel [Member] | Unconsolidated Joint Venture Vitruvian Park [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Number of Real Estate Properties	6			6
Development Community [Member] | Unconsolidated Joint Venture UDR Met Life I Partnership [Member]
Combined summary of balance sheets relating to unconsolidated joint ventures
Number of Real Estate Properties	1			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			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	$ 93,902			$ 93,902		$ 90,747
Income from Participating Loan	$ 1,560	1,352		$ 3,079	2,506
Participating Loan, Interest Rate, Stated Percentage	6.50%			6.50%
Participating Loan Years to Maturity				1 year 1 month 6 days
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	$ 147,501			$ 147,501		$ 144,696
Income from Participating Loan	$ 1,409	$ (548)		$ 3,198	$ (548)
Participating Loan, Interest Rate, Stated Percentage	6.50%			6.50%

Joint Ventures (Details Textual

Joint Ventures (Details Textual) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016USD ($)Communities	Jun. 30, 2015USD ($)	Jun. 30, 2016USD ($)Communities	Jun. 30, 2015USD ($)	Dec. 31, 2015USD ($)
Schedule of Equity Method Investments [Line Items]
Casualty-related charges/(recoveries), net	$ 1,629	$ 843	$ 1,629	$ 1,839
Proceeds from Sale of Property, Plant, and Equipment			$ 69,400
Number of Real Estate Properties | Communities	132		132
Community Threshold, Period Above Occupancy Threshold			3 months
Secured Debt	$ 1,256,119		$ 1,256,119		$ 1,376,945
Joint Ventures
Real Estate Owned Gross	9,312,412		9,312,412		9,190,276
Unamortized discount	8,400		8,400		10,000
First installment of payable incurred in partial consideration for acquisition of ownership interest in joint venture	3,559		3,559
Second installment of payable incurred in partial consideration for acquisition of ownership interest in joint venture	275,526		275,526
Interest expense	(30,678)	(29,673)	(61,782)	(58,473)
Investment in unconsolidated entities	933,403		933,403		938,906
Deferred profit from the sale of properties	8,300		8,300		6,800
Investment in unconsolidated joint ventures			20,635	184,078
Management fees for our involvement in the joint ventures	2,600	$ 2,600	5,400	$ 5,200
717 Olympic [Member]
Schedule of Equity Method Investments [Line Items]
Casualty-related charges/(recoveries), net	$ 0		$ 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		0
Unconsolidated Joint Venture 399 Fremont [Member]
Schedule of Equity Method Investments [Line Items]
Number of apartments of development community	447		447
Wilshire LaJolla [Member]
Joint Ventures
Investment in unconsolidated joint ventures			$ 20,100
Operating Community [Member] | Unconsolidated Joint Venture Vitruvian Park [Member]
Schedule of Equity Method Investments [Line Items]
Number of Real Estate Properties	3		3
Number of apartment homes	1,130		1,130
Joint Ventures
Investment in unconsolidated entities	$ 71,984		$ 71,984		$ 73,469
Equity Method Investment, Ownership Percentage	50.00%		50.00%		50.00%
Operating Community [Member] | Unconsolidated Joint Venture UDR Met Life I Partnership [Member]
Schedule of Equity Method Investments [Line Items]
Number of apartment homes	150		150
Joint Ventures
Investment in unconsolidated entities	$ 21,319		$ 21,319		$ 15,894
Equity Method Investment, Ownership Percentage	19.60%		19.60%		17.20%
Operating Community [Member] | Unconsolidated Joint Venture UDR MetLife II Partnership [Member]
Schedule of Equity Method Investments [Line Items]
Number of Real Estate Properties	21		21
Number of apartment homes	4,642		4,642
Joint Ventures
Investment in unconsolidated entities	$ 418,701		$ 418,701		$ 425,230
Equity Method Investment, Ownership Percentage	50.00%		50.00%		50.00%
Operating Community [Member] | Unconsolidated Joint Venture Three Washington DC [Member]
Schedule of Equity Method Investments [Line Items]
Number of Real Estate Properties	3		3
Number of apartment homes	660		660
Joint Ventures
Investment in unconsolidated entities	$ 15,126		$ 15,126		$ 17,211
Equity Method Investment, Ownership Percentage	30.00%		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		1
Number of apartment homes	1,437		1,437
Joint Ventures
Investment in unconsolidated entities	$ 164,870		$ 164,870		$ 171,659
Equity Method Investment, Ownership Percentage	50.60%		50.60%		50.60%
Development Community [Member] | Unconsolidated Joint Venture UDR Met Life I Partnership [Member]
Schedule of Equity Method Investments [Line Items]
Number of Real Estate Properties	1		1
Development Community [Member] | Unconsolidated Joint Venture Other MetLife [Member]
Schedule of Equity Method Investments [Line Items]
Number of Real Estate Properties	4		4
Development Community [Member] | Preferred Equity Investment West Coast Development JV [Member]
Joint Ventures
Investment in unconsolidated entities	$ 147,501		$ 147,501		$ 144,696
Subsequent Investment [Member] | Wilshire LaJolla [Member]
Joint Ventures
Equity Method Investment, Ownership Percentage	100.00%		100.00%
Initial Investment [Member] | Wilshire LaJolla [Member]
Joint Ventures
Equity Method Investment, Ownership Percentage	50.00%		50.00%

Unconsolidated Entities (UNIT67

Unconsolidated Entities (UNITED DOMINION REALTY, L.P.) Unconsolidated Entities (UNITED DOMINION REALTY, L.P.) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Equity Method Investments	$ 933,403		$ 933,403		$ 938,906
Income/(loss) from unconsolidated entities	325	$ (573)	1,004	$ 58,586
United Dominion Reality L.P. [Member]
Equity Method Investment Summarized Financial Information Real Estate, Net	1,432,291		1,432,291		1,457,244
Equity Method Investment Summarized Financial Information Cash and cash equivalents	0		0		89
Equity Method Investment Summarized Financial Information Other assets	15,334		15,334		37,228
Equity Method Investment Summarized Financial Information Amount Due From Related Party	0		0		35,293
Equity Method Investment, Summarized Financial Information, Assets	1,574,125		1,574,125		1,656,354
Equity Method Investment Summarized Financial Information Accounts payable and accrued liabilities	26,315		26,315		25,487
Equity Method Investment, Summarized Financial Information, Liabilities	515,302		515,302		549,539
Equity Method Investment Summarized Financial Information, Equity	1,058,823		1,058,823		1,106,815
Equity Method Investment, Summarized Financial Information, Liabilities and Equity	1,574,125		1,574,125		1,656,354
Equity Method Investments	134,823		134,823		166,186
Income/(loss) from unconsolidated entities	(10,030)	$ 0	(23,417)	$ 0
UDR Lighthouse DownREIT L.P. [Member] | United Dominion Reality L.P. [Member]
Equity Method Investment Summarized Financial Instrument, Note Receivable	126,500		126,500		126,500
Equity Method Investment Summarized Financial Information, Secured Debt, Net	443,639		443,639		524,052
Equity Method Investment Summarized Financial Information Amount Due to Related Party	45,348		45,348		$ 0
Equity Method Investment, Summarized Financial Information, Revenue	32,646		64,263
Equity Method Investment Summarized Financial Information Property Operating Expense	(11,084)		(22,441)
Equity Method Investment Summarized Financial Information Depreciation Amortization	(30,308)		(60,361)
Equity Method of Investment Summarized Financial Information Operating income/(loss)	(8,746)		(18,539)
Equity Method Investment Summarized Financial Information Interest expense	(3,524)		(7,265)
Equity Method Investment Summarized Financial Information Other income/(expense)	(1,358)		(3,090)
Net income /(loss)	$ (13,628)		$ (28,894)

