UDR (UDR) 10-Q 30 Oct 19 2019 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2019	Oct. 28, 2019
Entity information
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Sep. 30, 2019
Entity File Number	1-10524
Entity Registrant Name	UDR, Inc.
Entity Incorporation, State or Country Code	MD
Entity Tax Identification Number	54-0857512
Entity Address, Address Line One	1745 Shea Center Drive, Suite 200
Entity Address, City or Town	Highlands Ranch
Entity Address, State or Province	CO
Entity Address, Postal Zip Code	80129
City Area Code	720
Local Phone Number	283-6120
Title of 12(b) Security	Common Stock
Trading Symbol	UDR
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		293,053,423
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Entity Central Index Key	0000074208
Amendment Flag	false
United Dominion Realty L.P.
Entity information
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Sep. 30, 2019
Entity File Number	333-156002-01
Entity Registrant Name	United Dominion Realty, L.P.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	54-1776887
Entity Address, Address Line One	1745 Shea Center Drive, Suite 200
Entity Address, City or Town	Highlands Ranch
Entity Address, State or Province	CO
Entity Address, Postal Zip Code	80129
City Area Code	720
Local Phone Number	283-6120
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Entity Central Index Key	0001018254
Amendment Flag	false

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Real estate owned:
Real estate held for investment	$ 11,542,550	$ 10,196,159
Less: accumulated depreciation	(4,000,608)	(3,654,160)
Real estate held for investment, net	7,541,942	6,541,999
Real estate under development (net of accumulated depreciation of $0 and $0, respectively)	21,845
Total real estate owned, net of accumulated depreciation	7,563,787	6,541,999
Cash and cash equivalents	1,895	185,216
Restricted cash	21,646	23,675
Notes receivable, net	37,899	42,259
Investment in and advances to unconsolidated joint ventures, net	791,180	780,869
Operating lease right-of-use assets	135,889
Other assets	145,301	137,710
Total assets	8,697,597	7,711,728
Liabilities:
Secured debt, net	600,624	601,227
Unsecured debt, net	3,335,273	2,946,560
Operating lease liabilities	130,135
Real estate taxes payable	42,031	20,608
Accrued interest payable	27,577	38,747
Security deposits and prepaid rent	36,382	35,060
Distributions payable	108,939	97,666
Accounts payable, accrued expenses, and other liabilities	72,680	76,343
Total liabilities	4,353,641	3,816,211
Commitments and contingencies (Note 13)
Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership	1,072,181	972,740
Equity:
Common stock, $0.01 par value; 350,000,000 shares authorized: 292,948,423 and 275,545,900 shares issued and outstanding at September 30, 2019 and December 31, 2018, respectively	2,929	2,755
Additional paid-in capital	5,702,782	4,920,732
Distributions in excess of net income	(2,496,328)	(2,063,996)
Accumulated other comprehensive income/(loss), net	(9,022)	(67)
Total stockholders' equity	3,246,562	2,905,625
Noncontrolling interests	25,213	17,152
Total equity	3,271,775	2,922,777
Total liabilities and equity	8,697,597	7,711,728
8.00% Series E Cumulative Convertible Preferred Stock
Equity:
Preferred stock, no par value; 50,000,000 shares authorized:	46,200	46,200
Series F
Equity:
Preferred stock, no par value; 50,000,000 shares authorized:	$ 1	$ 1

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Real estate owned:
Real estate under development accumulated depreciation	$ 0	$ 0
Equity:
Preferred stock, no par value	$ 0	$ 0
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	292,948,423	275,545,900
Common stock, shares outstanding	292,948,423	275,545,900
8.00% Series E Cumulative Convertible Preferred Stock
Equity:
Preferred stock, dividend rate percentage	8.00%	8.00%
Preferred stock, shares issued	2,780,994	2,780,994
Preferred stock, shares outstanding	2,780,994	2,780,994
Series F
Equity:
Preferred stock, shares issued	14,986,275	15,802,393
Preferred stock, shares outstanding	14,986,275	15,802,393

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
REVENUES:
Rental income	$ 289,008	$ 263,256	$ 835,393	$ 770,373
Joint venture management and other fees	$ 6,386	$ 2,888	$ 11,982	$ 8,819
Type of revenue	udr:ManagementAndOtherFeesMember	udr:ManagementAndOtherFeesMember	udr:ManagementAndOtherFeesMember	udr:ManagementAndOtherFeesMember
Total revenues	$ 295,394	$ 266,144	$ 847,375	$ 779,192
OPERATING EXPENSES:
Property operating and maintenance	46,869	44,090	131,702	126,129
Real estate taxes and insurance	38,490	34,352	110,624	99,541
Property management	8,309	7,240	24,018	21,185
Other operating expenses	2,751	3,314	11,132	8,148
Real estate depreciation and amortization	127,391	107,881	357,793	322,537
General and administrative	12,197	11,896	37,002	36,028
Casualty-related charges/(recoveries), net	(1,088)	678	(842)	2,364
Other depreciation and amortization	1,619	1,682	4,953	5,057
Total operating expenses	236,538	211,133	676,382	620,989
Gain/(loss) on sale of real estate owned			5,282	70,300
Operating income	58,856	55,011	176,275	228,503
Income/(loss) from unconsolidated entities	12,713	(1,382)	19,387	(5,091)
Interest expense	(42,523)	(34,401)	(110,482)	(95,942)
Interest income and other income/(expense), net	1,875	1,188	12,998	5,075
Income/(loss) before income taxes	30,921	20,416	98,178	132,545
Tax (provision)/benefit, net	(1,499)	(158)	(3,836)	(618)
Net income/(loss)	29,422	20,258	94,342	131,927
Net (income)/loss attributable to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership	(2,162)	(1,616)	(6,871)	(10,819)
Net (income)/loss attributable to noncontrolling interests	(56)	(32)	(145)	(141)
Net income/(loss) attributable to UDR, Inc.	27,204	18,610	87,326	120,967
Distributions to preferred stockholders - Series E (Convertible)	(1,031)	(971)	(3,073)	(2,897)
Net income/(loss) attributable to common stockholders	$ 26,173	$ 17,639	$ 84,253	$ 118,070
Income/(loss) per weighted average common share - basic	$ 0.09	$ 0.07	$ 0.30	$ 0.44
Income/(loss) per weighted average common share - diluted	$ 0.09	$ 0.07	$ 0.30	$ 0.44
Weighted average number of common shares outstanding - Basic	288,706	267,727	282,598	267,529
Weighted average number of common shares outstanding - diluted	289,529	268,861	283,292	269,020

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME/(LOSS) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME/(LOSS)
Net income/(loss)	$ 29,422	$ 20,258	$ 94,342	$ 131,927
Other comprehensive income/(loss), including portion attributable to noncontrolling interests:
Unrealized holding gain/(loss)	(659)	2,320	(7,181)	4,312
(Gain)/loss reclassified into earnings from other comprehensive income/(loss)	(624)	(564)	(2,504)	(1,162)
Other comprehensive income/(loss), including portion attributable to noncontrolling interests	(1,283)	1,756	(9,685)	3,150
Comprehensive income/(loss)	28,139	22,014	84,657	135,077
Comprehensive (income)/loss attributable to noncontrolling interests	(2,119)	(1,798)	(6,286)	(11,230)
Comprehensive income/(loss) attributable to UDR, Inc.	$ 26,020	$ 20,216	$ 78,371	$ 123,847

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Thousands	Preferred Stock	Common Stock	Paid-in Capital	Distributions in Excess of Net Income	Accumulated Other Comprehensive Income/(Loss), net	Noncontrolling Interests	Total
Beginning Balance at Dec. 31, 2017	$ 46,201	$ 2,678	$ 4,651,205	$ (1,871,603)	$ (2,681)	$ 9,564	$ 2,835,364
Consolidated Statements of Changes in Equity
Net income/(loss) attributable to UDR, Inc.				120,967			120,967
Net income/(loss) attributable to noncontrolling interests						107	107
Contribution of noncontrolling interests in consolidated real estate						108	108
Repurchase of common shares		(6)	(19,982)				(19,988)
Long Term Incentive Plan Unit grants/(vestings), net						4,429	4,429
Other comprehensive income/(loss)					2,883		2,883
Exercise of stock options, net		8	(23,061)				(23,053)
Issuance/(forfeiture) of common and restricted shares, net		(1)	(1,738)				(1,739)
Adjustment for conversion of noncontrolling interest of unitholders in the Operating Partnership and DownREIT Partnership		5	13,146				13,151
Common stock distributions declared ($0.3425, $0.3225 per share for the three months ended September 30, 2019 and 2018 and $1.0275, $0.9675 per share for the nine months ended September 30, 2019 and 2018, respectively)				(259,214)			(259,214)
Preferred stock distributions declared-Series E ($0.3708, $0.3492 per share for the three months ended September 30, 2019 and 2018 and $1.1124, $1.0476 per share for the nine months ended September 30, 2019 and 2018, respectively)				(2,897)			(2,897)
Adjustment to reflect redemption value of redeemable noncontrolling interests				(62,655)			(62,655)
Ending Balance at Sep. 30, 2018	46,201	2,684	4,619,570	(2,075,402)	202	14,208	2,607,463
Beginning Balance at Jun. 30, 2018	46,201	2,677	4,639,147	(1,929,124)	(1,407)	11,256	2,768,750
Consolidated Statements of Changes in Equity
Net income/(loss) attributable to UDR, Inc.				18,610			18,610
Net income/(loss) attributable to noncontrolling interests						21	21
Long Term Incentive Plan Unit grants/(vestings), net						2,931	2,931
Other comprehensive income/(loss)					1,609		1,609
Exercise of stock options, net		8	(23,061)				(23,053)
Issuance/(forfeiture) of common and restricted shares, net		(1)	2,993				2,992
Adjustment for conversion of noncontrolling interest of unitholders in the Operating Partnership and DownREIT Partnership			491				491
Common stock distributions declared ($0.3425, $0.3225 per share for the three months ended September 30, 2019 and 2018 and $1.0275, $0.9675 per share for the nine months ended September 30, 2019 and 2018, respectively)				(86,560)			(86,560)
Preferred stock distributions declared-Series E ($0.3708, $0.3492 per share for the three months ended September 30, 2019 and 2018 and $1.1124, $1.0476 per share for the nine months ended September 30, 2019 and 2018, respectively)				(971)			(971)
Adjustment to reflect redemption value of redeemable noncontrolling interests				(77,357)			(77,357)
Ending Balance at Sep. 30, 2018	46,201	2,684	4,619,570	(2,075,402)	202	14,208	2,607,463
Beginning Balance at Dec. 31, 2018	46,201	2,755	4,920,732	(2,063,996)	(67)	17,152	2,922,777
Consolidated Statements of Changes in Equity
Net income/(loss) attributable to UDR, Inc.				87,326			87,326
Net income/(loss) attributable to noncontrolling interests						97	97
Contribution of noncontrolling interests in consolidated real estate						125	125
Long Term Incentive Plan Unit grants/(vestings), net						7,839	7,839
Other comprehensive income/(loss)					(8,955)		(8,955)
Issuance/(forfeiture) of common and restricted shares, net			877				877
Issuance of common shares through public offering, net		145	661,864				662,009
Adjustment for conversion of noncontrolling interest of unitholders in the Operating Partnership and DownREIT Partnership		29	119,309				119,338
Common stock distributions declared ($0.3425, $0.3225 per share for the three months ended September 30, 2019 and 2018 and $1.0275, $0.9675 per share for the nine months ended September 30, 2019 and 2018, respectively)				(294,180)			(294,180)
Preferred stock distributions declared-Series E ($0.3708, $0.3492 per share for the three months ended September 30, 2019 and 2018 and $1.1124, $1.0476 per share for the nine months ended September 30, 2019 and 2018, respectively)				(3,073)			(3,073)
Adjustment to reflect redemption value of redeemable noncontrolling interests				(222,405)			(222,405)
Ending Balance at Sep. 30, 2019	46,201	2,929	5,702,782	(2,496,328)	(9,022)	25,213	3,271,775
Beginning Balance at Jun. 30, 2019	46,201	2,831	5,244,819	(2,336,609)	(7,838)	18,611	2,968,015
Consolidated Statements of Changes in Equity
Net income/(loss) attributable to UDR, Inc.				27,204			27,204
Net income/(loss) attributable to noncontrolling interests						40	40
Long Term Incentive Plan Unit grants/(vestings), net						6,562	6,562
Other comprehensive income/(loss)					(1,184)		(1,184)
Issuance/(forfeiture) of common and restricted shares, net			1,175				1,175
Issuance of common shares through public offering, net		96	449,041				449,137
Adjustment for conversion of noncontrolling interest of unitholders in the Operating Partnership and DownREIT Partnership		2	7,747				7,749
Common stock distributions declared ($0.3425, $0.3225 per share for the three months ended September 30, 2019 and 2018 and $1.0275, $0.9675 per share for the nine months ended September 30, 2019 and 2018, respectively)				(100,657)			(100,657)
Preferred stock distributions declared-Series E ($0.3708, $0.3492 per share for the three months ended September 30, 2019 and 2018 and $1.1124, $1.0476 per share for the nine months ended September 30, 2019 and 2018, respectively)				(1,031)			(1,031)
Adjustment to reflect redemption value of redeemable noncontrolling interests				(85,235)			(85,235)
Ending Balance at Sep. 30, 2019	$ 46,201	$ 2,929	$ 5,702,782	$ (2,496,328)	$ (9,022)	$ 25,213	$ 3,271,775

CONSOLIDATED STATEMENTS OF CH_2

CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Parenthetical) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Common stock distributions declared per share	$ 0.3425	$ 0.3225	$ 1.0275	$ 0.9675
8.00% Series E Cumulative Convertible Preferred Stock
Preferred stock distributions declared	$ 0.3708	$ 0.3492	$ 1.1124	$ 1.0476

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Operating Activities
Net income/(loss)	$ 94,342	$ 131,927
Adjustments to reconcile net income/(loss) to net cash provided by/(used in) operating activities:
Depreciation and amortization	362,746	327,594
(Gain)/loss on sale of real estate owned	(5,282)	(70,300)
(Income)/loss from unconsolidated entities	(19,387)	5,091
Return on investment in unconsolidated joint ventures	4,104	2,848
Amortization of share-based compensation	13,020	10,694
Other	14,098	2,108
Changes in operating assets and liabilities:
(Increase)/decrease in operating assets	49	(13,199)
Increase/(decrease) in operating liabilities	(6,814)	9,961
Net cash provided by/(used in) operating activities	456,876	406,724
Investing Activities
Acquisition of real estate assets	(1,269,618)
Proceeds from sales of real estate investments, net	38,000	89,433
Development of real estate assets	(19,248)	(136,170)
Capital expenditures and other major improvements - real estate assets	(113,572)	(76,381)
Capital expenditures - non-real estate assets	(11,147)	(2,963)
Investment in unconsolidated joint ventures	(72,079)	(85,059)
Distributions received from unconsolidated joint ventures	61,412	30,574
Purchase deposits on pending acquisitions	(910)	(1,000)
Repayment/(issuance) of notes receivable, net	4,360	(21,540)
Net cash provided by/(used in) investing activities	(1,382,802)	(203,106)
Financing Activities
Payments on secured debt	(160,547)	(82,472)
Proceeds from the issuance of secured debt	162,500	80,000
Payments on unsecured debt	(300,000)
Net proceeds from the issuance of unsecured debt	697,826
Net proceeds/(repayment) of commercial paper	(41,115)	115,000
Net proceeds/(repayment) of revolving bank debt	34,431	29,243
Proceeds from the issuance of common shares through public offering, net	662,009
Repurchase of common shares		(19,988)
Distributions paid to redeemable noncontrolling interests	(24,764)	(24,297)
Distributions paid to preferred stockholders	(3,016)	(2,854)
Distributions paid to common stockholders	(282,709)	(255,683)
Other	(4,039)	(36,317)
Net cash provided by/(used in) financing activities	740,576	(197,368)
Net increase/(decrease) in cash, cash equivalents, and restricted cash	(185,350)	6,250
Cash, cash equivalents, and restricted cash, beginning of year	208,891	21,830
Cash, cash equivalents, and restricted cash, end of period	23,541	28,080
Supplemental Information:
Interest paid during the period, net of amounts capitalized	125,298	104,136
Cash paid/(refunds received) for income taxes	1,953	579
Non-cash transactions:
Transfer of investment in and advances to unconsolidated joint ventures to real estate owned	15,639
Recognition of operating lease right-of-use assets	94,349
Recognition of operating lease liabilities	88,336
Right-of-use asset obtained in exhange for operating lease liability remeasurement	42,143
Vesting of LTIP Units	14,742	4,397
Development costs and capital expenditures incurred but not yet paid	12,174	23,437
Conversion of Operating Partnership and DownREIT Partnership noncontrolling interests to common stock (2,862,780 shares in 2019 and 343,653 shares in 2018)	119,338	13,151
Dividends declared but not yet paid	$ 108,939	$ 95,372

CONSOLIDATED STATEMENTS OF CA_2

CONSOLIDATED STATEMENTS OF CASH FLOWS - SUPPLEMENTAL - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017
The following reconciles cash, cash equivalents, and restricted cash to the total of the same amounts as shown above:
Cash and cash equivalents	$ 1,895	$ 185,216	$ 1,084	$ 2,038
Restricted cash	21,646	23,675	26,996	19,792
Total cash, cash equivalents, and restricted cash as shown above	$ 23,541	$ 208,891	$ 28,080	$ 21,830

CONSOLIDATED STATEMENTS OF CA_3

CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) - shares	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Non-cash transactions:
Conversion of OP Units into common shares	2,862,780	343,653

BASIS OF PRESENTATION

BASIS OF PRESENTATION	9 Months Ended
	Sep. 30, 2019
BASIS OF PRESENTATION
BASIS OF PRESENTATION	1. 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 September 30, 2019, there were 184,063,542 units in the Operating Partnership (“OP Units”) outstanding, of which 176,210,072 OP Units, or 95.7%, were owned by UDR and 7,853,470 OP Units, or 4.3%, were owned by outside limited partners. As of September 30, 2019, there were 32,367,380 units in the DownREIT Partnership (“DownREIT Units”) outstanding, of which 18,104,895, or 55.9%, were owned by UDR (including 13,470,651 DownREIT Units, or 41.6%, that were held by the Operating Partnership) and 14,262,485, or 44.1%, 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 September 30, 2019, and results of operations for the three and nine months ended September 30, 2019 and 2018, 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, 2018 appearing in UDR’s Annual Report on Form 10-K, filed with the Securities and Exchange Commission on February 19, 2019. 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 other than those noted in Note 7, Secured and Unsecured Debt, Net Commitments and Contingencies

SIGNIFICANT ACCOUNTING POLICIES

SIGNIFICANT ACCOUNTING POLICIES	9 Months Ended
	Sep. 30, 2019
SIGNIFICANT ACCOUNTING POLICIES
SIGNIFICANT ACCOUNTING POLICIES	2. 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 Codification Improvements to Topic 326, Financial Instruments—Credit Losses, ​ In February 2016, the FASB issued ASU 2016-02, Leases ​ The Company elected the following package of practical expedients provided by the standard: (i) an entity need not reassess whether any expired or existing contract is a lease or contains a lease, (ii) an entity need not reassess the lease classification of any expired or existing leases, and (iii) an entity need not reassess initial direct costs for any existing leases. The Company also elected the short-term lease exception provided for in the standard and therefore only recognizes right-of-use assets and lease liabilities for leases with a term greater than one year. ​ The Company recognized right-of-use assets of $94.3 million and lease liabilities of $88.3 million as of January 1, 2019 upon adoption of the standard. The right-of-use assets included $6.0 million of prepaid rent and intangible assets that was included within Other assets ​ The lease liabilities represent the present value of the remaining minimum lease payments as of January 1, 2019 and primarily relate to ground leases for communities where we are the lessee. The right-of-use assets represent our right to use an underlying asset for the lease term, which are calculated utilizing the lease liabilities plus any prepaid lease payments and intangible assets for ground leases acquired in the purchase of real estate. Our right-of-use assets and related lease liabilities recognized as of January 1, 2019 may change as a result of updates to the projected future minimum lease payments. Certain of our ground lease agreements where we are the lessee have future minimum lease payments that reset in the future based upon a percentage of the fair market value of the land at the time of the reset. The Company will continue to recognize lease expense for these leases in a manner similar to previous accounting based on our election of the package of practical expedients. However, in the event we modify existing ground leases and/or enter into new ground leases subsequent to the adoption of the standard, such leases would likely be classified as finance leases under the standard and require expense recognition based on the effective interest method. Under the standard, initial direct costs for both lessees and lessors would include only those costs that are incremental to the arrangement and would not have been incurred if the lease had not been obtained. As a result, subsequent to the adoption of the standard, we are now expensing non-incremental leasing costs as incurred. ​ In July 2018, the FASB issued ASU 2018-11, Leases – Targeted Improvements Leases ​ Principles of Consolidation The Company accounts for subsidiary partnerships, joint ventures and other similar entities in which it holds an ownership interest in accordance with the consolidation guidance. The Company first evaluates whether each entity is a variable interest entity (“VIE”). Under the VIE model, the Company consolidates an entity when it has control to direct the activities of the VIE and the obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE. Under the voting model, the Company consolidates an entity when it controls the entity through ownership of a majority voting interest. Real Estate Sales Gain Recognition ​ For sale transactions resulting in a transfer of a controlling financial interest of a property, the Company generally derecognizes the related assets and liabilities from its Consolidated Balance Sheets and records the gain or loss in the period in which the transfer of control occurs. If control of the property has not transferred to the counterparty, the criteria for derecognition are not met and the Company will continue to recognize the related assets and liabilities on its Consolidated Balance Sheets. ​ Sale transactions to entities in which the Company sells a controlling financial interest in a property but retains a noncontrolling interest are accounted for as partial sales. Partial sales resulting in a change in control are accounted for at fair value and a full gain or loss is recognized. Therefore, the Company will record a gain or loss on the partial interest sold, and the initial measurement of our retained interest will be accounted for at fair value. ​ Sales of real estate to joint ventures or other noncontrolled investees are also accounted for at fair value and the Company will record a full gain or loss in the period the property is contributed. ​ To the extent that the Company acquires a controlling financial interest in a property that it previously accounted for as an equity method investment, the Company will not remeasure its previously held interest if the acquisition is treated as an asset acquisition. The Company will include the carrying amount of its previously held equity method interest along with the consideration paid and transaction costs incurred in determining the amounts to allocate to the related assets and liabilities acquired on its Consolidated Balance Sheets. When treated as an asset acquisition, the Company will not recognize a gain or loss on consolidation of a property. ​ Notes Receivable The following table summarizes our Notes receivable, net dollars in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate at ​ Balance Outstanding ​ September 30, September 30, December 31, ​ ​ 2019 ​ 2019 ​ 2018 Note due December 2019 (a) 12.00 % $ 20,000 ​ $ 20,000 Note due February 2020 (b) 10.00 % 15,649 ​ 14,659 Note due October 2020 (c) 8.00 % 2,250 ​ 2,000 Note due August 2022 (d) ​ 10.00 % ​ — ​ ​ 5,600 Total notes receivable, net ​ $ 37,899 ​ $ 42,259 (a) In March 2018, the Company entered into a secured note with an unaffiliated third party with an aggregate commitment of $20.0 million, of which $20.0 million has been funded. Interest payments are due when the loan matures. In March 2019, the note’s maturity was extended to December 27, 2019, and the note is secured by a parcel of land. (b) The Company has a secured note with an unaffiliated third party with an aggregate commitment of $16.4 million, of which $15.6 million has been funded, including $1.0 million funded during the nine months ended September 30, 2019. 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). (c) The Company has a secured note with an unaffiliated third party with an aggregate commitment of $2.3 million, of which $2.3 million has been funded, including $0.3 million funded during the nine months ended September 30, 2019. 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 January 2019, the $5.6 million secured note was repaid in full along with the contractually accrued interest of $0.2 million and an additional $8.5 million of promoted interest in conjunction with the unaffiliated third party being acquired. The Company recognized $1.2 million and $1.2 million of interest income from notes receivable during the three months ended September 30, 2019 and 2018, respectively, and $3.5 million and $2.9 million of interest income and $8.5 million and zero of promoted interest from notes receivable during the nine months ended September 30, 2019 and 2018, respectively, none of which was related party interest. Interest income and promoted interest are included in Interest income and other income/(expense), net Comprehensive Income/(Loss) Comprehensive income/(loss), which is defined as the change in equity during each period from transactions and other events and circumstances from nonowner sources, including all changes in equity during a period except for those resulting from investments by or distributions to stockholders, is displayed in the accompanying Consolidated Statements of Comprehensive Income/(Loss). For the three and nine months ended September 30, 2019 and 2018, the Company’s other comprehensive income/(loss) consisted of the gain/(loss) 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 Derivatives and Hedging Activity, Income Taxes Due to the structure of the Company as a REIT and the nature of the operations for the operating properties, no provision for federal income taxes has been provided for at UDR. Historically, the Company has generally incurred only state and local excise and franchise taxes. UDR has elected for certain consolidated subsidiaries to be treated as taxable REIT subsidiaries (“TRS”). Income taxes for our TRS are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities from a change in tax rate is recognized in earnings in the period of the enactment date. The Company’s deferred tax assets are generally the result of differing depreciable lives on capitalized assets and timing of expense recognition for certain accrued liabilities. As of September 30, 2019 and December 31, 2018, UDR’s net deferred tax asset/(liability) was $(1.3) million and less than $(0.1) million, respectively. GAAP defines a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. GAAP also provides guidance on derecognition, classification, interest and penalties, accounting for interim periods, disclosure and transition. The Company recognizes its tax positions and evaluates them using a two-step process. First, UDR determines whether a tax position is more likely than not (greater than 50 percent probability) to be sustained upon examination, including resolution of any related appeals or litigation processes, based on the technical merits of the position. Second, the Company will determine the amount of benefit to recognize and record the amount that is more likely than not to be realized upon ultimate settlement. UDR had no material unrecognized tax benefit, accrued interest or penalties at September 30, 2019. UDR and its subsidiaries are subject to federal income tax as well as income tax of various state and local jurisdictions. The tax years 2016 through 2018 remain open to examination by tax jurisdictions to which we are subject. When applicable, UDR recognizes interest and/or penalties related to uncertain tax positions in Tax (provision)/benefit, net ​ Forward Sales Agreements ​ The Company utilizes forward sales agreements for the future issuance of its common stock. When the Company enters into a forward sales agreement, the contract requires the Company to sell its shares to a counterparty at a predetermined price at a future date. The net sales price and proceeds attained by the Company will be determined on the dates of settlement, with adjustments during the term of the contract for the Company’s anticipated dividends as well as for a daily interest factor that varies with changes in the federal funds rate. The Company generally has the ability to determine the dates and method of settlement (i.e., gross physical settlement, net share settlement or cash settlement), subject to certain conditions and the right of the counterparty to accelerate settlement under certain circumstances. ​ The Company accounts for the shares of common stock reserved for issuance upon settlement as equity in accordance with ASC 815-40, Contracts in Entity's Own Equity ​ The guidance establishes a two-step process for evaluating whether an equity-linked financial instrument is considered indexed to its own stock by evaluating the instrument’s contingent exercise provisions and settlement provisions. We determined that (i) none of the agreements’ exercise contingencies were based on observable markets or indices besides those related to the market for our own stock price and operations; and (ii) none of the settlement provisions precluded the agreements from being indexed to our own stock. ​ Based upon our determination that the forward sales agreements are considered indexed to our own stock as well as the agreements permitting us to share settle, we have determined that the forward sales agreements qualify for equity classification. ​ Before the issuance of shares of common stock, upon physical or net share settlement of the forward sales agreements, the Company expects that the shares issuable upon settlement of the forward sales agreements will be reflected in its diluted income/(loss) per share calculations using the treasury stock method. Under this method, the number of shares of common stock used in calculating diluted income/(loss) per share is deemed to be increased by the excess, if any, of the number of shares of common stock that would be issued upon full physical settlement of the forward sales agreements over the number of shares of common stock that could be purchased by the Company in the open market (based on the average market price during the period) using the proceeds receivable upon full physical settlement (based on the adjusted forward sale price at the end of the reporting period). When the Company physically or net share settles any forward sales agreement, the delivery of shares of common stock would result in an increase in the number of weighted average common shares outstanding and dilution to basic income/(loss) per share. (See Note 8, Income/(Loss) per Share ​

REAL ESTATE OWNED

REAL ESTATE OWNED	9 Months Ended
	Sep. 30, 2019
REAL ESTATE OWNED
REAL ESTATE OWNED	3. 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 held for disposition properties. As of September 30, 2019, the Company owned and consolidated 138 communities in 13 states plus the District of Columbia totaling 43,683 apartment homes. The following table summarizes the carrying amounts for our real estate owned (at cost) as of September 30, 2019 and December 31, 2018 (dollars in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2019 ​ 2018 Land ​ $ 2,020,617 ​ $ 1,849,799 Depreciable property — held and used: ​ ​ Land improvements ​ 220,654 ​ 213,224 Building, improvements, and furniture, fixtures and equipment ​ 9,260,709 ​ 8,133,136 Real estate intangible assets ​ ​ 40,570 ​ ​ — Under development: ​ ​ Land and land improvements ​ 13,853 ​ — Building, improvements, and furniture, fixtures and equipment ​ 7,992 ​ — Real estate owned ​ 11,564,395 ​ 10,196,159 Accumulated depreciation ​ (4,000,608) ​ (3,654,160) Real estate owned, net ​ $ 7,563,787 ​ $ 6,541,999 ​ Acquisitions In January 2019, the Company exercised its fixed-price option to purchase its joint venture partner’s ownership interest in a 386 apartment home operating community in Anaheim, California, thereby increasing its ownership interest from 49% to 100%, for a cash purchase price of approximately $33.5 million. In connection with the acquisition, the Company repaid approximately $59.8 million of joint venture construction financing. Joint Ventures and Partnerships In January 2019, the Company exercised its fixed-price option to purchase its joint venture partner’s ownership interest in a 155 apartment home operating community located in Seattle, Washington, thereby increasing its ownership interest from 49% to 100%, for a cash purchase price of approximately $20.0 million. In connection with the acquisition, the Company repaid approximately $26.0 million of joint venture construction financing. In January 2019, the Company acquired a to-be-developed parcel of land located in Washington D.C. for approximately $27.1 million. In February 2019, the Company acquired a to-be-developed parcel of land located in Denver, Colorado for approximately $13.7 million. In February 2019, the Company acquired a 188 apartment home operating community located in Brooklyn, New York for approximately $132.1 million. T In February 2019, the Company acquired a 381 apartment home operating community located in St. Petersburg, Florida for approximately $98.3 million . ​ In April 2019, the Company acquired a 498 apartment home operating community located in Towson, Maryland for approximately $86.4 million. ​ In May 2019, the Company acquired a 313 apartment home operating community located in King of Prussia, Pennsylvania for approximately $107.3 million. The Company increased its real estate assets owned by approximately $106.4 million and recorded approximately $0.9 million of in-place lease intangibles. ​ In May 2019, the Company acquired a 240 apartment home operating community located in St. Petersburg, Florida for approximately $49.4 million. The Company increased its real estate assets owned by approximately $48.2 million and recorded approximately $1.2 million of in-place lease intangibles. ​ In June 2019, the Company acquired a 200 apartment home operating community located in Waltham, Massachusetts for approximately $84.6 million. The Company increased its real estate assets owned by approximately $82.6 million and recorded approximately $2.0 million of in-place lease intangibles. ​ In August 2019, the Company acquired a 914 apartment home operating community located in Norwood, Massachusetts for approximately $270.2 million. The Company increased its real estate assets owned by approximately $260.1 million and recorded approximately $10.1 million of in-place lease intangibles. ​ In August 2019, the Company acquired a 185 apartment home operating community located in Englewood, New Jersey for approximately $83.6 million. The Company increased its real estate assets owned by approximately $77.5 million and recorded approximately $4.6 million of real estate intangibles and approximately $1.5 million of in-place lease intangibles. ​ In August 2019, the Company purchased a 292 apartment home operating community in Washington, D.C., directly from the UDR/KFH joint venture, thereby increasing its ownership interest from 30% to 100%, for a purchase price at 100% of approximately $184.0 million, before $2.8 million of closing costs incurred by UDR at acquisition (see Note 5, Joint Ventures and Partnerships ​ Subsequent to the acquisition, the Company received a distribution from the UDR/KFH joint venture of $22.9 million related to the 30% interest it previously held in the community following the payment of closing costs and repayment of the joint venture mortgage debt. As a result of the acquisition, in August 2019, the Company consolidated the operating community. The Company had previously accounted for its 30% ownership interest as an unconsolidated joint venture. The Company accounted for the consolidation as an asset acquisition resulting in no gain or loss upon consolidation and increased its real estate owned by approximately $156.0 million and recorded approximately $5.9 million of in-place lease intangibles. ​ In August 2019, the Company entered into an agreement with the Metropolitan Life Insurance Company (“MetLife”), its joint venture partner, to acquire the approximately 50% ownership interest not previously owned in 10 UDR/MetLife operating communities, one development community and four land parcels valued at $1.1 billion, or $557 million at UDR’s share. The transaction is expected to close during the fourth quarter of 2019, subject to customary closing conditions and closing price adjustments (see Note 5, Joint Ventures and Partnerships ​ Dispositions In June 2019, the Company sold a parcel of land located in Los Angeles, California for $38.0 million, resulting in a gain of approximately $5.3 million. Prior to the sale, the parcel of land was subject to a ground lease, under which UDR was the lessor, scheduled to expire in 2065. The ground lease included a purchase option for the lessee to acquire the land during specific periods of the ground lease term. During the second quarter, the lessee exercised the purchase option resulting in this sale by the Company and the ground lease being terminated. ​ Prior to the sale, the purchase option was not deemed to be a bargain purchase option. This ground lease existed as of the adoption of the new lease accounting guidance on January 1, 2019 and we did not reassess lease classification per the practical expedient provided by the standard. As a result, this ground lease continued to be classified as an operating lease and the land parcel subject to the ground lease continued to be recognized in Real estate held for investment ​ Other Activity 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 In connection with the acquisition of certain properties, the Company agreed to pay certain of the tax liabilities of certain contributors if the Company sells one or more of the properties contributed in a taxable transaction prior to the expiration of specified periods of time following the acquisition. The Company may, however, sell, without being required to pay any tax liabilities, any of such properties in a non-taxable transaction, including, but not limited to, a tax-deferred Section 1031 exchange. Further, the Company has agreed to maintain certain debt that may be guaranteed by certain contributors for specified periods of time following the acquisition. The Company, however, has the ability to refinance or repay guaranteed debt or to substitute new debt if the debt and the guaranty continue to satisfy certain conditions.