Unconsolidated Entities (UNIT68

Unconsolidated Entities (UNITED DOMINION REALTY, L.P.) Unconsolidated Entities (UNITED DOMINION REALTY, L.P.) (Details Textual) $ in Thousands	Jun. 30, 2016USD ($)CommunitiesApartment_Homes	Dec. 31, 2015USD ($)
Schedule of Equity Method Investments [Line Items]
Number of Real Estate Properties | Communities	132
Number of apartment homes owned and consolidated by the Company | Apartment_Homes	40,728
Equity Method Investments | $	$ 933,403	$ 938,906
United Dominion Reality L.P. [Member]
Schedule of Equity Method Investments [Line Items]
Number of Real Estate Properties | Communities	56
Number of apartment homes owned and consolidated by the Company | Apartment_Homes	16,974
Equity Method Investments | $	$ 134,823	$ 166,186
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) $ in Thousands	6 Months Ended
	Jun. 30, 2016USD ($)	Dec. 31, 2015USD ($)
Secured debt instruments
Weighted average interest rate	3.76%
Long-term Debt	$ 3,465,177	$ 3,570,795
Unsecured Debt	$ 2,209,058	2,193,850
Weighted Average Years to Maturity	4 years 10 months 9 days
Line of Credit Facility, Amount Outstanding	$ 2,800	2,300
Fixed Rate Debt [Member]
Secured debt instruments
Principal outstanding	$ 831,791	952,801
Weighted average interest rate	4.87%
Weighted Average Years to Maturity	3 years 11 months 23 days
Number of Communities Encumbered	23
Variable Rate Debt [Member]
Secured debt instruments
Principal outstanding	$ 424,328	424,144
Weighted average interest rate	1.78%
Weighted Average Years to Maturity	4 years 10 days
Number of Communities Encumbered	11
Mortgages Notes Payable [Member] | Fixed Rate Debt [Member]
Secured debt instruments
Weighted average interest rate	4.30%
Weighted Average Years to Maturity	6 years 3 months 19 days
Number of Communities Encumbered	5
Mortgages Notes Payable [Member] | Variable Rate Debt [Member]
Secured debt instruments
Weighted average interest rate	2.25%
Weighted Average Years to Maturity	6 months 26 days
Number of Communities Encumbered	1
Tax-exempt secured notes payable [Member] | Variable Rate Debt [Member]
Secured debt instruments
Weighted average interest rate	1.18%
Weighted Average Years to Maturity	6 years 8 months 8 days
Number of Communities Encumbered	2
Fannie Mae credit facilities [Member] | Fixed Rate Debt [Member]
Secured debt instruments
Debt, Weighted Average Interest Rate	5.23%
Weighted Average Years to Maturity	2 years 6 months 22 days
Number of Communities Encumbered	18
Fannie Mae credit facilities [Member] | Variable Rate Debt [Member]
Secured debt instruments
Debt Instrument, Interest Rate at Period End	1.92%
Weighted Average Years to Maturity	3 years 6 months 19 days
Number of Communities Encumbered	8
Secured Debt [Member]
Secured debt instruments
Principal outstanding	$ 1,256,119	1,376,945
Weighted average interest rate	3.82%
Long-term Debt	$ 1,256,119
Weighted Average Years to Maturity	4 years
Number of Communities Encumbered	34
Secured Debt [Member] | Fixed Rate Debt [Member]
Secured debt instruments
Long-term Debt	$ 831,791
Secured Debt [Member] | Variable Rate Debt [Member]
Secured debt instruments
Long-term Debt	$ 424,328
Unsecured Revolving Credit Facility due October 2015 [Member]
Secured debt instruments
Weighted average interest rate	1.36%
Weighted Average Years to Maturity	3 years 6 months 29 days
Line of Credit Facility, Amount Outstanding	$ 255,000	150,000
Unsecured Working Capital Credit Facility due January 2019 [Member]
Secured debt instruments
Weighted average interest rate	1.37%
Weighted Average Years to Maturity	2 years 6 months
Line of Credit Facility, Amount Outstanding	$ 4,199	0
1.21% Term Loan Facility due January 2021 [Member]
Secured debt instruments
Weighted average interest rate	1.40%
Senior Notes	$ 35,000	35,000
Weighted Average Years to Maturity	4 years 6 months 29 days
ThreePointSevenTermNotesDueOctober2020 [Member]
Secured debt instruments
Senior Notes	$ 299,966	299,962
Weighted Average Years to Maturity	4 years 3 months 1 day
2.23% Term Loan Facility due January 2021 [Member]
Secured debt instruments
Weighted average interest rate	2.23%
Senior Notes	$ 315,000	315,000
Weighted Average Years to Maturity	4 years 6 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	$ 398,015	397,836
Weighted Average Years to Maturity	5 years 6 months 10 days
3.75 MTN Due July 2024 [Member]
Secured debt instruments
Weighted average interest rate	3.75%
Senior Notes	$ 299,166	299,114
Weighted Average Years to Maturity	8 years 1 day
Three point seven percent medium term note due October 2020 [Member]
Secured debt instruments
Weighted average interest rate	3.70%
Five Point Two Five Percent, Medium Term Notes, Due January 2016 [Member]
Secured debt instruments
Weighted average interest rate	0.00%
Senior Notes	$ 0	83,260
Weighted Average Years to Maturity	0 years
6.21 Medium Term Note, Due January 2016 [Member]
Secured debt instruments
Weighted average interest rate	0.00%
Senior Notes	$ 0	12,091
Weighted Average Years to Maturity	0 years
Eight Point Five Zero Percent, Debentures, Due September 2024 [Member]
Secured debt instruments
Weighted average interest rate	8.50%
Senior Notes	$ 15,644	15,644
Weighted Average Years to Maturity	8 years 2 months 15 days
4.00% Medium-Term Note due October 2025 [Member]
Secured debt instruments
Weighted average interest rate	4.00%
Senior Notes	$ 299,363	299,329
Weighted Average Years to Maturity	9 years 3 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	$ 299,178	298,963
Weighted Average Years to Maturity	1 year 11 months 1 day
Other [Member]
Secured debt instruments
Senior Notes	$ 23	24
Unsecured Debt [Member]
Secured debt instruments
Weighted average interest rate	3.58%
Long-term Debt	$ 2,209,058
Unsecured Debt	$ 2,209,058	2,193,850
Weighted Average Years to Maturity	5 years 5 months
Fair Value, Measurements, Recurring [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Mortgages Notes Payable [Member] | Mortgages Notes Payable [Member] | Fixed Rate Debt [Member]
Secured debt instruments
Principal outstanding	$ 322,689	442,617
Fair Value, Measurements, Recurring [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Mortgages Notes Payable [Member] | Mortgages Notes Payable [Member] | Variable Rate Debt [Member]
Secured debt instruments
Principal outstanding	31,337	31,337
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	512,584	514,462
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	299,378	299,378
Unsecured Debt [Member]
Secured debt instruments
Deferred Finance Costs, Net	(11,496)	(12,373)
Secured Debt [Member] | Variable Rate Debt [Member]
Secured debt instruments
Deferred Finance Costs, Net	(1,087)	(1,271)
Secured Debt [Member] | Fixed Rate Debt [Member]
Secured debt instruments
Deferred Finance Costs, Net	$ (3,482)	$ (4,278)

Secured and Unsecured Debt (D70

Secured and Unsecured Debt (Details 1) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Mar. 31, 2014	Jun. 30, 2016	Dec. 31, 2015
Line of Credit Facility [Line Items]
Unamortized discount		$ 8,400	$ 10,000
Secured credit facilities
Borrowings outstanding		$ 2,800	2,300
Debt Instrument Weighted Average Years to Maturity		4 years 10 months 9 days
6.21 Medium Term Note, Due January 2016 [Member]
Secured credit facilities
Debt Instrument Weighted Average Years to Maturity		0 years
Five Point Two Five Percent, Medium Term Notes, Due January 2015 [Member]
Line of Credit Facility [Line Items]
Unamortized discount		$ 0	0
Fannie Mae [Member]
Secured credit facilities
Borrowings outstanding		811,962	$ 813,840
Weighted average daily borrowings during the period ended	$ 822,521	812,752
Maximum daily borrowings during the period ended	$ 834,003	$ 813,544
Weighted average interest rate during the period ended	4.02%	4.00%
Interest rate at the end of the period		4.01%	3.93%
Four Point Two Five Percentage Medium-Term Notes due June 2018 [Member]
Line of Credit Facility [Line Items]
Unamortized discount		$ 822	$ 1,037
Secured credit facilities
Debt Instrument Weighted Average Years to Maturity		1 year 11 months 1 day
Three point seven percent medium term note due October 2020 [Member]
Line of Credit Facility [Line Items]
Unamortized discount		$ 34	38
Four Point Six Three Percent Term Medium Notes Due January Two Thousand Twenty-Two [Member]
Line of Credit Facility [Line Items]
Unamortized discount		$ 1,985	2,164
Secured credit facilities
Debt Instrument Weighted Average Years to Maturity		5 years 6 months 10 days
3.75 MTN Due July 2024 [Member]
Line of Credit Facility [Line Items]
Unamortized discount		$ 834	$ 886
Secured credit facilities
Debt Instrument Weighted Average Years to Maturity		8 years 1 day

Secured and Unsecured Debt (D71

Secured and Unsecured Debt (Details 2) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Secured Debt, Encumbers Real Estate Owned, Amount	$ 2,100,000
Secured Debt, Encumbers Real Estate Owned, Percent	22.50%
Debt Instrument Weighted Average Years to Maturity	4 years 10 months 9 days
Unamortized discount	$ 8,400	$ 10,000
Aggregate maturities of secured debt
2,014	3,559
2,015	275,526
2,016	511,065
2,017	319,695
2,018	725,664
Total	1,256,119	1,376,945
Secured Debt, Unencumbered Real Estate Owned, Amount	$ 7,200,000
Secured Debt, Unencumbered Real Estate Owned, Percent	77.50%
Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	3 years 11 months 23 days
Variable Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	4 years 10 days
ThreePointSevenTermNotesDueOctober2020 [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	4 years 3 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	5 years 6 months 10 days
Unamortized discount	$ 1,985	2,164
Mortgages Notes Payable [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	6 years 3 months 19 days
Mortgages Notes Payable [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	6 months 26 days
Tax Exempt Notes Payable [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	6 years 8 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 22 days
Fannie Mae credit facilities [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	3 years 6 months 19 days
3.75 MTN Due July 2024 [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	8 years 1 day
Unamortized discount	$ 834	886
Five Point Two Five Percent, Medium Term Notes, Due January 2015 [Member]
Debt Instrument [Line Items]
Unamortized discount	$ 0	$ 0
Five Point Two Five Percent, Medium Term Notes, Due January 2016 [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	0 years

Secured and Unsecured Debt (D72

Secured and Unsecured Debt (Details 3) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Summary of unsecured debt
Unsecured Debt, Total	$ 2,209,058	$ 2,193,850
Unamortized discount	8,400	10,000
4.63% Medium-Term Notes due January 2022 [Member]
Summary of unsecured debt
Senior Unsecured Notes	398,015	397,836
Unamortized discount	1,985	2,164
5.25% Medium-Term Notes due January 2015 [Member]
Summary of unsecured debt
Unamortized discount	0	0
5.25% Medium-Term Notes due January 2016 [Member]
Summary of unsecured debt
Senior Unsecured Notes	0	83,260
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	299,178	298,963
Unamortized discount	822	1,037
Other [Member]
Summary of unsecured debt
Senior Unsecured Notes	$ 23	$ 24

Secured and Unsecured Debt (D73

Secured and Unsecured Debt (Details 4) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Summary of short-term bank borrowings under unsecured commercial bank credit facility
Borrowings outstanding at end of period	$ 2,800
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	155,780	$ 353,647
Maximum daily borrowings during the period ended	$ 260,000	$ 541,500
Weighted average interest rate during the period ended	1.30%	1.10%
Interest rate at the end of the period	1.40%		1.20%
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	$ 30,000		$ 30,000
Borrowings outstanding at end of period	4,199
Weighted average daily borrowings during the period ended	12,601	$ 0
Maximum daily borrowings during the period ended	$ 29,361	$ 0
Weighted average interest rate during the period ended	1.30%	0.00%
Interest rate at the end of the period	1.40%		0.00%
Unsecured Revolving Credit Facility due October 2015 [Member]
Summary of short-term bank borrowings under unsecured commercial bank credit facility
Borrowings outstanding at end of period	$ 255,000