VARIABLE INTEREST ENTITIES

VARIABLE INTEREST ENTITIES	9 Months Ended
	Sep. 30, 2019
VARIABLE INTEREST ENTITIES
VARIABLE INTEREST ENTITIES	4. VARIABLE INTEREST ENTITIES The Company has determined that the Operating Partnership and DownREIT Partnership are VIEs as the limited partners lack substantive kick-out rights and substantive participating rights. The Company has concluded that it is the primary beneficiary of, and therefore consolidates, the Operating Partnership and DownREIT Partnership based on its role as the sole general partner of the Operating Partnership and DownREIT Partnership. The Company’s role as community manager and its equity interests give us the power to direct the activities that most significantly impact the economic performance and the obligation to absorb potentially significant losses or the right to receive potentially significant benefits of the Operating Partnership and DownREIT Partnership. See the consolidated financial statements of the Operating Partnership presented within this Report and Note 4, Unconsolidated Entities

JOINT VENTURES AND PARTNERSHIPS

JOINT VENTURES AND PARTNERSHIPS	9 Months Ended
	Sep. 30, 2019
JOINT VENTURES AND PARTNERSHIPS
JOINT VENTURES AND PARTNERSHIPS	5. JOINT VENTURES AND PARTNERSHIPS UDR has entered into joint ventures and partnerships with unrelated third parties to own, operate, acquire, renovate, develop, redevelop, dispose of, and manage real estate assets that are either consolidated and included in Real estate owned Investment in and advances to unconsolidated joint ventures, net beneficiary. 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. 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 September 30, 2019 and December 31, 2018 (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number of ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number of ​ Apartment ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Properties ​ Homes ​ Investment at ​ ​ UDR’s Ownership Interest ​ ​ Location of September 30, September 30, September 30, December 31, ​ ​ September 30, ​ December 31, Joint Venture Properties 2019 2019 2019 2018 ​ ​ 2019 ​ 2018 Operating and development: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ UDR/MetLife I ​ Los Angeles, CA ​ 1 operating community ​ 150 ​ $ 29,599 ​ $ 30,839 ​ ​ 50.0 % ​ 50.0 % UDR/MetLife II (a) Various 18 operating communities 4,059 ​ 300,479 ​ 296,807 ​ ​ 50.0 % ​ 50.0 % Other UDR/MetLife Various 5 operating communities 1,437 ​ 102,435 ​ 115,668 ​ ​ 50.6 % ​ 50.6 % Joint Ventures ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ UDR/MetLife Vitruvian Park ® (a) Addison, TX 4 operating communities; 1,879 ​ 75,858 ​ 71,730 ​ ​ 50.0 % ​ 50.0 % ​ 1 development community (b); ​ ​ ​ ​ ​ ​ ​ ​ ​ 4 land parcels ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ UDR/KFH (c) Washington, D.C. — ​ — ​ 156 ​ 5,507 ​ ​ — % ​ 30.0 % West Coast Development Joint Ventures (d) ​ Los Angeles, CA ​ 1 operating community ​ 293 ​ ​ 35,165 ​ ​ 36,143 ​ ​ 47.0 % ​ 47.0 % Investment in and advances to unconsolidated joint ventures, net, before participating loan investment, preferred equity investments and other investments ​ $ 543,692 ​ $ 556,694 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income/(loss) from investments ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Investment at ​ Three Months Ended ​ Nine Months Ended ​ Developer Capital Program ​ ​ Years To ​ UDR September 30, December 31, September 30, ​ September 30, ​ and Other Investments (e) Location Rate Maturity ​ Commitment (f) 2019 2018 2019 2018 2019 2018 ​ Preferred equity investments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ West Coast Development Joint Ventures (d) Various 6.5 % N/A ​ $ — ​ $ 17,080 ​ $ 65,417 ​ $ 71 ​ $ 25 ​ $ (100) ​ $ 974 ​ 1532 Harrison (g) ​ San Francisco, CA ​ 11.0 % 2.8 ​ ​ 24,645 ​ ​ 29,753 ​ ​ 24,986 ​ ​ 802 ​ ​ 721 ​ ​ 2,324 ​ ​ 1,492 ​ 1200 Broadway (h) ​ Nashville, TN ​ 8.0 % 3.0 ​ ​ 55,558 ​ ​ 62,666 ​ ​ 58,982 ​ ​ 1,244 ​ ​ 859 ​ ​ 3,619 ​ ​ 1,870 ​ Junction (i) ​ Santa Monica, CA ​ 12.0 % 2.8 ​ ​ 8,800 ​ ​ 10,072 ​ ​ 9,211 ​ ​ 299 ​ ​ 141 ​ ​ 861 ​ ​ 141 ​ 1300 Fairmount (j) ​ Philadelphia, PA ​ Variable ​ 3.9 ​ ​ 51,393 ​ ​ 36,404 ​ ​ 8,318 ​ ​ 930 ​ ​ 27 ​ ​ 1,724 ​ ​ 27 ​ Essex (k) ​ Orlando, FL ​ 12.5 % 3.9 ​ ​ 12,886 ​ ​ 14,347 ​ ​ 9,940 ​ ​ 443 ​ ​ 46 ​ ​ 1,182 ​ ​ 46 ​ Modera Lake Merritt (l) ​ Oakland, CA ​ 9.0 % 4.6 ​ ​ 27,250 ​ ​ 17,377 ​ ​ — ​ ​ 366 ​ ​ — ​ ​ 622 ​ ​ — ​ Other investments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The Portals (m) ​ Washington, D.C. ​ 11.0 % 1.7 ​ ​ 38,559 ​ ​ 46,863 ​ ​ 43,167 ​ ​ 1,287 ​ ​ 1,015 ​ ​ 3,694 ​ ​ 2,523 ​ Other investment ventures ​ N/A ​ N/A ​ N/A ​ $ 18,000 ​ ​ 12,926 ​ ​ 4,154 ​ $ 4,247 ​ $ (77) ​ $ 4,272 ​ $ (262) ​ Total Developer Capital Program and Other Investments ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 247,488 ​ ​ 224,175 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total investment in and advances to unconsolidated joint ventures, net ​ ​ ​ ​ $ 791,180 ​ $ 780,869 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (a) In August 2019, the Company entered into an agreement with MetLife, its joint venture partner, to acquire the approximately 50% ownership interest not previously owned in 10 UDR/MetLife operating communities, one development community and four land parcels valued at $1.1 billion, or $557 million at UDR’s share, and to sell its approximately 50% ownership interest in five UDR/MetLife operating communities valued at $645 million, or $323 million at UDR’s share, to MetLife. The transaction is expected to close during the fourth quarter of 2019, subject to customary closing conditions and closing price adjustments. Upon closing of the transaction, the UDR/MetLife II joint venture will hold seven operating communities and the UDR/MetLife Vitruvian Park ® joint venture will no longer hold any properties. (b) The number of apartment homes for the communities under development presented in the table above is based on the projected number of total homes upon completion of development. As of September 30, 2019, no apartment homes had been completed in the development community held by UDR/MetLife Vitruvian Park ® . (c) As of January 1, 2019, the joint venture held three operating communities. In May 2019, the joint venture sold one community, a 217 home operating community in Arlington, Virginia, for a sales price of approximately $74.8 million. As a result, the Company recorded a gain on the sale of approximately $5.3 million, which is included in Income/(loss) from unconsolidated entities In July 2019, the joint venture sold the second community, a 151 home operating community in Silver Spring, Maryland, for a sales price of approximately $43.5 million. As a result, the Company recorded a gain on the sale of approximately $5.3 million, which is included in Income/(loss) from unconsolidated entities In August 2019, the joint venture sold the third community, a 292 home operating community in Washington, D.C., directly to the Company for a sales price at 100% of approximately $184.0 million, before $2.8 million of closing costs incurred by UDR at acquisition. The Company deferred its share of the gain on sale of approximately $23.8 million and recorded it as a reduction of the carrying amount of real estate assets owned (see Note 3, Real Estate Owned (d) In 2015, the Company entered into a joint venture agreement with an unaffiliated joint venture partner and paid $136.3 million for a 48% ownership interest in a portfolio of five communities that were under construction. The communities are located in three of the Company’s core, coastal markets: Seattle, Washington, Los Angeles, California and Orange County, California. UDR earns a 6.5% preferred return on its investment through each individual community’s date of stabilization, defined as when a community reaches 80% occupancy for 90 consecutive days, while the joint venture partner is allocated all operating income and expense during the pre-stabilization period. Upon stabilization, income and expense are shared based on each partner’s ownership percentage and the Company no longer receives a 6.5% preferred return on its investment in the stabilized community. The Company serves as property manager and earns a management fee during the lease-up phase and subsequent operation of each of the communities. The unaffiliated joint venture partner is the general partner of the joint venture and the developer of the communities. The Company has concluded it does not control the joint ventures and, therefore, accounts for them under the equity method of accounting. During 2017, the Company exercised its fixed-price option to purchase the joint venture partner’s ownership interest in one of the five communities, and the joint venture sold two of the four remaining communities. In January 2019, the Company exercised its fixed-price option to purchase its joint venture partner’s ownership interest in one of the two remaining communities, a 386 apartment home operating community in Orange County, California, thereby increasing its ownership interest from 49% to 100%, for a cash purchase price of approximately $33.5 million. As a result, the Company consolidated the operating community and it is no longer accounted for as a preferred equity investment in an unconsolidated joint venture (see Note 3, Real Estate Owned The Company and its joint venture partner continue to operate the one remaining community. In 2017, the Company entered into two additional joint venture agreements with the unaffiliated joint venture partner and paid $15.5 million for a 49% ownership interest in a 155 apartment home community in Seattle, Washington and $16.1 million for a 49% ownership interest in a 276 apartment home community in Hillsboro, Oregon (together with the 2015 joint venture described above, the “West Coast Development Joint Ventures”). UDR earns a 6.5% preferred return on its investments through the communities’ date of stabilization, as defined above, while our joint venture partner is allocated all operating income and expense during the pre-stabilization period. Upon stabilization of the communities, income and expense will be shared based on each partner’s ownership percentage and the Company will no longer receive a 6.5% preferred return on its investment. The Company serves as property manager and earns a management fee during the lease-up phase and subsequent operation of the stabilized communities. The unaffiliated joint venture partner is the general partner and the developer of the communities. The Company has concluded it does not control the joint ventures and, therefore, accounts for them under the equity method of accounting. The Company has a fixed-price option to acquire the remaining interest in the communities beginning one year after completion. The unaffiliated joint venture partner is providing certain guaranties and there are construction loans on the communities. In January 2019, the Company exercised its fixed-price option to purchase its joint venture partner’s ownership interest in the 155 apartment home operating community in Seattle, Washington, thereby increasing its ownership interest from 49% to 100%, for a cash purchase price of approximately $20.0 million. As a result, the Company consolidated the operating community and it is no longer accounted for as a preferred equity investment in an unconsolidated joint venture (see Note 3, Real Estate Owned The Company’s recorded equity investment in the West Coast Development Joint Ventures at September 30, 2019 and December 31, 2018, of $52.2 million and $101.6 million, respectively, is inclusive of outside basis costs and our accrued but unpaid preferred return. (e) The Developer Capital Program is a program through which the Company makes investments, including preferred equity investments, mezzanine loans or other structured investments that may receive a fixed or variable yield on the investment and may include provisions pursuant to which the Company participates in the increase in value of the property upon monetization of the applicable property and/or holds fixed price purchase options. (f) Represents UDR’s maximum funding commitment only and therefore excludes other activity such as income from investments. (g) In June 2017, the Company entered into a joint venture agreement with an unaffiliated joint venture partner to develop and operate a 136 apartment home community in San Francisco, California. The Company’s preferred equity investment of up to $24.6 million earns a preferred return of 11.0% per annum. The unaffiliated joint venture partner is the managing member of the joint venture and the developer of the community. The Company has concluded that it does not control the joint venture and, therefore, accounts for it under the equity method of accounting. (h) In September 2017, the Company entered into a joint venture agreement with an unaffiliated joint venture partner to develop and operate a 313 apartment home community in Nashville, Tennessee. The Company’s preferred equity investment of up to $55.6 million earns a preferred return of 8.0% per annum and receives a variable percentage of the value created from the project upon a capital or liquidating event. The unaffiliated joint venture partner is the managing member of the joint venture and the developer of the community. The Company has concluded that it does not control the joint venture and, therefore, accounts for it under the equity method of accounting. (i) In August 2018, the Company entered into a joint venture agreement with an unaffiliated joint venture partner to develop and operate a 66 apartment home community in Santa Monica, CA. The Company’s preferred equity investment of $8.8 million earns a preferred return of 12.0% per annum. The unaffiliated joint venture partner is the managing member of the joint venture and the developer of the community. The Company has concluded that it does not control the joint venture and, therefore, accounts for it under the equity method of accounting. (j) In August 2018, the Company entered into a joint venture agreement with an unaffiliated joint venture partner to develop and operate a 471 apartment home community in Philadelphia, PA. The Company’s preferred equity investment of up to $51.4 million earns a preferred return between 8.5% and 12.0% per annum and receives a variable percentage of the value created from the project upon a capital or liquidating event. The unaffiliated joint venture partner is the managing member of the joint venture and the developer of the community. The Company has concluded that it does not control the joint venture and, therefore, accounts for it under the equity method of accounting. (k) In September 2018, the Company entered into a joint venture agreement with an unaffiliated joint venture partner to develop and operate a 330 apartment home community in Orlando, FL. The Company’s preferred equity investment of up to $12.9 million earns a preferred return of 12.5% per annum. The unaffiliated joint venture partner is the managing member of the joint venture and the developer of the community. The Company has concluded that it does not control the joint venture and, therefore, accounts for it under the equity method of accounting. (l) In April 2019, the Company entered into a joint venture agreement with an unaffiliated joint venture partner to develop and operate a 173 apartment home community in Oakland, CA. The Company’s preferred equity investment of up to $27.3 million earns a preferred return of 9.0% per annum and receives a variable percentage of the value created from the project upon a capital or liquidating event. The unaffiliated joint venture partner is the managing member of the joint venture and the developer of the community. The Company has concluded that it does not control the joint venture and, therefore, accounts for it under the equity method of accounting . (m) In May 2017, the Company entered into a joint venture agreement with an unaffiliated joint venture partner. The joint venture has made a mezzanine loan to a third party developer of a 373 apartment home community in Washington, D.C. The unaffiliated joint venture partner is the managing member of the joint venture. The mezzanine loan is for up to $71.0 million at an interest rate of 13.5% per annum and carries a term of four years with one 12-month extension option. The Company’s commitment to the joint venture is approximately $38.6 million and earns a weighted average return of approximately 11.0% per annum. The Company has concluded that it does not control the joint venture and , therefore, accounts for it under the equity method of accounting. As of September 30, 2019 and December 31, 2018, the Company had deferred fees of $10.6 million and $11.0 million, respectively, which will be recognized through earnings over the weighted average life of the related properties, upon the disposition of the properties to a third party, or upon completion of certain development obligations. The Company recognized management fees of $6.4 million and $2.9 million during the three months ended September 30, 2019 and 2018, respectively, and $12.0 million and $ 8.7 million for the nine months ended September 30, 2019 and 2018, respectively, for management of the communities held by the joint ventures and partnerships. The management fees are included in Joint venture management and other fees on the Consolidated Statements of Operations. The Company may, in the future, make additional capital contributions to certain of our joint ventures and partnerships should additional capital contributions be necessary to fund acquisitions or operations. We evaluate our investments in unconsolidated joint ventures and partnerships when events or changes in circumstances indicate that there may be an other-than-temporary decline in value. We consider various factors to determine if a decrease in the value of the investment is other-than-temporary. The Company did not recognize any other-than-temporary impairments in the value of its investments in unconsolidated joint ventures or partnerships during the three and nine months ended September 30, 2019 and 2018. Combined summary balance sheets relating to the unconsolidated joint ventures and partnerships (not just our proportionate share) are presented below as of September 30, 2019 and December 31, 2018 ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ 2019 2018 Total real estate, net $ 3,101,213 $ 3,311,034 Cash and cash equivalents ​ 56,829 ​ 49,867 Other assets ​ ​ 165,767 ​ 124,428 Total assets $ 3,323,809 $ 3,485,329 ​ ​ ​ ​ ​ ​ ​ Third party debt, net ​ $ 1,909,223 ​ $ 2,125,350 Accounts payable and accrued liabilities ​ ​ 73,803 ​ ​ 71,272 Total liabilities ​ 1,983,026 ​ 2,196,622 Total equity $ 1,340,783 $ 1,288,707 ​ 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 nine months ended September 30, 2019 and 2018 ( dollars in thousands : ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, ​ September 30, ​ 2019 2018 2019 2018 Total revenues $ 75,378 $ 76,203 $ 233,836 $ 215,140 Property operating expenses ​ 27,505 ​ 30,096 ​ 87,073 ​ 85,435 Real estate depreciation and amortization ​ 26,027 ​ 29,545 ​ 83,661 ​ 85,063 Operating income/(loss) ​ 21,846 ​ ​ 16,562 ​ 63,102 ​ ​ 44,642 Interest expense ​ (20,779) ​ (22,919) ​ (64,309) ​ (63,990) Gain/(loss) on sale of property (a) ​ ​ 97,201 ​ ​ — ​ ​ 115,558 ​ ​ — Net unrealized gain/(loss) on held investments ​ ​ 25,669 ​ ​ — ​ ​ 27,191 ​ ​ — Other income/(loss) ​ ​ 82 ​ ​ 40 ​ ​ 194 ​ ​ 141 Net income/(loss) $ 124,019 $ (6,317) $ 141,736 $ (19,207) ​ ​ ​ (a) Represent the gains on the sale of three operating communities at the UDR/KFH joint venture level, as described in note (c) to the table above summarizing the Company’s investment in and advances to unconsolidated joint ventures and partnerships, net.

LEASES

LEASES	9 Months Ended
	Sep. 30, 2019
LEASES
Leases	6. LEASES Lessee - Ground and Office Leases UDR owns six communities that are subject to ground leases, under which UDR is the lessee, expiring between 2043 and 2103, inclusive of extension options we are reasonably certain will be exercised. In addition, UDR is a lessee to an operating lease related to office space rented by the Company with an expiration date in 2021. All of these leases existed as of the adoption of the new lease accounting guidance on January 1, 2019 and we did not reassess lease classification per the practical expedient provided by the standard. As such, these leases will continue to be classified as operating leases through the lease term expiration. Rental expense for lease payments related to operating leases is recognized on a straight-line basis over the remaining lease term. We currently do not hold any finance leases. As of September 30, 2019, the Operating lease right-of-use assets Operating lease liabilities Operating lease right-of-use assets Operating lease liabilities As the discount rate implicit in the leases was not readily determinable, we determined the discount rate for these leases utilizing the Company’s incremental borrowing rate at a portfolio level, adjusted for the remaining lease term, and the form of underlying collateral. The weighted average remaining lease term for these leases was 55.2 years at September 30, 2019 and the weighted average discount rate was 5.1% at September 30, 2019. Future minimum lease payments and total operating lease liabilities from our ground leases and office space as of September 30, 2019 are as follows (dollars in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ground Leases ​ Office Space ​ Total 2019 ​ $ 1,953 ​ $ 19 ​ $ 1,972 2020 ​ ​ 7,813 ​ ​ 76 ​ ​ 7,889 2021 ​ ​ 7,813 ​ ​ 32 ​ ​ 7,845 2022 ​ ​ 7,813 ​ ​ - ​ ​ 7,813 2023 ​ ​ 7,813 ​ ​ - ​ ​ 7,813 Thereafter ​ ​ 370,467 ​ ​ - ​ ​ 370,467 Total future minimum lease payments (undiscounted) ​ ​ 403,672 ​ ​ 127 ​ ​ 403,799 Difference between future undiscounted cash flows and discounted cash flows ​ ​ (273,659) ​ ​ (5) ​ ​ (273,664) Total operating lease liabilities (discounted) ​ $ 130,013 ​ $ 122 ​ $ 130,135 ​ For purposes of recognizing our ground lease contracts, the Company uses the minimum lease payments, if stated in the agreement. For ground lease agreements where there is a rent reset provision based on a change in an index or a rate (i.e., changes in fair market rental rates or changes in the consumer price index) but that does not include a specified minimum lease payment, the Company uses the current rent over the remainder of the lease term. If there is a contingency upon which some or all of the variable lease payments that will be paid over the remainder of the lease term are based, which is resolved such that those payments now meet the definition of lease payments, the Company will remeasure the right-of-use asset and lease liability on the reset date. For the nine months ended September 30, 2019, Operating lease right-of-use assets Operating lease liabilities The components of operating lease expenses from our ground leases and office space were as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, 2019 ​ September 30, 2019 Ground lease expense: ​ ​ ​ ​ ​ ​ Contractual lease rent expense ​ $ 1,954 ​ $ 6,232 Variable ground lease expense (a) ​ ​ 187 ​ ​ 469 Total ground lease expense (b) ​ ​ 2,141 ​ ​ 6,701 Contractual office space expense (b) ​ ​ 19 ​ ​ 57 Total operating lease expense (c) ​ $ 2,160 ​ $ 6,758 (a) Variable ground lease expense includes adjustments such as changes in the consumer price index and payments based on a percentage of income of the lessee. (b) Ground lease expense is reported within the line item Other operating expenses and office space expense is recorded in General and administrative on the Consolidated Statements of Operations. (c) For the nine months ended September 30, 2019, Operating lease right-of-use assets and Operating lease liabilities amortized by $0.6 million and $0.3 million, respectively. The Company recorded $0.1 million and $0.3 million of total operating lease expense during the three and nine months ended September 30, 2019, respectively, due to the net impact of the amortization. ​ Lessor - Apartment Home, Retail and Commercial Space Leases ​ UDR’s communities and retail and commercial space are leased to tenants under operating leases. As of September 30, 2019, our apartment home leases generally have initial terms of 12 months or less and represent approximately 98.1% of our total lease revenue. As of September 30, 2019, our retail and commercial space leases generally have initial terms of between 5 and 15 years and represent approximately 1.9% of our total lease revenue. Our apartment home leases are generally renewable at the end of the lease term, subject to potential increases in rental rates, and our retail and commercial space leases generally have renewal options, subject to associated increases in rental rates and certain other conditions. (See Note 14, Reportable Segments ​ We previously owned a parcel of land subject to a ground lease under which UDR was the lessor, expiring in 2065. The ground lease included a purchase option for the lessee to acquire the land during specific periods of the ground lease term. In June 2019, the lessee exercised the purchase option and acquired the parcel of land for $38.0 million. (See Note 3, Real Estate ​ Future minimum lease payments from our retail and commercial leases as of September 30, 2019 are as follows (dollars in thousands): ​ ​ ​ ​ ​ ​ Retail and Commercial Leases 2019 ​ $ 4,958 2020 ​ ​ 20,565 2021 ​ ​ 19,788 2022 ​ ​ 18,094 2023 ​ ​ 16,843 Thereafter ​ ​ 92,719 Total future minimum lease payments (a) ​ $ 172,967 (a) We have excluded our apartment home leases from this table as our apartment home leases generally have initial terms of 12 months of less. Certain of our leases with retail and commercial tenants provide for the payment by the lessee of additional variable rent based on a percentage of the tenant’s revenue. The amounts shown in the table above do not include these variable percentage rents. The Company recorded variable percentage rents of $0.1 million and $0.3 million during the three and nine months ended September 30, 2019.

SECURED AND UNSECURED DEBT, NET

SECURED AND UNSECURED DEBT, NET	9 Months Ended
	Sep. 30, 2019
SECURED AND UNSECURED DEBT, NET
SECURED AND UNSECURED DEBT, NET	7. SECURED AND UNSECURED DEBT, NET The following is a summary of our secured and unsecured debt at September 30, 2019 and December 31, 2018 ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Principal Outstanding ​ As of September 30, 2019 ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ Weighted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Average ​ Average ​ Number of ​ ​ September 30, ​ December 31, ​ Interest ​ Years to ​ Communities ​ 2019 2018 Rate Maturity Encumbered Secured Debt: ​ ​ ​ ​ ​ ​ ​ Fixed Rate Debt ​ ​ Mortgage notes payable (a) ​ $ 575,965 ​ $ 417,989 3.55 % 6.6 9 Fannie Mae credit facilities (b) ​ — ​ 90,000 — % — — Deferred financing costs ​ (2,275) ​ (1,343) Total fixed rate secured debt, net ​ 573,690 ​ 506,646 3.55 % 6.6 9 Variable Rate Debt ​ ​ Tax-exempt secured notes payable (c) ​ 27,000 ​ 94,700 2.07 % 12.5 1 Deferred financing costs ​ (66) ​ (119) Total variable rate secured debt, net ​ 26,934 ​ 94,581 2.07 % 12.5 1 Total Secured Debt, net ​ 600,624 ​ 601,227 3.49 % 6.8 10 Unsecured Debt: ​ ​ Variable Rate Debt ​ ​ Borrowings outstanding under unsecured credit facility due January 2023 (d) (l) ​ — ​ — — % 3.3 Borrowings outstanding under unsecured commercial paper program due October 2019 (e) (l) ​ ​ 60,000 ​ ​ 101,115 ​ 2.28 % 0.1 ​ ​ Borrowings outstanding under unsecured working capital credit facility due January 2021 ​ 34,447 ​ 16 2.84 % 1.3 Term Loan due September 2023 (d) (l) ​ 35,000 ​ 35,000 3.01 % 4.0 Fixed Rate Debt ​ ​ 3.70% Medium-Term Notes due October 2020 (net of discounts of $0 and $14, respectively) (k) (l) ​ — ​ 299,986 — % — 4.63% Medium-Term Notes due January 2022 (net of discounts of $818 and $1,087, respectively) (l) ​ 399,182 ​ 398,913 4.63 % 2.3 1.93% Term Loan due September 2023 (d) (l) ​ ​ 315,000 ​ 315,000 1.93 % 4.0 ​ ​ 3.75% Medium-Term Notes due July 2024 (net of discounts of $495 and $574, respectively) (g) (l) ​ 299,505 ​ 299,426 3.75 % 4.8 8.50% Debentures due September 2024 ​ 15,644 ​ 15,644 8.50 % 5.0 4.00% Medium-Term Notes due October 2025 (net of discounts of $413 and $465, respectively) (h) (l) ​ 299,587 ​ 299,535 4.00 % 6.0 2.95% Medium-Term Notes due September 2026 (l) ​ 300,000 ​ 300,000 2.95 % 6.9 3.50% Medium-Term Notes due July 2027 (net of discounts of $547 and $600, respectively) (l) ​ ​ 299,453 ​ ​ 299,400 ​ 3.50 % 7.8 ​ ​ 3.50% Medium-Term Notes due January 2028 (net of discounts of $983 and $1,072, respectively) (l) ​ ​ 299,017 ​ ​ 298,928 ​ 3.50 % 8.3 ​ ​ 4.40% Medium-Term Notes due January 2029 (net of discounts of $6 and $6, respectively) (i) (l) ​ ​ 299,994 ​ ​ 299,994 ​ 4.40 % 9.3 ​ ​ 3.20% Medium-Term Notes due January 2030 (net of discounts of $990 and $0, respectively) (j) (l) ​ ​ 299,010 ​ ​ — ​ 3.20 % 10.3 ​ ​ 3.00% Medium-Term Notes due August 2031 (net of discounts of $1,148 and $0, respectively) (k) (l) ​ ​ 398,852 ​ ​ — ​ 3.00 % 11.9 ​ ​ Other ​ 14 ​ 16 Deferred financing costs ​ (19,432) ​ (16,413) Total Unsecured Debt, net ​ 3,335,273 ​ 2,946,560 3.54 % 6.9 Total Debt, net ​ $ 3,935,897 ​ $ 3,547,787 3.63 % 6.9 ​ 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 September 30, 2019, secured debt encumbered $1.2 billion or 10.3% of UDR’s total real estate owned based upon gross book value ($10.4 billion or 89.7% of UDR’s real estate owned based on gross book value is unencumbered). (a) During the three months ended September 30, 2019, the Company refinanced a $90.0 million loan with Fannie Mae to a fixed rate mortgage due in October 2029 and took out a new mortgage of $72.5 million due in February 2030. Interest payments are due monthly at interest rates of 2.70% and 3.10%, respectively. The refinancing was accounted for as a debt modification. The Company will from time to time acquire properties subject to fixed rate debt instruments. In those situations, the Company records the debt at its estimated fair value and amortizes any difference between the fair value and par value to interest expense over the life of the underlying debt instrument. During the three months ended September 30, 2019 and 2018, the Company had $0.6 million and $0.9 million, respectively, and during the nine months ended September 30, 2019 and 2018, the Company had $1.7 million and $2.4 million, respectively, of amortization of the fair market adjustment of debt assumed in the acquisition of properties, which was included in Interest expense (b) Further information related to the Fannie Mae credit facility is as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2019 ​ 2018 Borrowings outstanding ​ $ — ​ $ 90,000 ​ Weighted average borrowings during the period ended ​ 80,000 ​ 253,813 ​ Maximum daily borrowings during the period ended ​ 90,000 ​ 314,869 ​ Weighted average interest rate during the period ended ​ 4.0 % 4.7 % Weighted average interest rate at the end of the period ​ — % 4.0 % ​ (c) (d) six-month extension options, subject to certain conditions. The Term Loan has a scheduled maturity date of September 30, 2023. Based on the Company’s current credit rating, the Revolving Credit Facility has an interest rate equal to LIBOR plus a margin of 82.5 basis points and a facility fee of 15 basis points, and the Term Loan has an interest rate equal to LIBOR plus a margin of 90 basis points. Depending on the Company’s credit rating, the margin under the Revolving Credit Facility ranges from 75 to 145 basis points, the facility fee ranges from 10 to 30 basis points, and the margin under the Term Loan ranges from 80 to 165 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 September 30, 2019 and December 31, 2018 (dollars in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2019 2018 ​ Total revolving credit facility ​ $ 1,100,000 ​ $ 1,100,000 ​ Borrowings outstanding at end of period (1) ​ — ​ — ​ Weighted average daily borrowings during the period ended ​ — ​ — ​ Maximum daily borrowings during the period ended ​ — ​ — ​ Weighted average interest rate during the period ended ​ — % — % Interest rate at end of the period ​ — % — % (1) Excludes $2.8 million and $3.3 million of letters of credit at September 30, 2019 and December 31, 2018, respectively. (e) The following is a summary of short-term bank borrowings under the unsecured commercial paper program at September 30, 2019 and December 31, 2018 (dollars in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2019 ​ 2018 Total unsecured commercial paper program $ 500,000 ​ $ 500,000 ​ Borrowings outstanding at end of period ​ 60,000 ​ 101,115 ​ Weighted average daily borrowings during the period ended ​ 163,347 ​ 344,235 ​ Maximum daily borrowings during the period ended ​ 435,000 ​ 440,000 ​ Weighted average interest rate during the period ended ​ 2.7 % 2.4 % Interest rate at end of the period ​ 2.3 % 2.9 % ​ (f) 82.5 basis points. Depending on the Company’s credit rating, the margin ranges from 75 to 145 basis points. The following is a summary of short-term bank borrowings under the Working Capital Credit Facility at September 30, 2019 and December 31, 2018 (dollars in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2019 ​ 2018 Total working capital credit facility ​ $ 75,000 ​ $ 75,000 ​ Borrowings outstanding at end of period ​ 34,447 ​ 16 ​ Weighted average daily borrowings during the period ended ​ 24,870 ​ 26,101 ​ Maximum daily borrowings during the period ended ​ 66,170 ​ 64,633 ​ Weighted average interest rate during the period ended ​ 3.2 % 2.9 % Interest rate at end of the period ​ 2.8 % 3.3 % ​ (g) (h) (i) (j) . (k) (l) The aggregate maturities, including amortizing principal payments on secured and unsecured debt, of total debt for the next ten calendar years subsequent to September 30, 2019 are as follows (dollars in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Fixed Total Variable Total Total Total Year ​ Secured Debt ​ Secured Debt ​ Secured Debt ​ Unsecured Debt ​ Debt 2019 ​ $ 974 ​ $ — ​ $ 974 ​ $ 60,000 ​ $ 60,974 2020 ​ ​ 108,077 ​ ​ — ​ ​ 108,077 ​ ​ — ​ ​ 108,077 2021 ​ 1,117 ​ — ​ 1,117 ​ 34,447 ​ 35,564 2022 ​ 1,157 ​ — ​ 1,157 ​ 400,000 ​ 401,157 2023 ​ 41,245 ​ — ​ 41,245 ​ 350,000 ​ 391,245 2024 ​ — ​ — ​ — ​ 315,644 ​ 315,644 2025 ​ 127,600 ​ — ​ 127,600 ​ 300,000 ​ 427,600 2026 ​ 50,000 ​ — ​ 50,000 ​ 300,000 ​ 350,000 2027 ​ — ​ — ​ — ​ 300,000 ​ 300,000 2028 ​ 80,000 ​ — ​ 80,000 ​ 300,000 ​ 380,000 Thereafter ​ 162,500 ​ 27,000 ​ 189,500 ​ 1,000,000 ​ 1,189,500 Subtotal ​ 572,670 ​ 27,000 ​ 599,670 ​ 3,360,091 ​ 3,959,761 Non-cash (a) ​ 1,020 ​ (66) ​ 954 ​ (24,818) ​ (23,864) Total ​ $ 573,690 ​ $ 26,934 ​ $ 600,624 ​ $ 3,335,273 ​ $ 3,935,897 (a) Includes the unamortized balance of fair market value adjustments, premiums/discounts and deferred financing costs . The Company amortized $1.1 million and $ 1.1 million, respectively, during the three months ended September 30, 2019 and 2018, and $3.1 million and $3.2 million, respectively, during the nine months ended September 30, 2019 and 2018, of deferred financing costs into Interest expense. We were in compliance with the covenants of our debt instruments at September 30, 2019. In October 2019, the Company issued $100.0 million of 3.20% senior unsecured medium-term notes due 2030 and $300.0 million of 3.10% senior unsecured medium-term notes due 2034. Interest is payable semi-annually in arrears on January 15 and July 15 for the 2030 notes, and May 1 and November 1 for the 2034 notes. The 2030 notes were priced at 103.32% of the principal amount at issuance, and the 2034 notes were priced at 99.56% of the principal amount at issuance. In combination with the issuance, the Company entered into treasury lock agreements to hedge against interest rate risk on all of this debt. The all-in weighted average interest rate, inclusive of the impact of the treasury locks, was 3.24% for the 2030 notes and 3.13% for the 2034 notes. The Company will use the net proceeds for the repayment of all $400.0 million aggregate principal amount (plus the make-whole amount of approximately $21.5 million and accrued and unpaid interest) of its 4.63% senior unsecured medium-term notes due January 2022. The 2034 notes were issued as “green” bonds and, as a result, the Company intends to allocate the net proceeds from the sale of the 2034 notes to fund eligible green projects, including previously incurred development costs related to properties that have received at least a LEED Silver certification. The 2030 notes are a further issuance of, and form a single series with, the $300.0 million aggregate principal amount of the Company’s 3.20% notes due 2030 that were issued on July 2, 2019. As of the completion of the offering, the aggregate principal amount of outstanding 2030 notes was $400.0 million.

INCOME_(LOSS) PER SHARE

INCOME/(LOSS) PER SHARE	9 Months Ended
	Sep. 30, 2019
INCOME/(LOSS) PER SHARE
INCOME/(LOSS) PER SHARE	8. INCOME/(LOSS) PER SHARE The following table sets forth the computation of basic and diluted income/(loss) per share for the periods presented (dollars and shares in thousands, except per share data): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ 2019 2018 2019 2018 ​ Numerator for income/(loss) per share: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income/(loss) ​ $ 29,422 ​ $ 20,258 ​ $ 94,342 ​ $ 131,927 ​ Net (income)/loss attributable to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership ​ (2,162) ​ (1,616) ​ (6,871) ​ (10,819) ​ Net (income)/loss attributable to noncontrolling interests ​ (56) ​ (32) ​ (145) ​ (141) ​ Net income/(loss) attributable to UDR, Inc. ​ 27,204 ​ 18,610 ​ 87,326 ​ 120,967 ​ Distributions to preferred stockholders — Series E (Convertible) ​ (1,031) ​ (971) ​ (3,073) ​ (2,897) ​ Income/(loss) attributable to common stockholders - basic and diluted ​ $ 26,173 ​ $ 17,639 ​ $ 84,253 ​ $ 118,070 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Denominator for income/(loss) per share: ​ ​ ​ ​ ​ Weighted average common shares outstanding ​ 288,957 ​ 268,034 ​ 282,866 ​ 267,873 ​ Non-vested restricted stock awards ​ (251) ​ (307) ​ (268) ​ (344) ​ Denominator for basic income/(loss) per share ​ 288,706 ​ 267,727 ​ 282,598 ​ 267,529 ​ Incremental shares issuable from assumed conversion of stock options, unvested LTIP Units, unvested restricted stock, and shares issuable upon settlement of forward sales agreements ​ 823 ​ 1,134 ​ 694 ​ 1,491 ​ Denominator for diluted income/(loss) per share ​ 289,529 ​ 268,861 ​ 283,292 ​ 269,020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income/(loss) per weighted average common share: ​ ​ ​ ​ ​ Basic ​ $ 0.09 ​ $ 0.07 ​ $ 0.30 ​ $ 0.44 ​ Diluted ​ $ 0.09 ​ $ 0.07 ​ $ 0.30 ​ $ 0.44 ​ ​ 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”), unvested restricted stock and continuous equity program forward sales agreements. 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 nine months ended September 30, 2019 and 2018, the effect of the conversion of the OP Units, DownREIT Units, LTIP Units, the Company’s Series E preferred stock and shares issuable upon settlement of forward sales agreements was not dilutive and therefore not included in the above calculation. In July 2017, the Company entered into an ATM sales agreement under which the Company may offer and sell up to 20.0 million shares of its common stock, from time to time, to or through its sales agents and may enter into separate forward sales agreements to or through its forward purchasers. Upon entering into the ATM sales agreement, the Company simultaneously terminated the sales agreement for its prior at-the-market equity offering program, which was entered into in April 2017, which replaced the prior at-the-market equity offering program entered into in April 2012. During the three months ended September 30, 2019, the Company sold 2.2 million shares of common stock through its ATM program for aggregate gross proceeds of approximately $100.5 million at a weighted average price per share of $46.19. Aggregate net proceeds from such sales, after deducting related expenses, including commissions paid to the sales agents of approximately $1.1 million, were approximately $99.4 million, which were primarily used to fund the Company’s recent acquisitions. During the nine months ended September 30, 2019, the Company sold 7.0 million shares of common stock through its ATM program for aggregate gross proceeds of approximately $316.5 million at a weighted average price per share of $45.29. Aggregate net proceeds from such sales, after deducting related expenses, including commissions paid to the sales agents of approximately $4.0 million, were approximately $312.3 million, which were primarily used to fund the Company’s recent acquisitions. As of September 30, 2019, we had 13.0 million shares of common stock available for future issuance under the ATM program. In connection with any forward sales agreement under the Company’s ATM program, the relevant forward purchasers will borrow from third parties and, through the relevant sales agent, acting in its role as forward seller, sell a number of shares of the Company’s common stock equal to the number of shares underlying the agreement. The Company does not initially receive any proceeds from any sale of borrowed shares by the forward seller. ​ In September 2019, the Company entered into a forward sales agreement under its ATM program for 1.3 million shares of common stock at an initial forward price per share of $47.68. The initial forward price per share to be received by the Company upon settlement will be determined on the applicable settlement date based on adjustments made to the initial forward price to reflect the then-current federal funds rate and the amount of dividends paid to holders of UDR common stock over the term of the forward sales agreement. As of September 30, 2019, no shares under the forward sales agreement have been settled. The final date by which shares sold under the forward sales agreement must be settled is March 31, 2020. ​ The Company generally has the ability to determine the dates and method of settlement (i.e., gross physical settlement, net share settlement or cash settlement), subject to certain conditions and the right of the counterparty to accelerate settlement under certain circumstances. The Company currently expects to fully physically settle each forward sales agreement with the relevant forward purchaser on one or more dates specified by the Company on or prior to the maturity date of that particular forward sales agreement, in which case the Company expects to receive aggregate net cash proceeds at settlement equal to the number of shares underlying the particular forward sales agreement multiplied by the relevant forward sale price. However, subject to certain exceptions, the Company may also elect, in its discretion, to cash settle or net share settle a particular forward sales agreement, in which case the Company may not receive any proceeds (in the case of cash settlement) or will not receive any proceeds (in the case of net share settlement), and the Company may owe cash (in the case of cash settlement) or shares of UDR common stock (in the case of net share settlement) to the relevant forward purchaser. ​ In August 2019, the Company sold 7.5 million shares of its common stock for aggregate gross proceeds of approximately $349.9 million at a price per share of $46.65. Aggregate net proceeds from the sale, after offering-related expenses, were approximately $349.8 million, which were used for planned acquisitions of assets, working capital and general corporate purposes. ​ The following table sets forth the additional shares of common stock outstanding by equity instrument if converted to common stock for each of the three and nine months ended September 30, 2019 and 2018 (in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ ​ 2019 ​ 2018 ​ 2019 ​ 2018 ​ OP/DownREIT Units 22,211 24,558 23,068 24,546 Convertible preferred stock 3,011 3,011 3,011 3,011 Stock options, unvested LTIP Units, unvested restricted stock, and forward sales shares 823 1,134 694 1,491 ​

NONCONTROLLING INTERESTS

NONCONTROLLING INTERESTS	9 Months Ended
	Sep. 30, 2019
NONCONTROLLING INTERESTS
NONCONTROLLING INTERESTS	9. NONCONTROLLING INTERESTS Redeemable Noncontrolling Interests in the Operating Partnership and DownREIT Partnership Interests in the Operating Partnership and the DownREIT Partnership held by limited partners are represented by OP Units and DownREIT Units, respectively. The income is allocated to holders of OP Units/DownREIT Units based upon net income attributable to common stockholders and the weighted average number of OP Units/DownREIT Units outstanding to total common shares plus OP Units/DownREIT Units outstanding during the period. Capital contributions, distributions, and profits and losses are allocated to noncontrolling interests in accordance with the terms of the partnership agreements of the Operating Partnership and the DownREIT Partnership. Limited partners of the Operating Partnership and the DownREIT Partnership have the right to require such partnership to redeem all or a portion of the OP Units/DownREIT Units held by the limited partner at a redemption price equal to and in the form of the Cash Amount (as defined in the partnership agreement of the Operating Partnership or the DownREIT Partnership, as applicable), provided that such OP Units/DownREIT Units have been outstanding for at least one year, subject to certain exceptions. UDR, as the general partner of the Operating Partnership and the DownREIT Partnership may, in its sole discretion, purchase the OP Units/DownREIT Units by paying to the limited partner either the Cash Amount or the REIT Share Amount (generally one share of common stock of the Company for each OP Unit/DownREIT Unit), as defined in the partnership agreement of the Operating Partnership or the DownREIT Partnership, as applicable. Accordingly, the Company records the OP Units/DownREIT Units outside of permanent equity and reports the OP Units/DownREIT Units at their redemption value using the Company’s stock price at each balance sheet date. The following table sets forth redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership for the following period ( dollars in thousands ​ ​ ​ ​ ​ Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership, December 31, 2018 $ 972,740 ​ Mark-to-market adjustment to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership ​ 222,405 ​ Conversion of OP Units/DownREIT Units to Common Stock ​ (119,338) ​ Net income/(loss) attributable to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership ​ 6,871 ​ Distributions to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership ​ (24,509) ​ Vesting of Long-Term Incentive Plan Units ​ ​ 14,742 ​ Allocation of other comprehensive income/(loss) ​ (730) ​ Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership, September 30, 2019 ​ $ 1,072,181 ​ ​ Noncontrolling Interests Noncontrolling interests represent interests of unrelated partners and unvested LTIP Units in certain consolidated affiliates, and are presented as part of equity on the Consolidated Balance Sheets since these interests are not redeemable. Net (income)/loss attributable to noncontrolling interests The Company grants LTIP Units to certain employees and non-employee directors. The LTIP Units represent an ownership interest in the Operating Partnership and have vesting terms of between one and three years, specific to the individual grants. Noncontrolling interests related to long-term incentive plan units represent the unvested LTIP Units of these employees and non-employee directors in the Operating Partnership. The net income/(loss) allocated to the unvested LTIP Units is included in Net (income)/loss attributable to noncontrolling interests

FAIR VALUE OF DERIVATIVES AND F

FAIR VALUE OF DERIVATIVES AND FINANCIAL INSTRUMENTS	9 Months Ended
	Sep. 30, 2019
FAIR VALUE OF DERIVATIVES AND FINANCIAL INSTRUMENTS
FAIR VALUE OF DERIVATIVES AND FINANCIAL INSTRUMENTS	10. FAIR VALUE OF DERIVATIVES AND FINANCIAL INSTRUMENTS Fair value is based on the price that would be received to sell an asset or the exit price that would be paid to transfer a liability in an orderly transaction between market participants at the measurement date. A three-level valuation hierarchy prioritizes observable and unobservable inputs used to measure fair value. The fair value hierarchy consists of three broad levels, which are described below: ● Level 1 — Quoted prices in active markets for identical assets or liabilities that the entity has the ability to access. ● Level 2 — Observable inputs other than prices included in Level 1, such as quoted prices for similar assets and liabilities in active markets; quoted prices for identical or similar assets and liabilities in markets that are not active; or other inputs that are observable or can be corroborated with observable market data. ● Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets and liabilities. This includes certain pricing models, discounted cash flow methodologies and similar techniques that use significant unobservable inputs. The estimated fair values of the Company’s financial instruments either recorded or disclosed on a recurring basis as of September 30, 2019 and December 31, 2018, are summarized as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value at September 30, 2019, Using ​ ​ Total ​ ​ ​ Quoted ​ ​ ​ ​ ​ ​ Carrying ​ ​ ​ Prices in ​ ​ ​ ​ ​ ​ Amount in ​ ​ ​ Active ​ ​ ​ ​ ​ ​ ​ Statement of ​ ​ ​ ​ Markets ​ Significant ​ ​ ​ ​ ​ Financial ​ Fair Value ​ for Identical ​ Other ​ Significant ​ ​ Position at ​ Estimate at ​ Assets or ​ Observable ​ Unobservable ​ ​ September 30, ​ September 30, ​ Liabilities ​ Inputs ​ Inputs ​ ​ 2019 ​ 2019 ​ (Level 1) ​ (Level 2) ​ (Level 3) Description: ​ ​ ​ ​ ​ ​ Notes receivable (a) ​ $ 37,899 ​ $ 42,613 ​ $ — ​ $ — ​ $ 42,613 Derivatives - Interest rate contracts (b) ​ 730 ​ 730 ​ — ​ 730 ​ — Total assets ​ $ 38,629 ​ $ 43,343 ​ $ — ​ $ 730 ​ $ 42,613 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives - Interest rate contracts (b) ​ $ 469 ​ $ 469 ​ $ — ​ $ 469 ​ $ — Secured debt instruments - fixed rate: (c) ​ ​ ​ ​ ​ ​ Mortgage notes payable ​ ​ 575,965 ​ ​ 569,318 ​ ​ — ​ ​ — ​ ​ 569,318 Secured debt instruments - variable rate: (c) ​ ​ ​ ​ ​ ​ Tax-exempt secured notes payable ​ 27,000 ​ 27,000 ​ — ​ — ​ 27,000 Unsecured debt instruments: (c) ​ ​ ​ ​ ​ ​ Working capital credit facility ​ ​ 34,447 ​ ​ 34,447 ​ ​ — ​ ​ — ​ ​ 34,447 Commercial paper program ​ ​ 60,000 ​ ​ 60,000 ​ ​ — ​ ​ — ​ ​ 60,000 Unsecured notes ​ ​ 3,260,258 ​ ​ 3,415,618 ​ ​ — ​ ​ — ​ ​ 3,415,618 Total liabilities ​ $ 3,958,139 ​ $ 4,106,852 ​ $ — ​ $ 469 ​ $ 4,106,383 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (d) ​ $ 1,072,181 ​ $ 1,072,181 ​ $ — ​ $ 1,072,181 ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value at December 31, 2018, Using ​ ​ Total ​ ​ ​ Quoted ​ ​ ​ ​ ​ ​ Carrying ​ ​ ​ Prices in ​ ​ ​ ​ ​ ​ Amount in ​ ​ ​ Active ​ ​ ​ ​ ​ ​ Statement of ​ ​ ​ Markets ​ Significant ​ ​ ​ ​ Financial ​ Fair Value ​ for Identical ​ Other ​ Significant ​ ​ Position at ​ Estimate at ​ Assets or ​ Observable ​ Unobservable ​ ​ December 31, ​ December 31, ​ Liabilities ​ Inputs ​ Inputs ​ 2018 ​ 2018 ​ (Level 1) ​ (Level 2) ​ (Level 3) Description: ​ ​ ​ ​ ​ ​ Notes receivable (a) ​ $ 42,259 ​ $ 45,026 ​ $ — ​ $ — ​ $ 45,026 Derivatives - Interest rate contracts (b) ​ 4,757 ​ 4,757 ​ — ​ 4,757 ​ — Total assets ​ $ 47,016 ​ $ 49,783 ​ $ — ​ $ 4,757 ​ $ 45,026 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives - Interest rate contracts (b) ​ $ 356 ​ $ 356 ​ $ — ​ $ 356 ​ $ — Secured debt instruments - fixed rate: (c) ​ ​ ​ ​ ​ ​ Mortgage notes payable ​ ​ 417,989 ​ ​ 416,314 ​ ​ — ​ ​ — ​ ​ 416,314 Fannie Mae credit facility ​ 90,000 ​ 90,213 ​ — ​ — ​ 90,213 Secured debt instruments - variable rate: (c) ​ ​ ​ ​ ​ ​ Tax-exempt secured notes payable ​ 94,700 ​ 94,700 ​ — ​ — ​ 94,700 Unsecured debt instruments: (c) ​ ​ ​ ​ ​ ​ ​ Working capital credit facility ​ ​ 16 ​ ​ 16 ​ ​ — ​ ​ — ​ ​ 16 Commercial paper program ​ ​ 101,115 ​ ​ 101,115 ​ ​ — ​ ​ — ​ ​ 101,115 Unsecured notes ​ ​ 2,861,842 ​ ​ 2,829,390 ​ ​ — ​ ​ — ​ ​ 2,829,390 Total liabilities ​ $ 3,566,018 ​ $ 3,532,104 ​ $ — ​ $ 356 ​ $ 3,531,748 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (d) ​ $ 972,740 ​ $ 972,740 ​ $ — ​ $ 972,740 ​ $ — (a) See Note 2, Significant Accounting Policies . (b) See Note 11, Derivatives and Hedging Activity . (c) See Note 7, Secured and Unsecured Debt, Net . (d) See Note 9, Noncontrolling Interests. There were no transfers into or out of any of the levels of the fair value hierarchy during the nine months ended September 30, 2019. Financial Instruments Carried at Fair Value The fair values of interest rate swaps are determined using the market standard methodology of netting the discounted future fixed cash receipts (or payments) and the discounted expected variable cash payments (or receipts). The variable cash payments (or receipts) are based on an expectation of future interest rates (forward curves) derived from observable market interest rate curves. The fair values of interest rate options are determined using the market standard methodology of discounting the future expected cash receipts that would occur if variable interest rates rise above the strike rate of the caps. The variable interest rates used in the calculation of projected receipts on the cap are based on an expectation of future interest rates derived from observable market interest rate curves and volatilities. The Company incorporates credit valuation adjustments to appropriately reflect both its own nonperformance risk and the respective counterparty’s nonperformance risk in the fair value measurements. In adjusting the fair value of its derivative contracts for the effect of nonperformance risk, the Company has considered the impact of netting and any applicable credit enhancements, such as collateral postings, thresholds, mutual puts, and guarantees. Although the Company has determined that the majority of the inputs used to value its derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with its derivatives utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by itself and its counterparties. However, as of September 30, 2019 and December 31, 2018, 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 September 30, 2019 and December 31, 2018, 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, which includes notes receivable and debt instruments, are classified in Level 3 of the fair value hierarchy due to the significant unobservable inputs that are utilized in their respective valuations. 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 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.

DERIVATIVES AND HEDGING ACTIVIT

DERIVATIVES AND HEDGING ACTIVITY	9 Months Ended
	Sep. 30, 2019
DERIVATIVES AND HEDGING ACTIVITY
DERIVATIVES AND HEDGING ACTIVITY	11. 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 changes in the fair value of derivatives designated and that qualify as cash flow hedges are recorded in Accumulated other comprehensive income/(loss), net Amounts reported in Accumulated other comprehensive income/(loss), net Interest expense As of September 30, 2019, the Company had the following outstanding interest rate derivatives that were designated as cash flow hedges of interest rate risk ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ Number of ​ Product ​ Instruments ​ Notional Interest rate swaps (a) ​ 4 ​ $ 315,000 (a) In addition to the interest rate swaps summarized above, the Company entered into an additional interest rate swap with a notional value of $315.0 million that will become effective in January 2020 upon the maturity of the interest rate swaps summarized above. Additionally, the Company had previously entered into two additional interest rate swaps with a notional value totaling $75.0 million that were subsequently terminated and settled during the nine months ended September 30, 2019 in conjunction with the July 2019 issuance of $300.0 million of senior unsecured medium-term notes as disclosed in Note 7, Secured and Unsecured, Net ​ 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 no gain or loss for both the three and nine months ended September 30, 2019 and 2018. As of September 30, 2019, the Company had the following outstanding derivatives that were not designated as hedges in qualifying hedging relationships ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ Number of ​ ​ Product ​ Instruments ​ Notional Interest rate caps ​ 1 ​ $ 19,880 ​ Tabular Disclosure of Fair Values of Derivative Instruments on the Consolidated Balance Sheet The table below presents the fair value of the Company’s derivative financial instruments as well as their classification on the Consolidated Balance Sheets as of September 30, 2019 and December 31, 2018 ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Asset Derivatives ​ Liability Derivatives ​ ​ (included in Other assets ) ​ (included in Other liabilities ) ​ ​ Fair Value at: ​ Fair Value at: ​ ​ September 30, ​ December 31, ​ September 30, ​ December 31, ​ ​ 2019 ​ 2018 ​ 2019 ​ 2018 Derivatives designated as hedging instruments: ​ ​ ​ ​ Interest rate products ​ $ 730 ​ $ 4,757 ​ $ 469 ​ $ 356 ​ Tabular Disclosure of the Effect of Derivative Instruments on the Consolidated Statements of Operations The tables below present the effect of the Company’s derivative financial instruments on the Consolidated Statements of Operations for the three and nine months ended September 30, 2019 and 2018 ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gain/(Loss) Recognized in ​ ​ ​ ​ Gain/(Loss) Reclassified ​ Interest expense ​ ​ Unrealized holding gain/(loss) ​ from Accumulated OCI into ​ (Amount Excluded from ​ ​ Recognized in OCI ​ Interest expense ​ Effectiveness Testing) Derivatives in Cash Flow Hedging Relationships 2019 2018 2019 2018 2019 2018 Three Months Ended September 30, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate products ​ $ (659) ​ $ 2,320 ​ $ 624 ​ $ 564 ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate products ​ $ (7,181) ​ $ 4,312 ​ $ 2,504 ​ $ 1,162 ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, ​ September 30, ​ ​ 2019 ​ 2018 ​ 2019 ​ 2018 Total amount of Interest expense ​ $ 42,523 ​ $ 34,401 ​ $ 110,482 ​ $ 95,942 ​ The Company did not recognize any gain/(loss) in Interest income and other income/(expense), net Credit-risk-related Contingent Features The Company has agreements with its derivative counterparties that contain a provision where 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. 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 September 30, 2019, the fair value of derivatives was in a net asset position, which includes accrued interest but excludes any adjustment for nonperformance risk related to these agreements, of $0.5 million. Tabular Disclosure of Offsetting Derivatives The Company has elected not to offset derivative positions on the consolidated financial statements. The tables below present the effect on its financial position had the Company made the election to offset its derivative positions as of September 30, 2019 and December 31, 2018 (dollars in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross Net Amounts of Gross Amounts Not Offset ​ ​ ​ ​ ​ ​ ​ ​ Amounts ​ Assets ​ in the Consolidated ​ ​ ​ ​ ​ Gross ​ Offset in the ​ Presented in the ​ Balance Sheet ​ ​ ​ ​ ​ Amounts of ​ Consolidated ​ Consolidated ​ ​ ​ ​ Cash ​ ​ ​ ​ ​ Recognized ​ Balance ​ Balance Sheets ​ Financial ​ Collateral ​ ​ ​ Offsetting of Derivative Assets ​ Assets ​ Sheets ​ (a) ​ Instruments Received Net Amount September 30, 2019 ​ $ 730 ​ $ — ​ $ 730 ​ $ (371) ​ $ — ​ $ 359 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2018 ​ $ 4,757 ​ $ — ​ $ 4,757 ​ $ — ​ $ — ​ $ 4,757 (a) Amounts reconcile to the aggregate fair value of derivative assets in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Consolidated Balance Sheets” located in this footnote. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross Net Amounts of Gross Amounts Not Offset ​ ​ ​ ​ ​ ​ ​ ​ Amounts ​ Liabilities ​ in the Consolidated ​ ​ ​ ​ ​ Gross ​ Offset in the ​ Presented in the ​ Balance Sheet ​ ​ ​ ​ ​ Amounts of ​ Consolidated ​ Consolidated ​ ​ ​ ​ Cash ​ ​ ​ ​ ​ Recognized ​ Balance ​ Balance Sheets ​ Financial ​ Collateral ​ ​ ​ Offsetting of Derivative Liabilities Liabilities Sheets (a) Instruments Posted Net Amount September 30, 2019 ​ $ 469 ​ $ — ​ $ 469 ​ $ (371) ​ $ — ​ $ 98 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2018 ​ $ 356 ​ $ — ​ $ 356 ​ $ — ​ $ — ​ $ 356 (a) Amounts reconcile to the aggregate fair value of derivative liabilities in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Consolidated Balance Sheets” located in this footnote.

STOCK BASED COMPENSATION

STOCK BASED COMPENSATION	9 Months Ended
	Sep. 30, 2019
EMPLOYEE BENEFIT PLANS
STOCK BASED COMPENSATION	12. STOCK BASED COMPENSATION The Company recognized stock based compensation expense, inclusive of awards granted to our non-employee directors, net of capitalization, of $4.5 million and $3.6 million during the three months ended September 30, 2019 and 2018, respectively, and $13.0 million and $10.7 million during the nine months ended September 30, 2019 and 2018, respectively.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	9 Months Ended
	Sep. 30, 2019
COMMITMENTS AND CONTINGENCIES
COMMITMENTS AND CONTINGENCIES	13. COMMITMENTS AND CONTINGENCIES Commitments Real Estate Commitments The following summarizes the Company’s real estate commitments at September 30, 2019 ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number ​ UDR's ​ UDR's Remaining ​ ​ ​ Properties ​ Investment (a) ​ Commitment ​ Wholly-owned — under development 1 ​ $ 21,845 ​ $ 75,655 Wholly-owned — redevelopment 2 ​ ​ 11,582 ​ ​ 23,918 Joint ventures: ​ ​ Unconsolidated joint ventures - development 1 ​ 14,402 ​ 21,496 (b) Preferred equity investments 2 ​ ​ 53,781 (c) ​ 27,390 (d) Other investments ​ - ​ ​ 12,926 ​ ​ 9,000 (e) Total ​ $ 114,536 ​ $ 157,459 (a) Represents UDR’s investment as of September 30, 2019. (b) Represents UDR’s proportionate share of expected remaining costs to complete the development. (c) Represents UDR’s investment in 1300 Fairmount and Modera Lake Merritt for the properties under development as of September 30, 2019. (d) Represents UDR’s remaining commitment for 1300 Fairmount and Modera Lake Merritt. (e) Represents UDR’s remaining commitment for other investment ventures. ​ Purchase Commitments ​ In 2019, the Company entered into a contract to purchase a development land parcel located in King of Prussia, Pennsylvania for a purchase price of approximately $14.8 million. The Company made a $0.8 million deposit on the purchase, which is generally non-refundable other than due to a failure of closing conditions pursuant to the terms of the purchase agreement. The acquisition is expected to close in 2020, subject to customary closing conditions. ​ 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 flows.

REPORTABLE SEGMENTS

REPORTABLE SEGMENTS	9 Months Ended
	Sep. 30, 2019
REPORTABLE SEGMENTS
REPORTABLE SEGMENTS	14. 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 2.875% 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 Non-Mature Communities/Other ● Same-Store Communities represent those communities acquired, developed, and stabilized prior to July 1, 2018 (for quarter-to-date comparison) or January 1, 2018 (for year-to-date comparison) and held as of September 30, 2019. A comparison of operating results from the prior year is meaningful as these communities were owned and had stabilized occupancy and operating expenses as of the beginning of the prior period, there is no plan to conduct substantial redevelopment activities, and the community is not held for disposition within the current year. A community is considered to have stabilized occupancy once it achieves 90% occupancy for at least three consecutive months. ● Non-Mature Communities/Other represent those communities that do not meet the criteria to be included in Same-Store Communities , including, but not limited to, recently acquired, developed and redeveloped communities, and the non-apartment components of mixed use properties. Management evaluates the performance of each of our apartment communities on a Same-Store Community Non-Mature Community/Other Revenue is measured based on consideration specified in contracts with customers. The Company recognizes revenue when it satisfies a performance obligation by providing the services specified in a contract to the customer. All revenues are from external customers and no single tenant or related group of tenants contributed 10% or more of UDR’s total revenues during the three and nine months ended September 30, 2019 and 2018. ​ The following is a description of the principal streams from which the Company generates its revenue: Lease Revenue ​ Lease revenue related to leases is recognized on an accrual basis when due from residents or tenants in accordance with ASC 842, Leases ​ Lease revenue also includes all pass-through revenue from retail and residential leases and common area maintenance reimbursements from retail leases. These services represent non-lease components in a contract as the Company transfers a service to the lessee other than the right to use the underlying asset. The Company has elected the practical expedient under the leasing standard to not separate lease and non-lease components from its resident and retail lease contracts as the timing and pattern of revenue recognition for the non-lease component and related lease component are the same and the combined single lease component would be classified as an operating lease. ​ Other Revenue ​ ​ Joint venture management and other fees ​ The Joint venture management and other fees Joint venture management and other fees ​ The following table details rental income and NOI for UDR’s reportable segments for the three and nine months ended September 30, 2019 and 2018, and reconciles NOI to Net income/(loss) attributable to UDR, Inc. (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, (a) ​ September 30, (b) ​ 2019 2018 2019 2018 Reportable apartment home segment lease revenue ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Same-Store Communities ​ ​ ​ ​ ​ West Region ​ $ 99,316 ​ $ 95,447 ​ $ 293,294 ​ $ 281,722 Mid-Atlantic Region ​ 52,826 ​ 51,291 ​ 157,179 ​ 152,867 Southeast Region ​ 28,540 ​ 27,773 ​ 84,551 ​ 81,554 Northeast Region ​ 30,196 ​ 29,491 ​ 89,650 ​ 87,776 Southwest Region ​ 15,451 ​ 15,060 ​ 40,705 ​ 39,586 Non-Mature Communities/Other ​ 40,975 ​ 24,237 ​ 106,499 ​ 66,906 Total segment and consolidated rental income ​ $ 267,304 ​ $ 243,299 ​ $ 771,878 ​ $ 710,411 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Reportable apartment home segment other revenue ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Same-Store Communities ​ ​ ​ ​ ​ West Region ​ $ 7,869 ​ $ 7,168 ​ $ 23,488 ​ $ 21,567 Mid-Atlantic Region ​ 4,376 ​ 4,032 ​ 12,958 ​ 11,944 Southeast Region ​ 3,438 ​ 3,211 ​ 10,423 ​ 9,918 Northeast Region ​ 1,321 ​ 1,226 ​ 3,753 ​ 3,422 Southwest Region ​ 1,527 ​ 1,525 ​ 4,100 ​ 3,986 Non-Mature Communities/Other ​ 3,173 ​ 2,795 ​ 8,793 ​ 9,125 Total segment and consolidated rental income ​ $ 21,704 ​ $ 19,957 ​ $ 63,515 ​ $ 59,962 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total reportable apartment home segment rental income ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Same-Store Communities ​ ​ ​ ​ ​ West Region ​ $ 107,185 ​ $ 102,615 ​ $ 316,782 ​ $ 303,289 Mid-Atlantic Region ​ 57,202 ​ 55,323 ​ 170,137 ​ 164,811 Southeast Region ​ 31,978 ​ 30,984 ​ 94,974 ​ 91,472 Northeast Region ​ 31,517 ​ 30,717 ​ 93,403 ​ 91,198 Southwest Region ​ 16,978 ​ 16,585 ​ 44,805 ​ 43,572 Non-Mature Communities/Other ​ 44,148 ​ 27,032 ​ 115,292 ​ 76,031 Total segment and consolidated rental income ​ $ 289,008 ​ $ 263,256 ​ $ 835,393 ​ $ 770,373 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Reportable apartment home segment NOI ​ ​ ​ ​ Same-Store Communities ​ ​ ​ ​ West Region ​ $ 81,170 ​ $ 77,321 ​ $ 240,442 ​ $ 229,129 Mid-Atlantic Region ​ 39,850 ​ 38,220 ​ 119,075 ​ 114,465 Southeast Region ​ 22,133 ​ 21,597 ​ 66,301 ​ 63,806 Northeast Region ​ 20,560 ​ 20,640 ​ 63,012 ​ 62,710 Southwest Region ​ 10,449 ​ 9,899 ​ 26,995 ​ 25,760 Non-Mature Communities/Other ​ 29,487 ​ 17,137 ​ 77,242 ​ 48,833 Total segment and consolidated NOI ​ 203,649 ​ 184,814 ​ 593,067 ​ 544,703 Reconciling items: ​ ​ ​ ​ Joint venture management and other fees ​ 6,386 ​ 2,888 ​ 11,982 ​ 8,819 Property management ​ (8,309) ​ (7,240) ​ (24,018) ​ (21,185) Other operating expenses ​ (2,751) ​ (3,314) ​ (11,132) ​ (8,148) Real estate depreciation and amortization ​ (127,391) ​ (107,881) ​ (357,793) ​ (322,537) General and administrative ​ (12,197) ​ (11,896) ​ (37,002) ​ (36,028) Casualty-related (charges)/recoveries, net ​ 1,088 ​ (678) ​ 842 ​ (2,364) Other depreciation and amortization ​ (1,619) ​ (1,682) ​ (4,953) ​ (5,057) Gain/(loss) on sale of real estate owned ​ ​ — ​ ​ — ​ ​ 5,282 ​ ​ 70,300 Income/(loss) from unconsolidated entities ​ 12,713 ​ (1,382) ​ 19,387 ​ (5,091) Interest expense ​ (42,523) ​ (34,401) ​ (110,482) ​ (95,942) Interest income and other income/(expense), net ​ 1,875 ​ 1,188 ​ 12,998 ​ 5,075 Tax (provision)/benefit, net ​ (1,499) ​ (158) ​ (3,836) ​ (618) Net (income)/loss attributable to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership ​ (2,162) ​ (1,616) ​ (6,871) ​ (10,819) Net (income)/loss attributable to noncontrolling interests ​ (56) ​ (32) ​ (145) ​ (141) Net income/(loss) attributable to UDR, Inc. ​ $ 27,204 ​ $ 18,610 ​ $ 87,326 ​ $ 120,967 (a) Same-Store Community population consisted of 38,177 apartment homes. (b) Same-Store Community population consisted of 37,959 apartment homes. ​ The following table details the assets of UDR’s reportable segments as of September 30, 2019 and December 31, 2018 (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2019 ​ 2018 Reportable apartment home segment assets: ​ ​ Same-Store Communities (a): ​ ​ West Region ​ $ 3,797,149 ​ $ 3,763,366 Mid-Atlantic Region ​ 2,338,963 ​ 2,317,369 Southeast Region ​ 799,739 ​ 779,310 Northeast Region ​ 1,498,500 ​ 1,491,994 Southwest Region ​ 595,982 ​ 589,188 Non-Mature Communities/Other ​ 2,534,062 ​ 1,254,932 Total segment assets ​ 11,564,395 ​ 10,196,159 Accumulated depreciation ​ (4,000,608) ​ (3,654,160) Total segment assets — net book value ​ 7,563,787 ​ 6,541,999 Reconciling items: ​ ​ Cash and cash equivalents ​ 1,895 ​ 185,216 Restricted cash ​ 21,646 ​ 23,675 Notes receivable, net ​ 37,899 ​ 42,259 Investment in and advances to unconsolidated joint ventures, net ​ 791,180 ​ 780,869 Operating lease right-of-use assets ​ ​ 135,889 ​ ​ — Other assets ​ 145,301 ​ 137,710 Total consolidated assets ​ $ 8,697,597 ​ $ 7,711,728 (a) Same-Store Community population consisted of 38,177 apartment homes. ​ 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., Richmond and Baltimore iii. Southeast Region — Orlando, Nashville, Tampa and Other Florida iv. Northeast Region — New York and Boston v. Southwest Region — Dallas, Austin and Denver

SIGNIFICANT ACCOUNTING POLICI_2

SIGNIFICANT ACCOUNTING POLICIES (Policies)	9 Months Ended
	Sep. 30, 2019
SIGNIFICANT ACCOUNTING POLICIES
Recent Accounting Pronouncements	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 Codification Improvements to Topic 326, Financial Instruments—Credit Losses, ​ In February 2016, the FASB issued ASU 2016-02, Leases ​ The Company elected the following package of practical expedients provided by the standard: (i) an entity need not reassess whether any expired or existing contract is a lease or contains a lease, (ii) an entity need not reassess the lease classification of any expired or existing leases, and (iii) an entity need not reassess initial direct costs for any existing leases. The Company also elected the short-term lease exception provided for in the standard and therefore only recognizes right-of-use assets and lease liabilities for leases with a term greater than one year. ​ The Company recognized right-of-use assets of $94.3 million and lease liabilities of $88.3 million as of January 1, 2019 upon adoption of the standard. The right-of-use assets included $6.0 million of prepaid rent and intangible assets that was included within Other assets ​ The lease liabilities represent the present value of the remaining minimum lease payments as of January 1, 2019 and primarily relate to ground leases for communities where we are the lessee. The right-of-use assets represent our right to use an underlying asset for the lease term, which are calculated utilizing the lease liabilities plus any prepaid lease payments and intangible assets for ground leases acquired in the purchase of real estate. Our right-of-use assets and related lease liabilities recognized as of January 1, 2019 may change as a result of updates to the projected future minimum lease payments. Certain of our ground lease agreements where we are the lessee have future minimum lease payments that reset in the future based upon a percentage of the fair market value of the land at the time of the reset. The Company will continue to recognize lease expense for these leases in a manner similar to previous accounting based on our election of the package of practical expedients. However, in the event we modify existing ground leases and/or enter into new ground leases subsequent to the adoption of the standard, such leases would likely be classified as finance leases under the standard and require expense recognition based on the effective interest method. Under the standard, initial direct costs for both lessees and lessors would include only those costs that are incremental to the arrangement and would not have been incurred if the lease had not been obtained. As a result, subsequent to the adoption of the standard, we are now expensing non-incremental leasing costs as incurred. ​ In July 2018, the FASB issued ASU 2018-11, Leases – Targeted Improvements Leases
Principles of Consolidation	Principles of Consolidation The Company accounts for subsidiary partnerships, joint ventures and other similar entities in which it holds an ownership interest in accordance with the consolidation guidance. The Company first evaluates whether each entity is a variable interest entity (“VIE”). Under the VIE model, the Company consolidates an entity when it has control to direct the activities of the VIE and the obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE. Under the voting model, the Company consolidates an entity when it controls the entity through ownership of a majority voting interest.
Real Estate Sales Gain Recognition	Real Estate Sales Gain Recognition ​ For sale transactions resulting in a transfer of a controlling financial interest of a property, the Company generally derecognizes the related assets and liabilities from its Consolidated Balance Sheets and records the gain or loss in the period in which the transfer of control occurs. If control of the property has not transferred to the counterparty, the criteria for derecognition are not met and the Company will continue to recognize the related assets and liabilities on its Consolidated Balance Sheets. ​ Sale transactions to entities in which the Company sells a controlling financial interest in a property but retains a noncontrolling interest are accounted for as partial sales. Partial sales resulting in a change in control are accounted for at fair value and a full gain or loss is recognized. Therefore, the Company will record a gain or loss on the partial interest sold, and the initial measurement of our retained interest will be accounted for at fair value. ​ Sales of real estate to joint ventures or other noncontrolled investees are also accounted for at fair value and the Company will record a full gain or loss in the period the property is contributed. ​ To the extent that the Company acquires a controlling financial interest in a property that it previously accounted for as an equity method investment, the Company will not remeasure its previously held interest if the acquisition is treated as an asset acquisition. The Company will include the carrying amount of its previously held equity method interest along with the consideration paid and transaction costs incurred in determining the amounts to allocate to the related assets and liabilities acquired on its Consolidated Balance Sheets. When treated as an asset acquisition, the Company will not recognize a gain or loss on consolidation of a property.
Notes Receivable	Notes Receivable The following table summarizes our Notes receivable, net dollars in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate at ​ Balance Outstanding ​ September 30, September 30, December 31, ​ ​ 2019 ​ 2019 ​ 2018 Note due December 2019 (a) 12.00 % $ 20,000 ​ $ 20,000 Note due February 2020 (b) 10.00 % 15,649 ​ 14,659 Note due October 2020 (c) 8.00 % 2,250 ​ 2,000 Note due August 2022 (d) ​ 10.00 % ​ — ​ ​ 5,600 Total notes receivable, net ​ $ 37,899 ​ $ 42,259 (a) In March 2018, the Company entered into a secured note with an unaffiliated third party with an aggregate commitment of $20.0 million, of which $20.0 million has been funded. Interest payments are due when the loan matures. In March 2019, the note’s maturity was extended to December 27, 2019, and the note is secured by a parcel of land. (b) The Company has a secured note with an unaffiliated third party with an aggregate commitment of $16.4 million, of which $15.6 million has been funded, including $1.0 million funded during the nine months ended September 30, 2019. 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). (c) The Company has a secured note with an unaffiliated third party with an aggregate commitment of $2.3 million, of which $2.3 million has been funded, including $0.3 million funded during the nine months ended September 30, 2019. 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 January 2019, the $5.6 million secured note was repaid in full along with the contractually accrued interest of $0.2 million and an additional $8.5 million of promoted interest in conjunction with the unaffiliated third party being acquired. The Company recognized $1.2 million and $1.2 million of interest income from notes receivable during the three months ended September 30, 2019 and 2018, respectively, and $3.5 million and $2.9 million of interest income and $8.5 million and zero of promoted interest from notes receivable during the nine months ended September 30, 2019 and 2018, respectively, none of which was related party interest. Interest income and promoted interest are included in Interest income and other income/(expense), net
Comprehensive Income/(Loss)	Comprehensive Income/(Loss) Comprehensive income/(loss), which is defined as the change in equity during each period from transactions and other events and circumstances from nonowner sources, including all changes in equity during a period except for those resulting from investments by or distributions to stockholders, is displayed in the accompanying Consolidated Statements of Comprehensive Income/(Loss). For the three and nine months ended September 30, 2019 and 2018, the Company’s other comprehensive income/(loss) consisted of the gain/(loss) 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 Derivatives and Hedging Activity,
Income Taxes	Income Taxes Due to the structure of the Company as a REIT and the nature of the operations for the operating properties, no provision for federal income taxes has been provided for at UDR. Historically, the Company has generally incurred only state and local excise and franchise taxes. UDR has elected for certain consolidated subsidiaries to be treated as taxable REIT subsidiaries (“TRS”). Income taxes for our TRS are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities from a change in tax rate is recognized in earnings in the period of the enactment date. The Company’s deferred tax assets are generally the result of differing depreciable lives on capitalized assets and timing of expense recognition for certain accrued liabilities. As of September 30, 2019 and December 31, 2018, UDR’s net deferred tax asset/(liability) was $(1.3) million and less than $(0.1) million, respectively. GAAP defines a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. GAAP also provides guidance on derecognition, classification, interest and penalties, accounting for interim periods, disclosure and transition. The Company recognizes its tax positions and evaluates them using a two-step process. First, UDR determines whether a tax position is more likely than not (greater than 50 percent probability) to be sustained upon examination, including resolution of any related appeals or litigation processes, based on the technical merits of the position. Second, the Company will determine the amount of benefit to recognize and record the amount that is more likely than not to be realized upon ultimate settlement. UDR had no material unrecognized tax benefit, accrued interest or penalties at September 30, 2019. UDR and its subsidiaries are subject to federal income tax as well as income tax of various state and local jurisdictions. The tax years 2016 through 2018 remain open to examination by tax jurisdictions to which we are subject. When applicable, UDR recognizes interest and/or penalties related to uncertain tax positions in Tax (provision)/benefit, net
Forward Sales Agreements	Forward Sales Agreements ​ The Company utilizes forward sales agreements for the future issuance of its common stock. When the Company enters into a forward sales agreement, the contract requires the Company to sell its shares to a counterparty at a predetermined price at a future date. The net sales price and proceeds attained by the Company will be determined on the dates of settlement, with adjustments during the term of the contract for the Company’s anticipated dividends as well as for a daily interest factor that varies with changes in the federal funds rate. The Company generally has the ability to determine the dates and method of settlement (i.e., gross physical settlement, net share settlement or cash settlement), subject to certain conditions and the right of the counterparty to accelerate settlement under certain circumstances. ​ The Company accounts for the shares of common stock reserved for issuance upon settlement as equity in accordance with ASC 815-40, Contracts in Entity's Own Equity ​ The guidance establishes a two-step process for evaluating whether an equity-linked financial instrument is considered indexed to its own stock by evaluating the instrument’s contingent exercise provisions and settlement provisions. We determined that (i) none of the agreements’ exercise contingencies were based on observable markets or indices besides those related to the market for our own stock price and operations; and (ii) none of the settlement provisions precluded the agreements from being indexed to our own stock. ​ Based upon our determination that the forward sales agreements are considered indexed to our own stock as well as the agreements permitting us to share settle, we have determined that the forward sales agreements qualify for equity classification. ​ Before the issuance of shares of common stock, upon physical or net share settlement of the forward sales agreements, the Company expects that the shares issuable upon settlement of the forward sales agreements will be reflected in its diluted income/(loss) per share calculations using the treasury stock method. Under this method, the number of shares of common stock used in calculating diluted income/(loss) per share is deemed to be increased by the excess, if any, of the number of shares of common stock that would be issued upon full physical settlement of the forward sales agreements over the number of shares of common stock that could be purchased by the Company in the open market (based on the average market price during the period) using the proceeds receivable upon full physical settlement (based on the adjusted forward sale price at the end of the reporting period). When the Company physically or net share settles any forward sales agreement, the delivery of shares of common stock would result in an increase in the number of weighted average common shares outstanding and dilution to basic income/(loss) per share. (See Note 8, Income/(Loss) per Share

SIGNIFICANT ACCOUNTING POLICI_3

SIGNIFICANT ACCOUNTING POLICIES (Tables)	9 Months Ended
	Sep. 30, 2019
SIGNIFICANT ACCOUNTING POLICIES
Summary of notes receivable, net	The following table summarizes our Notes receivable, net dollars in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate at ​ Balance Outstanding ​ September 30, September 30, December 31, ​ ​ 2019 ​ 2019 ​ 2018 Note due December 2019 (a) 12.00 % $ 20,000 ​ $ 20,000 Note due February 2020 (b) 10.00 % 15,649 ​ 14,659 Note due October 2020 (c) 8.00 % 2,250 ​ 2,000 Note due August 2022 (d) ​ 10.00 % ​ — ​ ​ 5,600 Total notes receivable, net ​ $ 37,899 ​ $ 42,259 (a) In March 2018, the Company entered into a secured note with an unaffiliated third party with an aggregate commitment of $20.0 million, of which $20.0 million has been funded. Interest payments are due when the loan matures. In March 2019, the note’s maturity was extended to December 27, 2019, and the note is secured by a parcel of land. (b) The Company has a secured note with an unaffiliated third party with an aggregate commitment of $16.4 million, of which $15.6 million has been funded, including $1.0 million funded during the nine months ended September 30, 2019. 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). (c) The Company has a secured note with an unaffiliated third party with an aggregate commitment of $2.3 million, of which $2.3 million has been funded, including $0.3 million funded during the nine months ended September 30, 2019. 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 January 2019, the $5.6 million secured note was repaid in full along with the contractually accrued interest of $0.2 million and an additional $8.5 million of promoted interest in conjunction with the unaffiliated third party being acquired.