Secured and Unsecured Debt (D74

Secured and Unsecured Debt (Details 5) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 3,477,162
Debt Instrument, Unamortized Discount (Premium), Net	(11,985)
Aggregate maturities of unsecured debt
2,014	3,559
2,015	275,526
2,016	511,065
2,017	319,695
2,018	725,664
Unsecured Debt, Total	2,209,058	$ 2,193,850
Long-term Debt	3,465,177	3,570,795
Long-Term Debt, Maturities, Repayment of Principle in Year Six	350,000
Long-Term Debt, Maturities, Repayment of Principle in Year Seven	400,000
Long-Term Debt, Maturities, Repayment of Principle in Year Eight	96,409
Long-Term Debt, Maturities, Repayment of Principle in Year Nine	315,644
Long-Term Debt, Maturities, Repayment of Principle in Year Ten	427,600
Long-Term Debt, Maturities, Repayments of Principal after Year Ten	52,000
Secured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	1,252,319
Debt Instrument, Unamortized Discount (Premium), Net	3,800
Aggregate maturities of unsecured debt
2,014	3,559
2,015	275,526
2,016	211,065
2,017	315,496
2,018	170,664
Long-term Debt	1,256,119
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	96,409
Long-Term Debt, Maturities, Repayment of Principle in Year Nine	0
Long-Term Debt, Maturities, Repayment of Principle in Year Ten	127,600
Long-Term Debt, Maturities, Repayments of Principal after Year Ten	52,000
Unsecured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	2,224,843
Debt Instrument, Unamortized Discount (Premium), Net	(15,785)
Aggregate maturities of unsecured debt
2,014	0
2,015	0
2,016	300,000
2,017	4,199
2,018	555,000
Unsecured Debt, Total	2,209,058	$ 2,193,850
Long-term Debt	2,209,058
Long-Term Debt, Maturities, Repayment of Principle in Year Six	350,000
Long-Term Debt, Maturities, Repayment of Principle in Year Seven	400,000
Long-Term Debt, Maturities, Repayment of Principle in Year Eight	0
Long-Term Debt, Maturities, Repayment of Principle in Year Nine	315,644
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	826,904
Debt Instrument, Unamortized Discount (Premium), Net	4,887
Aggregate maturities of unsecured debt
2,014	3,559
2,015	179,189
2,016	73,096
2,017	247,796
2,018	170,664
Long-term Debt	831,791
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	127,600
Long-Term Debt, Maturities, Repayments of Principal after Year Ten	25,000
Variable Rate Debt [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	425,415
Debt Instrument, Unamortized Discount (Premium), Net	(1,087)
Aggregate maturities of unsecured debt
2,014	0
2,015	96,337
2,016	137,969
2,017	67,700
2,018	0
Long-term Debt	424,328
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	96,409
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 (D75

Secured and Unsecured Debt (Details Textual) $ in Thousands	Jun. 27, 2014	Jun. 30, 2016USD ($)	Jun. 30, 2015USD ($)	Jun. 30, 2016USD ($)	Jun. 30, 2015USD ($)	Jul. 18, 2016USD ($)	Dec. 31, 2015USD ($)
Debt Instrument [Line Items]
Amortization of Financing Costs		$ 1,200	$ 1,500	$ 2,400	$ 3,000
Secured Debt (Textual) [Abstract]
Secured debt amount which encumbers real estate owned based upon book value		$ 2,100,000		$ 2,100,000
Percentage of secured debt which encumbers real estate owned based upon book value		22.50%		22.50%
Secured debt amount of real estate owned which is unencumbered		$ 7,200,000		$ 7,200,000
Percentage of secured debt of real estate owned which is unencumbered		77.50%		77.50%
Weighted average interest rate				3.76%
Unamortized fair market adjustment		$ 8,400		$ 8,400			$ 10,000
Borrowings outstanding		2,800		2,800			2,300
Secured Debt		1,256,119		1,256,119			1,376,945
Fixed Rate Debt [Member]
Secured Debt (Textual) [Abstract]
Secured debt including debt on real estate held for sale		831,791		$ 831,791			952,801
Weighted average interest rate				4.87%
Fixed Rate Mortgage Due June 2026 [Member]
Secured Debt (Textual) [Abstract]
Weighted average interest rate				3.35%
Secured Debt		25,000		$ 25,000
Variable Rate Debt [Member]
Secured Debt (Textual) [Abstract]
Secured debt including debt on real estate held for sale		$ 424,328		$ 424,328			424,144
Weighted average interest rate				1.78%
Unsecured Debt [Member]
Secured Debt (Textual) [Abstract]
Weighted average interest rate				3.58%
Line of Credit Facility, Interest Rate Description				95
Line of Credit Facility, Description Range Low		90		90
Line of Credit Facility, Description Range High		175		175
Unsecured Working Capital Credit Facility due January 2019 [Member]
Secured Debt (Textual) [Abstract]
Credit facilities with aggregate commitment		$ 30,000		$ 30,000			30,000
Weighted average interest rate				1.37%
Borrowings outstanding		$ 4,199		$ 4,199			0
Line of Credit Facility, Interest Rate Description				90
Line of Credit Facility, Description Range Low		85		85
Line of Credit Facility, Description Range High		155		155
3.75 MTN Due July 2024 [Member]
Secured Debt (Textual) [Abstract]
Weighted average interest rate				3.75%
Unamortized fair market adjustment		$ 834		$ 834			886
Debt Instrument, Maturity Date	Jul. 1, 2024
Mortgages Notes Payable [Member] | Fixed Rate Debt [Member]
Secured Debt (Textual) [Abstract]
Weighted average interest rate				4.30%
Debt Instrument, Maturity Date Range, Start				Feb. 1, 2017
Debt instrument, maturity date range, end				Jun. 5, 2026
Notes payable minimum interest rates range				3.35%
Notes payable maximum interest rates range				5.86%
Mortgages Notes Payable [Member] | Variable Rate Debt [Member]
Secured Debt (Textual) [Abstract]
Weighted average interest rate				2.25%
Debt Assumed As Part of Acquisition [Member]
Secured Debt (Textual) [Abstract]
Amortization of Debt Discount (Premium)				$ 1,500	$ 2,400
Tax Exempt Notes Payable [Member] | Variable Rate Debt [Member]
Secured Debt (Textual) [Abstract]
Weighted average interest rate				1.18%
Fannie Mae credit facilities [Member] | Fixed Rate Debt [Member]
Secured Debt (Textual) [Abstract]
Debt, Weighted Average Interest Rate		5.23%		5.23%
Debt Instrument, Maturity Date Range, Start				May 1, 2017
Debt instrument, maturity date range, end				Jul. 1, 2023
Fannie Mae credit facilities [Member] | Variable Rate Debt [Member]
Secured Debt (Textual) [Abstract]
Debt Instrument, Interest Rate at Period End		1.92%		1.92%
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 maximum interest rates range				1.18%
Fannie Mae [Member]
Secured Debt (Textual) [Abstract]
Borrowings outstanding		$ 811,962		$ 811,962			813,840
Revolving Credit Facility [Member]
Secured Debt (Textual) [Abstract]
Line of Credit Facility, Interest Rate Description				90
Line of Credit Facility, Description Range Low		85		85
Line of Credit Facility, Description Range High		155		155
Line of Credit Facility, Commitment Fee Description Range Low		12.5		12.5
Line of Credit Facility, Commitment Fee Description Range High		30		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		$ 200,000
Long-term Debt, Weighted Average Interest Rate		4.55%		4.55%
UDR Bank Credit Facility [Member]
Secured Debt (Textual) [Abstract]
Credit facilities with aggregate commitment		$ 2,000,000		$ 2,000,000			1,100,000
Number of Extensions of loan		2		2
Extension period of option on loan				6 months
UDR Bank Credit Facility [Member] | Unsecured Debt [Member]
Secured Debt (Textual) [Abstract]
Credit facilities with aggregate commitment		$ 350,000		$ 350,000
UDR Bank Credit Facility [Member] | Revolving Credit Facility [Member]
Secured Debt (Textual) [Abstract]
Credit facilities with aggregate commitment		1,100,000		1,100,000
Unsecured Working Capital Credit Facility due January 2019 [Member]
Secured Debt (Textual) [Abstract]
Credit facilities with aggregate commitment		30,000		30,000
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		512,584		512,584			514,462
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		299,378		299,378			299,378
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		322,689		322,689			442,617
Mortgages Notes Payable [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Fair Value, Measurements, Recurring [Member] | Mortgages Notes Payable [Member] | Variable Rate Debt [Member]
Secured Debt (Textual) [Abstract]
Secured debt including debt on real estate held for sale		$ 31,337		$ 31,337			$ 31,337
Subsequent Event [Member] | Unsecured Working Capital Credit Facility due January 2019 [Member]
Secured Debt (Textual) [Abstract]
Credit facilities with aggregate commitment						$ 75,000
Subsequent Event [Member] | Mortgages Notes Payable [Member] | Fair Value, Measurements, Recurring [Member] | Mortgages Notes Payable [Member] | Variable Rate Debt [Member]
Secured Debt (Textual) [Abstract]
Secured debt including debt on real estate held for sale						$ 31,300

Secured and Unsecured Debt (D76

Secured and Unsecured Debt (Details Textual 1) - USD ($) $ in Thousands	Sep. 26, 2013	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Debt Instrument [Line Items]
Amortization of Financing Costs		$ 1,200	$ 1,500	$ 2,400	$ 3,000
Unsecured Debt (Textual) [Abstract]
Line of Credit Facility, Amount Outstanding		2,800		2,800		$ 2,300
Unamortized discount		8,400		$ 8,400		10,000
Debt Instrument, Interest Rate During Period				3.76%
ThreePointSevenTermNotesDueOctober2020 [Member]
Unsecured Debt (Textual) [Abstract]
Debt Instrument, Maturity Date	Oct. 31, 2020
Senior Notes		299,966		$ 299,966		299,962
4.63% Medium-Term Notes due January 2022 [Member]
Unsecured Debt (Textual) [Abstract]
Unamortized discount		1,985		1,985		2,164
Senior Notes		398,015		$ 398,015		397,836
Debt Instrument, Interest Rate During Period				4.63%
UDR Bank Credit Facility [Member]
Unsecured Debt (Textual) [Abstract]
Total revolving credit facility		$ 2,000,000		$ 2,000,000		$ 1,100,000
Interest rate		1.40%		1.40%		1.20%