REAL ESTATE OWNED (Tables)

REAL ESTATE OWNED (Tables)	9 Months Ended
	Sep. 30, 2019
REAL ESTATE OWNED
Summary of carrying amounts for real estate owned (at cost)	​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2019 ​ 2018 Land ​ $ 2,020,617 ​ $ 1,849,799 Depreciable property — held and used: ​ ​ Land improvements ​ 220,654 ​ 213,224 Building, improvements, and furniture, fixtures and equipment ​ 9,260,709 ​ 8,133,136 Real estate intangible assets ​ ​ 40,570 ​ ​ — Under development: ​ ​ Land and land improvements ​ 13,853 ​ — Building, improvements, and furniture, fixtures and equipment ​ 7,992 ​ — Real estate owned ​ 11,564,395 ​ 10,196,159 Accumulated depreciation ​ (4,000,608) ​ (3,654,160) Real estate owned, net ​ $ 7,563,787 ​ $ 6,541,999

JOINT VENTURES AND PARTNERSHI_2

JOINT VENTURES AND PARTNERSHIPS (Tables)	9 Months Ended
	Sep. 30, 2019
JOINT VENTURES AND PARTNERSHIPS
Schedule of unconsolidated joint ventures and partnerships	The following table summarizes the Company’s investment in and advances to unconsolidated joint ventures and partnerships, net, which are accounted for under the equity method of accounting as of September 30, 2019 and December 31, 2018 (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number of ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number of ​ Apartment ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Properties ​ Homes ​ Investment at ​ ​ UDR’s Ownership Interest ​ ​ Location of September 30, September 30, September 30, December 31, ​ ​ September 30, ​ December 31, Joint Venture Properties 2019 2019 2019 2018 ​ ​ 2019 ​ 2018 Operating and development: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ UDR/MetLife I ​ Los Angeles, CA ​ 1 operating community ​ 150 ​ $ 29,599 ​ $ 30,839 ​ ​ 50.0 % ​ 50.0 % UDR/MetLife II (a) Various 18 operating communities 4,059 ​ 300,479 ​ 296,807 ​ ​ 50.0 % ​ 50.0 % Other UDR/MetLife Various 5 operating communities 1,437 ​ 102,435 ​ 115,668 ​ ​ 50.6 % ​ 50.6 % Joint Ventures ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ UDR/MetLife Vitruvian Park ® (a) Addison, TX 4 operating communities; 1,879 ​ 75,858 ​ 71,730 ​ ​ 50.0 % ​ 50.0 % ​ 1 development community (b); ​ ​ ​ ​ ​ ​ ​ ​ ​ 4 land parcels ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ UDR/KFH (c) Washington, D.C. — ​ — ​ 156 ​ 5,507 ​ ​ — % ​ 30.0 % West Coast Development Joint Ventures (d) ​ Los Angeles, CA ​ 1 operating community ​ 293 ​ ​ 35,165 ​ ​ 36,143 ​ ​ 47.0 % ​ 47.0 % Investment in and advances to unconsolidated joint ventures, net, before participating loan investment, preferred equity investments and other investments ​ $ 543,692 ​ $ 556,694 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income/(loss) from investments ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Investment at ​ Three Months Ended ​ Nine Months Ended ​ Developer Capital Program ​ ​ Years To ​ UDR September 30, December 31, September 30, ​ September 30, ​ and Other Investments (e) Location Rate Maturity ​ Commitment (f) 2019 2018 2019 2018 2019 2018 ​ Preferred equity investments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ West Coast Development Joint Ventures (d) Various 6.5 % N/A ​ $ — ​ $ 17,080 ​ $ 65,417 ​ $ 71 ​ $ 25 ​ $ (100) ​ $ 974 ​ 1532 Harrison (g) ​ San Francisco, CA ​ 11.0 % 2.8 ​ ​ 24,645 ​ ​ 29,753 ​ ​ 24,986 ​ ​ 802 ​ ​ 721 ​ ​ 2,324 ​ ​ 1,492 ​ 1200 Broadway (h) ​ Nashville, TN ​ 8.0 % 3.0 ​ ​ 55,558 ​ ​ 62,666 ​ ​ 58,982 ​ ​ 1,244 ​ ​ 859 ​ ​ 3,619 ​ ​ 1,870 ​ Junction (i) ​ Santa Monica, CA ​ 12.0 % 2.8 ​ ​ 8,800 ​ ​ 10,072 ​ ​ 9,211 ​ ​ 299 ​ ​ 141 ​ ​ 861 ​ ​ 141 ​ 1300 Fairmount (j) ​ Philadelphia, PA ​ Variable ​ 3.9 ​ ​ 51,393 ​ ​ 36,404 ​ ​ 8,318 ​ ​ 930 ​ ​ 27 ​ ​ 1,724 ​ ​ 27 ​ Essex (k) ​ Orlando, FL ​ 12.5 % 3.9 ​ ​ 12,886 ​ ​ 14,347 ​ ​ 9,940 ​ ​ 443 ​ ​ 46 ​ ​ 1,182 ​ ​ 46 ​ Modera Lake Merritt (l) ​ Oakland, CA ​ 9.0 % 4.6 ​ ​ 27,250 ​ ​ 17,377 ​ ​ — ​ ​ 366 ​ ​ — ​ ​ 622 ​ ​ — ​ Other investments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The Portals (m) ​ Washington, D.C. ​ 11.0 % 1.7 ​ ​ 38,559 ​ ​ 46,863 ​ ​ 43,167 ​ ​ 1,287 ​ ​ 1,015 ​ ​ 3,694 ​ ​ 2,523 ​ Other investment ventures ​ N/A ​ N/A ​ N/A ​ $ 18,000 ​ ​ 12,926 ​ ​ 4,154 ​ $ 4,247 ​ $ (77) ​ $ 4,272 ​ $ (262) ​ Total Developer Capital Program and Other Investments ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 247,488 ​ ​ 224,175 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total investment in and advances to unconsolidated joint ventures, net ​ ​ ​ ​ $ 791,180 ​ $ 780,869 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (a) In August 2019, the Company entered into an agreement with MetLife, its joint venture partner, to acquire the approximately 50% ownership interest not previously owned in 10 UDR/MetLife operating communities, one development community and four land parcels valued at $1.1 billion, or $557 million at UDR’s share, and to sell its approximately 50% ownership interest in five UDR/MetLife operating communities valued at $645 million, or $323 million at UDR’s share, to MetLife. The transaction is expected to close during the fourth quarter of 2019, subject to customary closing conditions and closing price adjustments. Upon closing of the transaction, the UDR/MetLife II joint venture will hold seven operating communities and the UDR/MetLife Vitruvian Park ® joint venture will no longer hold any properties. (b) The number of apartment homes for the communities under development presented in the table above is based on the projected number of total homes upon completion of development. As of September 30, 2019, no apartment homes had been completed in the development community held by UDR/MetLife Vitruvian Park ® . (c) As of January 1, 2019, the joint venture held three operating communities. In May 2019, the joint venture sold one community, a 217 home operating community in Arlington, Virginia, for a sales price of approximately $74.8 million. As a result, the Company recorded a gain on the sale of approximately $5.3 million, which is included in Income/(loss) from unconsolidated entities In July 2019, the joint venture sold the second community, a 151 home operating community in Silver Spring, Maryland, for a sales price of approximately $43.5 million. As a result, the Company recorded a gain on the sale of approximately $5.3 million, which is included in Income/(loss) from unconsolidated entities In August 2019, the joint venture sold the third community, a 292 home operating community in Washington, D.C., directly to the Company for a sales price at 100% of approximately $184.0 million, before $2.8 million of closing costs incurred by UDR at acquisition. The Company deferred its share of the gain on sale of approximately $23.8 million and recorded it as a reduction of the carrying amount of real estate assets owned (see Note 3, Real Estate Owned (d) In 2015, the Company entered into a joint venture agreement with an unaffiliated joint venture partner and paid $136.3 million for a 48% ownership interest in a portfolio of five communities that were under construction. The communities are located in three of the Company’s core, coastal markets: Seattle, Washington, Los Angeles, California and Orange County, California. UDR earns a 6.5% preferred return on its investment through each individual community’s date of stabilization, defined as when a community reaches 80% occupancy for 90 consecutive days, while the joint venture partner is allocated all operating income and expense during the pre-stabilization period. Upon stabilization, income and expense are shared based on each partner’s ownership percentage and the Company no longer receives a 6.5% preferred return on its investment in the stabilized community. The Company serves as property manager and earns a management fee during the lease-up phase and subsequent operation of each of the communities. The unaffiliated joint venture partner is the general partner of the joint venture and the developer of the communities. The Company has concluded it does not control the joint ventures and, therefore, accounts for them under the equity method of accounting. During 2017, the Company exercised its fixed-price option to purchase the joint venture partner’s ownership interest in one of the five communities, and the joint venture sold two of the four remaining communities. In January 2019, the Company exercised its fixed-price option to purchase its joint venture partner’s ownership interest in one of the two remaining communities, a 386 apartment home operating community in Orange County, California, thereby increasing its ownership interest from 49% to 100%, for a cash purchase price of approximately $33.5 million. As a result, the Company consolidated the operating community and it is no longer accounted for as a preferred equity investment in an unconsolidated joint venture (see Note 3, Real Estate Owned The Company and its joint venture partner continue to operate the one remaining community. In 2017, the Company entered into two additional joint venture agreements with the unaffiliated joint venture partner and paid $15.5 million for a 49% ownership interest in a 155 apartment home community in Seattle, Washington and $16.1 million for a 49% ownership interest in a 276 apartment home community in Hillsboro, Oregon (together with the 2015 joint venture described above, the “West Coast Development Joint Ventures”). UDR earns a 6.5% preferred return on its investments through the communities’ date of stabilization, as defined above, while our joint venture partner is allocated all operating income and expense during the pre-stabilization period. Upon stabilization of the communities, income and expense will be shared based on each partner’s ownership percentage and the Company will no longer receive a 6.5% preferred return on its investment. The Company serves as property manager and earns a management fee during the lease-up phase and subsequent operation of the stabilized communities. The unaffiliated joint venture partner is the general partner and the developer of the communities. The Company has concluded it does not control the joint ventures and, therefore, accounts for them under the equity method of accounting. The Company has a fixed-price option to acquire the remaining interest in the communities beginning one year after completion. The unaffiliated joint venture partner is providing certain guaranties and there are construction loans on the communities. In January 2019, the Company exercised its fixed-price option to purchase its joint venture partner’s ownership interest in the 155 apartment home operating community in Seattle, Washington, thereby increasing its ownership interest from 49% to 100%, for a cash purchase price of approximately $20.0 million. As a result, the Company consolidated the operating community and it is no longer accounted for as a preferred equity investment in an unconsolidated joint venture (see Note 3, Real Estate Owned The Company’s recorded equity investment in the West Coast Development Joint Ventures at September 30, 2019 and December 31, 2018, of $52.2 million and $101.6 million, respectively, is inclusive of outside basis costs and our accrued but unpaid preferred return. (e) The Developer Capital Program is a program through which the Company makes investments, including preferred equity investments, mezzanine loans or other structured investments that may receive a fixed or variable yield on the investment and may include provisions pursuant to which the Company participates in the increase in value of the property upon monetization of the applicable property and/or holds fixed price purchase options. (f) Represents UDR’s maximum funding commitment only and therefore excludes other activity such as income from investments. (g) In June 2017, the Company entered into a joint venture agreement with an unaffiliated joint venture partner to develop and operate a 136 apartment home community in San Francisco, California. The Company’s preferred equity investment of up to $24.6 million earns a preferred return of 11.0% per annum. The unaffiliated joint venture partner is the managing member of the joint venture and the developer of the community. The Company has concluded that it does not control the joint venture and, therefore, accounts for it under the equity method of accounting. (h) In September 2017, the Company entered into a joint venture agreement with an unaffiliated joint venture partner to develop and operate a 313 apartment home community in Nashville, Tennessee. The Company’s preferred equity investment of up to $55.6 million earns a preferred return of 8.0% per annum and receives a variable percentage of the value created from the project upon a capital or liquidating event. The unaffiliated joint venture partner is the managing member of the joint venture and the developer of the community. The Company has concluded that it does not control the joint venture and, therefore, accounts for it under the equity method of accounting. (i) In August 2018, the Company entered into a joint venture agreement with an unaffiliated joint venture partner to develop and operate a 66 apartment home community in Santa Monica, CA. The Company’s preferred equity investment of $8.8 million earns a preferred return of 12.0% per annum. The unaffiliated joint venture partner is the managing member of the joint venture and the developer of the community. The Company has concluded that it does not control the joint venture and, therefore, accounts for it under the equity method of accounting. (j) In August 2018, the Company entered into a joint venture agreement with an unaffiliated joint venture partner to develop and operate a 471 apartment home community in Philadelphia, PA. The Company’s preferred equity investment of up to $51.4 million earns a preferred return between 8.5% and 12.0% per annum and receives a variable percentage of the value created from the project upon a capital or liquidating event. The unaffiliated joint venture partner is the managing member of the joint venture and the developer of the community. The Company has concluded that it does not control the joint venture and, therefore, accounts for it under the equity method of accounting. (k) In September 2018, the Company entered into a joint venture agreement with an unaffiliated joint venture partner to develop and operate a 330 apartment home community in Orlando, FL. The Company’s preferred equity investment of up to $12.9 million earns a preferred return of 12.5% per annum. The unaffiliated joint venture partner is the managing member of the joint venture and the developer of the community. The Company has concluded that it does not control the joint venture and, therefore, accounts for it under the equity method of accounting. (l) In April 2019, the Company entered into a joint venture agreement with an unaffiliated joint venture partner to develop and operate a 173 apartment home community in Oakland, CA. The Company’s preferred equity investment of up to $27.3 million earns a preferred return of 9.0% per annum and receives a variable percentage of the value created from the project upon a capital or liquidating event. The unaffiliated joint venture partner is the managing member of the joint venture and the developer of the community. The Company has concluded that it does not control the joint venture and, therefore, accounts for it under the equity method of accounting . (m) In May 2017, the Company entered into a joint venture agreement with an unaffiliated joint venture partner. The joint venture has made a mezzanine loan to a third party developer of a 373 apartment home community in Washington, D.C. The unaffiliated joint venture partner is the managing member of the joint venture. The mezzanine loan is for up to $71.0 million at an interest rate of 13.5% per annum and carries a term of four years with one 12-month extension option. The Company’s commitment to the joint venture is approximately $38.6 million and earns a weighted average return of approximately 11.0% per annum. The Company has concluded that it does not control the joint venture and , therefore, accounts for it under the equity method of accounting.
Combined summary of balance sheets relating to unconsolidated joint ventures and partnerships	Combined summary balance sheets relating to the unconsolidated joint ventures and partnerships (not just our proportionate share) are presented below as of September 30, 2019 and December 31, 2018 ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ 2019 2018 Total real estate, net $ 3,101,213 $ 3,311,034 Cash and cash equivalents ​ 56,829 ​ 49,867 Other assets ​ ​ 165,767 ​ 124,428 Total assets $ 3,323,809 $ 3,485,329 ​ ​ ​ ​ ​ ​ ​ Third party debt, net ​ $ 1,909,223 ​ $ 2,125,350 Accounts payable and accrued liabilities ​ ​ 73,803 ​ ​ 71,272 Total liabilities ​ 1,983,026 ​ 2,196,622 Total equity $ 1,340,783 $ 1,288,707
Schedule of combined financial information relating to unconsolidated joint ventures and partnerships operations (not just proportionate share)	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 nine months ended September 30, 2019 and 2018 ( dollars in thousands : ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, ​ September 30, ​ 2019 2018 2019 2018 Total revenues $ 75,378 $ 76,203 $ 233,836 $ 215,140 Property operating expenses ​ 27,505 ​ 30,096 ​ 87,073 ​ 85,435 Real estate depreciation and amortization ​ 26,027 ​ 29,545 ​ 83,661 ​ 85,063 Operating income/(loss) ​ 21,846 ​ ​ 16,562 ​ 63,102 ​ ​ 44,642 Interest expense ​ (20,779) ​ (22,919) ​ (64,309) ​ (63,990) Gain/(loss) on sale of property (a) ​ ​ 97,201 ​ ​ — ​ ​ 115,558 ​ ​ — Net unrealized gain/(loss) on held investments ​ ​ 25,669 ​ ​ — ​ ​ 27,191 ​ ​ — Other income/(loss) ​ ​ 82 ​ ​ 40 ​ ​ 194 ​ ​ 141 Net income/(loss) $ 124,019 $ (6,317) $ 141,736 $ (19,207) ​ ​ ​ (a) Represent the gains on the sale of three operating communities at the UDR/KFH joint venture level, as described in note (c) to the table above summarizing the Company’s investment in and advances to unconsolidated joint ventures and partnerships, net.

LEASES (Tables)

LEASES (Tables)	9 Months Ended
	Sep. 30, 2019
LEASES
Lessee - Future minimum lease payments and total operating lease liabilities	Future minimum lease payments and total operating lease liabilities from our ground leases and office space as of September 30, 2019 are as follows (dollars in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ground Leases ​ Office Space ​ Total 2019 ​ $ 1,953 ​ $ 19 ​ $ 1,972 2020 ​ ​ 7,813 ​ ​ 76 ​ ​ 7,889 2021 ​ ​ 7,813 ​ ​ 32 ​ ​ 7,845 2022 ​ ​ 7,813 ​ ​ - ​ ​ 7,813 2023 ​ ​ 7,813 ​ ​ - ​ ​ 7,813 Thereafter ​ ​ 370,467 ​ ​ - ​ ​ 370,467 Total future minimum lease payments (undiscounted) ​ ​ 403,672 ​ ​ 127 ​ ​ 403,799 Difference between future undiscounted cash flows and discounted cash flows ​ ​ (273,659) ​ ​ (5) ​ ​ (273,664) Total operating lease liabilities (discounted) ​ $ 130,013 ​ $ 122 ​ $ 130,135
Lessee - components of operating lease expenses	The components of operating lease expenses from our ground leases and office space were as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, 2019 ​ September 30, 2019 Ground lease expense: ​ ​ ​ ​ ​ ​ Contractual lease rent expense ​ $ 1,954 ​ $ 6,232 Variable ground lease expense (a) ​ ​ 187 ​ ​ 469 Total ground lease expense (b) ​ ​ 2,141 ​ ​ 6,701 Contractual office space expense (b) ​ ​ 19 ​ ​ 57 Total operating lease expense (c) ​ $ 2,160 ​ $ 6,758 (a) Variable ground lease expense includes adjustments such as changes in the consumer price index and payments based on a percentage of income of the lessee. (b) Ground lease expense is reported within the line item Other operating expenses and office space expense is recorded in General and administrative on the Consolidated Statements of Operations. (c) For the nine months ended September 30, 2019, Operating lease right-of-use assets and Operating lease liabilities amortized by $0.6 million and $0.3 million, respectively. The Company recorded $0.1 million and $0.3 million of total operating lease expense during the three and nine months ended September 30, 2019, respectively, due to the net impact of the amortization.
Lessor - Future minimum lease payments	Future minimum lease payments from our retail and commercial leases as of September 30, 2019 are as follows (dollars in thousands): ​ ​ ​ ​ ​ ​ Retail and Commercial Leases 2019 ​ $ 4,958 2020 ​ ​ 20,565 2021 ​ ​ 19,788 2022 ​ ​ 18,094 2023 ​ ​ 16,843 Thereafter ​ ​ 92,719 Total future minimum lease payments (a) ​ $ 172,967 (a) We have excluded our apartment home leases from this table as our apartment home leases generally have initial terms of 12 months of less.

SECURED AND UNSECURED DEBT, N_2

SECURED AND UNSECURED DEBT, NET (Tables)	9 Months Ended
	Sep. 30, 2019
Unsecured Debt
Schedule of debt instruments	The following is a summary of our secured and unsecured debt at September 30, 2019 and December 31, 2018 ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Principal Outstanding ​ As of September 30, 2019 ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ Weighted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Average ​ Average ​ Number of ​ ​ September 30, ​ December 31, ​ Interest ​ Years to ​ Communities ​ 2019 2018 Rate Maturity Encumbered Secured Debt: ​ ​ ​ ​ ​ ​ ​ Fixed Rate Debt ​ ​ Mortgage notes payable (a) ​ $ 575,965 ​ $ 417,989 3.55 % 6.6 9 Fannie Mae credit facilities (b) ​ — ​ 90,000 — % — — Deferred financing costs ​ (2,275) ​ (1,343) Total fixed rate secured debt, net ​ 573,690 ​ 506,646 3.55 % 6.6 9 Variable Rate Debt ​ ​ Tax-exempt secured notes payable (c) ​ 27,000 ​ 94,700 2.07 % 12.5 1 Deferred financing costs ​ (66) ​ (119) Total variable rate secured debt, net ​ 26,934 ​ 94,581 2.07 % 12.5 1 Total Secured Debt, net ​ 600,624 ​ 601,227 3.49 % 6.8 10 Unsecured Debt: ​ ​ Variable Rate Debt ​ ​ Borrowings outstanding under unsecured credit facility due January 2023 (d) (l) ​ — ​ — — % 3.3 Borrowings outstanding under unsecured commercial paper program due October 2019 (e) (l) ​ ​ 60,000 ​ ​ 101,115 ​ 2.28 % 0.1 ​ ​ Borrowings outstanding under unsecured working capital credit facility due January 2021 ​ 34,447 ​ 16 2.84 % 1.3 Term Loan due September 2023 (d) (l) ​ 35,000 ​ 35,000 3.01 % 4.0 Fixed Rate Debt ​ ​ 3.70% Medium-Term Notes due October 2020 (net of discounts of $0 and $14, respectively) (k) (l) ​ — ​ 299,986 — % — 4.63% Medium-Term Notes due January 2022 (net of discounts of $818 and $1,087, respectively) (l) ​ 399,182 ​ 398,913 4.63 % 2.3 1.93% Term Loan due September 2023 (d) (l) ​ ​ 315,000 ​ 315,000 1.93 % 4.0 ​ ​ 3.75% Medium-Term Notes due July 2024 (net of discounts of $495 and $574, respectively) (g) (l) ​ 299,505 ​ 299,426 3.75 % 4.8 8.50% Debentures due September 2024 ​ 15,644 ​ 15,644 8.50 % 5.0 4.00% Medium-Term Notes due October 2025 (net of discounts of $413 and $465, respectively) (h) (l) ​ 299,587 ​ 299,535 4.00 % 6.0 2.95% Medium-Term Notes due September 2026 (l) ​ 300,000 ​ 300,000 2.95 % 6.9 3.50% Medium-Term Notes due July 2027 (net of discounts of $547 and $600, respectively) (l) ​ ​ 299,453 ​ ​ 299,400 ​ 3.50 % 7.8 ​ ​ 3.50% Medium-Term Notes due January 2028 (net of discounts of $983 and $1,072, respectively) (l) ​ ​ 299,017 ​ ​ 298,928 ​ 3.50 % 8.3 ​ ​ 4.40% Medium-Term Notes due January 2029 (net of discounts of $6 and $6, respectively) (i) (l) ​ ​ 299,994 ​ ​ 299,994 ​ 4.40 % 9.3 ​ ​ 3.20% Medium-Term Notes due January 2030 (net of discounts of $990 and $0, respectively) (j) (l) ​ ​ 299,010 ​ ​ — ​ 3.20 % 10.3 ​ ​ 3.00% Medium-Term Notes due August 2031 (net of discounts of $1,148 and $0, respectively) (k) (l) ​ ​ 398,852 ​ ​ — ​ 3.00 % 11.9 ​ ​ Other ​ 14 ​ 16 Deferred financing costs ​ (19,432) ​ (16,413) Total Unsecured Debt, net ​ 3,335,273 ​ 2,946,560 3.54 % 6.9 Total Debt, net ​ $ 3,935,897 ​ $ 3,547,787 3.63 % 6.9
Secured credit facilities	Further information related to the Fannie Mae credit facility is as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2019 ​ 2018 Borrowings outstanding ​ $ — ​ $ 90,000 ​ Weighted average borrowings during the period ended ​ 80,000 ​ 253,813 ​ Maximum daily borrowings during the period ended ​ 90,000 ​ 314,869 ​ Weighted average interest rate during the period ended ​ 4.0 % 4.7 % Weighted average interest rate at the end of the period ​ — % 4.0 % ​ (c) (d) six-month extension options, subject to certain conditions. The Term Loan has a scheduled maturity date of September 30, 2023.
Schedule of aggregate maturities, including amortizing principal payments of secured and unsecured debt	The aggregate maturities, including amortizing principal payments on secured and unsecured debt, of total debt for the next ten calendar years subsequent to September 30, 2019 are as follows (dollars in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Fixed Total Variable Total Total Total Year ​ Secured Debt ​ Secured Debt ​ Secured Debt ​ Unsecured Debt ​ Debt 2019 ​ $ 974 ​ $ — ​ $ 974 ​ $ 60,000 ​ $ 60,974 2020 ​ ​ 108,077 ​ ​ — ​ ​ 108,077 ​ ​ — ​ ​ 108,077 2021 ​ 1,117 ​ — ​ 1,117 ​ 34,447 ​ 35,564 2022 ​ 1,157 ​ — ​ 1,157 ​ 400,000 ​ 401,157 2023 ​ 41,245 ​ — ​ 41,245 ​ 350,000 ​ 391,245 2024 ​ — ​ — ​ — ​ 315,644 ​ 315,644 2025 ​ 127,600 ​ — ​ 127,600 ​ 300,000 ​ 427,600 2026 ​ 50,000 ​ — ​ 50,000 ​ 300,000 ​ 350,000 2027 ​ — ​ — ​ — ​ 300,000 ​ 300,000 2028 ​ 80,000 ​ — ​ 80,000 ​ 300,000 ​ 380,000 Thereafter ​ 162,500 ​ 27,000 ​ 189,500 ​ 1,000,000 ​ 1,189,500 Subtotal ​ 572,670 ​ 27,000 ​ 599,670 ​ 3,360,091 ​ 3,959,761 Non-cash (a) ​ 1,020 ​ (66) ​ 954 ​ (24,818) ​ (23,864) Total ​ $ 573,690 ​ $ 26,934 ​ $ 600,624 ​ $ 3,335,273 ​ $ 3,935,897 (a) Includes the unamortized balance of fair market value adjustments, premiums/discounts and deferred financing costs . The Company amortized $1.1 million and $ 1.1 million, respectively, during the three months ended September 30, 2019 and 2018, and $3.1 million and $3.2 million, respectively, during the nine months ended September 30, 2019 and 2018, of deferred financing costs into Interest expense.
Commercial Paper
Unsecured Debt
Schedule of short-term debt	The following is a summary of short-term bank borrowings under the unsecured commercial paper program at September 30, 2019 and December 31, 2018 (dollars in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2019 ​ 2018 Total unsecured commercial paper program $ 500,000 ​ $ 500,000 ​ Borrowings outstanding at end of period ​ 60,000 ​ 101,115 ​ Weighted average daily borrowings during the period ended ​ 163,347 ​ 344,235 ​ Maximum daily borrowings during the period ended ​ 435,000 ​ 440,000 ​ Weighted average interest rate during the period ended ​ 2.7 % 2.4 % Interest rate at end of the period ​ 2.3 % 2.9 %
Revolving Credit Facility
Unsecured Debt
Schedule of short-term debt	The following is a summary of short-term bank borrowings under the Revolving Credit Facility at September 30, 2019 and December 31, 2018 (dollars in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2019 2018 ​ Total revolving credit facility ​ $ 1,100,000 ​ $ 1,100,000 ​ Borrowings outstanding at end of period (1) ​ — ​ — ​ Weighted average daily borrowings during the period ended ​ — ​ — ​ Maximum daily borrowings during the period ended ​ — ​ — ​ Weighted average interest rate during the period ended ​ — % — % Interest rate at end of the period ​ — % — % (1) Excludes $2.8 million and $3.3 million of letters of credit at September 30, 2019 and December 31, 2018, respectively. (e)
Unsecured Working Capital Credit Facility due January 2021
Unsecured Debt
Schedule of short-term debt	The following is a summary of short-term bank borrowings under the Working Capital Credit Facility at September 30, 2019 and December 31, 2018 (dollars in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2019 ​ 2018 Total working capital credit facility ​ $ 75,000 ​ $ 75,000 ​ Borrowings outstanding at end of period ​ 34,447 ​ 16 ​ Weighted average daily borrowings during the period ended ​ 24,870 ​ 26,101 ​ Maximum daily borrowings during the period ended ​ 66,170 ​ 64,633 ​ Weighted average interest rate during the period ended ​ 3.2 % 2.9 % Interest rate at end of the period ​ 2.8 % 3.3 %

INCOME_(LOSS) PER SHARE (Tables

INCOME/(LOSS) PER SHARE (Tables)	9 Months Ended
	Sep. 30, 2019
INCOME/(LOSS) PER SHARE
Computation of basic and diluted income/(loss) per share	The following table sets forth the computation of basic and diluted income/(loss) per share for the periods presented (dollars and shares in thousands, except per share data): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ 2019 2018 2019 2018 ​ Numerator for income/(loss) per share: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income/(loss) ​ $ 29,422 ​ $ 20,258 ​ $ 94,342 ​ $ 131,927 ​ Net (income)/loss attributable to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership ​ (2,162) ​ (1,616) ​ (6,871) ​ (10,819) ​ Net (income)/loss attributable to noncontrolling interests ​ (56) ​ (32) ​ (145) ​ (141) ​ Net income/(loss) attributable to UDR, Inc. ​ 27,204 ​ 18,610 ​ 87,326 ​ 120,967 ​ Distributions to preferred stockholders — Series E (Convertible) ​ (1,031) ​ (971) ​ (3,073) ​ (2,897) ​ Income/(loss) attributable to common stockholders - basic and diluted ​ $ 26,173 ​ $ 17,639 ​ $ 84,253 ​ $ 118,070 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Denominator for income/(loss) per share: ​ ​ ​ ​ ​ Weighted average common shares outstanding ​ 288,957 ​ 268,034 ​ 282,866 ​ 267,873 ​ Non-vested restricted stock awards ​ (251) ​ (307) ​ (268) ​ (344) ​ Denominator for basic income/(loss) per share ​ 288,706 ​ 267,727 ​ 282,598 ​ 267,529 ​ Incremental shares issuable from assumed conversion of stock options, unvested LTIP Units, unvested restricted stock, and shares issuable upon settlement of forward sales agreements ​ 823 ​ 1,134 ​ 694 ​ 1,491 ​ Denominator for diluted income/(loss) per share ​ 289,529 ​ 268,861 ​ 283,292 ​ 269,020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income/(loss) per weighted average common share: ​ ​ ​ ​ ​ Basic ​ $ 0.09 ​ $ 0.07 ​ $ 0.30 ​ $ 0.44 ​ Diluted ​ $ 0.09 ​ $ 0.07 ​ $ 0.30 ​ $ 0.44 ​
Schedule of Antidilutive Securities Excluded from Computation of 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 nine months ended September 30, 2019 and 2018 (in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ ​ 2019 ​ 2018 ​ 2019 ​ 2018 ​ OP/DownREIT Units 22,211 24,558 23,068 24,546 Convertible preferred stock 3,011 3,011 3,011 3,011 Stock options, unvested LTIP Units, unvested restricted stock, and forward sales shares 823 1,134 694 1,491

NONCONTROLLING INTERESTS (Table

NONCONTROLLING INTERESTS (Tables)	9 Months Ended
	Sep. 30, 2019
NONCONTROLLING INTERESTS
Redeemable noncontrolling interests in the Operating Partnership and DownREIT 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, 2018 $ 972,740 ​ Mark-to-market adjustment to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership ​ 222,405 ​ Conversion of OP Units/DownREIT Units to Common Stock ​ (119,338) ​ Net income/(loss) attributable to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership ​ 6,871 ​ Distributions to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership ​ (24,509) ​ Vesting of Long-Term Incentive Plan Units ​ ​ 14,742 ​ Allocation of other comprehensive income/(loss) ​ (730) ​ Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership, September 30, 2019 ​ $ 1,072,181 ​

FAIR VALUE OF DERIVATIVES AND_2

FAIR VALUE OF DERIVATIVES AND FINANCIAL INSTRUMENTS (Tables)	9 Months Ended
	Sep. 30, 2019
FAIR VALUE OF DERIVATIVES AND FINANCIAL INSTRUMENTS
Schedule of estimated fair values	The estimated fair values of the Company’s financial instruments either recorded or disclosed on a recurring basis as of September 30, 2019 and December 31, 2018, are summarized as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value at September 30, 2019, Using ​ ​ Total ​ ​ ​ Quoted ​ ​ ​ ​ ​ ​ Carrying ​ ​ ​ Prices in ​ ​ ​ ​ ​ ​ Amount in ​ ​ ​ Active ​ ​ ​ ​ ​ ​ ​ Statement of ​ ​ ​ ​ Markets ​ Significant ​ ​ ​ ​ ​ Financial ​ Fair Value ​ for Identical ​ Other ​ Significant ​ ​ Position at ​ Estimate at ​ Assets or ​ Observable ​ Unobservable ​ ​ September 30, ​ September 30, ​ Liabilities ​ Inputs ​ Inputs ​ ​ 2019 ​ 2019 ​ (Level 1) ​ (Level 2) ​ (Level 3) Description: ​ ​ ​ ​ ​ ​ Notes receivable (a) ​ $ 37,899 ​ $ 42,613 ​ $ — ​ $ — ​ $ 42,613 Derivatives - Interest rate contracts (b) ​ 730 ​ 730 ​ — ​ 730 ​ — Total assets ​ $ 38,629 ​ $ 43,343 ​ $ — ​ $ 730 ​ $ 42,613 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives - Interest rate contracts (b) ​ $ 469 ​ $ 469 ​ $ — ​ $ 469 ​ $ — Secured debt instruments - fixed rate: (c) ​ ​ ​ ​ ​ ​ Mortgage notes payable ​ ​ 575,965 ​ ​ 569,318 ​ ​ — ​ ​ — ​ ​ 569,318 Secured debt instruments - variable rate: (c) ​ ​ ​ ​ ​ ​ Tax-exempt secured notes payable ​ 27,000 ​ 27,000 ​ — ​ — ​ 27,000 Unsecured debt instruments: (c) ​ ​ ​ ​ ​ ​ Working capital credit facility ​ ​ 34,447 ​ ​ 34,447 ​ ​ — ​ ​ — ​ ​ 34,447 Commercial paper program ​ ​ 60,000 ​ ​ 60,000 ​ ​ — ​ ​ — ​ ​ 60,000 Unsecured notes ​ ​ 3,260,258 ​ ​ 3,415,618 ​ ​ — ​ ​ — ​ ​ 3,415,618 Total liabilities ​ $ 3,958,139 ​ $ 4,106,852 ​ $ — ​ $ 469 ​ $ 4,106,383 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (d) ​ $ 1,072,181 ​ $ 1,072,181 ​ $ — ​ $ 1,072,181 ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value at December 31, 2018, Using ​ ​ Total ​ ​ ​ Quoted ​ ​ ​ ​ ​ ​ Carrying ​ ​ ​ Prices in ​ ​ ​ ​ ​ ​ Amount in ​ ​ ​ Active ​ ​ ​ ​ ​ ​ Statement of ​ ​ ​ Markets ​ Significant ​ ​ ​ ​ Financial ​ Fair Value ​ for Identical ​ Other ​ Significant ​ ​ Position at ​ Estimate at ​ Assets or ​ Observable ​ Unobservable ​ ​ December 31, ​ December 31, ​ Liabilities ​ Inputs ​ Inputs ​ 2018 ​ 2018 ​ (Level 1) ​ (Level 2) ​ (Level 3) Description: ​ ​ ​ ​ ​ ​ Notes receivable (a) ​ $ 42,259 ​ $ 45,026 ​ $ — ​ $ — ​ $ 45,026 Derivatives - Interest rate contracts (b) ​ 4,757 ​ 4,757 ​ — ​ 4,757 ​ — Total assets ​ $ 47,016 ​ $ 49,783 ​ $ — ​ $ 4,757 ​ $ 45,026 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives - Interest rate contracts (b) ​ $ 356 ​ $ 356 ​ $ — ​ $ 356 ​ $ — Secured debt instruments - fixed rate: (c) ​ ​ ​ ​ ​ ​ Mortgage notes payable ​ ​ 417,989 ​ ​ 416,314 ​ ​ — ​ ​ — ​ ​ 416,314 Fannie Mae credit facility ​ 90,000 ​ 90,213 ​ — ​ — ​ 90,213 Secured debt instruments - variable rate: (c) ​ ​ ​ ​ ​ ​ Tax-exempt secured notes payable ​ 94,700 ​ 94,700 ​ — ​ — ​ 94,700 Unsecured debt instruments: (c) ​ ​ ​ ​ ​ ​ ​ Working capital credit facility ​ ​ 16 ​ ​ 16 ​ ​ — ​ ​ — ​ ​ 16 Commercial paper program ​ ​ 101,115 ​ ​ 101,115 ​ ​ — ​ ​ — ​ ​ 101,115 Unsecured notes ​ ​ 2,861,842 ​ ​ 2,829,390 ​ ​ — ​ ​ — ​ ​ 2,829,390 Total liabilities ​ $ 3,566,018 ​ $ 3,532,104 ​ $ — ​ $ 356 ​ $ 3,531,748 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (d) ​ $ 972,740 ​ $ 972,740 ​ $ — ​ $ 972,740 ​ $ — (a) See Note 2, Significant Accounting Policies . (b) See Note 11, Derivatives and Hedging Activity . (c) See Note 7, Secured and Unsecured Debt, Net . (d) See Note 9, Noncontrolling Interests.

DERIVATIVES AND HEDGING ACTIV_2

DERIVATIVES AND HEDGING ACTIVITY (Tables)	9 Months Ended
	Sep. 30, 2019
DERIVATIVES AND HEDGING ACTIVITY
Schedule of outstanding interest rate derivatives	As of September 30, 2019, the Company had the following outstanding interest rate derivatives that were designated as cash flow hedges of interest rate risk ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ Number of ​ Product ​ Instruments ​ Notional Interest rate swaps (a) ​ 4 ​ $ 315,000 (a) In addition to the interest rate swaps summarized above, the Company entered into an additional interest rate swap with a notional value of $315.0 million that will become effective in January 2020 upon the maturity of the interest rate swaps summarized above. Additionally, the Company had previously entered into two additional interest rate swaps with a notional value totaling $75.0 million that were subsequently terminated and settled during the nine months ended September 30, 2019 in conjunction with the July 2019 issuance of $300.0 million of senior unsecured medium-term notes as disclosed in Note 7, Secured and Unsecured, Net ​ 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 no gain or loss for both the three and nine months ended September 30, 2019 and 2018. As of September 30, 2019, the Company had the following outstanding derivatives that were not designated as hedges in qualifying hedging relationships ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ Number of ​ ​ Product ​ Instruments ​ Notional Interest rate caps ​ 1 ​ $ 19,880
Fair value of Company's derivative financial instruments and their classification on Consolidated Balance Sheets	The table below presents the fair value of the Company’s derivative financial instruments as well as their classification on the Consolidated Balance Sheets as of September 30, 2019 and December 31, 2018 ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Asset Derivatives ​ Liability Derivatives ​ ​ (included in Other assets ) ​ (included in Other liabilities ) ​ ​ Fair Value at: ​ Fair Value at: ​ ​ September 30, ​ December 31, ​ September 30, ​ December 31, ​ ​ 2019 ​ 2018 ​ 2019 ​ 2018 Derivatives designated as hedging instruments: ​ ​ ​ ​ Interest rate products ​ $ 730 ​ $ 4,757 ​ $ 469 ​ $ 356
Effect of Company's derivative financial instruments on Consolidated Statements of Operations	The tables below present the effect of the Company’s derivative financial instruments on the Consolidated Statements of Operations for the three and nine months ended September 30, 2019 and 2018 ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gain/(Loss) Recognized in ​ ​ ​ ​ Gain/(Loss) Reclassified ​ Interest expense ​ ​ Unrealized holding gain/(loss) ​ from Accumulated OCI into ​ (Amount Excluded from ​ ​ Recognized in OCI ​ Interest expense ​ Effectiveness Testing) Derivatives in Cash Flow Hedging Relationships 2019 2018 2019 2018 2019 2018 Three Months Ended September 30, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate products ​ $ (659) ​ $ 2,320 ​ $ 624 ​ $ 564 ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate products ​ $ (7,181) ​ $ 4,312 ​ $ 2,504 ​ $ 1,162 ​ $ — ​ $ —
Effect of Company's derivatives not designated as hedging instruments on the Consolidated Statements of Operations	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, ​ September 30, ​ ​ 2019 ​ 2018 ​ 2019 ​ 2018 Total amount of Interest expense ​ $ 42,523 ​ $ 34,401 ​ $ 110,482 ​ $ 95,942 ​
Offsetting of Derivative Assets	The Company has elected not to offset derivative positions on the consolidated financial statements. The tables below present the effect on its financial position had the Company made the election to offset its derivative positions as of September 30, 2019 and December 31, 2018 (dollars in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross Net Amounts of Gross Amounts Not Offset ​ ​ ​ ​ ​ ​ ​ ​ Amounts ​ Assets ​ in the Consolidated ​ ​ ​ ​ ​ Gross ​ Offset in the ​ Presented in the ​ Balance Sheet ​ ​ ​ ​ ​ Amounts of ​ Consolidated ​ Consolidated ​ ​ ​ ​ Cash ​ ​ ​ ​ ​ Recognized ​ Balance ​ Balance Sheets ​ Financial ​ Collateral ​ ​ ​ Offsetting of Derivative Assets ​ Assets ​ Sheets ​ (a) ​ Instruments Received Net Amount September 30, 2019 ​ $ 730 ​ $ — ​ $ 730 ​ $ (371) ​ $ — ​ $ 359 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2018 ​ $ 4,757 ​ $ — ​ $ 4,757 ​ $ — ​ $ — ​ $ 4,757 (a) Amounts reconcile to the aggregate fair value of derivative assets in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Consolidated Balance Sheets” located in this footnote.
Offsetting of Derivative Liabilities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross Net Amounts of Gross Amounts Not Offset ​ ​ ​ ​ ​ ​ ​ ​ Amounts ​ Liabilities ​ in the Consolidated ​ ​ ​ ​ ​ Gross ​ Offset in the ​ Presented in the ​ Balance Sheet ​ ​ ​ ​ ​ Amounts of ​ Consolidated ​ Consolidated ​ ​ ​ ​ Cash ​ ​ ​ ​ ​ Recognized ​ Balance ​ Balance Sheets ​ Financial ​ Collateral ​ ​ ​ Offsetting of Derivative Liabilities Liabilities Sheets (a) Instruments Posted Net Amount September 30, 2019 ​ $ 469 ​ $ — ​ $ 469 ​ $ (371) ​ $ — ​ $ 98 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2018 ​ $ 356 ​ $ — ​ $ 356 ​ $ — ​ $ — ​ $ 356 (a) Amounts reconcile to the aggregate fair value of derivative liabilities in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Consolidated Balance Sheets” located in this footnote.