Debt (UNITED DOMINION REALTY,77

Debt (UNITED DOMINION REALTY, L.P.) (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2016USD ($)Communities	Dec. 31, 2015USD ($)
Debt Instrument [Line Items]
Weighted average interest rate	3.76%
Debt Instrument Weighted Average Years to Maturity	4 years 10 months 9 days
Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Principal outstanding	$ 831,791	$ 952,801
Weighted average interest rate	4.87%
Debt Instrument Weighted Average Years to Maturity	3 years 11 months 23 days
Number of Communities Encumbered (in communities)	23
Fixed Rate Debt [Member] | Mortgages Notes Payable [Member]
Debt Instrument [Line Items]
Weighted average interest rate	4.30%
Debt Instrument Weighted Average Years to Maturity	6 years 3 months 19 days
Number of Communities Encumbered (in communities)	5
Fixed Rate Debt [Member] | Fannie Mae credit facilities [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	2 years 6 months 22 days
Number of Communities Encumbered (in communities)	18
Variable Rate Debt [Member]
Debt Instrument [Line Items]
Principal outstanding	$ 424,328	424,144
Weighted average interest rate	1.78%
Debt Instrument Weighted Average Years to Maturity	4 years 10 days
Number of Communities Encumbered (in communities)	11
Variable Rate Debt [Member] | Mortgages Notes Payable [Member]
Debt Instrument [Line Items]
Weighted average interest rate	2.25%
Debt Instrument Weighted Average Years to Maturity	6 months 26 days
Number of Communities Encumbered (in communities)	1
Variable Rate Debt [Member] | Fannie Mae credit facilities [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity	3 years 6 months 19 days
Number of Communities Encumbered (in communities)	8
Variable Rate Debt [Member] | Tax Exempt Notes Payable [Member]
Debt Instrument [Line Items]
Weighted average interest rate	1.18%
Debt Instrument Weighted Average Years to Maturity	6 years 8 months 8 days
Number of Communities Encumbered (in communities)	2
United Dominion Reality L.P. [Member]
Debt Instrument [Line Items]
Principal outstanding	$ 446,009	475,964
Weighted average interest rate	3.86%
Debt Instrument Weighted Average Years to Maturity	4 years 3 months 14 days
Number of Communities Encumbered (in communities) | Communities	15
United Dominion Reality L.P. [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Principal outstanding	$ 249,342	279,333
Weighted average interest rate	5.08%
Debt Instrument Weighted Average Years to Maturity	3 years 1 month 27 days
Number of Communities Encumbered (in communities) | Communities	8
United Dominion Reality L.P. [Member] | Fixed Rate Debt [Member] | Mortgages Notes Payable [Member]
Debt Instrument [Line Items]
Principal outstanding	$ 0	30,132
Debt Instrument Weighted Average Years to Maturity	0 years
Number of Communities Encumbered (in communities) | Communities	0
United Dominion Reality L.P. [Member] | Fixed Rate Debt [Member] | Fannie Mae credit facilities [Member]
Debt Instrument [Line Items]
Weighted average interest rate	5.08%
Debt Instrument Weighted Average Years to Maturity	3 years 1 month 27 days
Number of Communities Encumbered (in communities) | Communities	8
United Dominion Reality L.P. [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Principal outstanding	$ 196,667	196,631
Weighted average interest rate	1.99%
Debt Instrument Weighted Average Years to Maturity	5 years 9 months
Number of Communities Encumbered (in communities) | Communities	7
United Dominion Reality L.P. [Member] | Variable Rate Debt [Member] | Fannie Mae credit facilities [Member]
Debt Instrument [Line Items]
Weighted average interest rate	2.12%
Debt Instrument Weighted Average Years to Maturity	4 years 2 months 1 day
Number of Communities Encumbered (in communities) | Communities	6
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	1.18%
Debt Instrument Weighted Average Years to Maturity	15 years 8 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	$ 512,584	514,462
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	299,378	299,378
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	250,638	250,828
Fannie Mae credit facilities [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Fair Value, Measurements, Recurring [Member] | United Dominion Reality L.P. [Member] | Variable Rate Debt [Member] | Fannie Mae credit facilities [Member]
Debt Instrument [Line Items]
Principal outstanding	170,203	170,203
Secured Debt [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Deferred Finance Costs, Net	(1,087)	(1,271)
Secured Debt [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Deferred Finance Costs, Net	(3,482)	(4,278)
Secured Debt [Member] | United Dominion Reality L.P. [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Deferred Finance Costs, Net	(536)	(572)
Secured Debt [Member] | United Dominion Reality L.P. [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Deferred Finance Costs, Net	$ (1,296)	$ (1,627)

Debt (UNITED DOMINION REALTY,78

Debt (UNITED DOMINION REALTY, L.P.) (Details 1) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Mar. 31, 2014	Jun. 30, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity		4 years 10 months 9 days
Borrowings outstanding		$ 2,800	$ 2,300
Fannie Mae [Member]
Debt Instrument [Line Items]
Borrowings outstanding		811,962	$ 813,840
Weighted average daily borrowings during the period ended	$ 822,521	812,752
Maximum daily borrowings during the period ended	$ 834,003	$ 813,544
Weighted average interest rate during the period ended	4.02%	4.00%
Interest rate at the end of the period		4.01%	3.93%
United Dominion Reality L.P. [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity		4 years 3 months 14 days
United Dominion Reality L.P. [Member] | Fannie Mae [Member]
Debt Instrument [Line Items]
Borrowings outstanding		$ 420,841	$ 421,031
Weighted average daily borrowings during the period ended	$ 425,522	421,251
Maximum daily borrowings during the period ended	$ 431,462	$ 421,661
Weighted average interest rate during the period ended	3.80%	3.80%
Interest rate at the end of the period		3.90%	3.80%
Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity		3 years 11 months 23 days
Fixed Rate Debt [Member] | Mortgages [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity		6 years 3 months 19 days
Fixed Rate Debt [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity		2 years 6 months 22 days
Fixed Rate Debt [Member] | United Dominion Reality L.P. [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity		3 years 1 month 27 days
Fixed Rate Debt [Member] | United Dominion Reality L.P. [Member] | Mortgages [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity		0 years
Fixed Rate Debt [Member] | United Dominion Reality L.P. [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity		3 years 1 month 27 days
Variable Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity		4 years 10 days
Variable Rate Debt [Member] | Mortgages [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity		6 months 26 days
Variable Rate Debt [Member] | Tax Exempt Notes Payable [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity		6 years 8 months 8 days
Variable Rate Debt [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity		3 years 6 months 19 days
Variable Rate Debt [Member] | United Dominion Reality L.P. [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity		5 years 9 months
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		15 years 8 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		4 years 2 months 1 day

Debt (UNITED DOMINION REALTY,79

Debt (UNITED DOMINION REALTY, L.P.) (Details 2) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
2,014	$ 3,559
2,015	275,526
2,016	511,065
2,017	319,695
2,018	725,664
Long-term Debt, Gross	3,477,162
Debt Instrument, Unamortized Discount (Premium), Net	(11,985)
Total	1,256,119	$ 1,376,945
Long-Term Debt, Maturities, Repayment of Principle in Year Six	350,000
Long-Term Debt, Maturities, Repayment of Principle in Year Seven	400,000
Long-Term Debt, Maturities, Repayment of Principle in Year Eight	96,409
Long-Term Debt, Maturities, Repayment of Principle in Year Nine	315,644
Long-Term Debt, Maturities, Repayment of Principle in Year Ten	427,600
Long-Term Debt, Maturities, Repayments of Principal after Year Ten	52,000
United Dominion Reality L.P. [Member]
Debt Instrument [Line Items]
2,014	195
2,015	22,206
2,016	145,199
2,017	123,095
2,018	62,836
Thereafter	27,000
Long-term Debt, Gross	447,841
Debt Instrument, Unamortized Discount (Premium), Net	(1,832)
Total	446,009	$ 475,964
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	67,310
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	195
2,015	15,640
2,016	48,872
2,017	123,095
2,018	62,836
Long-term Debt, Gross	250,638
Debt Instrument, Unamortized Discount (Premium), Net	(1,296)
Total	249,342
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	6,566
2,016	96,327
2,017	0
2,018	0
Long-term Debt, Gross	170,203
Debt Instrument, Unamortized Discount (Premium), Net	(447)
Total	169,756
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	67,310
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	(89)
Total	26,911
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,80

Debt (UNITED DOMINION REALTY, L.P.) (Details Textual) - USD ($)	Jun. 27, 2014	Sep. 26, 2013	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity					4 years 10 months 9 days
Amortization of Financing Costs			$ 1,200,000	$ 1,500,000	$ 2,400,000	$ 3,000,000
Borrowings outstanding			2,800,000		$ 2,800,000		$ 2,300,000
Weighted average interest rate					3.76%
Unamortized fair market adjustment			8,400,000		$ 8,400,000		10,000,000
UDR Bank Credit Facility [Member]
Debt Instrument [Line Items]
Total revolving credit facility			2,000,000,000		$ 2,000,000,000		1,100,000,000
Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity					3 years 11 months 23 days
Secured debt including debt on real estate held for sale			831,791,000		$ 831,791,000		952,801,000
Weighted average interest rate					4.87%
Variable Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity					4 years 10 days
Secured debt including debt on real estate held for sale			424,328,000		$ 424,328,000		424,144,000
Weighted average interest rate					1.78%
Fannie Mae [Member]
Debt Instrument [Line Items]
Borrowings outstanding			$ 811,962,000		$ 811,962,000		813,840,000
Fannie Mae credit facilities [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity					2 years 6 months 22 days
Debt Instrument, Maturity Date Range, Start					May 1, 2017
Debt Instrument, Maturity Date Range, End					Jul. 1, 2023
Debt, Weighted Average Interest Rate			5.23%		5.23%
Fannie Mae credit facilities [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity					3 years 6 months 19 days
Debt Instrument, Interest Rate at Period End			1.92%		1.92%
Mortgages [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity					6 years 3 months 19 days
Debt Instrument, Maturity Date Range, Start					Feb. 1, 2017
Weighted average interest rate					4.30%
Notes payable minimum interest rates range					3.35%
Notes payable maximum interest rates range					5.86%
Debt Instrument, Maturity Date Range, End					Jun. 5, 2026
Mortgages [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity					6 months 26 days
Weighted average interest rate					2.25%
Tax Exempt Notes Payable [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity					6 years 8 months 8 days
Weighted average interest rate					1.18%
Unsecured Revolving Credit Facility due October 2015 [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity					3 years 6 months 29 days
Borrowings outstanding			$ 255,000,000		$ 255,000,000		150,000,000
Weighted average interest rate					1.36%
Five Point Two Five Percent, Medium Term Notes, Due January 2016 [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity					0 years
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 11 months 1 day
Weighted average interest rate					4.25%
Unamortized fair market adjustment			822,000		$ 822,000		1,037,000
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			34,000		$ 34,000		38,000
ThreePointSevenTermNotesDueOctober2020 [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity					4 years 3 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					4 years 6 months 29 days
Weighted average interest rate					2.23%
4.63% Medium-Term Notes due January 2022 [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity					5 years 6 months 10 days
Weighted average interest rate					4.63%
Unamortized fair market adjustment			1,985,000		$ 1,985,000		2,164,000
3.75 MTN Due July 2024 [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity					8 years 1 day
Weighted average interest rate					3.75%
Unamortized fair market adjustment			834,000		$ 834,000		886,000
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					9 years 3 months 1 day
Weighted average interest rate					4.00%
United Dominion Reality L.P. [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity					4 years 3 months 14 days
Amortization of Financing Costs			100,000	$ 400,000	$ 300,000	$ 700,000
Secured debt including debt on real estate held for sale			446,009,000		$ 446,009,000		475,964,000
Weighted average interest rate					3.86%
United Dominion Reality L.P. [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity					3 years 1 month 27 days
Secured debt including debt on real estate held for sale			249,342,000		$ 249,342,000		279,333,000
Weighted average interest rate					5.08%
United Dominion Reality L.P. [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity					5 years 9 months
Secured debt including debt on real estate held for sale			196,667,000		$ 196,667,000		196,631,000
Weighted average interest rate					1.99%
United Dominion Reality L.P. [Member] | Fannie Mae [Member]
Debt Instrument [Line Items]
Borrowings outstanding			420,841,000		$ 420,841,000		421,031,000
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					3 years 1 month 27 days
Weighted average interest rate					5.08%
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					4 years 2 months 1 day
Weighted average interest rate					2.12%
United Dominion Reality L.P. [Member] | Mortgages [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Weighted Average Years to Maturity					0 years
Secured debt including debt on real estate held for sale			0		$ 0		30,132,000
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					15 years 8 months 19 days
Secured debt including debt on real estate held for sale			27,000,000		$ 27,000,000		27,000,000
Weighted average interest rate					1.18%
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		$ 300,000,000
United Dominion Reality L.P. [Member] | Three point seven percent medium term note due October 2020 [Member] | Financial Guarantee [Member]
Debt Instrument [Line Items]
Guarantor borrowing capacity			300,000,000		$ 300,000,000
United Dominion Reality L.P. [Member] | 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		$ 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		$ 400,000,000
United Dominion Reality L.P. [Member] | 3.75 MTN Due July 2024 [Member] | Financial Guarantee [Member]
Debt Instrument [Line Items]
Guarantor borrowing capacity			300,000,000		$ 300,000,000
United Dominion Reality L.P. [Member] | 4.00% 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		$ 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			322,689,000		322,689,000		442,617,000
Mortgages [Member] | Fair Value, Measurements, Recurring [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Mortgages [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Secured debt including debt on real estate held for sale			31,337,000		31,337,000		31,337,000
Mortgages [Member] | Fair Value, Measurements, Recurring [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member]
Debt Instrument [Line Items]
Fixed Rate Secured Debt Instruments Fair Value							30,132,000
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			512,584,000		512,584,000		514,462,000
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			299,378,000		299,378,000		299,378,000
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			170,203,000		170,203,000		170,203,000
Fixed Rate Secured Debt Instruments Fair Value			250,638,000		250,638,000		250,828,000
Fannie Mae credit facilities [Member] | Fair Value, Measurements, Recurring [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Fannie Mae credit facilities [Member] | Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Secured debt including debt on real estate held for sale			250,638,000		250,638,000		250,828,000
Fannie Mae credit facilities [Member] | Fair Value, Measurements, Recurring [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Fannie Mae credit facilities [Member] | Variable Rate Debt [Member]
Debt Instrument [Line Items]
Secured debt including debt on real estate held for sale			$ 170,203,000		$ 170,203,000		$ 170,203,000

Income_(Loss) Per Share (Detail

Income/(Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Income/(loss) from continuing operations	$ 12,249	$ 10,842	$ 20,783	$ 87,259
Net Income (Loss) Attributable to Noncontrolling Interest	8	0	314	7
Income/(loss) from continuing operations attributable to UDR, Inc.	17,946	86,855	28,339	160,677
Distributions to preferred stockholders - Series E (Convertible)	(929)	(931)	(1,858)	(1,862)
Income/(loss) from continuing operations operations attributable to common stockholders	17,017	85,924	26,481	158,815
Dilutive Securities, Effect on Basic Earnings Per Share, ESOP Convertible Preferred Stock	0	931	0	0
Income/(Loss) Continuing Operations Available to Common Stockholders - Dilutive	17,017	86,855	26,481	158,815
Net income/(loss)	19,564	89,884	31,168	166,301
Net (income)/loss attributable to noncontrolling interests			(301)
Net (income)/loss attributable to redeemable non-controlling interests in Operating Partnership	1,610	3,029	2,515	5,617
Net (loss)/income attributable to common stockholders	$ 17,017	$ 85,924	$ 26,481	$ 158,815
Denominator for earnings per share - basic and diluted:
Weighted average common shares outstanding	267,113	259,028	265,234	258,567
Incremental Common Shares Attributable to Participating Nonvested Shares with Non-forfeitable Dividend Rights	(845)	(1,179)	(872)	(1,223)
Weighted average number of common shares outstanding — basic	266,268	257,849	264,362	257,344
Incremental shares issuable for assumed conversion of: Stock options and unvested restricted stock	(1,906)	(4,957)	(1,865)	(1,923)
Weighted average number of common shares outstanding — diluted	268,174	262,806	266,227	259,267
Net income/(loss) attributable to common stockholders	$ 0.06	$ 0.33	$ 0.10	$ 0.62
Net income/(loss) attributable to common stockholders	$ 0.06	$ 0.33	$ 0.10	$ 0.61
OP Units [Member]
Denominator for earnings per share - basic and diluted:
Antidilutive securities	25,190	9,125	25,191	9,145
Convertible Preferred Stock [Member]
Denominator for earnings per share - basic and diluted:
Antidilutive securities	3,028	3,036	3,028	3,036
Stock options and unvested restricted stock [Member]
Denominator for earnings per share - basic and diluted:
Antidilutive securities	1,906	1,921	1,865	1,923
RedeemableNoncontrollingInterest [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
(Income)/loss from continuing operations attributable to noncontrolling interest	$ (1,610)	$ (3,029)	$ (2,515)	$ (5,617)

Noncontrolling Interests (Detai

Noncontrolling Interests (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Noncontrolling Interest [Line Items]
Net Income (Loss) Attributable to Noncontrolling Interest	$ 8	$ 0	$ 314	$ 7
Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership	929,985		929,985		$ 946,436
Net Income (Loss) Available to Common Stockholders, Basic	17,017	85,924	26,481	158,815
Change in equity from net income(loss) attributable to common stockholders and conversion of OP Units to UDR Common Stock	17,098	89,403	26,562	162,313
Redeemable noncontrolling interests in the Operating Partnership
Mark to market adjustment to redeemable noncontrolling interests in the Operating Partnership			(3,192)
Adjustment for conversion of noncontrolling interest of unitholders in Operating Partnership	(81)	(3,479)	(81)	(3,498)
Net (income)/loss attributable to redeemable non-controlling interests in Operating Partnership	1,610	$ 3,029	2,515	$ 5,617
Distributions to redeemable noncontrolling interests in the Operating Partnership			(15,093)
Redeemable non-controlling interests in operating partnership	$ 929,985		929,985
Net income attributable to non-controlling interests			$ 301

Related Party Transactions (U83

Related Party Transactions (UNITED DOMINION REALTY, L.P.) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Related Party Transaction [Line Items]
Related party management fees	$ 3,700	$ 4,300	$ 7,300	$ 8,600
United Dominion Reality L.P. [Member]
Related Party Transaction [Line Items]
Limited partnership units owned	183,167,815		183,167,815		183,167,815
Related Party Transaction, Management Fee Percentage			2.75%
Interest Expense, Related Party	$ 3,053	1,151	$ 6,106	2,302
Notes payable due to General Partner	273,334		273,334		$ 273,334
United Dominion Reality L.P. [Member] | Taxable REIT Subsidiaries [Member]
Related Party Transaction [Line Items]
Net receivable balances from General Partner	(26,875)		$ (26,875)
Due to Related Parties					(11,270)
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	$ 2,900	$ 5,700	$ 7,500	$ 9,900
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%		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%		5.34%
Debt Instrument, Maturity Date Range, End			Dec. 31, 2023