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	9 Months Ended
	Sep. 30, 2019
COMMITMENTS AND CONTINGENCIES
Summary of real estate commitments	The following summarizes the Company’s real estate commitments at September 30, 2019 ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number ​ UDR's ​ UDR's Remaining ​ ​ ​ Properties ​ Investment (a) ​ Commitment ​ Wholly-owned — under development 1 ​ $ 21,845 ​ $ 75,655 Wholly-owned — redevelopment 2 ​ ​ 11,582 ​ ​ 23,918 Joint ventures: ​ ​ Unconsolidated joint ventures - development 1 ​ 14,402 ​ 21,496 (b) Preferred equity investments 2 ​ ​ 53,781 (c) ​ 27,390 (d) Other investments ​ - ​ ​ 12,926 ​ ​ 9,000 (e) Total ​ $ 114,536 ​ $ 157,459 (a) Represents UDR’s investment as of September 30, 2019. (b) Represents UDR’s proportionate share of expected remaining costs to complete the development. (c) Represents UDR’s investment in 1300 Fairmount and Modera Lake Merritt for the properties under development as of September 30, 2019. (d) Represents UDR’s remaining commitment for 1300 Fairmount and Modera Lake Merritt. (e) Represents UDR’s remaining commitment for other investment ventures. ​

REPORTABLE SEGMENTS (Tables)

REPORTABLE SEGMENTS (Tables)	9 Months Ended
	Sep. 30, 2019
REPORTABLE SEGMENTS
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to Net income/(loss)	The following table details rental income and NOI for UDR’s reportable segments for the three and nine months ended September 30, 2019 and 2018, and reconciles NOI to Net income/(loss) attributable to UDR, Inc. (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, (a) ​ September 30, (b) ​ 2019 2018 2019 2018 Reportable apartment home segment lease revenue ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Same-Store Communities ​ ​ ​ ​ ​ West Region ​ $ 99,316 ​ $ 95,447 ​ $ 293,294 ​ $ 281,722 Mid-Atlantic Region ​ 52,826 ​ 51,291 ​ 157,179 ​ 152,867 Southeast Region ​ 28,540 ​ 27,773 ​ 84,551 ​ 81,554 Northeast Region ​ 30,196 ​ 29,491 ​ 89,650 ​ 87,776 Southwest Region ​ 15,451 ​ 15,060 ​ 40,705 ​ 39,586 Non-Mature Communities/Other ​ 40,975 ​ 24,237 ​ 106,499 ​ 66,906 Total segment and consolidated rental income ​ $ 267,304 ​ $ 243,299 ​ $ 771,878 ​ $ 710,411 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Reportable apartment home segment other revenue ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Same-Store Communities ​ ​ ​ ​ ​ West Region ​ $ 7,869 ​ $ 7,168 ​ $ 23,488 ​ $ 21,567 Mid-Atlantic Region ​ 4,376 ​ 4,032 ​ 12,958 ​ 11,944 Southeast Region ​ 3,438 ​ 3,211 ​ 10,423 ​ 9,918 Northeast Region ​ 1,321 ​ 1,226 ​ 3,753 ​ 3,422 Southwest Region ​ 1,527 ​ 1,525 ​ 4,100 ​ 3,986 Non-Mature Communities/Other ​ 3,173 ​ 2,795 ​ 8,793 ​ 9,125 Total segment and consolidated rental income ​ $ 21,704 ​ $ 19,957 ​ $ 63,515 ​ $ 59,962 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total reportable apartment home segment rental income ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Same-Store Communities ​ ​ ​ ​ ​ West Region ​ $ 107,185 ​ $ 102,615 ​ $ 316,782 ​ $ 303,289 Mid-Atlantic Region ​ 57,202 ​ 55,323 ​ 170,137 ​ 164,811 Southeast Region ​ 31,978 ​ 30,984 ​ 94,974 ​ 91,472 Northeast Region ​ 31,517 ​ 30,717 ​ 93,403 ​ 91,198 Southwest Region ​ 16,978 ​ 16,585 ​ 44,805 ​ 43,572 Non-Mature Communities/Other ​ 44,148 ​ 27,032 ​ 115,292 ​ 76,031 Total segment and consolidated rental income ​ $ 289,008 ​ $ 263,256 ​ $ 835,393 ​ $ 770,373 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Reportable apartment home segment NOI ​ ​ ​ ​ Same-Store Communities ​ ​ ​ ​ West Region ​ $ 81,170 ​ $ 77,321 ​ $ 240,442 ​ $ 229,129 Mid-Atlantic Region ​ 39,850 ​ 38,220 ​ 119,075 ​ 114,465 Southeast Region ​ 22,133 ​ 21,597 ​ 66,301 ​ 63,806 Northeast Region ​ 20,560 ​ 20,640 ​ 63,012 ​ 62,710 Southwest Region ​ 10,449 ​ 9,899 ​ 26,995 ​ 25,760 Non-Mature Communities/Other ​ 29,487 ​ 17,137 ​ 77,242 ​ 48,833 Total segment and consolidated NOI ​ 203,649 ​ 184,814 ​ 593,067 ​ 544,703 Reconciling items: ​ ​ ​ ​ Joint venture management and other fees ​ 6,386 ​ 2,888 ​ 11,982 ​ 8,819 Property management ​ (8,309) ​ (7,240) ​ (24,018) ​ (21,185) Other operating expenses ​ (2,751) ​ (3,314) ​ (11,132) ​ (8,148) Real estate depreciation and amortization ​ (127,391) ​ (107,881) ​ (357,793) ​ (322,537) General and administrative ​ (12,197) ​ (11,896) ​ (37,002) ​ (36,028) Casualty-related (charges)/recoveries, net ​ 1,088 ​ (678) ​ 842 ​ (2,364) Other depreciation and amortization ​ (1,619) ​ (1,682) ​ (4,953) ​ (5,057) Gain/(loss) on sale of real estate owned ​ ​ — ​ ​ — ​ ​ 5,282 ​ ​ 70,300 Income/(loss) from unconsolidated entities ​ 12,713 ​ (1,382) ​ 19,387 ​ (5,091) Interest expense ​ (42,523) ​ (34,401) ​ (110,482) ​ (95,942) Interest income and other income/(expense), net ​ 1,875 ​ 1,188 ​ 12,998 ​ 5,075 Tax (provision)/benefit, net ​ (1,499) ​ (158) ​ (3,836) ​ (618) Net (income)/loss attributable to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership ​ (2,162) ​ (1,616) ​ (6,871) ​ (10,819) Net (income)/loss attributable to noncontrolling interests ​ (56) ​ (32) ​ (145) ​ (141) Net income/(loss) attributable to UDR, Inc. ​ $ 27,204 ​ $ 18,610 ​ $ 87,326 ​ $ 120,967 (a) Same-Store Community population consisted of 38,177 apartment homes. (b) Same-Store Community population consisted of 37,959 apartment homes. ​
Details of assets of UDR's reportable segments	The following table details the assets of UDR’s reportable segments as of September 30, 2019 and December 31, 2018 (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2019 ​ 2018 Reportable apartment home segment assets: ​ ​ Same-Store Communities (a): ​ ​ West Region ​ $ 3,797,149 ​ $ 3,763,366 Mid-Atlantic Region ​ 2,338,963 ​ 2,317,369 Southeast Region ​ 799,739 ​ 779,310 Northeast Region ​ 1,498,500 ​ 1,491,994 Southwest Region ​ 595,982 ​ 589,188 Non-Mature Communities/Other ​ 2,534,062 ​ 1,254,932 Total segment assets ​ 11,564,395 ​ 10,196,159 Accumulated depreciation ​ (4,000,608) ​ (3,654,160) Total segment assets — net book value ​ 7,563,787 ​ 6,541,999 Reconciling items: ​ ​ Cash and cash equivalents ​ 1,895 ​ 185,216 Restricted cash ​ 21,646 ​ 23,675 Notes receivable, net ​ 37,899 ​ 42,259 Investment in and advances to unconsolidated joint ventures, net ​ 791,180 ​ 780,869 Operating lease right-of-use assets ​ ​ 135,889 ​ ​ — Other assets ​ 145,301 ​ 137,710 Total consolidated assets ​ $ 8,697,597 ​ $ 7,711,728 (a) Same-Store Community population consisted of 38,177 apartment homes. ​

BASIS OF PRESENTATION (Details)

BASIS OF PRESENTATION (Details) - shares	Sep. 30, 2019	Dec. 31, 2018
Consolidation And Basis Of Presentation
Operating Partnership units outstanding related to limited partner	184,063,542	183,636,543
Operating Partnership outstanding units	184,063,542
United Dominion Realty L.P.
Consolidation And Basis Of Presentation
Operating Partnership units outstanding related to limited partner	176,210,072
General Partners' ownership (as a percent)	95.70%
UDR Lighthouse DownREIT L.P.
Consolidation And Basis Of Presentation
Operating Partnership outstanding units	13,470,651
Percentage of units outstanding in Partnership	41.60%
UDR Lighthouse DownREIT L.P.
Consolidation And Basis Of Presentation
Operating Partnership outstanding units	32,367,380
Non-affiliated Partners
Consolidation And Basis Of Presentation
Operating Partnership units outstanding related to limited partner	7,853,470
Operating Partnership outstanding units	14,262,485
Percentage of units outstanding in Partnership	4.30%
Non-affiliated Partners | United Dominion Realty L.P.
Consolidation And Basis Of Presentation
Operating Partnership units outstanding related to limited partner	7,853,470
Operating Partnership outstanding units		9,387,844
Percentage of units outstanding in Partnership	4.30%	5.10%
Non-affiliated Partners | UDR Lighthouse DownREIT L.P.
Consolidation And Basis Of Presentation
Percentage of units outstanding in Partnership	44.10%
UDR, Inc.
Consolidation And Basis Of Presentation
Operating Partnership units outstanding related to limited partner	176,099,189	174,137,816
General Partners' ownership (as a percent)	55.90%
Operating Partnership outstanding units	18,104,895
Percentage of units outstanding in Partnership	95.70%	94.90%
UDR, Inc. | United Dominion Realty L.P.
Consolidation And Basis Of Presentation
General Partners' ownership (as a percent)	95.70%
Operating Partnership outstanding units		174,248,699
Percentage of units outstanding in Partnership		94.90%

SIGNIFICANT ACCOUNTING POLICI_4

SIGNIFICANT ACCOUNTING POLICIES (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Jan. 31, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Jan. 01, 2019	Dec. 31, 2018	Mar. 31, 2018
Accounting policies
Notes receivable, net		$ 37,899		$ 37,899			$ 42,259
Significant Accounting Policies
Lease classification per practical expedient				true
Operating lease right-of-use assets		135,889		$ 135,889
Operating lease liabilities		130,135		130,135
Recognition of operating lease right-of-use assets				94,349
Increase in operating lease liabilities				42,100
Increase in operating lease liabilities				88,336
Proceeds from secured notes receivable	$ 5,600
Procceds from accrued interest	200
Note receivable interest income		1,200	$ 1,200	3,500	$ 2,900
Promoted interest received	$ 8,500			8,500	0
Allocation of other comprehensive income/(loss)				(730)
Current Income Tax Expense (Benefit)				0
Deferred tax liabilities, net		(1,300)		(1,300)
Unrecognized tax benefit, accrued interest or penalties due to examination		0		0
Interest Income, Related Party				0	0
Noncontrolling Interests
Significant Accounting Policies
Allocation of other comprehensive income/(loss)		$ (100)	$ 200	$ (700)	$ 300
Note due December 2019
Accounting policies
Note receivable interest rate		12.00%		12.00%
Notes receivable, net		$ 20,000		$ 20,000			20,000
Significant Accounting Policies
Notes receivable								$ 20,000
Note due February 2020
Accounting policies
Note receivable interest rate		10.00%		10.00%
Notes receivable, net		$ 15,649		$ 15,649			14,659
Significant Accounting Policies
Notes receivable		$ 16,400		16,400
Note maturity public capital threshold				5,000
Additional amount loaned				$ 1,000
Note due October 2020
Accounting policies
Note receivable interest rate		8.00%		8.00%
Notes receivable, net		$ 2,250		$ 2,250			2,000
Significant Accounting Policies
Notes receivable		$ 2,300		2,300
Note maturity public capital threshold				10,000
Additional amount loaned				$ 300
Note due August 2022
Accounting policies
Note receivable interest rate		10.00%		10.00%
Notes receivable, net							5,600
Maximum
Significant Accounting Policies
Deferred tax liabilities, net							(100)
ASU 2016-02 | Adjustment
Significant Accounting Policies
Operating lease right-of-use assets						$ 94,300
Operating lease liabilities						$ 88,300
Prepaid rent and intangible assets							$ 6,000

REAL ESTATE OWNED - Summarizes

REAL ESTATE OWNED - Summarizes the carrying amounts for our real estate owned (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Real estate owned
Land	$ 2,020,617	$ 1,849,799
Depreciable property - held and used:
Land improvements	220,654	213,224
Building, improvements, and furniture, fixtures and equipment	9,260,709	8,133,136
In-place intangibles	40,570
Under development:
Real estate under development	21,845
Real estate owned	11,564,395	10,196,159
Accumulated depreciation	(4,000,608)	(3,654,160)
Total real estate owned, net of accumulated depreciation	7,563,787	$ 6,541,999
Ground Leases
Under development:
Real estate under development	13,853
Construction in progress
Under development:
Real estate under development	$ 7,992

REAL ESTATE OWNED - Additional

REAL ESTATE OWNED - Additional Information (Details) $ in Thousands	1 Months Ended						3 Months Ended		9 Months Ended
	Aug. 31, 2019USD ($)homecommunityitem	Jun. 30, 2019USD ($)home	May 31, 2019USD ($)home	Apr. 30, 2019USD ($)home	Feb. 28, 2019USD ($)home	Jan. 31, 2019USD ($)item	Sep. 30, 2019USD ($)communityitemstate	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)communityitemstate	Sep. 30, 2018USD ($)	Jul. 31, 2019	Dec. 31, 2018
Real Estate Owned Disclosure
Number of real estate properties | community							138		138
Number of states in which there are owned and consolidated communities | state							13		13
Number of apartment homes owned and consolidated | item							43,683		43,683
Development costs excluding direct costs and capitalized interest							$ 1,900	$ 1,600	$ 6,900	$ 6,600
Interest capitalized during period							1,400	$ 1,600	3,800	$ 9,800
In-place intangibles							$ 40,570		$ 40,570
Ground Leases
Real Estate Owned Disclosure
Proceeds from sale of real estate		$ 38,000
Gain on sale of real estate owned		$ 5,300
386 Home Operating Community In Anaheim
Real Estate Owned Disclosure
Number of apartment homes acquired | item						386
Ownership (as a percent)						100.00%						49.00%
Payment to acquire real estate						$ 33,500
Repayments of joint venture construction financing						59,800
Real estate acquired						115,700
In-place intangibles						2,400
Gain on consolidation						$ 0
155 Home Operating Community in Seattle
Real Estate Owned Disclosure
Number of apartment homes acquired | item						155
Ownership (as a percent)						100.00%						49.00%
Real estate intangibles						$ 2,400
Payment to acquire real estate						20,000
Repayments of joint venture construction financing						26,000
Real estate acquired						58,100
In-place intangibles						600
Gain on consolidation						0
To-Be-Developed Parcel of Land in Washington D.C
Real Estate Owned Disclosure
Payment to acquire real estate						$ 27,100
To Be Developed Parcel Of Land In Denver, Colorado
Real Estate Owned Disclosure
Payment to acquire real estate					$ 13,700
Operating Community in Brooklyn, New York
Real Estate Owned Disclosure
Number of apartment homes acquired | home					188
Real estate intangibles					$ 33,600
Payment to acquire real estate					132,100
Real estate acquired					97,500
In-place intangibles					$ 1,000
Operating Community in St. Petersburg, Florida
Real Estate Owned Disclosure
Number of apartment homes acquired | home			240		381
Payment to acquire real estate			$ 49,400		$ 98,300
Real estate acquired			48,200		96,000
In-place intangibles			$ 1,200		$ 2,300
Operating Community in Towson, Maryland
Real Estate Owned Disclosure
Number of apartment homes acquired | home				498
Payment to acquire real estate				$ 86,400
Real estate acquired				82,500
In-place intangibles				$ 3,900
Operating Community in King of Prussia, Pennsylvania
Real Estate Owned Disclosure
Number of apartment homes acquired | home			313
Payment to acquire real estate			$ 107,300
Real estate acquired			106,400
In-place intangibles			$ 900
Operating Community in Waltham, Massachusetts
Real Estate Owned Disclosure
Number of apartment homes acquired | home		200
Payment to acquire real estate		$ 84,600
Real estate acquired		82,600
In-place intangibles		$ 2,000
Operating Community in Norwood, Massachusetts
Real Estate Owned Disclosure
Number of apartment homes acquired | home	914
Payment to acquire real estate	$ 270,200
Real estate acquired	260,100
In-place intangibles	$ 10,100
Operating Community in Englewood, New Jersey
Real Estate Owned Disclosure
Number of apartment homes acquired | home	185
Real estate intangibles	$ 4,600
Payment to acquire real estate	83,600
Real estate acquired	77,500
In-place intangibles	$ 1,500
Unconsolidated Joint Venture Three Washington DC
Real Estate Owned Disclosure
Number of apartment homes owned and consolidated | home	292
Ownership (as a percent)	100.00%										30.00%
Cash purchase price ( as a percent)	100.00%
Distributions received	$ 22,900
Gain or loss on consolidation	0
Acquisition-related costs	2,800
Payment to acquire real estate	184,000
Acquisition-related costs	2,800
Real estate acquired	156,000
In-place intangibles	$ 5,900
UDR/MetLife operating communities
Real Estate Owned Disclosure
Ownership (as a percent)	50.00%
Number of communities acquired | community	10
Number of communities under development purchased | community	1
Number of land parcels | item	4
Value of joint venture	$ 1,100,000
Value of joint venture UDR's share	$ 557,000

JOINT VENTURES AND PARTNERSHI_3

JOINT VENTURES AND PARTNERSHIPS - Summary (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019USD ($)homecommunityproperty	Sep. 30, 2018USD ($)item	Sep. 30, 2019USD ($)homecommunityproperty	Sep. 30, 2018USD ($)item	Aug. 31, 2019	Jul. 31, 2019	Apr. 30, 2019community	Dec. 31, 2018USD ($)	Aug. 31, 2018item	Sep. 30, 2017item	Dec. 31, 2015community
Unconsolidated entities
Investment in unconsolidated entities	$ 791,180		$ 791,180					$ 780,869
Number of real estate properties | community	138		138
Financial information relating to unconsolidated joint ventures operations
Operating income/(loss)	$ 12,713	$ (1,382)	$ 19,387	$ (5,091)
Unconsolidated Joint Ventures
Unconsolidated entities
Investment in unconsolidated entities	543,692		543,692					556,694
Combined summary of balance sheets relating to unconsolidated joint ventures
Total real estate, net	3,101,213		3,101,213					3,311,034
Cash and cash equivalents	56,829		56,829					49,867
Other assets	165,767		165,767					124,428
Total assets	3,323,809		3,323,809					3,485,329
Third party debt, net	1,909,223		1,909,223					2,125,350
Accounts payable and accrued liabilities	73,803		73,803					71,272
Total liabilities	1,983,026		1,983,026					2,196,622
Total equity	1,340,783		1,340,783					1,288,707
Financial information relating to unconsolidated joint ventures operations
Total revenues	75,378	76,203	233,836	215,140
Property operating expenses	27,505	30,096	87,073	85,435
Real estate depreciation and amortization	26,027	29,545	83,661	85,063
Operating income/(loss)	21,846	16,562	63,102	44,642
Interest expense	(20,779)	(22,919)	(64,309)	(63,990)
Gain (loss) on sale of property	97,201		115,558
Net unrealized gain/(loss) on held investments	25,669		27,191
Other income/(loss)	82	40	194	141
Net income /(loss)	124,019	$ (6,317)	141,736	$ (19,207)
Unconsolidated Joint Venture Three Washington DC
Unconsolidated entities
UDR's Ownership Interest					100.00%	30.00%
Unconsolidated Joint Venture West Coast Development JV
Unconsolidated entities
Investment in unconsolidated entities	$ 52,200		$ 52,200					101,600
Preferred Equity Investment West Coast Development JV
Unconsolidated entities
UDR's Ownership Interest											48.00%
Number of real estate properties | community											5
Rate	6.50%		6.50%								6.50%
Preferred Equity Investment 1200 Broadway Nashville TN
Unconsolidated entities
Number of apartment homes | item										313
Rate										8.00%
Preferred Equity Investment 1641 Lincoln Santa Monica CA
Unconsolidated entities
Number of apartment homes | item									66
Rate									12.00%
Preferred Equity Investment 1300 Fairmount Philadelphia, PA
Unconsolidated entities
Number of apartment homes | item									471
Preferred Equity Investment Essex Orlando, FL
Unconsolidated entities
Number of apartment homes | item		330		330
Rate		12.50%		12.50%
Preferred Equity Investment Modera Lake Merritt, Oakland
Unconsolidated entities
Number of apartment homes | community							173
Rate							9.00%
Operating Community | Unconsolidated Joint Venture UDR Met Life I Partnership
Unconsolidated entities
Number of apartment homes | home	150		150
Investment in unconsolidated entities	$ 29,599		$ 29,599					$ 30,839
UDR's Ownership Interest	50.00%		50.00%					50.00%
Number of real estate properties | property	1		1
Operating Community | Unconsolidated Joint Venture UDR MetLife II Partnership
Unconsolidated entities
Number of apartment homes | home	4,059		4,059
Investment in unconsolidated entities	$ 300,479		$ 300,479					$ 296,807
UDR's Ownership Interest	50.00%		50.00%					50.00%
Number of real estate properties | property	18		18
Operating Community | Unconsolidated Joint Venture Other MetLife
Unconsolidated entities
Number of apartment homes | home	1,437		1,437
Investment in unconsolidated entities	$ 102,435		$ 102,435					$ 115,668
UDR's Ownership Interest	50.60%		50.60%					50.60%
Number of real estate properties | property	5		5
Operating Community | Unconsolidated Joint Venture Vitruvian Park
Unconsolidated entities
Number of apartment homes | home	1,879		1,879
Investment in unconsolidated entities	$ 75,858		$ 75,858					$ 71,730
UDR's Ownership Interest	50.00%		50.00%					50.00%
Number of real estate properties | property	4		4
Operating Community | Unconsolidated Joint Venture Three Washington DC
Unconsolidated entities
Investment in unconsolidated entities	$ 156		$ 156					$ 5,507
UDR's Ownership Interest								30.00%
Operating Community | Unconsolidated Joint Venture West Coast Development JV
Unconsolidated entities
Number of apartment homes | home	293		293
Investment in unconsolidated entities	$ 35,165		$ 35,165					$ 36,143
UDR's Ownership Interest	47.00%		47.00%					47.00%
Number of real estate properties | property	1		1
Development Community
Unconsolidated entities
Investment in unconsolidated entities	$ 247,488		$ 247,488					$ 224,175
Development Community | Unconsolidated Joint Venture Vitruvian Park
Unconsolidated entities
Number of real estate properties | property	1		1
Development Community | Preferred Equity Investment West Coast Development JV
Unconsolidated entities
Investment in unconsolidated entities	$ 17,080		$ 17,080					65,417
Rate	6.50%		6.50%
Income from investments	$ 71	$ 25	$ (100)	$ 974
Development Community | Preferred Equity Investment 1532 Harrison San Francisco, CA
Unconsolidated entities
Investment in unconsolidated entities	29,753		29,753					24,986
UDR commitment	$ 24,645		$ 24,645
Rate	11.00%		11.00%
Years to Maturity			2 years 9 months 18 days
Income from investments	$ 802	721	$ 2,324	1,492
Development Community | Preferred Equity Investment 1200 Broadway Nashville TN
Unconsolidated entities
Investment in unconsolidated entities	62,666		62,666					58,982
UDR commitment	$ 55,558		$ 55,558
Rate	8.00%		8.00%
Years to Maturity			3 years
Income from investments	$ 1,244	859	$ 3,619	1,870
Development Community | Preferred Equity Investment 1641 Lincoln Santa Monica CA
Unconsolidated entities
Investment in unconsolidated entities	10,072		10,072					9,211
UDR commitment	$ 8,800		$ 8,800
Rate	12.00%		12.00%
Years to Maturity			2 years 9 months 18 days
Income from investments	$ 299	141	$ 861	141
Development Community | Preferred Equity Investment 1300 Fairmount Philadelphia, PA
Unconsolidated entities
Investment in unconsolidated entities	36,404		36,404					8,318
UDR commitment	51,393		$ 51,393
Years to Maturity			3 years 10 months 24 days
Income from investments	930	27	$ 1,724	27
Development Community | Preferred Equity Investment Essex Orlando, FL
Unconsolidated entities
Investment in unconsolidated entities	14,347		14,347					9,940
UDR commitment	$ 12,886		$ 12,886
Rate	12.50%		12.50%
Years to Maturity			3 years 10 months 24 days
Income from investments	$ 443	46	$ 1,182	46
Development Community | Preferred Equity Investment Modera Lake Merritt, Oakland
Unconsolidated entities
Investment in unconsolidated entities	17,377		17,377
UDR commitment	$ 27,250		$ 27,250
Rate	9.00%		9.00%
Years to Maturity			4 years 7 months 6 days
Income from investments	$ 366		$ 622
Development Community | Other Investment The Portals Washington, DC
Unconsolidated entities
Investment in unconsolidated entities	46,863		46,863					43,167
UDR commitment	$ 38,559		$ 38,559
Rate	11.00%		11.00%
Years to Maturity			1 year 8 months 12 days
Income from investments	$ 1,287	1,015	$ 3,694	2,523
Development Community | Other Investment Ventures
Unconsolidated entities
Investment in unconsolidated entities	12,926		12,926					$ 4,154
UDR commitment	18,000		18,000
Income from investments	$ 4,247	$ (77)	$ 4,272	$ (262)
Land Parcel | Unconsolidated Joint Venture Vitruvian Park
Unconsolidated entities
Number of real estate properties | property	4		4

JOINT VENTURES AND PARTNERSHI_4

JOINT VENTURES AND PARTNERSHIPS - Commitments (Details)	1 Months Ended							3 Months Ended		9 Months Ended		12 Months Ended
	Aug. 31, 2019USD ($)communityitem	Jul. 31, 2019USD ($)community	Jun. 30, 2019USD ($)	May 31, 2019USD ($)homecommunity	Jan. 31, 2019USD ($)itemcommunity	May 31, 2017USD ($)itemloan	Mar. 31, 2017	Sep. 30, 2019USD ($)community	Sep. 30, 2018USD ($)item	Sep. 30, 2019USD ($)community	Sep. 30, 2018USD ($)item	Dec. 31, 2017USD ($)itemcommunity	Dec. 31, 2015USD ($)item	Apr. 30, 2019USD ($)community	Jan. 01, 2019community	Dec. 31, 2018USD ($)	Aug. 31, 2018USD ($)item	Sep. 30, 2017USD ($)item	Jun. 30, 2017USD ($)item
Joint Ventures
Real estate owned								$ 11,564,395,000		$ 11,564,395,000						$ 10,196,159,000
Second installment of payable incurred in partial consideration for acquisition of ownership interest in joint venture								108,077,000		108,077,000
Investment in unconsolidated entities								791,180,000		$ 791,180,000						780,869,000
Condition for Community considered to have stabilized occupancy										90%
Time to maintain percent occupancy to be considered a community										3 months
Investment in unconsolidated joint ventures										$ 72,079,000	$ 85,059,000
Long-term Debt								3,935,897,000		3,935,897,000						3,547,787,000
Deferred fees from the sale of properties								10,600,000		10,600,000						11,000,000
Joint venture management and other fees									$ 2,900,000		8,700,000
Joint venture management and other fees								$ 6,386,000	$ 2,888,000	$ 11,982,000	$ 8,819,000
Type of revenue								udr:ManagementAndOtherFeesMember	udr:ManagementAndOtherFeesMember	udr:ManagementAndOtherFeesMember	udr:ManagementAndOtherFeesMember
UDR/MetLife operating communities
Joint Ventures
UDR's Ownership Interest	50.00%
Number of communities acquired | community	10
Number of communities under development purchased | community	1
Number of land parcels | item	4
Value of joint venture	$ 1,100,000,000
Value of joint venture UDR's share	557,000,000
Sale value of joint venture	645,000,000
Sale value of joint venture UDR's share	$ 323,000,000
Number of communities sold | community	5
Ownership interest (percentage)	50.00%
UDR/MetLife II operating communities
Joint Ventures
Number of operating communities held upon closing of transaction | community	7
Unconsolidated Joint Venture Vitruvian Park
Joint Ventures
Number of apartments of development community								0		0
Unconsolidated Joint Venture Three Washington DC
Joint Ventures
UDR's Ownership Interest	100.00%	30.00%
Payment to acquire real estate	$ 184,000,000
Number of communities | community															3
Number of communities sold | community	292
Acquisition-related costs	$ 2,800,000
Reduction of carrying amount of real estate	$ 23,800,000
Ownership interest (percentage)	100.00%
Unconsolidated Joint Venture West Coast Development JV
Joint Ventures
Investment in unconsolidated entities								$ 52,200,000		$ 52,200,000						$ 101,600,000
Preferred Equity Investment West Coast Development JV
Joint Ventures
UDR's Ownership Interest													48.00%
Number of communities are located in coastal market | item													3
Preferred return (as a percent)								6.50%		6.50%			6.50%
Condition for Community considered to have stabilized occupancy										80%
Time to maintain percent occupancy to be considered a community										90 days
Hold period						1 year	1 year
Number of communities acquired | community												1
Number of communities | community												5
Number of communities sold | community												2
Number of remaining communities | community												4
Number of joint ventures agreements entered into | item												2
Cost of ownership interest													$ 136,300,000
Preferred Equity Investment Anaheim CA
Joint Ventures
UDR's Ownership Interest					100.00%											49.00%
Number of communities acquired | community					1
Number of apartment homes acquired					386
Payment to acquire real estate					$ 33,500,000
Number of remaining communities acquired | community					2
Number of remaining communities | community					1
Preferred Equity Investment Seattle WA
Joint Ventures
UDR's Ownership Interest					100.00%							49.00%				49.00%
Number of apartment homes acquired | item					155							155
Payment to acquire real estate					$ 20,000,000
Cost of ownership interest												$ 15,500,000
Preferred Equity Investment Hillsboro Oregon
Joint Ventures
UDR's Ownership Interest												49.00%
Number of apartment homes acquired | item												276
Cost of ownership interest												$ 16,100,000
Preferred Equity Investment San Francisco California JV
Joint Ventures
Preferred return (as a percent)																			11.00%
Number of apartment homes | item																			136
Equity Investment																			$ 24,600,000
Preferred Equity Investment 1200 Broadway Nashville TN
Joint Ventures
Preferred return (as a percent)																		8.00%
Number of apartment homes | item																		313
Equity Investment																		$ 55,600,000
Preferred Equity Investment 1641 Lincoln Santa Monica CA
Joint Ventures
Preferred return (as a percent)																	12.00%
Number of apartment homes | item																	66
Equity Investment																	$ 8,800,000
Preferred Equity Investment 1300 Fairmount Philadelphia, PA
Joint Ventures
Number of apartment homes | item																	471
Equity Investment																	$ 51,400,000
Preferred Equity Investment 1300 Fairmount Philadelphia, PA | Minimum
Joint Ventures
Preferred return (as a percent)																	8.50%
Preferred Equity Investment 1300 Fairmount Philadelphia, PA | Maximum
Joint Ventures
Preferred return (as a percent)																	12.00%
Preferred Equity Investment Essex Orlando, FL
Joint Ventures
Preferred return (as a percent)									12.50%		12.50%
Number of apartment homes | item									330		330
Equity Investment									$ 12,900,000		$ 12,900,000
Preferred Equity Investment Modera Lake Merritt, Oakland
Joint Ventures
Preferred return (as a percent)														9.00%
Number of apartment homes | community														173
Equity Investment														$ 27,300,000
Third Party Developer in Washington D.C.
Joint Ventures
Number of apartments of development community | item						373
Equity Investment						$ 38,600,000
Long-term Debt						$ 71,000,000
Interest rate of medium-term notes						13.50%
Debt instrument term						4 years
Number of extensions available | loan						1
Loan extension term						12 months
Weighted average interest rate of Company's committed portion						11
Operating Community in Arlington, Virginia
Joint Ventures
Number of communities sold | community				1
Number of apartment homes | home				217
Proceeds from sale of real estate				$ 74,800,000
Gain/(loss) on sales of real estate owned, net of tax				$ 5,300,000
Operating Community in Silver Spring, Maryland
Joint Ventures
Number of communities sold | community		151
Proceeds from sale of real estate		$ 43,500,000
Gain/(loss) on sales of real estate owned, net of tax		$ 5,300,000
UDR/KFH joint venture
Joint Ventures
Number of communities sold | community								3		3
Ground Leases
Joint Ventures
Proceeds from sale of real estate			$ 38,000,000
Gain/(loss) on sales of real estate owned, net of tax			$ 5,300,000

LEASES - Lessee Future Minimum

LEASES - Lessee Future Minimum Payments (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2019USD ($)community
Lessee operating leases
Number of communities subject to ground leases | community	6
Operating leases existence of option to extend	true
Lease classification per practical expedient	true
Operating lease right-of-use assets	$ 135,889
Weighted average remaining lease term	55 years 2 months 12 days
Weighted average discount rate	5.10%
Increase in operating lease right-to-use assets	$ 42,143
Increase in operating lease liabilities	42,100
Increase in operating lease liabilities	88,336
Future minimum lease payments
2019	1,972
2020	7,889
2021	7,845
2022	7,813
2023	7,813
Thereafter	370,467
Total future minimum lease payments (undiscounted)	403,799
Difference between future undiscounted cash flows and discounted cash flows	(273,664)
Operating lease liabilities	130,135
Ground Leases
Future minimum lease payments
2019	1,953
2020	7,813
2021	7,813
2022	7,813
2023	7,813
Thereafter	370,467
Total future minimum lease payments (undiscounted)	403,672
Difference between future undiscounted cash flows and discounted cash flows	(273,659)
Operating lease liabilities	130,013
Office Space
Future minimum lease payments
2019	19
2020	76
2021	32
Total future minimum lease payments (undiscounted)	127
Difference between future undiscounted cash flows and discounted cash flows	(5)
Operating lease liabilities	$ 122

LEASES - Lessee Expenses (Detai

LEASES - Lessee Expenses (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Lessee operating leases
Contractual lease expense	$ 100	$ 300
Variable lease expense	100	300
Total lease expense	2,160	6,758
Operating lease right-of-use asset amortization		600
Operating lease liabilities amortization		300
Ground Leases
Lessee operating leases
Contractual lease expense	1,954	6,232
Variable lease expense	187	469
Ground Leases | Other operating expense
Lessee operating leases
Total lease expense	2,141	6,701
Office Space | General and administrative expense
Lessee operating leases
Contractual lease expense	$ 19	$ 57

LEASES - Lessor (Details)

LEASES - Lessor (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended	9 Months Ended
	Jun. 30, 2019	Sep. 30, 2019	Sep. 30, 2019
Future minimum lease payments
Variable lease expense		$ 100	$ 300
Ground Leases
Lessor leases
Proceeds from sale of real estate	$ 38,000
Future minimum lease payments
Variable lease expense		$ 187	$ 469
Apartment Homes
Lessor leases
Percentage of lease revenue			98.10%
Option to extend			true
Apartment Homes | Maximum
Lessor leases
Lease terms		12 months	12 months
Retail and Commercial Spaces
Lessor leases
Percentage of lease revenue			1.90%
Option to extend			true
Future minimum lease payments
2019		$ 4,958	$ 4,958
2020		20,565	20,565
2021		19,788	19,788
2022		18,094	18,094
2023		16,843	16,843
Thereafter		92,719	92,719
Total future minimum payments		$ 172,967	$ 172,967
Retail and Commercial Spaces | Minimum
Lessor leases
Lease terms		5 years	5 years
Retail and Commercial Spaces | Maximum
Lessor leases
Lease terms		15 years	15 years