Fair Value of Derivatives and84

Fair Value of Derivatives and Financial Instruments (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes receivable, net	$ 19,694	$ 16,694
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	3	13
Derivative Liability	3,554	2,112
Secured debt instruments - variable rate
Borrowings outstanding	2,800	2,300
Unsecured debt instruments
Redeemable Noncontrolling Interest, Equity, Carrying Amount	929,985
Redeemable noncontrolling interests in the Operating Partnership (d)	929,985	946,436
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	19,694	16,694
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Total assets	19,697	16,707
Unsecured debt instruments
Total liabilities	3,484,796	3,590,829
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		2,112
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Senior Unsecured Notes [Member] | Fair Value, Measurements, Recurring [Member]
Unsecured debt instruments
Unsecured debt instruments (c)	1,961,355	2,056,223
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)	19,501	16,938
Total assets	19,504	16,951
Unsecured debt instruments
Total liabilities	3,666,854	3,673,283
Redeemable noncontrolling interests in the Operating Partnership (d)	929,985	946,436
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	3	13
Derivatives - Interest rate contracts (b)	3,554	2,112
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	340,060	448,019
Secured debt instruments - variable rate
Secured debt instruments - variable rate	31,337	31,337
Estimate of Fair Value, Fair Value Disclosure [Member] | Tax Exempt Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - variable rate
Secured debt instruments - variable rate	94,700	94,700
Estimate of Fair Value, Fair Value Disclosure [Member] | Line of Credit [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	542,250	539,050
Secured debt instruments - variable rate
Secured debt instruments - variable rate	299,378	299,378
Unsecured debt instruments
Unsecured debt instruments (c)	259,199	150,000
Estimate of Fair Value, Fair Value Disclosure [Member] | Senior Unsecured Notes [Member] | Fair Value, Measurements, Recurring [Member]
Unsecured debt instruments
Unsecured debt instruments (c)	2,096,376	2,108,687
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Notes receivable (a)	0	0
Total assets	0	0
Unsecured debt instruments
Total liabilities	0	0
Redeemable noncontrolling interests in the Operating Partnership (d)	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 1 [Member] | Interest Rate Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Derivatives - Interest rate contracts	0	0
Derivatives - Interest rate contracts (b)	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 1 [Member] | Mortgages Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	0	0
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 1 [Member] | Tax Exempt Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 1 [Member] | Line of Credit [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	0	0
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 1 [Member] | Commercial bank [Member] | Fair Value, Measurements, Recurring [Member]
Unsecured debt instruments
Unsecured debt instruments (c)	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 1 [Member] | Senior Unsecured Notes [Member] | Fair Value, Measurements, Recurring [Member]
Unsecured debt instruments
Unsecured debt instruments (c)	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 2 [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Notes receivable (a)	0	0
Total assets	3	13
Unsecured debt instruments
Total liabilities	3,554	2,112
Redeemable noncontrolling interests in the Operating Partnership (d)	929,985	946,436
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	3	13
Derivatives - Interest rate contracts (b)	3,554	2,112
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 2 [Member] | Mortgages Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	0	0
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 2 [Member] | Tax Exempt Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 2 [Member] | Line of Credit [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	0	0
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 2 [Member] | Commercial bank [Member] | Fair Value, Measurements, Recurring [Member]
Unsecured debt instruments
Unsecured debt instruments (c)	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 2 [Member] | Senior Unsecured Notes [Member] | Fair Value, Measurements, Recurring [Member]
Unsecured debt instruments
Unsecured debt instruments (c)	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Notes receivable (a)	19,501	16,938
Total assets	19,501	16,938
Unsecured debt instruments
Total liabilities	3,663,300	3,671,171
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	340,060	448,019
Secured debt instruments - variable rate
Secured debt instruments - variable rate	31,337	31,337
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 3 [Member] | Tax Exempt Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - variable rate
Secured debt instruments - variable rate	94,700	94,700
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 3 [Member] | Line of Credit [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	542,250	539,050
Secured debt instruments - variable rate
Secured debt instruments - variable rate	299,378	299,378
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 3 [Member] | Commercial bank [Member] | Fair Value, Measurements, Recurring [Member]
Unsecured debt instruments
Unsecured debt instruments (c)	259,199	150,000
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)	2,096,376	2,108,687
Unsecured Revolving Credit Facility and Working Capital Credit Facility [Member]
Secured debt instruments - variable rate
Borrowings outstanding	259,199
Unsecured Revolving Credit Facility due October 2015 [Member]
Secured debt instruments - variable rate
Borrowings outstanding	255,000	150,000
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	424,328	424,144
Variable Rate Debt [Member] | Tax Exempt Notes Payable [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Tax Exempt Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Secured debt including debt on real estate held for sale	94,700	94,700
Variable Rate Debt [Member] | Line of Credit [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Line of Credit [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Secured debt including debt on real estate held for sale	299,378	299,378
Variable Rate Debt [Member] | Mortgages Notes Payable [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Mortgages Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Secured debt including debt on real estate held for sale	31,337	31,337
Fixed Rate Debt [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Secured debt including debt on real estate held for sale	831,791	952,801
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	512,584	514,462
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	$ 322,689	$ 442,617

Fair Value of Derivatives and85

Fair Value of Derivatives and Financial Instruments (UNITED DOMINION REALTY, L.P.) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
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	$ 2	$ 8
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	19,697	16,707
Secured debt instruments - variable rate
Total liabilities	3,484,796	3,590,829
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	2	8
Secured debt instruments - variable rate
Total liabilities	447,841	478,163
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	2	8
Carrying (Reported) Amount, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Mortgages Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate		30,132
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	250,638	250,828
Secured debt instruments - variable rate
Secured debt instruments - variable rate	170,203	170,203
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	19,504	16,951
Secured debt instruments - variable rate
Total liabilities	3,666,854	3,673,283
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	3	13
Derivative Liability Designated as Hedging Instrument, Fair Value	3,554	2,112
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	340,060	448,019
Secured debt instruments - variable rate
Secured debt instruments - variable rate	31,337	31,337
Estimate of Fair Value, Fair Value Disclosure [Member] | Tax Exempt Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - variable rate
Secured debt instruments - variable rate	94,700	94,700
Estimate of Fair Value, Fair Value Disclosure [Member] | Line of Credit [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	542,250	539,050
Secured debt instruments - variable rate
Secured debt instruments - variable rate	299,378	299,378
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Total assets	0	0
Secured debt instruments - variable rate
Total liabilities	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 1 [Member] | Interest Rate Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Derivatives - Interest rate contracts	0	0
Derivative Liability Designated as Hedging Instrument, Fair Value	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 1 [Member] | Mortgages Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	0	0
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 1 [Member] | Tax Exempt Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 1 [Member] | Line of Credit [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	0	0
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 2 [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Total assets	3	13
Secured debt instruments - variable rate
Total liabilities	3,554	2,112
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	3	13
Derivative Liability Designated as Hedging Instrument, Fair Value	3,554	2,112
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 2 [Member] | Mortgages Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	0	0
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 2 [Member] | Tax Exempt Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 2 [Member] | Line of Credit [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	0	0
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Total assets	19,501	16,938
Secured debt instruments - variable rate
Total liabilities	3,663,300	3,671,171
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	340,060	448,019
Secured debt instruments - variable rate
Secured debt instruments - variable rate	31,337	31,337
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 3 [Member] | Tax Exempt Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - variable rate
Secured debt instruments - variable rate	94,700	94,700
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 3 [Member] | Line of Credit [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	542,250	539,050
Secured debt instruments - variable rate
Secured debt instruments - variable rate	299,378	299,378
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	2	8
Secured debt instruments - variable rate
Total liabilities	464,729	490,581
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	2	8
Estimate of Fair Value, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Mortgages Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate		30,308
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	267,526	263,070
Secured debt instruments - variable rate
Secured debt instruments - variable rate	170,203	170,203
Estimate of Fair Value, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Total assets	0	0
Secured debt instruments - variable rate
Total liabilities	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Level 1 [Member] | Interest Rate Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Derivatives - Interest rate contracts	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Level 1 [Member] | Mortgages Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate		0
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	2	8
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	2	8
Estimate of Fair Value, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Level 2 [Member] | Mortgages Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate		0
Estimate of Fair Value, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Level 2 [Member] | Tax Exempt Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Level 2 [Member] | Line of Credit [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	0	0
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Total assets	0	0
Secured debt instruments - variable rate
Total liabilities	464,729	490,581
Estimate of Fair Value, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Level 3 [Member] | Interest Rate Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Derivatives - Interest rate contracts	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | United Dominion Reality L.P. [Member] | Level 3 [Member] | Mortgages Notes Payable [Member] | Fair Value, Measurements, Recurring [Member]
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate		30,308
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	267,526	263,070
Secured debt instruments - variable rate
Secured debt instruments - variable rate	$ 170,203	$ 170,203

Derivatives and Hedging Activ86

Derivatives and Hedging Activity (Details) $ in Thousands	Jun. 30, 2016USD ($)instruments
Designated as Hedging Instrument [Member] | Interest rate swaps [Member]
Derivative [Line Items]
Number instruments	3
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 Activ87

Derivatives and Hedging Activity (Details 1) $ in Thousands	Jun. 30, 2016USD ($)instruments	Dec. 31, 2015USD ($)
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	$ 2	$ 9
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	1	4
Interest Rate Products [Member] | Other Liabilities [Member] | Designated as Hedging Instrument [Member]
Fair value of Company's derivative financial instruments and their classification on Consolidated Balance Sheet
Derivative Liability Designated as Hedging Instrument, Fair Value	3,554	2,112
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 Activ88

Derivatives and Hedging Activity (Details 2) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Effect of derivative instruments on the Consolidated Statements of Operations
Unrealized holding gain/(loss)	$ (1,963)	$ 6,186	$ (2,774)	$ (1,366)
Amount of Gain or (Loss) Recognized in Income on Derivative	(3)	(22)	(3)	(24)
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)	(943)	(292)	(1,878)	(1,029)
Amount of Gain or (Loss) Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness Testing)	$ 0	$ 0	$ 0	$ 0

Derivatives and Hedging Activ89

Derivatives and Hedging Activity (Details 3) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
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)	3	13
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	3	13
Offsetting Derivative Liabilities [Abstract]
Gross Amounts Offset in the Consolidated Balance Sheets	0	0
Net Amounts of Liabilities Presented in the Consolidated Balance Sheets (b)	3,554	2,112
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	$ 3,554	2,112
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)		$ 2,112

Derivatives and Hedging Activ90

Derivatives and Hedging Activity (Details Textual) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Derivative, Collateral, Obligation to Return Cash	$ 0		$ 0		$ 0
Derivatives And Hedging Activity (Textual) [Abstract]
Estimated additional accumulated other comprehensive Income/(Loss) transferred to interest expense	3,600		3,600
Derivative instruments not designated as hedging instruments, gain (loss), net	(3)	$ (22)	(3)	$ (24)
Payment required to pay for contract termination	3,800		3,800
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	100	100	100
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	0	$ 0	0	$ 0
Interest rate swaps [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Notional	$ 315,000		$ 315,000

Derivatives and Hedging Activ91

Derivatives and Hedging Activity (UNITED DOMINION REALTY, L.P.) (Details) $ in Thousands	Jun. 30, 2016USD ($)instruments
Designated as Hedging Instrument [Member] | Interest rate swaps [Member]
Derivative [Line Items]
Number instruments	3
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	$ 96,327
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	$ 98,932

Derivatives and Hedging Activ92

Derivatives and Hedging Activity (UNITED DOMINION REALTY, L.P.) (Details 1) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Interest Rate Products [Member] | Other Assets [Member] | Designated as Hedging Instrument [Member]
Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract]
Derivative Asset Designated as Hedging Instrument, Fair Value	$ 2	$ 9
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	1	4
Interest Rate Products [Member] | Other Liabilities [Member] | Designated as Hedging Instrument [Member]
Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract]
Derivative Liability Designated as Hedging Instrument, Fair Value	3,554	2,112
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	2	8
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	1	4
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	1	4
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 Activ93

Derivatives and Hedging Activity (UNITED DOMINION REALTY, L.P.) (Details 2) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized holding gain/(loss)	$ (1,963)	$ 6,186	$ (2,774)	$ (1,366)
Amount of Gain or (Loss) Recognized in Income on Derivative	(3)	(22)	(3)	(24)
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	100	100	100
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)	(943)	(292)	(1,878)	(1,029)
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net	0	0	0	0
United Dominion Reality L.P. [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized holding gain/(loss)	(1)	(26)	(3)	(77)
Amount of Gain or (Loss) Recognized in Income on Derivative	(3)	(22)	100	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			(3)	(23)
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)	(2)	(267)	(3)	(553)
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net	$ 0	$ 0	$ 0	$ 0