SECURED AND UNSECURED DEBT, N_3

SECURED AND UNSECURED DEBT, NET - Summary (Details) $ in Thousands	1 Months Ended	9 Months Ended
	Oct. 30, 2019USD ($)	Sep. 30, 2019USD ($)community	Dec. 31, 2018USD ($)
Secured debt instruments
Interest rate at end of the period	4.63%	3.63%
Long-term Debt		$ 3,935,897	$ 3,547,787
Unsecured Debt		3,335,273	2,946,560
Borrowings outstanding		$ 2,800	3,300
Weighted Average
Secured debt instruments
Years to maturity		6 years 10 months 24 days
Commercial Paper
Secured debt instruments
Interest rate at end of the period		2.28%
Borrowings outstanding at end of period		$ 60,000	101,115
Commercial Paper | Weighted Average
Secured debt instruments
Years to maturity		1 month 6 days
Mortgages Notes Payable | Fixed Rate Debt
Secured debt instruments
Principal outstanding		$ 575,965	417,989
Interest rate at end of the period		3.55%
Number of Communities Encumbered | community		9
Mortgages Notes Payable | Fixed Rate Debt | Weighted Average
Secured debt instruments
Years to maturity		6 years 7 months 6 days
Tax-exempt secured notes payable | Variable Rate Debt
Secured debt instruments
Principal outstanding		$ 27,000	94,700
Interest rate at end of the period		2.07%
Number of Communities Encumbered | community		1
Tax-exempt secured notes payable | Variable Rate Debt | Weighted Average
Secured debt instruments
Years to maturity		12 years 6 months
Fannie Mae credit facilities | Fixed Rate Debt
Secured debt instruments
Principal outstanding			90,000
Secured Debt
Secured debt instruments
Principal outstanding		$ 600,624	601,227
Interest rate at end of the period		3.49%
Long-term Debt		$ 600,624
Number of Communities Encumbered | community		10
Secured Debt | Weighted Average
Secured debt instruments
Years to maturity		6 years 9 months 18 days
Secured Debt | Fixed Rate Debt
Secured debt instruments
Principal outstanding		$ 573,690	506,646
Interest rate at end of the period		3.55%
Long-term Debt		$ 573,690
Number of Communities Encumbered | community		9
Deferred finance costs, net		$ (2,275)	(1,343)
Secured Debt | Fixed Rate Debt | Weighted Average
Secured debt instruments
Years to maturity		6 years 7 months 6 days
Secured Debt | Variable Rate Debt
Secured debt instruments
Principal outstanding		$ 26,934	94,581
Interest rate at end of the period		2.07%
Long-term Debt		$ 26,934
Number of Communities Encumbered | community		1
Deferred finance costs, net		$ (66)	(119)
Secured Debt | Variable Rate Debt | Weighted Average
Secured debt instruments
Years to maturity		12 years 6 months
Unsecured Revolving credit facility due 2023 | Weighted Average
Secured debt instruments
Years to maturity		3 years 3 months 18 days
Unsecured Working Capital Credit Facility due January 2021
Secured debt instruments
Interest rate at end of the period		2.84%
Borrowings outstanding		$ 34,447	16
Unsecured Working Capital Credit Facility due January 2021 | Weighted Average
Secured debt instruments
Years to maturity		1 year 3 months 18 days
Term Loan due September 2023
Secured debt instruments
Interest rate at end of the period		3.01%
Senior Notes		$ 35,000	35,000
Term Loan due September 2023 | Weighted Average
Secured debt instruments
Years to maturity		4 years
3.70% Term Notes Due October 2020
Secured debt instruments
Unamortized discount		$ 0	14
Senior Notes			299,986
4.63% Medium-Term Notes due January 2022
Secured debt instruments
Unamortized discount		$ 818	1,087
Interest rate at end of the period		4.63%
Senior Notes		$ 399,182	398,913
4.63% Medium-Term Notes due January 2022 | Weighted Average
Secured debt instruments
Years to maturity		2 years 3 months 18 days
1.93% Term Loan due September 2023
Secured debt instruments
Interest rate at end of the period		1.93%
Senior Notes		$ 315,000	315,000
1.93% Term Loan due September 2023 | Weighted Average
Secured debt instruments
Years to maturity		4 years
3.75% Medium-Term Notes Due July 2024
Secured debt instruments
Unamortized discount		$ 495	574
Interest rate at end of the period		3.75%
Senior Notes		$ 299,505	299,426
3.75% Medium-Term Notes Due July 2024 | Weighted Average
Secured debt instruments
Years to maturity		4 years 9 months 18 days
8.50% Debentures, Due September 2024
Secured debt instruments
Interest rate at end of the period		8.50%
Senior Notes		$ 15,644	15,644
8.50% Debentures, Due September 2024 | Weighted Average
Secured debt instruments
Years to maturity		5 years
4.00% Medium-Term Note due October 2025
Secured debt instruments
Unamortized discount		$ 413	465
Interest rate at end of the period		4.00%
Senior Notes		$ 299,587	299,535
4.00% Medium-Term Note due October 2025 | Weighted Average
Secured debt instruments
Years to maturity		6 years
2.95% Medium-Term Note due September 2026
Secured debt instruments
Interest rate at end of the period		2.95%
Senior Notes		$ 300,000	300,000
2.95% Medium-Term Note due September 2026 | Weighted Average
Secured debt instruments
Years to maturity		6 years 10 months 24 days
3.50 Medium-Term Note due July 2027
Secured debt instruments
Unamortized discount		$ 547	600
Interest rate at end of the period		3.50%
Senior Notes		$ 299,453	299,400
3.50 Medium-Term Note due July 2027 | Weighted Average
Secured debt instruments
Years to maturity		7 years 9 months 18 days
3.50% Medium-Term Notes Due January 2028
Secured debt instruments
Unamortized discount		$ 983	1,072
Interest rate at end of the period		3.50%
Senior Notes		$ 299,017	298,928
3.50% Medium-Term Notes Due January 2028 | Weighted Average
Secured debt instruments
Years to maturity		8 years 3 months 18 days
4.40% Medium-Term Notes due January 2029
Secured debt instruments
Unamortized discount		$ 6	6
Interest rate at end of the period		4.40%
Senior Notes		$ 299,994	299,994
4.40% Medium-Term Notes due January 2029 | Weighted Average
Secured debt instruments
Years to maturity		9 years 3 months 18 days
3.20% Medium-Term Notes due January 2030
Secured debt instruments
Unamortized discount		$ 990	0
Interest rate at end of the period		3.20%
Senior Notes		$ 299,010
Borrowings outstanding	$ 400,000
3.20% Medium-Term Notes due January 2030 | Weighted Average
Secured debt instruments
Years to maturity		10 years 3 months 18 days
3.00% Medium-Term Notes due August 2031
Secured debt instruments
Unamortized discount		$ 1,148	0
Interest rate at end of the period		3.00%
Senior Notes		$ 398,852
3.00% Medium-Term Notes due August 2031 | Weighted Average
Secured debt instruments
Years to maturity		11 years 10 months 24 days
Other
Secured debt instruments
Senior Notes		$ 14	16
Unsecured Debt
Secured debt instruments
Interest rate at end of the period		3.54%
Long-term Debt		$ 3,335,273
Unsecured Debt		3,335,273	2,946,560
Deferred finance costs, net		$ (19,432)	(16,413)
Unsecured Debt | Weighted Average
Secured debt instruments
Years to maturity		6 years 10 months 24 days
United Dominion Realty L.P.
Secured debt instruments
Principal outstanding		$ 99,064	26,929
Interest rate at end of the period		2.85%
Number of Communities Encumbered | community		2
United Dominion Realty L.P. | Weighted Average
Secured debt instruments
Years to maturity		10 years 10 months 24 days
United Dominion Realty L.P. | Fixed Rate Debt
Secured debt instruments
Principal outstanding		$ 72,130
Interest rate at end of the period		3.10%
Number of Communities Encumbered | community		1
United Dominion Realty L.P. | Fixed Rate Debt | Weighted Average
Secured debt instruments
Years to maturity		10 years 3 months 18 days
United Dominion Realty L.P. | Variable Rate Debt
Secured debt instruments
Deferred finance costs, net		$ (66)	(71)
United Dominion Realty L.P. | Mortgages Notes Payable
Secured debt instruments
Principal outstanding		72,500
United Dominion Realty L.P. | Mortgages Notes Payable | Fixed Rate Debt
Secured debt instruments
Principal outstanding		$ 72,500
Interest rate at end of the period		3.10%
Number of Communities Encumbered | community		1
Deferred finance costs, net		$ (370)
United Dominion Realty L.P. | Mortgages Notes Payable | Fixed Rate Debt | Weighted Average
Secured debt instruments
Years to maturity		10 years 3 months 18 days
United Dominion Realty L.P. | Tax-exempt secured notes payable | Variable Rate Debt
Secured debt instruments
Principal outstanding		$ 27,000	$ 27,000
Interest rate at end of the period		2.07%
Number of Communities Encumbered | community		1
United Dominion Realty L.P. | Tax-exempt secured notes payable | Variable Rate Debt | Weighted Average
Secured debt instruments
Years to maturity		12 years 6 months

SECURED AND UNSECURED DEBT, N_4

SECURED AND UNSECURED DEBT, NET - Variable Rate Debt (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Credit facilities
Unamortized net premium	$ 3,900	$ 5,000
Secured credit facilities
Borrowings outstanding at end of period	2,800	3,300
Fannie Mae
Secured credit facilities
Borrowings outstanding at end of period		90,000
Weighted average daily borrowings during the period ended	80,000	253,813
Maximum daily borrowings during the period ended	$ 90,000	$ 314,869
Weighted average interest rate during the period ended	4.00%	4.70%
Interest rate at the end of the period		4.00%

SECURED AND UNSECURED DEBT, N_5

SECURED AND UNSECURED DEBT, NET - Credit Facilities (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Summary of short-term bank borrowings under unsecured commercial bank credit facility
Borrowings outstanding at end of period	$ 2,800	$ 3,300
Unsecured Commercial Bank Credit Facility
Summary of short-term bank borrowings under unsecured commercial bank credit facility
Total revolving credit facility	2,000,000
Unsecured Revolving credit facility due 2023 | Unsecured Commercial Bank Credit Facility
Summary of short-term bank borrowings under unsecured commercial bank credit facility
Total revolving credit facility	1,100,000
Term Loan due September 2023 | Unsecured Commercial Bank Credit Facility
Summary of short-term bank borrowings under unsecured commercial bank credit facility
Total revolving credit facility	350,000
Revolving Credit Facility | Unsecured Commercial Bank Credit Facility
Summary of short-term bank borrowings under unsecured commercial bank credit facility
Total revolving credit facility	1,100,000	1,100,000
Unsecured Working Capital Credit Facility due January 2021
Summary of short-term bank borrowings under unsecured commercial bank credit facility
Total revolving credit facility	75,000	75,000
Borrowings outstanding at end of period	34,447	16
Weighted average daily borrowings during the period ended	24,870	26,101
Maximum daily borrowings during the period ended	$ 66,170	$ 64,633
Weighted average interest rate during the period ended	3.20%	2.90%
Interest rate at the end of the period	2.80%	3.30%
Unsecured Commercial Paper | United Dominion Realty L.P.
Summary of short-term bank borrowings under unsecured commercial bank credit facility
Borrowings outstanding at end of period	$ 60,000	$ 101,100

SECURED AND UNSECURED DEBT, N_6

SECURED AND UNSECURED DEBT, NET - Short Term Debt (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Commercial Paper
Unsecured Debt
Total unsecured commercial paper program	$ 500,000	$ 500,000
Borrowings outstanding at end of period	60,000	101,115
Weighted average daily borrowings during the period ended	163,347	344,235
Maximum daily borrowings during the period ended	$ 435,000	$ 440,000
Weighted average interest rate during the period ended	2.70%	2.40%
Interest rate at the end of the period	2.30%	2.90%
4.00% Medium-Term Note due October 2025
Unsecured Debt
Weighted average interest rate during the period ended	4.53%

SECURED AND UNSECURED DEBT, N_7

SECURED AND UNSECURED DEBT, NET - Unsecured Maturities (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Aggregate maturities of unsecured debt
2019	$ 60,974
2020	108,077
2021	35,564
2022	401,157
2023	391,245
2024	315,644
2025	427,600
2026	350,000
2027	300,000
2028	380,000
Thereafter	1,189,500
Subtotal	3,959,761
Non-cash (a)	(23,864)
Long-term Debt, Total	3,935,897	$ 3,547,787
Secured Debt
Aggregate maturities of unsecured debt
2019	974
2020	108,077
2021	1,117
2022	1,157
2023	41,245
2025	127,600
2026	50,000
2028	80,000
Thereafter	189,500
Subtotal	599,670
Non-cash (a)	954
Long-term Debt, Total	600,624
Unsecured Debt
Aggregate maturities of unsecured debt
2019	60,000
2021	34,447
2022	400,000
2023	350,000
2024	315,644
2025	300,000
2026	300,000
2027	300,000
2028	300,000
Thereafter	1,000,000
Subtotal	3,360,091
Non-cash (a)	(24,818)
Long-term Debt, Total	3,335,273
Fixed Rate Debt | Secured Debt
Aggregate maturities of unsecured debt
2019	974
2020	108,077
2021	1,117
2022	1,157
2023	41,245
2025	127,600
2026	50,000
2028	80,000
Thereafter	162,500
Subtotal	572,670
Non-cash (a)	1,020
Long-term Debt, Total	573,690
Variable Rate Debt | Secured Debt
Aggregate maturities of unsecured debt
Thereafter	27,000
Subtotal	27,000
Non-cash (a)	(66)
Long-term Debt, Total	$ 26,934

SECURED AND UNSECURED DEBT, N_8

SECURED AND UNSECURED DEBT, NET - Debt Covenants (Details) $ in Thousands	Jul. 02, 2019USD ($)	Oct. 30, 2019USD ($)	Aug. 31, 2019USD ($)	Jul. 31, 2019USD ($)	Sep. 30, 2019USD ($)loan	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)loan	Sep. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Fixed and variable rate debt
Amortization of financing costs					$ 1,100	$ 1,100	$ 3,100	$ 3,200
Secured Debt
Secured debt amount which encumbers real estate owned based upon book value					$ 1,200,000		$ 1,200,000
Percentage of secured debt which encumbers real estate owned based upon book value					10.30%		10.30%
Secured debt amount of real estate owned which is unencumbered					$ 10,400,000		$ 10,400,000
Percentage of secured debt of real estate owned which is unencumbered					89.70%		89.70%
Long-term commercial paper					$ 500,000		$ 500,000
Interest rate at end of the period		4.63%					3.63%
Secured Debt					600,624		$ 600,624		$ 601,227
Commercial Paper
Secured Debt
Commercial paper program					60,000		$ 60,000		101,115
Interest rate at end of the period							2.28%
Fixed Rate Mortgage Due October 2029
Secured Debt
Principal outstanding					90,000		$ 90,000
Interest rate at end of the period							2.70%
Mortgage Due February 2020
Secured Debt
Principal outstanding					72,500		$ 72,500
Interest rate at end of the period							3.10%
3.20% senior unsecured notes due 2030
Secured Debt
Principal outstanding		$ 400,000
Interest rate at end of the period	3.20%	3.20%
Senior Notes	$ 300,000	$ 100,000
Percentage of notes price		103.32%
3.20% senior unsecured notes due 2030 | Treasury Lock
Secured Debt
Weighted average interest rate (as a percent)		3.24%
3.10% senior unsecured notes due 2034
Secured Debt
Interest rate at end of the period		3.10%
Senior Notes		$ 300,000
Percentage of notes price		99.56%
3.10% senior unsecured notes due 2034 | Treasury Lock
Secured Debt
Weighted average interest rate (as a percent)		3.13%
4.63% Medium-Term Notes due January 2022
Secured Debt
Make-whole amount		$ 21,500
Senior Notes		400,000
Fannie Mae credit facilities
Secured Debt
Redemption of debt					90,000
Unsecured Debt
Secured Debt
Interest rate at end of the period							3.54%
Credit facility interest rate							90
Basis points added to to variable rate							90.00%
Unsecured Debt | Maximum
Secured Debt
Basis points added to to variable rate							165.00%
Unsecured Debt | Minimum
Secured Debt
Basis points added to to variable rate							80.00%
Unsecured Working Capital Credit Facility due January 2021
Secured Debt
Credit facilities with aggregate commitment					75,000		$ 75,000		75,000
Interest rate at end of the period							2.84%
Credit facility interest rate							82.5
Unsecured Working Capital Credit Facility due January 2021 | Maximum
Secured Debt
Basis points added to to variable rate							145.00%
Unsecured Working Capital Credit Facility due January 2021 | Minimum
Secured Debt
Basis points added to to variable rate							75.00%
3.75% Medium-Term Notes Due July 2024
Secured Debt
Interest rate at end of the period							3.75%
Portion of medium term note subject to interest rate swaps					100,000		$ 100,000
Long-term Debt, Weighted Average Interest Rate							3.69%
Senior Notes					299,505		$ 299,505		299,426
Mortgages Notes Payable | Fixed Rate Debt
Secured Debt
Principal outstanding					575,965		$ 575,965		417,989
Interest rate at end of the period							3.55%
Debt Assumed As Part of Acquisition
Secured Debt
Amortization of Debt Discount (Premium)					600	$ 900	$ 1,700	$ 2,400
Tax-exempt secured notes payable | Variable Rate Debt
Secured Debt
Principal outstanding					$ 27,000		$ 27,000		94,700
Interest rate at end of the period							2.07%
Fannie Mae credit facilities | Fixed Rate Debt
Secured Debt
Principal outstanding									90,000
Tax-exempt secured notes payable | Variable Rate Debt
Secured Debt
Notes payable maximum interest rates range					2.07%		2.07%
Payment of notes payable					$ 67,700
Revolving Credit Facility
Secured Debt
Basis points added to to variable rate							82.50%
Commitment fee							15.00%
Revolving Credit Facility | Maximum
Secured Debt
Basis points added to to variable rate							145.00%
Commitment fee							30.00%
Revolving Credit Facility | Minimum
Secured Debt
Basis points added to to variable rate							75.00%
Commitment fee							10.00%
4.00% Medium-Term Note due October 2025
Secured Debt
Interest rate at end of the period							4.00%
Portion of medium term note subject to interest rate swaps					200,000		$ 200,000
Senior Notes					299,587		$ 299,587		299,535
4.40% Medium-Term Notes due January 2029
Secured Debt
Interest rate at end of the period							4.40%
Portion of medium term note subject to interest rate swaps					150,000		$ 150,000
Long-term Debt, Weighted Average Interest Rate							4.27%
Senior Notes					299,994		$ 299,994		299,994
2.95% Medium-Term Note due September 2026
Secured Debt
Interest rate at end of the period							2.95%
Senior Notes					300,000		$ 300,000		300,000
3.20% Medium-Term Notes due January 2030
Secured Debt
Interest rate at end of the period							3.20%
Medium-term notes	$ 300,000	$ 100,000		$ 300,000
Interest rate of medium-term notes	3.20%	3.20%		3.20%
Percentage of principal amount at issuance				99.66
Long-term Debt, Weighted Average Interest Rate				3.42%
Senior Notes					299,010		$ 299,010
3.00% Medium-Term Notes due August 2031
Secured Debt
Interest rate at end of the period							3.00%
Medium-term notes			$ 400,000
Interest rate of medium-term notes			3.00%
Percentage of principal amount at issuance			99.71
Senior Notes					398,852		$ 398,852
3.00% Medium-Term Notes due August 2031 | Treasury Lock
Secured Debt
Medium-term notes			$ 150,000
Weighted average interest rate (as a percent)			3.01%
3.70% Term Notes Due October 2020
Secured Debt
Make-whole amount			$ 5,400
Interest rate of medium-term notes			3.70%
Redemption of debt			$ 300,000
Senior Notes									299,986
Unsecured Commercial Bank Credit Facility
Secured Debt
Credit facilities with aggregate commitment					2,000,000		2,000,000
Unsecured Commercial Bank Credit Facility | Unsecured Revolving credit facility due 2023
Secured Debt
Credit facilities with aggregate commitment					$ 1,100,000		$ 1,100,000
Number of Extensions of loan | loan					2		2
Extension period of option on loan							6 months
Unsecured Commercial Bank Credit Facility | Revolving Credit Facility
Secured Debt
Credit facilities with aggregate commitment					$ 1,100,000		$ 1,100,000		1,100,000
United Dominion Realty L.P.
Secured Debt
Notes payable maximum interest rates range					3.63%		3.63%
Principal outstanding					$ 99,064		$ 99,064		26,929
Interest rate at end of the period							2.85%
Secured Debt					99,064		$ 99,064		26,929
United Dominion Realty L.P. | Fixed Rate Debt
Secured Debt
Principal outstanding					72,130		$ 72,130
Interest rate at end of the period							3.10%
United Dominion Realty L.P. | Mortgages Notes Payable
Secured Debt
Principal outstanding					$ 72,500		$ 72,500
Interest rate of medium-term notes					3.10%		3.10%
United Dominion Realty L.P. | Mortgages Notes Payable | Fixed Rate Debt
Secured Debt
Principal outstanding					$ 72,500		$ 72,500
Interest rate at end of the period							3.10%
United Dominion Realty L.P. | Tax-exempt secured notes payable | Variable Rate Debt
Secured Debt
Principal outstanding					27,000		$ 27,000		27,000
Interest rate at end of the period							2.07%
United Dominion Realty L.P. | Unsecured Commercial Bank Credit Facility
Secured Debt
Long-term commercial paper					$ 500,000		$ 500,000
Fannie Mae credit facilities | Fair Value, Measurements, Recurring | Carrying Amount | Fannie Mae credit facilities | Fixed Rate Debt
Secured Debt
Principal outstanding									90,000
Mortgages Notes Payable | Fixed Rate Debt | Maximum
Secured Debt
Notes payable maximum interest rates range					4.35%		4.35%
Mortgages Notes Payable | Fixed Rate Debt | Minimum
Secured Debt
Notes payable maximum interest rates range					2.70%		2.70%
Mortgages Notes Payable | Fair Value, Measurements, Recurring | Carrying Amount | Mortgages Notes Payable | Fixed Rate Debt
Secured Debt
Principal outstanding					$ 575,965		$ 575,965		$ 417,989

INCOME_(LOSS) PER SHARE (Detail

INCOME/(LOSS) PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2019	Aug. 31, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Jul. 31, 2017
Antidilutive securities
Net income/(loss)			$ 29,422	$ 20,258	$ 94,342	$ 131,927
Net (income)/loss attributable to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership			(2,162)	(1,616)	(6,871)	(10,819)
Net (income)/loss attributable to noncontrolling interests			(56)	(32)	(145)	(141)
Net income/(loss) attributable to UDR, Inc.			27,204	18,610	87,326	120,967
Distributions to preferred stockholders - Series E (Convertible)			(1,031)	(971)	(3,073)	(2,897)
Net income/(loss) attributable to common stockholders			$ 26,173	$ 17,639	$ 84,253	$ 118,070
Denominator for earnings per share - basic and diluted:
Weighted average common shares outstanding			288,957,000	268,034,000	282,866,000	267,873,000
Non-vested restricted stock awards			(251,000)	(307,000)	(268,000)	(344,000)
Denominator for basic income/(loss) per share			288,706,000	267,727,000	282,598,000	267,529,000
Incremental shares issuable from assumed conversion of stock options, unvested LTIP Units, unvested restricted stock, and shares issuable upon settlement of forward purchase agreements			823,000	1,134,000	694,000	1,491,000
Denominator for diluted income/(loss) per share			289,529,000	268,861,000	283,292,000	269,020,000
Income/(loss) per weighted average common share - basic			$ 0.09	$ 0.07	$ 0.30	$ 0.44
Income/(loss) per weighted average common share - diluted			$ 0.09	$ 0.07	$ 0.30	$ 0.44
Number of shares authorized	350,000,000		350,000,000		350,000,000		350,000,000
Number of shares sold		7,500,000
Aggregate gross proceeds		$ 349,900			$ 662,009
Weighted average price per share		$ 46.65
Aggregate net proceeds from sales, after deducting related costs		$ 349,800	$ 449,137		$ 662,009
OP/DownREIT Units
Antidilutive securities
Antidilutive securities			22,211,000	24,558,000	23,068,000	24,546,000
Convertible preferred stock
Antidilutive securities
Antidilutive securities			3,011,000	3,011,000	3,011,000	3,011,000
Stock options, unvested LTIP Units, unvested restricted stock, and forward sales shares
Antidilutive securities
Antidilutive securities			823,000	1,134,000	694,000	1,491,000
ATM
Denominator for earnings per share - basic and diluted:
Number of shares authorized								20,000,000
Number of shares sold			2,200,000		7,000,000
Aggregate gross proceeds			$ 100,500		$ 316,500
Weighted average price per share			$ 46.19		$ 45.29
Commissions paid to sales agents			$ 1,100		$ 4,000
Aggregate net proceeds from sales, after deducting related costs			$ 99,400		$ 312,300
Shares of common stock available for future issuance	13,000,000		13,000,000		13,000,000
Forward Sales Agreement
Denominator for earnings per share - basic and diluted:
Number of shares authorized	1,300,000		1,300,000		1,300,000
Weighted average price per share	$ 47.68
Shares settled	0

NONCONTROLLING INTERESTS (Detai

NONCONTROLLING INTERESTS (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Redeemable noncontrolling interests in the Operating Partnership
Minimum holding period prior to redemption (in years)			1 year
Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership, beginning of year			$ 972,740
Mark-to-market adjustment to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership	$ 85,235	$ 77,357	222,405	$ 62,655
Conversion of OP Units/DownREIT Units to Common Stock			(119,338)
Net income/(loss) attributable o redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership	2,162	1,616	6,871	10,819
Distributions to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership			(24,509)
Vesting of Long-Term Incentive Plan Units			14,742
Allocation of other comprehensive income/(loss)			(730)
Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership, end of year	1,072,181		1,072,181
Net income/(loss) attributable to noncontrolling interests	40	21	97	107
Maximum
Redeemable noncontrolling interests in the Operating Partnership
Net income/(loss) attributable to noncontrolling interests	$ (100)	$ (100)	$ (100)	$ (100)
LTIP Units | Minimum
Redeemable noncontrolling interests in the Operating Partnership
Vesting period			1 year
LTIP Units | Maximum
Redeemable noncontrolling interests in the Operating Partnership
Vesting period			3 years

FAIR VALUE OF DERIVATIVES AND_3

FAIR VALUE OF DERIVATIVES AND FINANCIAL INSTRUMENTS (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Fair Value
Notes receivable, net	$ 37,899	$ 42,259
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Gross Amounts of Recognized Assets	730	4,757
Gross Amounts of Recognized Liabilities	469	356
Unsecured debt instruments
Redeemable Noncontrolling Interest, Equity, Carrying Amount	1,072,181	972,740
Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership	1,072,181	972,740
Carrying Amount | Fair Value, Measurements, Recurring
Fair Value
Notes receivable, net	37,899	42,259
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Total assets	38,629	47,016
Unsecured debt instruments
Total liabilities	3,958,139	3,566,018
Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership	1,072,181	972,740
Carrying Amount | Interest rate contracts | Fair Value, Measurements, Recurring
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Derivative Asset Designated as Hedging Instrument, Fair Value	730	4,757
Derivatives - Interest rate contracts (b)	469	356
Carrying Amount | Commercial bank | Fair Value, Measurements, Recurring
Unsecured debt instruments
Unsecured debt instruments	34,447	16
Commercial paper program	60,000	101,115
Carrying Amount | Senior Unsecured Notes | Fair Value, Measurements, Recurring
Unsecured debt instruments
Unsecured debt instruments	3,260,258	2,861,842
Fair Value | Fair Value, Measurements, Recurring
Fair Value
Notes receivable, net	42,613	45,026
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Total assets	43,343	49,783
Unsecured debt instruments
Total liabilities	4,106,852	3,532,104
Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership	1,072,181	972,740
Fair Value | Interest rate contracts | Fair Value, Measurements, Recurring
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Derivative Asset Designated as Hedging Instrument, Fair Value	730	4,757
Derivatives - Interest rate contracts (b)	469	356
Fair Value | Commercial bank | Fair Value, Measurements, Recurring
Unsecured debt instruments
Unsecured debt instruments	34,447	16
Commercial paper program	60,000	101,115
Fair Value | Senior Unsecured Notes | Fair Value, Measurements, Recurring
Unsecured debt instruments
Unsecured debt instruments	3,415,618	2,829,390
Fair Value | Level 2 | Fair Value, Measurements, Recurring
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Total assets	730	4,757
Unsecured debt instruments
Total liabilities	469	356
Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership	1,072,181	972,740
Fair Value | Level 2 | Interest rate contracts | Fair Value, Measurements, Recurring
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Derivative Asset Designated as Hedging Instrument, Fair Value	730	4,757
Derivatives - Interest rate contracts (b)	469	356
Fair Value | Level 3 | Fair Value, Measurements, Recurring
Fair Value
Notes receivable, net	42,613	45,026
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Total assets	42,613	45,026
Unsecured debt instruments
Total liabilities	4,106,383	3,531,748
Fair Value | Level 3 | Commercial bank | Fair Value, Measurements, Recurring
Unsecured debt instruments
Unsecured debt instruments	34,447	16
Commercial paper program	60,000	101,115
Fair Value | Level 3 | Senior Unsecured Notes | Fair Value, Measurements, Recurring
Unsecured debt instruments
Unsecured debt instruments	3,415,618	2,829,390
Tax-exempt secured notes payable | Variable Rate Debt
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	27,000	94,700
Tax-exempt secured notes payable | Variable Rate Debt | Carrying Amount | Tax-exempt secured notes payable | Fair Value, Measurements, Recurring
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	27,000	94,700
Tax-exempt secured notes payable | Variable Rate Debt | Fair Value | Tax-exempt secured notes payable | Fair Value, Measurements, Recurring
Debt instruments - fair value
Fair value	27,000	94,700
Tax-exempt secured notes payable | Variable Rate Debt | Fair Value | Level 3 | Tax-exempt secured notes payable | Fair Value, Measurements, Recurring
Debt instruments - fair value
Fair value	27,000	94,700
Fannie Mae credit facilities | Fixed Rate Debt
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		90,000
Fannie Mae credit facilities | Fixed Rate Debt | Carrying Amount | Fannie Mae credit facilities | Fair Value, Measurements, Recurring
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		90,000
Fannie Mae credit facilities | Fixed Rate Debt | Fair Value | Fannie Mae credit facilities | Fair Value, Measurements, Recurring
Debt instruments - fair value
Fair value		90,213
Fannie Mae credit facilities | Fixed Rate Debt | Fair Value | Level 3 | Fannie Mae credit facilities | Fair Value, Measurements, Recurring
Debt instruments - fair value
Fair value		90,213
Mortgages Notes Payable | Fixed Rate Debt
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	575,965	417,989
Mortgages Notes Payable | Fixed Rate Debt | Carrying Amount | Mortgages Notes Payable | Fair Value, Measurements, Recurring
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	575,965	417,989
Mortgages Notes Payable | Fixed Rate Debt | Fair Value | Mortgages Notes Payable | Fair Value, Measurements, Recurring
Debt instruments - fair value
Fair value	569,318	416,314
Mortgages Notes Payable | Fixed Rate Debt | Fair Value | Level 3 | Mortgages Notes Payable | Fair Value, Measurements, Recurring
Debt instruments - fair value
Fair value	$ 569,318	$ 416,314

DERIVATIVES AND HEDGING ACTIV_3

DERIVATIVES AND HEDGING ACTIVITY - Interest Rate Derivatives (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019USD ($)instrument	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)instrument	Sep. 30, 2018USD ($)	Oct. 30, 2019USD ($)	Jul. 31, 2019USD ($)	Jul. 02, 2019USD ($)	Jun. 30, 2019USD ($)instrument
Derivatives
Unrealized holding gain/(loss)	$ (659)	$ 2,320	$ (7,181)	$ 4,312
Unsecured Commercial Bank Credit Facility
Derivatives
Total revolving credit facility	$ 2,000,000		$ 2,000,000
3.20% Medium-Term Notes due January 2030
Derivatives
Medium-term notes					$ 100,000	$ 300,000	$ 300,000
Designated as Hedging Instrument | Interest rate swaps
Derivatives
Number of Interest Rate Derivatives Held | instrument	4		4
Notional	$ 315,000		$ 315,000
Designated as Hedging Instrument | Interest rate swaps subsequently terminated and settled
Derivatives
Number of Interest Rate Derivatives Held | instrument								2
Notional								$ 75,000
Not Designated as Hedging Instrument | Interest rate caps
Derivatives
Number of Interest Rate Derivatives Held | instrument	1		1
Notional	$ 19,880		$ 19,880

DERIVATIVES AND HEDGING ACTIV_4

DERIVATIVES AND HEDGING ACTIVITY - Undesignated Interest Rate Derivatives (Details) - Interest rate contracts - Designated as Hedging Instrument - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Other assets
Fair value of Company's derivative financial instruments and their classification on Consolidated Balance Sheet
Derivative Asset Designated as Hedging Instrument, Fair Value	$ 730	$ 4,757
Other liabilities
Fair value of Company's derivative financial instruments and their classification on Consolidated Balance Sheet
Derivative Liability Designated as Hedging Instrument, Fair Value	$ 469	$ 356

DERIVATIVES AND HEDGING ACTIV_5

DERIVATIVES AND HEDGING ACTIVITY - Fair Value (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Effect of derivative instruments on the Consolidated Statements of Operations
Unrealized holding gain/(loss)	$ (659)	$ 2,320	$ (7,181)	$ 4,312
Interest rate contracts | Interest expense | Cash Flow Hedging
Effect of derivative instruments on the Consolidated Statements of Operations
Unrealized holding gain/(loss)	(659)	2,320	(7,181)	4,312
Gain/(Loss) reclassified from Accumulated OCI in Interest Expense	624	564	2,504	1,162
Interest rate contracts | Other income/(expense)
Effect of derivative instruments on the Consolidated Statements of Operations
Gain/(Loss) recognized in Interest Income and Other Income/(Expense), net	$ 0	$ 0	$ 0	$ 0

DERIVATIVES AND HEDGING ACTIV_6

DERIVATIVES AND HEDGING ACTIVITY - Effectiveness (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Derivatives and hedging activity
Estimated additional accumulated other comprehensive Income/(Loss) transferred to interest expense	$ 9,800		$ 9,800
Total amount of Interest expense presented on the Consolidated Statements of Operations	42,523	$ 34,401	110,482	$ 95,942
Payment required to pay for contract termination	500		500
Interest rate swaps | Designated as Hedging Instrument
Fair value
Notional	$ 315,000		$ 315,000

DERIVATIVES AND HEDGING ACTIV_7

DERIVATIVES AND HEDGING ACTIVITY - Offsetting Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Offsetting derivative assets
Net Amounts of Assets Presented in the Consolidated Balance Sheets (a)	$ 730	$ 4,757
Gross Amounts Not Offset in the Consolidated Balance Sheets, Financial Instruments	(371)
Net Amount	359	4,757
Offsetting derivative liabilities
Gross Amounts of Recognized Liabilities	469	356
Net Amounts of Liabilities Presented in the Consolidated Balance Sheets (b)	469	356
Gross Amounts Not Offset in the Consolidated Balance Sheets, Financial Instruments	(371)
Net Amount	$ 98	$ 356

STOCK BASED COMPENSATION (Detai

STOCK BASED COMPENSATION (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Stock based compensation
Stock based compensation expense	$ 4.5	$ 3.6	$ 13	$ 10.7

COMMITMENTS AND CONTINGENCIES_2

COMMITMENTS AND CONTINGENCIES (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2019USD ($)community	Sep. 30, 2018USD ($)
Real estate properties
Development costs and capital expenditures incurred but not yet paid	$ 12,174	$ 23,437
Number of communities owned (in communities) | community	138
Costs Incurred to Date	$ 114,536
UDR's Remaining Commitment	157,459
King of Prussia
Real estate properties
Contractual purchase price commitment	14,800
Deposit on purchase	$ 800
Wholly owned - under development
Real estate properties
Number of communities owned (in communities) | community	1
Costs Incurred to Date	$ 21,845
UDR's Remaining Commitment	$ 75,655
Wholly owned - redevelopment
Real estate properties
Number of communities owned (in communities) | community	2
Costs Incurred to Date	$ 11,582
UDR's Remaining Commitment	$ 23,918
Unconsolidated joint ventures -development
Real estate properties
Number of communities owned (in communities) | community	1
Costs Incurred to Date	$ 14,402
UDR's Remaining Commitment	$ 21,496
Preferred Equity Investments
Real estate properties
Number of communities owned (in communities) | community	2
Costs Incurred to Date	$ 53,781
UDR's Remaining Commitment	27,390
Other investments
Real estate properties
Costs Incurred to Date	12,926
UDR's Remaining Commitment	$ 9,000

REPORTABLE SEGMENTS (Details)

REPORTABLE SEGMENTS (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019USD ($)item	Sep. 30, 2018USD ($)item	Sep. 30, 2019USD ($)	Sep. 30, 2019USD ($)segment	Sep. 30, 2019USD ($)item	Sep. 30, 2019USD ($)home	Sep. 30, 2019USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)item	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Segments
Same store communities	38,177	38,177			37,959	38,177			37,959
Reportable Segments
Number of reportable segments | segment				2
Condition for Community considered to have stabilized occupancy			90%
Time to maintain percent occupancy to be considered a community			3 months
Practical expedient, single lease component			true
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Rental income	$ 289,008	$ 263,256						$ 835,393	$ 770,373
Reconciling items:
Joint venture management and other fees	$ 6,386	$ 2,888						11,982	$ 8,819
Type of revenue	udr:ManagementAndOtherFeesMember	udr:ManagementAndOtherFeesMember	udr:ManagementAndOtherFeesMember						udr:ManagementAndOtherFeesMember
Property management	$ (8,309)	$ (7,240)						(24,018)	$ (21,185)
Other operating expenses	(2,751)	(3,314)						(11,132)	(8,148)
Real estate depreciation and amortization	(127,391)	(107,881)						(357,793)	(322,537)
General and administrative	(12,197)	(11,896)						(37,002)	(36,028)
Casualty-related (charges)/recoveries, net	1,088	(678)						842	(2,364)
Other depreciation and amortization	(1,619)	(1,682)						(4,953)	(5,057)
Gain/(loss) on sale of real estate owned								5,282	70,300
Income/(loss) from unconsolidated entities	12,713	(1,382)						19,387	(5,091)
Interest expense	(42,523)	(34,401)						(110,482)	(95,942)
Interest and other income/(expense), net	1,875	1,188						12,998	5,075
Tax (provision)/benefit, net	(1,499)	(158)						(3,836)	(618)
Net (income)/loss attributable to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership	(2,162)	(1,616)						(6,871)	(10,819)
Net (income)/loss attributable to noncontrolling interests	(56)	(32)						(145)	(141)
Net income/(loss) attributable to UDR, Inc.	27,204	18,610						87,326	120,967
Reportable apartment home segment assets:
Total segment assets	11,564,395		$ 11,564,395	$ 11,564,395	$ 11,564,395	$ 11,564,395	$ 11,564,395	11,564,395		$ 10,196,159
Accumulated depreciation	(4,000,608)		(4,000,608)	(4,000,608)	(4,000,608)	(4,000,608)	(4,000,608)	(4,000,608)		(3,654,160)
Total real estate owned, net of accumulated depreciation	7,563,787		7,563,787	7,563,787	7,563,787	7,563,787	7,563,787	7,563,787		6,541,999
Reconciling items:
Cash and cash equivalents	1,895	1,084	1,895	1,895	1,895	1,895	1,895	1,895	1,084	185,216	$ 2,038
Restricted cash	21,646	26,996	21,646	21,646	21,646	21,646	21,646	21,646	26,996	23,675	$ 19,792
Notes receivable, net	37,899		37,899	37,899	37,899	37,899	37,899	37,899		42,259
Investment in and advances to unconsolidated joint ventures, net	791,180		791,180	791,180	791,180	791,180	791,180	791,180		780,869
Operating lease right-of-use assets	135,889		135,889	135,889	135,889	135,889	135,889	135,889
Other assets	145,301		145,301	145,301	145,301	145,301	145,301	145,301		137,710
Total consolidated assets	8,697,597		8,697,597	8,697,597	8,697,597	8,697,597	8,697,597	8,697,597		7,711,728
Same Store Communities West Region
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Lease revenue	99,316	95,447						293,294	281,722
Other revenue	7,869	7,168						23,488	21,567
Rental income	107,185	102,615						316,782	303,289
Reportable apartment home segment NOI	81,170	77,321						240,442	229,129
Reportable apartment home segment assets:
Total segment assets	3,797,149		3,797,149	3,797,149	3,797,149	3,797,149	3,797,149	3,797,149		3,763,366
Same Store Communities Mid-Atlantic Region
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Lease revenue	52,826	51,291						157,179	152,867
Other revenue	4,376	4,032						12,958	11,944
Rental income	57,202	55,323						170,137	164,811
Reportable apartment home segment NOI	39,850	38,220						119,075	114,465
Reportable apartment home segment assets:
Total segment assets	2,338,963		2,338,963	2,338,963	2,338,963	2,338,963	2,338,963	2,338,963		2,317,369
Same Store Communities Southeast Region
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Lease revenue	28,540	27,773						84,551	81,554
Other revenue	3,438	3,211						10,423	9,918
Rental income	31,978	30,984						94,974	91,472
Reportable apartment home segment NOI	22,133	21,597						66,301	63,806
Reportable apartment home segment assets:
Total segment assets	799,739		799,739	799,739	799,739	799,739	799,739	799,739		779,310
Same Store Communities Northeast Region
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Lease revenue	30,196	29,491						89,650	87,776
Other revenue	1,321	1,226						3,753	3,422
Rental income	31,517	30,717						93,403	91,198
Reportable apartment home segment NOI	20,560	20,640						63,012	62,710
Reportable apartment home segment assets:
Total segment assets	1,498,500		1,498,500	1,498,500	1,498,500	1,498,500	1,498,500	1,498,500		1,491,994
Same Store Communities Southwest Region
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Lease revenue	15,451	15,060						40,705	39,586
Other revenue	1,527	1,525						4,100	3,986
Rental income	16,978	16,585						44,805	43,572
Reportable apartment home segment NOI	10,449	9,899						26,995	25,760
Reportable apartment home segment assets:
Total segment assets	595,982		595,982	595,982	595,982	595,982	595,982	595,982		589,188
Non-Mature communities/Other
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Lease revenue	40,975	24,237						106,499	66,906
Other revenue	3,173	2,795						8,793	9,125
Rental income	44,148	27,032						115,292	76,031
Reportable apartment home segment NOI	29,487	17,137						77,242	48,833
Reportable apartment home segment assets:
Total segment assets	2,534,062		$ 2,534,062	$ 2,534,062	$ 2,534,062	$ 2,534,062	$ 2,534,062	2,534,062		$ 1,254,932
Total Communities
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Lease revenue	267,304	243,299						771,878	710,411
Other revenue	21,704	19,957						63,515	59,962
Rental income	289,008	263,256						835,393	770,373
Reportable apartment home segment NOI	$ 203,649	$ 184,814						$ 593,067	$ 544,703
Taxable REIT Subsidiaries
Reportable Segments
Management fee (as a percent)							2.875%

CONSOLIDATED BALANCE SHEETS (UN

CONSOLIDATED BALANCE SHEETS (UNITED DOMINION REALTY, L.P.) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Real estate owned:
Real estate held for investment	$ 11,542,550	$ 10,196,159
Less: accumulated depreciation	(4,000,608)	(3,654,160)
Total real estate owned, net of accumulated depreciation	7,563,787	6,541,999
Cash and cash equivalents	1,895	185,216
Restricted cash	21,646	23,675
Investment in unconsolidated entities	791,180	780,869
Operating lease right-of-use assets	135,889
Other assets	145,301	137,710
Total assets	8,697,597	7,711,728
LIABILITIES AND CAPITAL
Secured debt, net	600,624	601,227
Operating lease liabilities	130,135
Real estate taxes payable	42,031	20,608
Accrued interest payable	27,577	38,747
Security deposits and prepaid rent	36,382	35,060
Distributions payable	108,939	97,666
Accounts payable, accrued expenses, and other liabilities	72,680	76,343
Total liabilities	4,353,641	3,816,211
Commitments and contingencies (Note 11)
Partners' capital:
Total liabilities and equity	8,697,597	7,711,728
United Dominion Realty L.P.
Real estate owned:
Real estate held for investment	3,861,754	3,811,985
Less: accumulated depreciation	(1,762,168)	(1,658,161)
Total real estate owned, net of accumulated depreciation	2,099,586	2,153,824
Cash and cash equivalents	40	125
Restricted cash	14,637	13,563
Investment in unconsolidated entities	82,269	103,026
Operating lease right-of-use assets	135,766
Other assets	23,321	34,052
Total assets	2,355,619	2,304,590
LIABILITIES AND CAPITAL
Secured debt, net	99,064	26,929
Notes payable due to the General Partner	623,967	700,115
Operating lease liabilities	130,013
Real estate taxes payable	11,747	2,699
Accrued interest payable	213	32
Security deposits and prepaid rent	14,878	15,250
Distributions payable	63,367	59,461
Accounts payable, accrued expenses, and other liabilities	12,153	14,215
Total liabilities	955,402	818,701
Commitments and contingencies (Note 11)
Partners' capital:
General partner: 110,883 OP Units outstanding at September 30, 2019 and December 31, 2018	883	950
Limited partners: 183,952,659 and 183,525,660 OP Units outstanding at September 30, 2019 and December 31, 2018, respectively	1,381,446	1,471,120
Total partners' capital	1,382,329	1,472,070
Noncontrolling interests	17,888	13,819
Total capital	1,400,217	1,485,889
Total liabilities and equity	$ 2,355,619	$ 2,304,590

CONSOLIDATED BALANCE SHEETS (_2

CONSOLIDATED BALANCE SHEETS (UNITED DOMINION REALTY, L.P.) (Parenthetical) - shares	Sep. 30, 2019	Dec. 31, 2018
Partners' capital:
Operating Partnership units outstanding related to limited partner	184,063,542	183,636,543
United Dominion Realty L.P.
Partners' capital:
OP units outstanding related to general partner	110,883	110,883
Operating Partnership units outstanding related to limited partner	183,952,659	183,525,660

CONSOLIDATED STATEMENTS OF OP_2

CONSOLIDATED STATEMENTS OF OPERATIONS (UNITED DOMINION REALTY, L.P.) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
REVENUES:
Rental income	$ 289,008	$ 263,256	$ 835,393	$ 770,373
OPERATING EXPENSES:
Property operating and maintenance	46,869	44,090	131,702	126,129
Real estate taxes and insurance	38,490	34,352	110,624	99,541
Property management	8,309	7,240	24,018	21,185
Other operating expenses	2,751	3,314	11,132	8,148
Real estate depreciation and amortization	127,391	107,881	357,793	322,537
General and administrative	12,197	11,896	37,002	36,028
Casualty-related charges/(recoveries), net	(1,088)	678	(842)	2,364
Total operating expenses	236,538	211,133	676,382	620,989
Gain/(loss) on sale of real estate owned			5,282	70,300
Operating income	58,856	55,011	176,275	228,503
Income/(loss) from unconsolidated entities	12,713	(1,382)	19,387	(5,091)
Interest expense	(42,523)	(34,401)	(110,482)	(95,942)
Net income/(loss)	29,422	20,258	94,342	131,927
United Dominion Realty L.P.
REVENUES:
Rental income	111,700	109,539	330,384	323,397
OPERATING EXPENSES:
Property operating and maintenance	17,835	17,412	50,945	50,535
Real estate taxes and insurance	13,033	11,979	37,788	34,890
Property management	3,211	3,012	9,498	8,893
Other operating expenses	2,301	2,347	7,123	6,098
Real estate depreciation and amortization	35,155	35,043	104,730	108,906
General and administrative	4,066	4,143	12,878	12,997
Casualty-related charges/(recoveries), net	(1,088)	(10)	(1,169)	906
Total operating expenses	74,513	73,926	221,793	223,225
Gain/(loss) on sale of real estate owned				70,300
Operating income	37,187	35,613	108,591	170,472
Income/(loss) from unconsolidated entities	(2,383)	(2,378)	(6,917)	(10,102)
Interest expense	(538)	(2,047)	(889)	(6,050)
Interest expense on notes payable due to the General Partner	(6,983)	(3,053)	(21,358)	(9,159)
Net income/(loss)	27,283	28,135	79,427	145,161
Net (income)/loss attributable to noncontrolling interests	(448)	(440)	(1,252)	(1,278)
Net income/(loss) attributable to OP unitholders	$ 26,835	$ 27,695	$ 78,175	$ 143,883
Income/(loss) per OP unit- basic and diluted:
Net income/(loss) per weighted average OP Unit - basic and diluted	$ 0.15	$ 0.15	$ 0.42	$ 0.78
Weighted average OP Units outstanding - basic and diluted	184,064	183,637	184,024	183,599

CONSOLIDATED STATEMENTS OF CH_3

CONSOLIDATED STATEMENTS OF CHANGES IN CAPITAL (UNITED DOMINION REALTY, L.P.) (Unaudited). - United Dominion Realty L.P. - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Beginning Balance	$ 1,429,738	$ 1,784,720	$ 1,485,889	$ 1,875,130
Net income/(loss)	27,283	28,135	79,427	145,161
Distributions	(63,367)	(59,460)	(189,896)	(178,365)
Long Term Incentive Plan Unit grants	6,563	2,932	21,980	12,964
Net contributions/(distributions) to/(from) noncontrolling interests			2,817
Net change in advances (to)/from the General Partner		(4,882)		(103,445)
Ending Balance	1,400,217	1,751,445	1,400,217	1,751,445
Advances (to)/from General Partner
Beginning Balance		299,336		397,899
Net change in advances (to)/from the General Partner		(4,882)		(103,445)
Ending Balance		294,454		294,454
Total Partner's Capital
Beginning Balance	1,412,298	1,471,610	1,472,070	1,464,295
Net income/(loss)	26,835	27,695	78,175	143,883
Distributions	(63,367)	(59,460)	(189,896)	(178,365)
Long Term Incentive Plan Unit grants	6,563	2,932	21,980	12,964
Ending Balance	1,382,329	1,442,777	1,382,329	1,442,777
Noncontrolling Interests
Beginning Balance	17,440	13,774	13,819	12,936
Net income/(loss)	448	440	1,252	1,278
Net contributions/(distributions) to/(from) noncontrolling interests			2,817
Ending Balance	17,888	14,214	17,888	14,214
Class A Limited Partner
Beginning Balance	78,633	65,758	69,401	67,474
Net income/(loss)	255	264	743	1,387
Distributions	(599)	(582)	(1,797)	(1,746)
Adjustment to reflect limited partners' capital at redemption value	6,632	5,380	16,574	3,705
Ending Balance	84,921	70,820	84,921	70,820
Limited Partners and LTIP Units
Beginning Balance	273,910	286,662	302,545	283,568
Net income/(loss)	890	1,151	2,610	6,195
Distributions	(2,416)	(2,683)	(7,095)	(8,035)
OP Unit redemptions for common shares of UDR			(78,622)	(416)
Adjustment to reflect limited partners' capital at redemption value	16,868	20,669	54,397	14,455
Long Term Incentive Plan Unit grants	6,563	2,932	21,980	12,964
Ending Balance	295,815	308,731	295,815	308,731
Limited Partner
Beginning Balance	1,058,850	1,118,237	1,099,174	1,112,298
Net income/(loss)	25,674	26,263	74,775	136,214
Distributions	(60,314)	(56,159)	(180,890)	(168,476)
OP Unit redemptions for common shares of UDR			78,622	416
Adjustment to reflect limited partners' capital at redemption value	(23,500)	(26,049)	(70,971)	(18,160)
Ending Balance	1,000,710	1,062,292	1,000,710	1,062,292
General Partner
Beginning Balance	905	953	950	955
Net income/(loss)	16	17	47	87
Distributions	(38)	(36)	(114)	(108)
Ending Balance	$ 883	$ 934	$ 883	$ 934

CONSOLIDATED STATEMENTS OF CA_4

CONSOLIDATED STATEMENTS OF CASH FLOWS (UNITED DOMINION REALTY, L.P.) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Operating Activities
Net income/(loss)	$ 94,342	$ 131,927
Adjustments to reconcile net income/(loss) to net cash provided by/(used in) operating activities:
Depreciation and amortization	362,746	327,594
(Gain)/loss on sale of real estate owned	(5,282)	(70,300)
(Income)/loss from unconsolidated entities	(19,387)	5,091
Other	14,098	2,108
Changes in operating assets and liabilities:
(Increase)/decrease in operating assets	49	(13,199)
Increase/(decrease) in operating liabilities	(6,814)	9,961
Net cash provided by/(used in) operating activities	456,876	406,724
Investing Activities
Proceeds from sales of real estate investments, net	38,000	89,433
Capital expenditures and other major improvements - real estate assets	(113,572)	(76,381)
Distributions received from unconsolidated entities	61,412	30,574
Net cash provided by/(used in) investing activities	(1,382,802)	(203,106)
Financing Activities
Proceeds from the issuance of secured debt	162,500	80,000
Other	(4,039)	(36,317)
Net cash provided by/(used in) financing activities	740,576	(197,368)
Net increase/(decrease) in cash, cash equivalents, and restricted cash	(185,350)	6,250
Cash, cash equivalents, and restricted cash, beginning of year	208,891	21,830
Cash, cash equivalents, and restricted cash, end of period	23,541	28,080
Supplemental Information:
Interest paid during the period, net of amounts capitalized	125,298	104,136
Non-cash transactions:
Development costs and capital expenditures incurred but not yet paid	12,174	23,437
Recognition of operating lease right-of-use assets	94,349
Recognition of operating lease liabilities	88,336
Right-of-use asset obtained in exhange for operating lease liability remeasurement	42,143
Dividends declared but not yet paid	108,939	95,372
United Dominion Realty L.P.
Operating Activities
Net income/(loss)	79,427	145,161
Adjustments to reconcile net income/(loss) to net cash provided by/(used in) operating activities:
Depreciation and amortization	104,730	108,906
(Gain)/loss on sale of real estate owned		(70,300)
(Income)/loss from unconsolidated entities	6,917	10,102
Other	843	850
Changes in operating assets and liabilities:
(Increase)/decrease in operating assets	2,801	(2,968)
Increase/(decrease) in operating liabilities	3,156	4,747
Net cash provided by/(used in) operating activities	197,874	196,498
Investing Activities
Proceeds from sales of real estate investments, net		89,433
Capital expenditures and other major improvements - real estate assets	(45,508)	(31,828)
Distributions received from unconsolidated entities	13,840	13,033
Net cash provided by/(used in) investing activities	(31,668)	70,638
Financing Activities
Advances (to)/from the General Partner, net		(256,972)
Proceeds from the issuance of secured debt	72,500
Issuance/(repayment) of notes payable to the General Partner	(231,011)
Distributions paid to partnership unitholders	(6,330)	(9,438)
Other	(376)
Net cash provided by/(used in) financing activities	(165,217)	(266,410)
Net increase/(decrease) in cash, cash equivalents, and restricted cash	989	726
Cash, cash equivalents, and restricted cash, beginning of year	13,688	12,872
Cash, cash equivalents, and restricted cash, end of period	14,677	13,598
Supplemental Information:
Interest paid during the period, net of amounts capitalized	28,755	20,139
Non-cash transactions:
Development costs and capital expenditures incurred but not yet paid	4,520	3,472
Recognition of operating lease right-of-use assets	94,174
Recognition of operating lease liabilities	88,161
Right-of-use asset obtained in exhange for operating lease liability remeasurement	42,143
LTIP Unit grants	21,980	12,964
Dividends declared but not yet paid	$ 63,367	$ 59,461

CONSOLIDATED STATEMENTS OF CA_5

CONSOLIDATED STATEMENTS OF CASH FLOWS - SUPPLEMENTAL (UNITED DOMINION REALTY, L.P.) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017
The following reconciles cash, cash equivalents, and restricted cash to the total of the same amounts as shown above:
Cash and cash equivalents	$ 1,895	$ 185,216	$ 1,084	$ 2,038
Restricted cash	21,646	23,675	26,996	19,792
Total cash, cash equivalents, and restricted cash as shown above	23,541	208,891	28,080	21,830
United Dominion Realty L.P.
The following reconciles cash, cash equivalents, and restricted cash to the total of the same amounts as shown above:
Cash and cash equivalents	40	125	83	293
Restricted cash	14,637	13,563	13,515	12,579
Total cash, cash equivalents, and restricted cash as shown above	$ 14,677	$ 13,688	$ 13,598	$ 12,872

CONSOLIDATION AND BASIS OF PRES

CONSOLIDATION AND BASIS OF PRESENTATION (UNITED DOMINION REALTY, L.P.)	9 Months Ended
	Sep. 30, 2019
Entity information
BASIS OF PRESENTATION	1. 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 September 30, 2019, there were 184,063,542 units in the Operating Partnership (“OP Units”) outstanding, of which 176,210,072 OP Units, or 95.7%, were owned by UDR and 7,853,470 OP Units, or 4.3%, were owned by outside limited partners. As of September 30, 2019, there were 32,367,380 units in the DownREIT Partnership (“DownREIT Units”) outstanding, of which 18,104,895, or 55.9%, were owned by UDR (including 13,470,651 DownREIT Units, or 41.6%, that were held by the Operating Partnership) and 14,262,485, or 44.1%, 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 September 30, 2019, and results of operations for the three and nine months ended September 30, 2019 and 2018, 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, 2018 appearing in UDR’s Annual Report on Form 10-K, filed with the Securities and Exchange Commission on February 19, 2019. 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 other than those noted in Note 7, Secured and Unsecured Debt, Net Commitments and Contingencies
United Dominion Realty L.P.
Entity information
BASIS OF PRESENTATION	1. 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 September 30, 2019 and 2018, rental revenues of the Operating Partnership represented 39% and 42%, respectively, and for the nine months ended September 30, 2019 and 2018, 40% and 42%, respectively, of the General Partner’s consolidated rental revenues. As of September 30, 2019, the Operating Partnership’s apartment portfolio consisted of 52 communities located in 15 markets consisting of 16,434 apartment homes. Interests in UDR, L.P. are represented by operating partnership units (“OP Units”). The Operating Partnership’s net income is allocated to the partners, which is initially based on their respective distributions made during the year and secondly, their percentage interests. Distributions are made in accordance with the terms of the Amended and Restated Agreement of Limited Partnership of United Dominion Realty, L.P. (the “Operating Partnership Agreement”), on a per unit basis that is generally equal to the dividend per share on UDR’s common stock, which is publicly traded on the New York Stock Exchange (“NYSE”) under the ticker symbol “UDR.” As of September 30, 2019, there were 184,063,542 OP Units outstanding, of which 176,210,072, or 95.7%, were owned by UDR and affiliated entities and 7,853,470, or 4.3%, were owned by non-affiliated limited partners. There were 183,636,543 OP Units outstanding as of December 31, 2018, of which 174,248,699, or 94.9%, were owned by UDR and affiliated entities and 9,387,844, or 5.1%, were owned by non-affiliated limited partners. See Note 10, Capital Structure The accompanying interim unaudited consolidated financial statements have been prepared according to the rules and regulations of the Securities and Exchange Commission (“SEC”). Certain information and note disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States have been condensed or omitted according to such rules and regulations, although management believes that the disclosures are adequate to make the information presented not misleading. In the opinion of management, all adjustments and eliminations necessary for the fair presentation of our financial position as of September 30, 2019, and results of operations for the three and nine months ended September 30, 2019 and 2018, 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, 2018 included in the Annual Report on Form 10-K filed by UDR and the Operating Partnership with the SEC on February 19, 2019. 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 significant recognized or non-recognized subsequent events were noted other than those noted in Note 6, Debt, Net.

SIGNIFICANT ACCOUNTING POLICI_5

SIGNIFICANT ACCOUNTING POLICIES (UNITED DOMINION REALTY, L.P.)	9 Months Ended
	Sep. 30, 2019
Entity information
SIGNIFICANT ACCOUNTING POLICIES	2. 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 Codification Improvements to Topic 326, Financial Instruments—Credit Losses, ​ In February 2016, the FASB issued ASU 2016-02, Leases ​ The Company elected the following package of practical expedients provided by the standard: (i) an entity need not reassess whether any expired or existing contract is a lease or contains a lease, (ii) an entity need not reassess the lease classification of any expired or existing leases, and (iii) an entity need not reassess initial direct costs for any existing leases. The Company also elected the short-term lease exception provided for in the standard and therefore only recognizes right-of-use assets and lease liabilities for leases with a term greater than one year. ​ The Company recognized right-of-use assets of $94.3 million and lease liabilities of $88.3 million as of January 1, 2019 upon adoption of the standard. The right-of-use assets included $6.0 million of prepaid rent and intangible assets that was included within Other assets ​ The lease liabilities represent the present value of the remaining minimum lease payments as of January 1, 2019 and primarily relate to ground leases for communities where we are the lessee. The right-of-use assets represent our right to use an underlying asset for the lease term, which are calculated utilizing the lease liabilities plus any prepaid lease payments and intangible assets for ground leases acquired in the purchase of real estate. Our right-of-use assets and related lease liabilities recognized as of January 1, 2019 may change as a result of updates to the projected future minimum lease payments. Certain of our ground lease agreements where we are the lessee have future minimum lease payments that reset in the future based upon a percentage of the fair market value of the land at the time of the reset. The Company will continue to recognize lease expense for these leases in a manner similar to previous accounting based on our election of the package of practical expedients. However, in the event we modify existing ground leases and/or enter into new ground leases subsequent to the adoption of the standard, such leases would likely be classified as finance leases under the standard and require expense recognition based on the effective interest method. Under the standard, initial direct costs for both lessees and lessors would include only those costs that are incremental to the arrangement and would not have been incurred if the lease had not been obtained. As a result, subsequent to the adoption of the standard, we are now expensing non-incremental leasing costs as incurred. ​ In July 2018, the FASB issued ASU 2018-11, Leases – Targeted Improvements Leases ​ Principles of Consolidation The Company accounts for subsidiary partnerships, joint ventures and other similar entities in which it holds an ownership interest in accordance with the consolidation guidance. The Company first evaluates whether each entity is a variable interest entity (“VIE”). Under the VIE model, the Company consolidates an entity when it has control to direct the activities of the VIE and the obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE. Under the voting model, the Company consolidates an entity when it controls the entity through ownership of a majority voting interest. Real Estate Sales Gain Recognition ​ For sale transactions resulting in a transfer of a controlling financial interest of a property, the Company generally derecognizes the related assets and liabilities from its Consolidated Balance Sheets and records the gain or loss in the period in which the transfer of control occurs. If control of the property has not transferred to the counterparty, the criteria for derecognition are not met and the Company will continue to recognize the related assets and liabilities on its Consolidated Balance Sheets. ​ Sale transactions to entities in which the Company sells a controlling financial interest in a property but retains a noncontrolling interest are accounted for as partial sales. Partial sales resulting in a change in control are accounted for at fair value and a full gain or loss is recognized. Therefore, the Company will record a gain or loss on the partial interest sold, and the initial measurement of our retained interest will be accounted for at fair value. ​ Sales of real estate to joint ventures or other noncontrolled investees are also accounted for at fair value and the Company will record a full gain or loss in the period the property is contributed. ​ To the extent that the Company acquires a controlling financial interest in a property that it previously accounted for as an equity method investment, the Company will not remeasure its previously held interest if the acquisition is treated as an asset acquisition. The Company will include the carrying amount of its previously held equity method interest along with the consideration paid and transaction costs incurred in determining the amounts to allocate to the related assets and liabilities acquired on its Consolidated Balance Sheets. When treated as an asset acquisition, the Company will not recognize a gain or loss on consolidation of a property. ​ Notes Receivable The following table summarizes our Notes receivable, net dollars in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate at ​ Balance Outstanding ​ September 30, September 30, December 31, ​ ​ 2019 ​ 2019 ​ 2018 Note due December 2019 (a) 12.00 % $ 20,000 ​ $ 20,000 Note due February 2020 (b) 10.00 % 15,649 ​ 14,659 Note due October 2020 (c) 8.00 % 2,250 ​ 2,000 Note due August 2022 (d) ​ 10.00 % ​ — ​ ​ 5,600 Total notes receivable, net ​ $ 37,899 ​ $ 42,259 (a) In March 2018, the Company entered into a secured note with an unaffiliated third party with an aggregate commitment of $20.0 million, of which $20.0 million has been funded. Interest payments are due when the loan matures. In March 2019, the note’s maturity was extended to December 27, 2019, and the note is secured by a parcel of land. (b) The Company has a secured note with an unaffiliated third party with an aggregate commitment of $16.4 million, of which $15.6 million has been funded, including $1.0 million funded during the nine months ended September 30, 2019. 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). (c) The Company has a secured note with an unaffiliated third party with an aggregate commitment of $2.3 million, of which $2.3 million has been funded, including $0.3 million funded during the nine months ended September 30, 2019. 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 January 2019, the $5.6 million secured note was repaid in full along with the contractually accrued interest of $0.2 million and an additional $8.5 million of promoted interest in conjunction with the unaffiliated third party being acquired. The Company recognized $1.2 million and $1.2 million of interest income from notes receivable during the three months ended September 30, 2019 and 2018, respectively, and $3.5 million and $2.9 million of interest income and $8.5 million and zero of promoted interest from notes receivable during the nine months ended September 30, 2019 and 2018, respectively, none of which was related party interest. Interest income and promoted interest are included in Interest income and other income/(expense), net Comprehensive Income/(Loss) Comprehensive income/(loss), which is defined as the change in equity during each period from transactions and other events and circumstances from nonowner sources, including all changes in equity during a period except for those resulting from investments by or distributions to stockholders, is displayed in the accompanying Consolidated Statements of Comprehensive Income/(Loss). For the three and nine months ended September 30, 2019 and 2018, the Company’s other comprehensive income/(loss) consisted of the gain/(loss) 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 Derivatives and Hedging Activity, Income Taxes Due to the structure of the Company as a REIT and the nature of the operations for the operating properties, no provision for federal income taxes has been provided for at UDR. Historically, the Company has generally incurred only state and local excise and franchise taxes. UDR has elected for certain consolidated subsidiaries to be treated as taxable REIT subsidiaries (“TRS”). Income taxes for our TRS are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities from a change in tax rate is recognized in earnings in the period of the enactment date. The Company’s deferred tax assets are generally the result of differing depreciable lives on capitalized assets and timing of expense recognition for certain accrued liabilities. As of September 30, 2019 and December 31, 2018, UDR’s net deferred tax asset/(liability) was $(1.3) million and less than $(0.1) million, respectively. GAAP defines a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. GAAP also provides guidance on derecognition, classification, interest and penalties, accounting for interim periods, disclosure and transition. The Company recognizes its tax positions and evaluates them using a two-step process. First, UDR determines whether a tax position is more likely than not (greater than 50 percent probability) to be sustained upon examination, including resolution of any related appeals or litigation processes, based on the technical merits of the position. Second, the Company will determine the amount of benefit to recognize and record the amount that is more likely than not to be realized upon ultimate settlement. UDR had no material unrecognized tax benefit, accrued interest or penalties at September 30, 2019. UDR and its subsidiaries are subject to federal income tax as well as income tax of various state and local jurisdictions. The tax years 2016 through 2018 remain open to examination by tax jurisdictions to which we are subject. When applicable, UDR recognizes interest and/or penalties related to uncertain tax positions in Tax (provision)/benefit, net ​ Forward Sales Agreements ​ The Company utilizes forward sales agreements for the future issuance of its common stock. When the Company enters into a forward sales agreement, the contract requires the Company to sell its shares to a counterparty at a predetermined price at a future date. The net sales price and proceeds attained by the Company will be determined on the dates of settlement, with adjustments during the term of the contract for the Company’s anticipated dividends as well as for a daily interest factor that varies with changes in the federal funds rate. The Company generally has the ability to determine the dates and method of settlement (i.e., gross physical settlement, net share settlement or cash settlement), subject to certain conditions and the right of the counterparty to accelerate settlement under certain circumstances. ​ The Company accounts for the shares of common stock reserved for issuance upon settlement as equity in accordance with ASC 815-40, Contracts in Entity's Own Equity ​ The guidance establishes a two-step process for evaluating whether an equity-linked financial instrument is considered indexed to its own stock by evaluating the instrument’s contingent exercise provisions and settlement provisions. We determined that (i) none of the agreements’ exercise contingencies were based on observable markets or indices besides those related to the market for our own stock price and operations; and (ii) none of the settlement provisions precluded the agreements from being indexed to our own stock. ​ Based upon our determination that the forward sales agreements are considered indexed to our own stock as well as the agreements permitting us to share settle, we have determined that the forward sales agreements qualify for equity classification. ​ Before the issuance of shares of common stock, upon physical or net share settlement of the forward sales agreements, the Company expects that the shares issuable upon settlement of the forward sales agreements will be reflected in its diluted income/(loss) per share calculations using the treasury stock method. Under this method, the number of shares of common stock used in calculating diluted income/(loss) per share is deemed to be increased by the excess, if any, of the number of shares of common stock that would be issued upon full physical settlement of the forward sales agreements over the number of shares of common stock that could be purchased by the Company in the open market (based on the average market price during the period) using the proceeds receivable upon full physical settlement (based on the adjusted forward sale price at the end of the reporting period). When the Company physically or net share settles any forward sales agreement, the delivery of shares of common stock would result in an increase in the number of weighted average common shares outstanding and dilution to basic income/(loss) per share. (See Note 8, Income/(Loss) per Share ​
United Dominion Realty L.P.
Entity information
SIGNIFICANT ACCOUNTING POLICIES	2. 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 Codification Improvements to Topic 326, Financial Instruments—Credit Losses, I n February 2016, the FASB issued ASU 2016-02, Leases . The standard amended the existing lease accounting guidance and required lessees to recognize a lease liability and a right-of-use asset for all leases on their balance sheets. Lessees of operating leases continued to recognize lease expense in a manner similar to previous accounting. For lessors, accounting for leases under the new guidance was substantially the same as in prior periods, but eliminated current real estate-specific provisions and changed the treatment of initial direct costs. The standard was effective for the Operating Partnership on January 1, 2019. ​ The Operating Partnership elected the following package of practical expedients provided by the standard: (i) an entity need not reassess whether any expired or existing contract is a lease or contains a lease, (ii) an entity need not reassess the lease classification of any expired or existing leases, and (iii) an entity need not reassess initial direct costs for any existing leases. The Operating Partnership also elected the short-term lease exception provided for in the standard and therefore only recognizes right-of-use assets and lease liabilities for leases with a term greater than one year. ​ The Operating Partnership recognized right-of-use assets of $94.2 million and lease liabilities of $88.2 million as of January 1, 2019 upon adoption of the standard. The right-of-use assets included $6.0 million of prepaid rent and intangible assets that was included within Other assets ​ The lease liabilities represent the present value of the remaining minimum lease payments as of January 1, 2019 related to ground leases for communities where we are the lessee. The right-of-use assets represent our right to use an underlying asset for the lease term, which are calculated utilizing the lease liabilities plus any prepaid lease payments and intangible assets for ground leases acquired in the purchase of real estate. Our right-of-use assets and related lease liabilities recognized as of January 1, 2019 may change as a result of updates to the projected future minimum lease payments. Certain of our ground lease agreements where we are the lessee have future minimum lease payments that reset in the future based upon a percentage of the fair market value of the land at the time of the reset. The Operating Partnership will continue to recognize lease expense for these leases in a manner similar to previous accounting based on our election of the package of practical expedients. However, in the event we modify existing ground leases and/or enter into new ground leases subsequent to the adoption of the standard, such leases would likely be classified as finance leases under the standard and require expense recognition based on the effective interest method. Under the standard, initial direct costs for both lessees and lessors would include only those costs that are incremental to the arrangement and would not have been incurred if the lease had not been obtained. As a result, subsequent to the adoption of the standard, we are now expensing non-incremental leasing costs as incurred. ​ In July 2018, the FASB issued ASU 2018-11, Leases – Targeted Improvements Leases option that permitted entities to not recast the comparative periods presented when transitioning to the standard, which the Operating Partnership also elected. ​ 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 consolidation guidance. The Operating Partnership first evaluates whether each entity is a variable interest entity (“VIE”). Under the VIE model, the Operating Partnership consolidates an entity when it has control to direct the activities of the VIE and the obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE. Under the voting model, the Operating Partnership consolidates an entity when it controls the entity through ownership of a majority voting interest. 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. Real Estate Sales Gain Recognition ​ For sale transactions resulting in a transfer of a controlling financial interest of a property, the Operating Partnership generally derecognizes the related assets and liabilities from its Consolidated Balance Sheets and records the gain or loss in the period in which the transfer of control occurs. If control of the property has not transferred to the counterparty, the criteria for derecognition are not met and the Operating Partnership will continue to recognize the related assets and liabilities on its Consolidated Balance Sheets. ​ Sale transactions to entities in which the Operating Partnership sells a controlling financial interest in a property but retains a noncontrolling interest are accounted for as partial sales. Partial sales resulting in a change in control are accounted for at fair value and a full gain or loss is recognized. Therefore, the Operating Partnership will record a gain or loss on the partial interest sold, and the initial measurement of our retained interest will be accounted for at fair value. ​ Sales of real estate to joint ventures or other noncontrolled investees are also accounted for at fair value and the Operating Partnership will record a full gain or loss in the period the property is contributed. ​ To the extent that the Operating Partnership acquires a controlling financial interest in a property that it previously accounted for as an equity method investment, the Operating Partnership will not remeasure its previously held interest if the acquisition is treated as an asset acquisition. The Operating Partnership will include the carrying amount of its previously held equity method interest along with the consideration paid and transaction costs incurred in determining the amounts to allocate to the related assets and liabilities acquired on its Consolidated Balance Sheets. When treated as an asset acquisition, the Operating Partnership will not recognize a gain or loss on consolidation of a property. ​ Comprehensive Income/(Loss) Comprehensive income/(loss), which is defined as the change in equity during each period from transactions and other events and circumstances from nonowner sources, including all changes in equity during a period except for those resulting from investments by or distributions to unitholders, is displayed in the accompanying Consolidated Statements of Comprehensive Income/(Loss). For the three and nine months ended September 30, 2019 and 2018, the Operating Partnership’s other comprehensive income/(loss) consisted of the gain/(loss) 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 Derivatives and Hedging Activity, 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 (2016 through 2018) 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 (UNITED DOMIN

REAL ESTATE OWNED (UNITED DOMINION REALTY, L.P.)	9 Months Ended
	Sep. 30, 2019
Entity information
REAL ESTATE OWNED	3. 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 held for disposition properties. As of September 30, 2019, the Company owned and consolidated 138 communities in 13 states plus the District of Columbia totaling 43,683 apartment homes. The following table summarizes the carrying amounts for our real estate owned (at cost) as of September 30, 2019 and December 31, 2018 (dollars in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2019 ​ 2018 Land ​ $ 2,020,617 ​ $ 1,849,799 Depreciable property — held and used: ​ ​ Land improvements ​ 220,654 ​ 213,224 Building, improvements, and furniture, fixtures and equipment ​ 9,260,709 ​ 8,133,136 Real estate intangible assets ​ ​ 40,570 ​ ​ — Under development: ​ ​ Land and land improvements ​ 13,853 ​ — Building, improvements, and furniture, fixtures and equipment ​ 7,992 ​ — Real estate owned ​ 11,564,395 ​ 10,196,159 Accumulated depreciation ​ (4,000,608) ​ (3,654,160) Real estate owned, net ​ $ 7,563,787 ​ $ 6,541,999 ​ Acquisitions In January 2019, the Company exercised its fixed-price option to purchase its joint venture partner’s ownership interest in a 386 apartment home operating community in Anaheim, California, thereby increasing its ownership interest from 49% to 100%, for a cash purchase price of approximately $33.5 million. In connection with the acquisition, the Company repaid approximately $59.8 million of joint venture construction financing. Joint Ventures and Partnerships In January 2019, the Company exercised its fixed-price option to purchase its joint venture partner’s ownership interest in a 155 apartment home operating community located in Seattle, Washington, thereby increasing its ownership interest from 49% to 100%, for a cash purchase price of approximately $20.0 million. In connection with the acquisition, the Company repaid approximately $26.0 million of joint venture construction financing. In January 2019, the Company acquired a to-be-developed parcel of land located in Washington D.C. for approximately $27.1 million. In February 2019, the Company acquired a to-be-developed parcel of land located in Denver, Colorado for approximately $13.7 million. In February 2019, the Company acquired a 188 apartment home operating community located in Brooklyn, New York for approximately $132.1 million. T In February 2019, the Company acquired a 381 apartment home operating community located in St. Petersburg, Florida for approximately $98.3 million . ​ In April 2019, the Company acquired a 498 apartment home operating community located in Towson, Maryland for approximately $86.4 million. ​ In May 2019, the Company acquired a 313 apartment home operating community located in King of Prussia, Pennsylvania for approximately $107.3 million. The Company increased its real estate assets owned by approximately $106.4 million and recorded approximately $0.9 million of in-place lease intangibles. ​ In May 2019, the Company acquired a 240 apartment home operating community located in St. Petersburg, Florida for approximately $49.4 million. The Company increased its real estate assets owned by approximately $48.2 million and recorded approximately $1.2 million of in-place lease intangibles. ​ In June 2019, the Company acquired a 200 apartment home operating community located in Waltham, Massachusetts for approximately $84.6 million. The Company increased its real estate assets owned by approximately $82.6 million and recorded approximately $2.0 million of in-place lease intangibles. ​ In August 2019, the Company acquired a 914 apartment home operating community located in Norwood, Massachusetts for approximately $270.2 million. The Company increased its real estate assets owned by approximately $260.1 million and recorded approximately $10.1 million of in-place lease intangibles. ​ In August 2019, the Company acquired a 185 apartment home operating community located in Englewood, New Jersey for approximately $83.6 million. The Company increased its real estate assets owned by approximately $77.5 million and recorded approximately $4.6 million of real estate intangibles and approximately $1.5 million of in-place lease intangibles. ​ In August 2019, the Company purchased a 292 apartment home operating community in Washington, D.C., directly from the UDR/KFH joint venture, thereby increasing its ownership interest from 30% to 100%, for a purchase price at 100% of approximately $184.0 million, before $2.8 million of closing costs incurred by UDR at acquisition (see Note 5, Joint Ventures and Partnerships ​ Subsequent to the acquisition, the Company received a distribution from the UDR/KFH joint venture of $22.9 million related to the 30% interest it previously held in the community following the payment of closing costs and repayment of the joint venture mortgage debt. As a result of the acquisition, in August 2019, the Company consolidated the operating community. The Company had previously accounted for its 30% ownership interest as an unconsolidated joint venture. The Company accounted for the consolidation as an asset acquisition resulting in no gain or loss upon consolidation and increased its real estate owned by approximately $156.0 million and recorded approximately $5.9 million of in-place lease intangibles. ​ In August 2019, the Company entered into an agreement with the Metropolitan Life Insurance Company (“MetLife”), its joint venture partner, to acquire the approximately 50% ownership interest not previously owned in 10 UDR/MetLife operating communities, one development community and four land parcels valued at $1.1 billion, or $557 million at UDR’s share. The transaction is expected to close during the fourth quarter of 2019, subject to customary closing conditions and closing price adjustments (see Note 5, Joint Ventures and Partnerships ​ Dispositions In June 2019, the Company sold a parcel of land located in Los Angeles, California for $38.0 million, resulting in a gain of approximately $5.3 million. Prior to the sale, the parcel of land was subject to a ground lease, under which UDR was the lessor, scheduled to expire in 2065. The ground lease included a purchase option for the lessee to acquire the land during specific periods of the ground lease term. During the second quarter, the lessee exercised the purchase option resulting in this sale by the Company and the ground lease being terminated. ​ Prior to the sale, the purchase option was not deemed to be a bargain purchase option. This ground lease existed as of the adoption of the new lease accounting guidance on January 1, 2019 and we did not reassess lease classification per the practical expedient provided by the standard. As a result, this ground lease continued to be classified as an operating lease and the land parcel subject to the ground lease continued to be recognized in Real estate held for investment ​ Other Activity 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 In connection with the acquisition of certain properties, the Company agreed to pay certain of the tax liabilities of certain contributors if the Company sells one or more of the properties contributed in a taxable transaction prior to the expiration of specified periods of time following the acquisition. The Company may, however, sell, without being required to pay any tax liabilities, any of such properties in a non-taxable transaction, including, but not limited to, a tax-deferred Section 1031 exchange. Further, the Company has agreed to maintain certain debt that may be guaranteed by certain contributors for specified periods of time following the acquisition. The Company, however, has the ability to refinance or repay guaranteed debt or to substitute new debt if the debt and the guaranty continue to satisfy certain conditions.
United Dominion Realty L.P.
Entity information
REAL ESTATE OWNED	3. REAL ESTATE OWNED Real estate assets owned by the Operating Partnership consist of income producing operating properties, properties under development, land held for future development, and sold or held for disposition properties. At September 30, 2019, the Operating Partnership owned and consolidated 52 communities in nine states plus the District of Columbia totaling 16,434 apartment homes. The following table summarizes the carrying amounts for our real estate owned (at cost) as of September 30, 2019 and December 31, 2018 (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2019 ​ 2018 Land ​ $ 711,256 ​ $ 711,256 Depreciable property — held and used: ​ ​ ​ ​ Land improvements ​ ​ 95,096 ​ ​ 92,000 Buildings, improvements, and furniture, fixtures and equipment ​ 3,055,402 ​ 3,008,729 Real estate owned ​ 3,861,754 ​ 3,811,985 Accumulated depreciation ​ (1,762,168) ​ (1,658,161) Real estate owned, net ​ $ 2,099,586 ​ $ 2,153,824 ​ Acquisitions The Operating Partnership did not have any acquisitions of real estate during the nine months ended September 30, 2019. Dispositions The Operating Partnership did not have any dispositions of real estate during the nine months ended September 30, 2019. Other Activity 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 In connection with the acquisition of certain properties, the Operating Partnership agreed to pay certain of the tax liabilities of certain contributors if the Operating Partnership sells one or more of the properties contributed in a taxable transaction prior to the expiration of specified periods of time following the acquisition. The Operating Partnership may, however, sell, without being required to pay any tax liabilities, any of such properties in a non-taxable transaction, including, but not limited to, a tax deferred Section 1031 exchange. Further, the Operating Partnership has agreed to maintain certain debt that may be guaranteed by certain contributors for specified periods of time following the acquisition. The Operating Partnership, however, has the ability to refinance or repay guaranteed debt or to substitute new debt if the debt and the guaranty continue to satisfy certain conditions.