Derivatives and Hedging Activ94

Derivatives and Hedging Activity (UNITED DOMINION REALTY, L.P.) (Details 3) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
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)	3	13
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	3	13
Offsetting Derivative Liabilities [Abstract]
Gross Amounts Offset in the Consolidated Balance Sheets	0	0
Net Amounts of Liabilities Presented in the Consolidated Balance Sheets (b)	3,554	2,112
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	3,554	2,112
United Dominion Reality L.P. [Member]
Offsetting Derivative Assets [Abstract]
Derivative Asset Designated as Hedging Instrument, Fair Value	2	8
Gross Amounts Offset in the Consolidated Balance Sheets	0	0
Net Amounts of Assets Presented in the Consolidated Balance Sheets (a)	2	8
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	2	8
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 Activ95

Derivatives and Hedging Activity (UNITED DOMINION REALTY, L.P.) (Details Textual) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Entity Information [Line Items]
Estimated additional accumulated other comprehensive Income/(Loss) transferred to interest expense	$ 3,600,000		$ 3,600,000
Losses in the fair value of derivatives not designated in hedging relationships	3,000	$ 22,000	3,000	$ 24,000
Payment required to pay for contract termination	3,800,000		3,800,000
Derivative, Collateral, Obligation to Return Cash	$ 0		$ 0		$ 0
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
Cash flow hedge ineffectiveness in earnings materiality	0	0	0	0
Losses in the fair value of derivatives not designated in hedging relationships	$ 3,000	$ 22,000	$ (100,000)	$ 0
Fair value of derivatives in a net liability position	0		0
Derivative, Collateral, Obligation to Return Cash	$ 0		$ 0		$ 0

Stock Based Compensation (Detai

Stock Based Compensation (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Stock Based Compensation (Textual) [Abstract]
Stock based compensation expense	$ 3.2	$ 4.8	$ 7.1	$ 9.1

Capital Structure (UNITED DOM97

Capital Structure (UNITED DOMINION REALTY, L.P.) (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2016USD ($)$ / Unitsshares	Dec. 31, 2015USD ($)shares
Limited Partners' Capital Account [Line Items]
Redeemable Noncontrolling Interest, Equity, Carrying Amount | $	$ 929,985
Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership | $	$ 929,985	$ 946,436
United Dominion Reality L.P. [Member]
Limited Partners' Capital Account [Line Items]
General Partnership units outstanding	110,883	110,883
Limited partnership units owned	183,167,815	183,167,815
Limited Partners' Capital Account, Required Period To Be Outstanding Before Unit is Redeemable	1 year
Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership | $	$ 334,200	$ 340,100
UDR, Inc. [Member]
Limited Partners' Capital Account [Line Items]
Limited partnership units owned	174,116,596
Percentage of units	95.10%
Non-affiliated Partners [Member]
Limited Partners' Capital Account [Line Items]
Limited partnership units owned	9,051,219
Percentage of units	4.90%
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	1,873,332
Class A Limited Partner [Member] | UDR, Inc. [Member]
Limited Partners' Capital Account [Line Items]
Limited partnership units owned	121,661

Commitments and Contingencies98

Commitments and Contingencies (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2016USD ($)Communities	Jun. 30, 2015USD ($)
Real Estate Properties [Line Items]
Development costs and capital expenditures incurred but not yet paid	$ 42,940	$ 23,523
Number of communities owned (in communities) | Communities	132
Costs Incurred to Date	$ 1,025,766
Expected Costs to Complete	582,296
Wholly owned — under development [Member]
Real Estate Properties [Line Items]
Development costs and capital expenditures incurred but not yet paid	$ 28,400
Number of communities owned (in communities)	2
Costs Incurred to Date	$ 238,938
Expected Costs to Complete	$ 469,562
Average Ownership Stake	100.00%
Wholly owned — redevelopment [Member]
Real Estate Properties [Line Items]
Development costs and capital expenditures incurred but not yet paid	$ 5,100
Number of communities owned (in communities)	4
Costs Incurred to Date	$ 20,752
Expected Costs to Complete	$ 24,648
Average Ownership Stake	100.00%
Unconsolidated joint ventures [Member]
Real Estate Properties [Line Items]
Number of communities owned (in communities)	5
Costs Incurred to Date	$ 614,300
Expected Costs to Complete	$ 88,086
Participating Loan Investment Steele Creek Denver Colorado [Member]
Real Estate Properties [Line Items]
Number of communities owned (in communities)	1
Costs Incurred to Date	$ 93,902
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	$ 57,874
Expected Costs to Complete	$ 0
Average Ownership Stake	48.00%

Commitments and Contingencies99

Commitments and Contingencies (UNITED DOMINION REALTY, L.P.) Commitments and Contingencies (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2016USD ($)Communities	Jun. 30, 2015USD ($)
Loss Contingencies [Line Items]
Development costs and capital expenditures incurred but not yet paid	$ 42,940	$ 23,523
Number of communities owned (in communities) | Communities	132
Cost Incurred to Date	$ 1,025,766
Expected Costs to Complete	582,296
United Dominion Reality L.P. [Member]
Loss Contingencies [Line Items]
Development costs and capital expenditures incurred but not yet paid	$ 7,020	$ 5,200
Number of communities owned (in communities) | Communities	56
Wholly owned — redevelopment [Member]
Loss Contingencies [Line Items]
Development costs and capital expenditures incurred but not yet paid	$ 5,100
Number of communities owned (in communities)	4
Cost Incurred to Date	$ 20,752
Expected Costs to Complete	24,648
Wholly owned — redevelopment [Member] | United Dominion Reality L.P. [Member]
Loss Contingencies [Line Items]
Development costs and capital expenditures incurred but not yet paid	$ 3,300
Number of communities owned (in communities)	2
Cost Incurred to Date	$ 14,351
Expected Costs to Complete	18,649
Wholly owned — under development [Member]
Loss Contingencies [Line Items]
Development costs and capital expenditures incurred but not yet paid	$ 28,400
Number of communities owned (in communities)	2
Cost Incurred to Date	$ 238,938
Expected Costs to Complete	$ 469,562

Reportable Segments (Details)

Reportable Segments (Details) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2016USD ($)Segments	Jun. 30, 2015USD ($)	Mar. 31, 2014USD ($)	Jun. 30, 2016USD ($)	Jun. 30, 2015USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Segment Reporting Information [Line Items]
Same Store Communities	34,179			34,017
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment NOI	$ 167,315	$ 150,432		$ 331,449	$ 294,007
Reconciling items:
Joint venture management and other fees	2,618	3,098		5,476	15,804
Property management	6,494	5,851		(12,873)	(11,545)
Other operating expenses	(1,892)	(1,769)		(3,644)	(3,535)
Segment Reporting Reconciling Items Cost of Services Depreciation and Amortization	(105,937)	(90,344)		(211,276)	(179,121)
General and administrative	(10,835)	(13,721)		(24,679)	(25,873)
Casualty-related (recoveries)/charges, net	1,629	843		1,629	1,839
Other depreciation and amortization	(1,486)	(1,700)		(3,039)	(3,323)
Income/(loss) from unconsolidated entities	325	(573)		1,004	58,586
Interest expense	30,678	29,673		61,782	58,473
Interest and other income/(expense), net	540	382		971	742
Tax benefit, net	402	1,404		805	1,829
Gain Loss on the Sale of Real Estate, Including Discontinued Operations	7,315	79,042		10,385	79,042
Net (income)/loss attributable to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership	(1,610)	(3,029)		(2,515)	(5,617)
Net (income)/loss attributable to noncontrolling interests	8	0		(314)	(7)
Net income/(loss) attributable to UDR, Inc.	17,946	86,855		28,339	160,677
Reportable apartment home segment assets:
Total segment assets	9,312,412			9,312,412		$ 9,190,276
Accumulated depreciation	(2,842,273)			(2,842,273)		(2,646,874)
Total segment asset - net book value	6,470,139			6,470,139		6,543,402
Reconciling items:
Cash and cash equivalents	5,167	$ 2,990		5,167	$ 2,990	6,742	$ 15,224
Restricted Cash	20,524			20,524		20,798
Funds held in escrow from Internal Revenue Code Section 1031 exchanges	34,732			34,732		0
Notes receivable, net	19,694			19,694		16,694
Investments in and advances to unconsolidated joint ventures, net	933,403			933,403		938,906
Other assets	126,423			126,423		137,302
Total consolidated assets	$ 7,610,082			$ 7,610,082		7,663,844
Reportable Segment (Textual) [Abstract]
Number of reportable segments | Segments	2
Condition for Community considered to have stabilized occupancy				0.9
Number of Tenants or related group of tenants that contributed 10% or more of company total revenue	0	0		0	0
Same Communities [Member]
Reportable Segment (Textual) [Abstract]
SEC Schedule III, Real Estate, Improvements	$ 24,300	$ 18,700		$ 37,500	$ 30,600
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	75,060	69,510		147,423	135,777
Reportable apartment home segment NOI	55,265	51,781		109,541	100,718
Reportable apartment home segment assets:
Total segment assets	2,778,642			2,778,642		2,766,939
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	41,706	41,041		82,910	81,418
Reportable apartment home segment NOI	29,301	28,456		57,357	55,989
Reportable apartment home segment assets:
Total segment assets	1,532,799			1,532,799		1,522,868
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	32,490	30,935		64,560	61,230
Reportable apartment home segment NOI	23,677	22,408		46,609	43,941
Reportable apartment home segment assets:
Total segment assets	1,629,365			1,629,365		1,621,555
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	27,702	25,844		54,839	51,126
Reportable apartment home segment NOI	19,081	17,426		37,877	34,312
Reportable apartment home segment assets:
Total segment assets	737,292			737,292		730,060
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	13,285	12,697		26,428	25,171
Reportable apartment home segment NOI	8,187	8,078		16,415	15,702
Reportable apartment home segment assets:
Total segment assets	387,874			387,874		384,487
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	45,925	32,737		91,965	65,089
Reportable apartment home segment NOI	31,804	22,283		63,650	43,345
Reportable apartment home segment assets:
Total segment assets	2,246,440			2,246,440		2,164,367
Reportable Segment (Textual) [Abstract]
SEC Schedule III, Real Estate, Improvements	1,700	3,200		4,100	7,100
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	$ 236,168	212,764		$ 468,125	419,811
United Dominion Reality L.P. [Member]
Segment Reporting Information [Line Items]
Same Store Communities	14,277			14,277
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment NOI	$ 74,658	82,283	$ 160,398	$ 147,210
Reconciling items:
Property management	(2,775)	(3,112)		(5,492)	(6,139)
Other operating expenses	(1,519)	(1,496)		(3,019)	(2,986)
Segment Reporting Reconciling Items Cost of Services Depreciation and Amortization			(88,578)	(73,844)
General and administrative	(3,844)	(7,032)		(9,265)	(12,671)
Casualty-related (recoveries)/charges, net	(465)	(280)		465	873
Income/(loss) from unconsolidated entities	(10,030)	0		(23,417)	0
Interest expense	7,578	10,908		15,183	21,679
Net (income)/loss attributable to noncontrolling interests	(350)	(347)		(694)	(741)
Net income/(loss) attributable to UDR, Inc.	11,044	47,383	83,729	15,831
Reportable apartment home segment assets:
Total segment assets	3,664,728			3,664,728		3,630,905
Total segment asset - net book value	2,311,112			2,311,112		2,349,647
Reconciling items:
Cash and cash equivalents	1,535	$ 164		1,535	$ 164	3,103	$ 502
Restricted Cash	11,659			11,659		11,344
Other assets	23,864			23,864		24,528
Total consolidated assets	$ 2,482,993			$ 2,482,993		2,554,808
Reportable Segment (Textual) [Abstract]
Related Party Transaction, Management Fee Percentage				2.75%
Number of reportable segments | Segments	2
Number of Tenants or related group of tenants that contributed 10% or more of company total revenue	0	0			0
United Dominion Reality L.P. [Member] | Same-Store [Member]
Reportable Segment (Textual) [Abstract]
SEC Schedule III, Real Estate, Improvements	$ 11,600	$ 9,100		$ 16,700	$ 14,400
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	45,493	41,715		90,095	82,451
Reportable apartment home segment NOI	34,203	31,481		67,830	61,598
Reportable apartment home segment assets:
Total segment assets	1,506,255			1,506,255		1,497,867
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	10,805	10,554		21,455	20,882
Reportable apartment home segment NOI	7,479	7,294		14,704	14,310
Reportable apartment home segment assets:
Total segment assets	413,093			413,093		410,710
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	13,203	12,784		26,209	25,173
Reportable apartment home segment NOI	10,406	9,972		20,463	19,657
Reportable apartment home segment assets:
Total segment assets	672,588			672,588		669,082
United Dominion Reality L.P. [Member] | Same Store Communities Southeastern Region [Member]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	11,918	11,175		23,615	22,172
Reportable apartment home segment NOI	8,165	7,488		16,208	14,755
Reportable apartment home segment assets:
Total segment assets	324,514			324,514		321,787
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	19,473	36,930		38,304	72,575
Reportable apartment home segment NOI	14,405	26,048		28,005	50,078
Reportable apartment home segment assets:
Total segment assets	748,278			748,278		$ 731,459
Reportable Segment (Textual) [Abstract]
SEC Schedule III, Real Estate, Improvements	500	4,100		900	$ 7,100
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	$ 100,892	$ 113,158	$ 223,253	$ 199,678
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 101

Reportable Segments (UNITED DOMINION REALTY, L.P.) (Details) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2016USD ($)Segments	Jun. 30, 2015USD ($)	Mar. 31, 2014USD ($)	Jun. 30, 2016USD ($)	Jun. 30, 2015USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Segment Reporting Information [Line Items]
Equity Method Investments	$ 933,403			$ 933,403		$ 938,906
Same Store Communities	34,179			34,017
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment NOI	$ (167,315)	$ (150,432)		$ (331,449)	$ (294,007)
Reconciling items:
Property management	6,494	5,851		(12,873)	(11,545)
Other operating expenses	(1,892)	(1,769)		(3,644)	(3,535)
General and administrative	(10,835)	(13,721)		(24,679)	(25,873)
Casualty-related (recoveries)/charges, net	1,629	843		1,629	1,839
Income/(loss) from unconsolidated entities	325	(573)		1,004	58,586
Interest expense	30,678	29,673		61,782	58,473
Net (income)/loss attributable to noncontrolling interests	8	0		(314)	(7)
Net income/(loss) attributable to OP unitholders	17,946	86,855		28,339	160,677
Reportable apartment home segment assets:
Total segment assets	9,312,412			9,312,412		9,190,276
Real Estate Investment Property, Accumulated Depreciation	2,842,273			2,842,273		2,646,044
Accumulated depreciation	(2,842,273)			(2,842,273)		(2,646,874)
Total segment asset - net book value	6,470,139			6,470,139		6,543,402
Reconciling items:
Cash and cash equivalents	5,167	$ 2,990		5,167	$ 2,990	6,742	$ 15,224
Restricted cash	20,524			20,524		20,798
Other assets	126,423			126,423		137,302
Total assets	$ 7,610,082			$ 7,610,082		7,663,844
Reportable Segment (Textual) [Abstract]
Number of reportable segments | Segments	2
Condition for Community considered to have stabilized occupancy				0.9
Time to maintain percent occupancy to be considered a community				3 months
Number of Tenants or related group of tenants that contributed 10% or more of company total revenue	0	0		0	0
Same Store Communities Western Region [Member]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	$ 75,060	$ 69,510		$ 147,423	$ 135,777
Reportable apartment home segment NOI	(55,265)	(51,781)		(109,541)	(100,718)
Reportable apartment home segment assets:
Total segment assets	2,778,642			2,778,642		2,766,939
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	41,706	41,041		82,910	81,418
Reportable apartment home segment NOI	(29,301)	(28,456)		(57,357)	(55,989)
Reportable apartment home segment assets:
Total segment assets	1,532,799			1,532,799		1,522,868
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	32,490	30,935		64,560	61,230
Reportable apartment home segment NOI	(23,677)	(22,408)		(46,609)	(43,941)
Reportable apartment home segment assets:
Total segment assets	1,629,365			1,629,365		1,621,555
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	27,702	25,844		54,839	51,126
Reportable apartment home segment NOI	(19,081)	(17,426)		(37,877)	(34,312)
Reportable apartment home segment assets:
Total segment assets	737,292			737,292		730,060
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	13,285	12,697		26,428	25,171
Reportable apartment home segment NOI	(8,187)	(8,078)		(16,415)	(15,702)
Reportable apartment home segment assets:
Total segment assets	387,874			387,874		384,487
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	45,925	32,737		91,965	65,089
Reportable apartment home segment NOI	(31,804)	(22,283)		(63,650)	(43,345)
Reportable apartment home segment assets:
Total segment assets	2,246,440			2,246,440		2,164,367
Reportable Segment (Textual) [Abstract]
SEC Schedule III, Real Estate, Improvements	1,700	3,200		4,100	7,100
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	236,168	212,764		468,125	419,811
United Dominion Reality L.P. [Member]
Segment Reporting Information [Line Items]
Equity Method Investments	$ 134,823			$ 134,823		166,186
Same Store Communities	14,277			14,277
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment NOI	$ (74,658)	(82,283)	$ (160,398)	$ (147,210)
Reconciling items:
Property management	(2,775)	(3,112)		(5,492)	(6,139)
Other operating expenses	(1,519)	(1,496)		(3,019)	(2,986)
General and administrative	(3,844)	(7,032)		(9,265)	(12,671)
Casualty-related (recoveries)/charges, net	(465)	(280)		465	873
Income/(loss) from unconsolidated entities	(10,030)	0		(23,417)	0
Interest expense	7,578	10,908		15,183	21,679
Gains/(loss) on sales of real estate, net of tax	0	32,375
Segment Reporting Reconciling Items Gain Loss on Sale of Property				0	56,998
Net (income)/loss attributable to noncontrolling interests	(350)	(347)		(694)	(741)
Net income/(loss) attributable to OP unitholders	11,044	47,383	83,729	15,831
Reportable apartment home segment assets:
Total segment assets	3,664,728			3,664,728		3,630,905
Real Estate Investment Property, Accumulated Depreciation	1,353,616			1,353,616		1,281,258
Total segment asset - net book value	2,311,112			2,311,112		2,349,647
Reconciling items:
Cash and cash equivalents	1,535	$ 164		1,535	$ 164	3,103	$ 502
Restricted cash	11,659			11,659		11,344
Other assets	23,864			23,864		24,528
Total assets	$ 2,482,993			$ 2,482,993		2,554,808
Reportable Segment (Textual) [Abstract]
Number of reportable segments | Segments	2
Number of Tenants or related group of tenants that contributed 10% or more of company total revenue	0	0			0
Related Party Transaction, Management Fee Percentage				2.75%
Cost of Services, Depreciation and Amortization	$ 37,053	$ 44,100
United Dominion Reality L.P. [Member] | Same-Store [Member]
Reportable Segment (Textual) [Abstract]
SEC Schedule III, Real Estate, Improvements	11,600	9,100		$ 16,700	$ 14,400
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	45,493	41,715		90,095	82,451
Reportable apartment home segment NOI	(34,203)	(31,481)		(67,830)	(61,598)
Reportable apartment home segment assets:
Total segment assets	1,506,255			1,506,255		1,497,867
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	10,805	10,554		21,455	20,882
Reportable apartment home segment NOI	(7,479)	(7,294)		(14,704)	(14,310)
Reportable apartment home segment assets:
Total segment assets	413,093			413,093		410,710
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	13,203	12,784		26,209	25,173
Reportable apartment home segment NOI	(10,406)	(9,972)		(20,463)	(19,657)
Reportable apartment home segment assets:
Total segment assets	672,588			672,588		669,082
United Dominion Reality L.P. [Member] | Same Store Communities Southeastern Region [Member]
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Reportable apartment home segment rental income	11,918	11,175		23,615	22,172
Reportable apartment home segment NOI	(8,165)	(7,488)		(16,208)	(14,755)
Reportable apartment home segment assets:
Total segment assets	324,514			324,514		321,787
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	19,473	36,930		38,304	72,575
Reportable apartment home segment NOI	(14,405)	(26,048)		(28,005)	(50,078)
Reportable apartment home segment assets:
Total segment assets	748,278			748,278		$ 731,459
Reportable Segment (Textual) [Abstract]
SEC Schedule III, Real Estate, Improvements	500	4,100		900	$ 7,100
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	$ 100,892	$ 113,158	$ 223,253	$ 199,678