UNCONSOLIDATED ENTITIES (UNITED

UNCONSOLIDATED ENTITIES (UNITED DOMINION REALTY, L.P.)	9 Months Ended
	Sep. 30, 2019
Unconsolidated entities
UNCONSOLIDATED ENTITIES	5. JOINT VENTURES AND PARTNERSHIPS UDR has entered into joint ventures and partnerships with unrelated third parties to own, operate, acquire, renovate, develop, redevelop, dispose of, and manage real estate assets that are either consolidated and included in Real estate owned Investment in and advances to unconsolidated joint ventures, net beneficiary. 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. 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 September 30, 2019 and December 31, 2018 (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number of ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number of ​ Apartment ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Properties ​ Homes ​ Investment at ​ ​ UDR’s Ownership Interest ​ ​ Location of September 30, September 30, September 30, December 31, ​ ​ September 30, ​ December 31, Joint Venture Properties 2019 2019 2019 2018 ​ ​ 2019 ​ 2018 Operating and development: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ UDR/MetLife I ​ Los Angeles, CA ​ 1 operating community ​ 150 ​ $ 29,599 ​ $ 30,839 ​ ​ 50.0 % ​ 50.0 % UDR/MetLife II (a) Various 18 operating communities 4,059 ​ 300,479 ​ 296,807 ​ ​ 50.0 % ​ 50.0 % Other UDR/MetLife Various 5 operating communities 1,437 ​ 102,435 ​ 115,668 ​ ​ 50.6 % ​ 50.6 % Joint Ventures ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ UDR/MetLife Vitruvian Park ® (a) Addison, TX 4 operating communities; 1,879 ​ 75,858 ​ 71,730 ​ ​ 50.0 % ​ 50.0 % ​ 1 development community (b); ​ ​ ​ ​ ​ ​ ​ ​ ​ 4 land parcels ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ UDR/KFH (c) Washington, D.C. — ​ — ​ 156 ​ 5,507 ​ ​ — % ​ 30.0 % West Coast Development Joint Ventures (d) ​ Los Angeles, CA ​ 1 operating community ​ 293 ​ ​ 35,165 ​ ​ 36,143 ​ ​ 47.0 % ​ 47.0 % Investment in and advances to unconsolidated joint ventures, net, before participating loan investment, preferred equity investments and other investments ​ $ 543,692 ​ $ 556,694 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income/(loss) from investments ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Investment at ​ Three Months Ended ​ Nine Months Ended ​ Developer Capital Program ​ ​ Years To ​ UDR September 30, December 31, September 30, ​ September 30, ​ and Other Investments (e) Location Rate Maturity ​ Commitment (f) 2019 2018 2019 2018 2019 2018 ​ Preferred equity investments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ West Coast Development Joint Ventures (d) Various 6.5 % N/A ​ $ — ​ $ 17,080 ​ $ 65,417 ​ $ 71 ​ $ 25 ​ $ (100) ​ $ 974 ​ 1532 Harrison (g) ​ San Francisco, CA ​ 11.0 % 2.8 ​ ​ 24,645 ​ ​ 29,753 ​ ​ 24,986 ​ ​ 802 ​ ​ 721 ​ ​ 2,324 ​ ​ 1,492 ​ 1200 Broadway (h) ​ Nashville, TN ​ 8.0 % 3.0 ​ ​ 55,558 ​ ​ 62,666 ​ ​ 58,982 ​ ​ 1,244 ​ ​ 859 ​ ​ 3,619 ​ ​ 1,870 ​ Junction (i) ​ Santa Monica, CA ​ 12.0 % 2.8 ​ ​ 8,800 ​ ​ 10,072 ​ ​ 9,211 ​ ​ 299 ​ ​ 141 ​ ​ 861 ​ ​ 141 ​ 1300 Fairmount (j) ​ Philadelphia, PA ​ Variable ​ 3.9 ​ ​ 51,393 ​ ​ 36,404 ​ ​ 8,318 ​ ​ 930 ​ ​ 27 ​ ​ 1,724 ​ ​ 27 ​ Essex (k) ​ Orlando, FL ​ 12.5 % 3.9 ​ ​ 12,886 ​ ​ 14,347 ​ ​ 9,940 ​ ​ 443 ​ ​ 46 ​ ​ 1,182 ​ ​ 46 ​ Modera Lake Merritt (l) ​ Oakland, CA ​ 9.0 % 4.6 ​ ​ 27,250 ​ ​ 17,377 ​ ​ — ​ ​ 366 ​ ​ — ​ ​ 622 ​ ​ — ​ Other investments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The Portals (m) ​ Washington, D.C. ​ 11.0 % 1.7 ​ ​ 38,559 ​ ​ 46,863 ​ ​ 43,167 ​ ​ 1,287 ​ ​ 1,015 ​ ​ 3,694 ​ ​ 2,523 ​ Other investment ventures ​ N/A ​ N/A ​ N/A ​ $ 18,000 ​ ​ 12,926 ​ ​ 4,154 ​ $ 4,247 ​ $ (77) ​ $ 4,272 ​ $ (262) ​ Total Developer Capital Program and Other Investments ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 247,488 ​ ​ 224,175 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total investment in and advances to unconsolidated joint ventures, net ​ ​ ​ ​ $ 791,180 ​ $ 780,869 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (a) In August 2019, the Company entered into an agreement with MetLife, its joint venture partner, to acquire the approximately 50% ownership interest not previously owned in 10 UDR/MetLife operating communities, one development community and four land parcels valued at $1.1 billion, or $557 million at UDR’s share, and to sell its approximately 50% ownership interest in five UDR/MetLife operating communities valued at $645 million, or $323 million at UDR’s share, to MetLife. The transaction is expected to close during the fourth quarter of 2019, subject to customary closing conditions and closing price adjustments. Upon closing of the transaction, the UDR/MetLife II joint venture will hold seven operating communities and the UDR/MetLife Vitruvian Park ® joint venture will no longer hold any properties. (b) The number of apartment homes for the communities under development presented in the table above is based on the projected number of total homes upon completion of development. As of September 30, 2019, no apartment homes had been completed in the development community held by UDR/MetLife Vitruvian Park ® . (c) As of January 1, 2019, the joint venture held three operating communities. In May 2019, the joint venture sold one community, a 217 home operating community in Arlington, Virginia, for a sales price of approximately $74.8 million. As a result, the Company recorded a gain on the sale of approximately $5.3 million, which is included in Income/(loss) from unconsolidated entities In July 2019, the joint venture sold the second community, a 151 home operating community in Silver Spring, Maryland, for a sales price of approximately $43.5 million. As a result, the Company recorded a gain on the sale of approximately $5.3 million, which is included in Income/(loss) from unconsolidated entities In August 2019, the joint venture sold the third community, a 292 home operating community in Washington, D.C., directly to the Company for a sales price at 100% of approximately $184.0 million, before $2.8 million of closing costs incurred by UDR at acquisition. The Company deferred its share of the gain on sale of approximately $23.8 million and recorded it as a reduction of the carrying amount of real estate assets owned (see Note 3, Real Estate Owned (d) In 2015, the Company entered into a joint venture agreement with an unaffiliated joint venture partner and paid $136.3 million for a 48% ownership interest in a portfolio of five communities that were under construction. The communities are located in three of the Company’s core, coastal markets: Seattle, Washington, Los Angeles, California and Orange County, California. UDR earns a 6.5% preferred return on its investment through each individual community’s date of stabilization, defined as when a community reaches 80% occupancy for 90 consecutive days, while the joint venture partner is allocated all operating income and expense during the pre-stabilization period. Upon stabilization, income and expense are shared based on each partner’s ownership percentage and the Company no longer receives a 6.5% preferred return on its investment in the stabilized community. The Company serves as property manager and earns a management fee during the lease-up phase and subsequent operation of each of the communities. The unaffiliated joint venture partner is the general partner of the joint venture and the developer of the communities. The Company has concluded it does not control the joint ventures and, therefore, accounts for them under the equity method of accounting. During 2017, the Company exercised its fixed-price option to purchase the joint venture partner’s ownership interest in one of the five communities, and the joint venture sold two of the four remaining communities. In January 2019, the Company exercised its fixed-price option to purchase its joint venture partner’s ownership interest in one of the two remaining communities, a 386 apartment home operating community in Orange County, California, thereby increasing its ownership interest from 49% to 100%, for a cash purchase price of approximately $33.5 million. As a result, the Company consolidated the operating community and it is no longer accounted for as a preferred equity investment in an unconsolidated joint venture (see Note 3, Real Estate Owned The Company and its joint venture partner continue to operate the one remaining community. In 2017, the Company entered into two additional joint venture agreements with the unaffiliated joint venture partner and paid $15.5 million for a 49% ownership interest in a 155 apartment home community in Seattle, Washington and $16.1 million for a 49% ownership interest in a 276 apartment home community in Hillsboro, Oregon (together with the 2015 joint venture described above, the “West Coast Development Joint Ventures”). UDR earns a 6.5% preferred return on its investments through the communities’ date of stabilization, as defined above, while our joint venture partner is allocated all operating income and expense during the pre-stabilization period. Upon stabilization of the communities, income and expense will be shared based on each partner’s ownership percentage and the Company will no longer receive a 6.5% preferred return on its investment. The Company serves as property manager and earns a management fee during the lease-up phase and subsequent operation of the stabilized communities. The unaffiliated joint venture partner is the general partner and the developer of the communities. The Company has concluded it does not control the joint ventures and, therefore, accounts for them under the equity method of accounting. The Company has a fixed-price option to acquire the remaining interest in the communities beginning one year after completion. The unaffiliated joint venture partner is providing certain guaranties and there are construction loans on the communities. In January 2019, the Company exercised its fixed-price option to purchase its joint venture partner’s ownership interest in the 155 apartment home operating community in Seattle, Washington, thereby increasing its ownership interest from 49% to 100%, for a cash purchase price of approximately $20.0 million. As a result, the Company consolidated the operating community and it is no longer accounted for as a preferred equity investment in an unconsolidated joint venture (see Note 3, Real Estate Owned The Company’s recorded equity investment in the West Coast Development Joint Ventures at September 30, 2019 and December 31, 2018, of $52.2 million and $101.6 million, respectively, is inclusive of outside basis costs and our accrued but unpaid preferred return. (e) The Developer Capital Program is a program through which the Company makes investments, including preferred equity investments, mezzanine loans or other structured investments that may receive a fixed or variable yield on the investment and may include provisions pursuant to which the Company participates in the increase in value of the property upon monetization of the applicable property and/or holds fixed price purchase options. (f) Represents UDR’s maximum funding commitment only and therefore excludes other activity such as income from investments. (g) In June 2017, the Company entered into a joint venture agreement with an unaffiliated joint venture partner to develop and operate a 136 apartment home community in San Francisco, California. The Company’s preferred equity investment of up to $24.6 million earns a preferred return of 11.0% per annum. The unaffiliated joint venture partner is the managing member of the joint venture and the developer of the community. The Company has concluded that it does not control the joint venture and, therefore, accounts for it under the equity method of accounting. (h) In September 2017, the Company entered into a joint venture agreement with an unaffiliated joint venture partner to develop and operate a 313 apartment home community in Nashville, Tennessee. The Company’s preferred equity investment of up to $55.6 million earns a preferred return of 8.0% per annum and receives a variable percentage of the value created from the project upon a capital or liquidating event. The unaffiliated joint venture partner is the managing member of the joint venture and the developer of the community. The Company has concluded that it does not control the joint venture and, therefore, accounts for it under the equity method of accounting. (i) In August 2018, the Company entered into a joint venture agreement with an unaffiliated joint venture partner to develop and operate a 66 apartment home community in Santa Monica, CA. The Company’s preferred equity investment of $8.8 million earns a preferred return of 12.0% per annum. The unaffiliated joint venture partner is the managing member of the joint venture and the developer of the community. The Company has concluded that it does not control the joint venture and, therefore, accounts for it under the equity method of accounting. (j) In August 2018, the Company entered into a joint venture agreement with an unaffiliated joint venture partner to develop and operate a 471 apartment home community in Philadelphia, PA. The Company’s preferred equity investment of up to $51.4 million earns a preferred return between 8.5% and 12.0% per annum and receives a variable percentage of the value created from the project upon a capital or liquidating event. The unaffiliated joint venture partner is the managing member of the joint venture and the developer of the community. The Company has concluded that it does not control the joint venture and, therefore, accounts for it under the equity method of accounting. (k) In September 2018, the Company entered into a joint venture agreement with an unaffiliated joint venture partner to develop and operate a 330 apartment home community in Orlando, FL. The Company’s preferred equity investment of up to $12.9 million earns a preferred return of 12.5% per annum. The unaffiliated joint venture partner is the managing member of the joint venture and the developer of the community. The Company has concluded that it does not control the joint venture and, therefore, accounts for it under the equity method of accounting. (l) In April 2019, the Company entered into a joint venture agreement with an unaffiliated joint venture partner to develop and operate a 173 apartment home community in Oakland, CA. The Company’s preferred equity investment of up to $27.3 million earns a preferred return of 9.0% per annum and receives a variable percentage of the value created from the project upon a capital or liquidating event. The unaffiliated joint venture partner is the managing member of the joint venture and the developer of the community. The Company has concluded that it does not control the joint venture and, therefore, accounts for it under the equity method of accounting . (m) In May 2017, the Company entered into a joint venture agreement with an unaffiliated joint venture partner. The joint venture has made a mezzanine loan to a third party developer of a 373 apartment home community in Washington, D.C. The unaffiliated joint venture partner is the managing member of the joint venture. The mezzanine loan is for up to $71.0 million at an interest rate of 13.5% per annum and carries a term of four years with one 12-month extension option. The Company’s commitment to the joint venture is approximately $38.6 million and earns a weighted average return of approximately 11.0% per annum. The Company has concluded that it does not control the joint venture and , therefore, accounts for it under the equity method of accounting. As of September 30, 2019 and December 31, 2018, the Company had deferred fees of $10.6 million and $11.0 million, respectively, which will be recognized through earnings over the weighted average life of the related properties, upon the disposition of the properties to a third party, or upon completion of certain development obligations. The Company recognized management fees of $6.4 million and $2.9 million during the three months ended September 30, 2019 and 2018, respectively, and $12.0 million and $ 8.7 million for the nine months ended September 30, 2019 and 2018, respectively, for management of the communities held by the joint ventures and partnerships. The management fees are included in Joint venture management and other fees on the Consolidated Statements of Operations. The Company may, in the future, make additional capital contributions to certain of our joint ventures and partnerships should additional capital contributions be necessary to fund acquisitions or operations. We evaluate our investments in unconsolidated joint ventures and partnerships when events or changes in circumstances indicate that there may be an other-than-temporary decline in value. We consider various factors to determine if a decrease in the value of the investment is other-than-temporary. The Company did not recognize any other-than-temporary impairments in the value of its investments in unconsolidated joint ventures or partnerships during the three and nine months ended September 30, 2019 and 2018. Combined summary balance sheets relating to the unconsolidated joint ventures and partnerships (not just our proportionate share) are presented below as of September 30, 2019 and December 31, 2018 ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ 2019 2018 Total real estate, net $ 3,101,213 $ 3,311,034 Cash and cash equivalents ​ 56,829 ​ 49,867 Other assets ​ ​ 165,767 ​ 124,428 Total assets $ 3,323,809 $ 3,485,329 ​ ​ ​ ​ ​ ​ ​ Third party debt, net ​ $ 1,909,223 ​ $ 2,125,350 Accounts payable and accrued liabilities ​ ​ 73,803 ​ ​ 71,272 Total liabilities ​ 1,983,026 ​ 2,196,622 Total equity $ 1,340,783 $ 1,288,707 ​ 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 nine months ended September 30, 2019 and 2018 ( dollars in thousands : ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, ​ September 30, ​ 2019 2018 2019 2018 Total revenues $ 75,378 $ 76,203 $ 233,836 $ 215,140 Property operating expenses ​ 27,505 ​ 30,096 ​ 87,073 ​ 85,435 Real estate depreciation and amortization ​ 26,027 ​ 29,545 ​ 83,661 ​ 85,063 Operating income/(loss) ​ 21,846 ​ ​ 16,562 ​ 63,102 ​ ​ 44,642 Interest expense ​ (20,779) ​ (22,919) ​ (64,309) ​ (63,990) Gain/(loss) on sale of property (a) ​ ​ 97,201 ​ ​ — ​ ​ 115,558 ​ ​ — Net unrealized gain/(loss) on held investments ​ ​ 25,669 ​ ​ — ​ ​ 27,191 ​ ​ — Other income/(loss) ​ ​ 82 ​ ​ 40 ​ ​ 194 ​ ​ 141 Net income/(loss) $ 124,019 $ (6,317) $ 141,736 $ (19,207) ​ ​ ​ (a) Represent the gains on the sale of three operating communities at the UDR/KFH joint venture level, as described in note (c) to the table above summarizing the Company’s investment in and advances to unconsolidated joint ventures and partnerships, net.
United Dominion Realty L.P.
Unconsolidated entities
UNCONSOLIDATED ENTITIES	4. UNCONSOLIDATED ENTITIES The DownREIT Partnership is accounted for by the Operating Partnership under the equity method of accounting and is included in Investment in unconsolidated entities The DownREIT Partnership is a VIE as the limited partners lack substantive kick-out rights and substantive participating rights. The Operating Partnership is not the primary beneficiary of the DownREIT Partnership as it lacks the power to direct the activities that most significantly impact its economic performance and will continue to account for its interest as an equity method investment. See Note 2, Significant Accounting Policies As of September 30, 2019, the DownREIT Partnership owned 12 communities with 5,657 apartment homes. The Operating Partnership’s investment in the DownREIT Partnership was $82.3 million and $103.0 million as of September 30, 2019 and December 31, 2018, respectively. Combined summary balance sheets relating to all of the DownREIT Partnership (not just our proportionate share) are presented below as of September 30, 2019 and December 31, 2018 ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ 2019 2018 Total real estate, net $ 1,119,828 $ 1,167,720 Cash and cash equivalents ​ 22 ​ 39 Note receivable from the General Partner ​ 221,789 ​ 221,022 Other assets ​ 5,259 ​ 5,561 Total assets $ 1,346,898 $ 1,394,342 ​ ​ ​ ​ ​ ​ ​ Secured debt, net ​ $ 428,457 ​ $ 431,735 Other liabilities ​ 25,880 ​ 26,597 Total liabilities ​ 454,337 ​ 458,332 Total capital ​ $ 892,561 ​ $ 936,010 ​ Combined summary financial information relating to all of the DownREIT Partnership (not just our proportionate share) is presented below for the three and nine months ended September 30, 2019 and 2018 ( dollars in thousands : ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, ​ September 30, ​ ​ 2019 2018 2019 2018 Rental income $ 32,434 $ 35,069 ​ $ 96,065 $ 103,842 Property operating expenses ​ (13,087) ​ (14,303) ​ (38,934) ​ (43,180) Real estate depreciation and amortization ​ (20,620) ​ (22,097) ​ (61,424) ​ (65,704) Operating income/(loss) ​ (1,273) ​ (1,331) ​ (4,293) ​ (5,042) Interest expense ​ (4,162) ​ (3,343) ​ (11,979) ​ (10,553) Interest income on note receivable from the General Partner ​ 2,054 ​ 1,196 ​ 6,060 ​ 3,587 Net income/(loss) $ (3,381) $ (3,478) ​ $ (10,212) $ (12,008) ​

LEASES (UNITED DOMINION REALTY,

LEASES (UNITED DOMINION REALTY, L.P.)	9 Months Ended
	Sep. 30, 2019
Entity information
Leases	6. LEASES Lessee - Ground and Office Leases UDR owns six communities that are subject to ground leases, under which UDR is the lessee, expiring between 2043 and 2103, inclusive of extension options we are reasonably certain will be exercised. In addition, UDR is a lessee to an operating lease related to office space rented by the Company with an expiration date in 2021. All of these leases existed as of the adoption of the new lease accounting guidance on January 1, 2019 and we did not reassess lease classification per the practical expedient provided by the standard. As such, these leases will continue to be classified as operating leases through the lease term expiration. Rental expense for lease payments related to operating leases is recognized on a straight-line basis over the remaining lease term. We currently do not hold any finance leases. As of September 30, 2019, the Operating lease right-of-use assets Operating lease liabilities Operating lease right-of-use assets Operating lease liabilities As the discount rate implicit in the leases was not readily determinable, we determined the discount rate for these leases utilizing the Company’s incremental borrowing rate at a portfolio level, adjusted for the remaining lease term, and the form of underlying collateral. The weighted average remaining lease term for these leases was 55.2 years at September 30, 2019 and the weighted average discount rate was 5.1% at September 30, 2019. Future minimum lease payments and total operating lease liabilities from our ground leases and office space as of September 30, 2019 are as follows (dollars in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ground Leases ​ Office Space ​ Total 2019 ​ $ 1,953 ​ $ 19 ​ $ 1,972 2020 ​ ​ 7,813 ​ ​ 76 ​ ​ 7,889 2021 ​ ​ 7,813 ​ ​ 32 ​ ​ 7,845 2022 ​ ​ 7,813 ​ ​ - ​ ​ 7,813 2023 ​ ​ 7,813 ​ ​ - ​ ​ 7,813 Thereafter ​ ​ 370,467 ​ ​ - ​ ​ 370,467 Total future minimum lease payments (undiscounted) ​ ​ 403,672 ​ ​ 127 ​ ​ 403,799 Difference between future undiscounted cash flows and discounted cash flows ​ ​ (273,659) ​ ​ (5) ​ ​ (273,664) Total operating lease liabilities (discounted) ​ $ 130,013 ​ $ 122 ​ $ 130,135 ​ For purposes of recognizing our ground lease contracts, the Company uses the minimum lease payments, if stated in the agreement. For ground lease agreements where there is a rent reset provision based on a change in an index or a rate (i.e., changes in fair market rental rates or changes in the consumer price index) but that does not include a specified minimum lease payment, the Company uses the current rent over the remainder of the lease term. If there is a contingency upon which some or all of the variable lease payments that will be paid over the remainder of the lease term are based, which is resolved such that those payments now meet the definition of lease payments, the Company will remeasure the right-of-use asset and lease liability on the reset date. For the nine months ended September 30, 2019, Operating lease right-of-use assets Operating lease liabilities The components of operating lease expenses from our ground leases and office space were as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, 2019 ​ September 30, 2019 Ground lease expense: ​ ​ ​ ​ ​ ​ Contractual lease rent expense ​ $ 1,954 ​ $ 6,232 Variable ground lease expense (a) ​ ​ 187 ​ ​ 469 Total ground lease expense (b) ​ ​ 2,141 ​ ​ 6,701 Contractual office space expense (b) ​ ​ 19 ​ ​ 57 Total operating lease expense (c) ​ $ 2,160 ​ $ 6,758 (a) Variable ground lease expense includes adjustments such as changes in the consumer price index and payments based on a percentage of income of the lessee. (b) Ground lease expense is reported within the line item Other operating expenses and office space expense is recorded in General and administrative on the Consolidated Statements of Operations. (c) For the nine months ended September 30, 2019, Operating lease right-of-use assets and Operating lease liabilities amortized by $0.6 million and $0.3 million, respectively. The Company recorded $0.1 million and $0.3 million of total operating lease expense during the three and nine months ended September 30, 2019, respectively, due to the net impact of the amortization. ​ Lessor - Apartment Home, Retail and Commercial Space Leases ​ UDR’s communities and retail and commercial space are leased to tenants under operating leases. As of September 30, 2019, our apartment home leases generally have initial terms of 12 months or less and represent approximately 98.1% of our total lease revenue. As of September 30, 2019, our retail and commercial space leases generally have initial terms of between 5 and 15 years and represent approximately 1.9% of our total lease revenue. Our apartment home leases are generally renewable at the end of the lease term, subject to potential increases in rental rates, and our retail and commercial space leases generally have renewal options, subject to associated increases in rental rates and certain other conditions. (See Note 14, Reportable Segments ​ We previously owned a parcel of land subject to a ground lease under which UDR was the lessor, expiring in 2065. The ground lease included a purchase option for the lessee to acquire the land during specific periods of the ground lease term. In June 2019, the lessee exercised the purchase option and acquired the parcel of land for $38.0 million. (See Note 3, Real Estate ​ Future minimum lease payments from our retail and commercial leases as of September 30, 2019 are as follows (dollars in thousands): ​ ​ ​ ​ ​ ​ Retail and Commercial Leases 2019 ​ $ 4,958 2020 ​ ​ 20,565 2021 ​ ​ 19,788 2022 ​ ​ 18,094 2023 ​ ​ 16,843 Thereafter ​ ​ 92,719 Total future minimum lease payments (a) ​ $ 172,967 (a) We have excluded our apartment home leases from this table as our apartment home leases generally have initial terms of 12 months of less. Certain of our leases with retail and commercial tenants provide for the payment by the lessee of additional variable rent based on a percentage of the tenant’s revenue. The amounts shown in the table above do not include these variable percentage rents. The Company recorded variable percentage rents of $0.1 million and $0.3 million during the three and nine months ended September 30, 2019.
United Dominion Realty L.P.
Entity information
Leases	5. LEASES Lessee - Ground Leases The Operating Partnership owns six communities that are subject to ground leases, under which the Operating Partnership is the lessee, expiring between 2043 and 2103, inclusive of extension options we are reasonably certain will be exercised. All of these leases existed as of the adoption of the new lease accounting guidance on January 1, 2019 and we did not reassess lease classification per the practical expedient provided by the standard. As such, these leases will continue to be classified as operating leases through the lease term expiration. Rental expense for lease payments related to operating leases is recognized on a straight-line basis over the remaining lease term. We currently do not hold any finance leases. As of September 30, 2019, the Operating lease right-of-use assets Operating lease liabilities Operating lease right-of-use assets Operating lease liabilities As the discount rate implicit in the leases was not readily determinable, we determined the discount rate for these leases utilizing the Operating Partnership’s incremental borrowing rate at a portfolio level, adjusted for the remaining lease term, and the form of underlying collateral. The weighted average remaining lease term for these leases was 55.3 years at September 30, 2019 and the weighted average discount rate was 5.1% at September 30, 2019. Future minimum lease payments and total operating lease liabilities from our ground leases as of September 30, 2019 are as follows (dollars in thousands): ​ ​ ​ ​ ​ ​ Ground Leases 2019 ​ $ 1,953 2020 ​ ​ 7,813 2021 ​ ​ 7,813 2022 ​ ​ 7,813 2023 ​ ​ 7,813 Thereafter ​ ​ 370,467 Total future minimum lease payments (undiscounted) ​ ​ 403,672 Difference between future undiscounted cash flows and discounted cash flows ​ ​ (273,659) Total operating lease liabilities (discounted) ​ $ 130,013 ​ For purposes of recognizing our ground lease contracts, the Operating Partnership uses the minimum lease payments, if stated in the agreement. For ground lease agreements where there is a rent reset provision based on a change in an index or a rate (i.e., changes in fair market rental rates or changes in the consumer price index) but that does not include a specified minimum lease payment, the Operating Partnership uses the current rent over the remainder of the lease term. If there is a contingency, upon which some or all of the variable lease payments that will be paid over the remainder of the lease term are based, which is resolved such that those payments now meet the definition of lease payments, the Operating Partnership will remeasure the right-of-use asset and lease liability on the reset date. For the nine months ended September 30, 2019, Operating lease right-of-use assets Operating lease liabilities The components of operating lease expenses from our ground leases were as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, 2019 ​ September 30, 2019 Ground lease expense: ​ ​ ​ ​ ​ ​ Contractual lease rent expense ​ $ 1,954 ​ $ 6,232 Variable ground lease expense (a) ​ ​ 187 ​ ​ 469 Total operating lease expense (b)(c) ​ $ 2,141 ​ $ 6,701 (a) Variable ground lease expense includes adjustments such as changes in the consumer price index and payments based on a percentage of income of the lessee. (b) Ground lease expense is reported within the line item Other operating expenses on the Consolidated Statements of Operations. (c) For the nine months ended September 30, 2019, Operating lease right-of-use assets and Operating lease liabilities amortized by $0.6 million and $0.3 million, respectively. The Operating Partnership recorded $0.1 million and $0.3 million of total operating lease expense during the three and nine months ended September 30, 2019, respectively, due to the net impact of the amortization. ​ Lessor - Apartment Home and Retail and Commercial Leases ​ The Operating Partnership’s communities and retail and commercial space are leased to tenants under operating leases. As of September 30, 2019, our apartment home leases generally have initial terms of 12 months or less and represent 98.4% of our total lease revenue. As of September 30, 2019, our retail and commercial space leases generally have initial terms between 5 and 15 years and represent approximately 1.6% of our total lease revenue. Our apartment home leases are generally renewable at the end of the lease term, subject to potential increases in rental rates, and our retail and commercial space leases generally have renewal options, subject to associated increases in rental rates and certain other conditions. (See Note 12, Reportable Segments ​ Future minimum lease payments from our retail and commercial leases as of September 30, 2019 are as follows (dollars in thousands): ​ ​ ​ ​ ​ ​ Retail and Commercial Leases 2019 ​ $ 1,810 2020 ​ ​ 7,778 2021 ​ ​ 7,442 2022 ​ ​ 6,841 2023 ​ ​ 6,517 Thereafter ​ ​ 19,874 Total future minimum lease payments (a) ​ $ 50,262 (a) We have excluded our apartment home leases from this table as our apartment home leases generally have initial terms of 12 months of less. Certain of our leases with retail and commercial tenants provide for the payment by the lessee of additional variable rent based on a percentage of the tenant’s revenue. The amounts shown in the table above do not include these variable percentage rents. The Operating Partnership recorded variable percentage rents of less than $0.1 million and $0.1 million during the three and nine months ended September 30, 2019, respectively.

DEBT, NET (UNITED DOMINION REAL

DEBT, NET (UNITED DOMINION REALTY, L.P.)	9 Months Ended
	Sep. 30, 2019
Entity information
DEBT, NET	7. SECURED AND UNSECURED DEBT, NET The following is a summary of our secured and unsecured debt at September 30, 2019 and December 31, 2018 ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Principal Outstanding ​ As of September 30, 2019 ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ Weighted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Average ​ Average ​ Number of ​ ​ September 30, ​ December 31, ​ Interest ​ Years to ​ Communities ​ 2019 2018 Rate Maturity Encumbered Secured Debt: ​ ​ ​ ​ ​ ​ ​ Fixed Rate Debt ​ ​ Mortgage notes payable (a) ​ $ 575,965 ​ $ 417,989 3.55 % 6.6 9 Fannie Mae credit facilities (b) ​ — ​ 90,000 — % — — Deferred financing costs ​ (2,275) ​ (1,343) Total fixed rate secured debt, net ​ 573,690 ​ 506,646 3.55 % 6.6 9 Variable Rate Debt ​ ​ Tax-exempt secured notes payable (c) ​ 27,000 ​ 94,700 2.07 % 12.5 1 Deferred financing costs ​ (66) ​ (119) Total variable rate secured debt, net ​ 26,934 ​ 94,581 2.07 % 12.5 1 Total Secured Debt, net ​ 600,624 ​ 601,227 3.49 % 6.8 10 Unsecured Debt: ​ ​ Variable Rate Debt ​ ​ Borrowings outstanding under unsecured credit facility due January 2023 (d) (l) ​ — ​ — — % 3.3 Borrowings outstanding under unsecured commercial paper program due October 2019 (e) (l) ​ ​ 60,000 ​ ​ 101,115 ​ 2.28 % 0.1 ​ ​ Borrowings outstanding under unsecured working capital credit facility due January 2021 ​ 34,447 ​ 16 2.84 % 1.3 Term Loan due September 2023 (d) (l) ​ 35,000 ​ 35,000 3.01 % 4.0 Fixed Rate Debt ​ ​ 3.70% Medium-Term Notes due October 2020 (net of discounts of $0 and $14, respectively) (k) (l) ​ — ​ 299,986 — % — 4.63% Medium-Term Notes due January 2022 (net of discounts of $818 and $1,087, respectively) (l) ​ 399,182 ​ 398,913 4.63 % 2.3 1.93% Term Loan due September 2023 (d) (l) ​ ​ 315,000 ​ 315,000 1.93 % 4.0 ​ ​ 3.75% Medium-Term Notes due July 2024 (net of discounts of $495 and $574, respectively) (g) (l) ​ 299,505 ​ 299,426 3.75 % 4.8 8.50% Debentures due September 2024 ​ 15,644 ​ 15,644 8.50 % 5.0 4.00% Medium-Term Notes due October 2025 (net of discounts of $413 and $465, respectively) (h) (l) ​ 299,587 ​ 299,535 4.00 % 6.0 2.95% Medium-Term Notes due September 2026 (l) ​ 300,000 ​ 300,000 2.95 % 6.9 3.50% Medium-Term Notes due July 2027 (net of discounts of $547 and $600, respectively) (l) ​ ​ 299,453 ​ ​ 299,400 ​ 3.50 % 7.8 ​ ​ 3.50% Medium-Term Notes due January 2028 (net of discounts of $983 and $1,072, respectively) (l) ​ ​ 299,017 ​ ​ 298,928 ​ 3.50 % 8.3 ​ ​ 4.40% Medium-Term Notes due January 2029 (net of discounts of $6 and $6, respectively) (i) (l) ​ ​ 299,994 ​ ​ 299,994 ​ 4.40 % 9.3 ​ ​ 3.20% Medium-Term Notes due January 2030 (net of discounts of $990 and $0, respectively) (j) (l) ​ ​ 299,010 ​ ​ — ​ 3.20 % 10.3 ​ ​ 3.00% Medium-Term Notes due August 2031 (net of discounts of $1,148 and $0, respectively) (k) (l) ​ ​ 398,852 ​ ​ — ​ 3.00 % 11.9 ​ ​ Other ​ 14 ​ 16 Deferred financing costs ​ (19,432) ​ (16,413) Total Unsecured Debt, net ​ 3,335,273 ​ 2,946,560 3.54 % 6.9 Total Debt, net ​ $ 3,935,897 ​ $ 3,547,787 3.63 % 6.9 ​ 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 September 30, 2019, secured debt encumbered $1.2 billion or 10.3% of UDR’s total real estate owned based upon gross book value ($10.4 billion or 89.7% of UDR’s real estate owned based on gross book value is unencumbered). (a) During the three months ended September 30, 2019, the Company refinanced a $90.0 million loan with Fannie Mae to a fixed rate mortgage due in October 2029 and took out a new mortgage of $72.5 million due in February 2030. Interest payments are due monthly at interest rates of 2.70% and 3.10%, respectively. The refinancing was accounted for as a debt modification. The Company will from time to time acquire properties subject to fixed rate debt instruments. In those situations, the Company records the debt at its estimated fair value and amortizes any difference between the fair value and par value to interest expense over the life of the underlying debt instrument. During the three months ended September 30, 2019 and 2018, the Company had $0.6 million and $0.9 million, respectively, and during the nine months ended September 30, 2019 and 2018, the Company had $1.7 million and $2.4 million, respectively, of amortization of the fair market adjustment of debt assumed in the acquisition of properties, which was included in Interest expense (b) Further information related to the Fannie Mae credit facility is as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2019 ​ 2018 Borrowings outstanding ​ $ — ​ $ 90,000 ​ Weighted average borrowings during the period ended ​ 80,000 ​ 253,813 ​ Maximum daily borrowings during the period ended ​ 90,000 ​ 314,869 ​ Weighted average interest rate during the period ended ​ 4.0 % 4.7 % Weighted average interest rate at the end of the period ​ — % 4.0 % ​ (c) (d) six-month extension options, subject to certain conditions. The Term Loan has a scheduled maturity date of September 30, 2023. Based on the Company’s current credit rating, the Revolving Credit Facility has an interest rate equal to LIBOR plus a margin of 82.5 basis points and a facility fee of 15 basis points, and the Term Loan has an interest rate equal to LIBOR plus a margin of 90 basis points. Depending on the Company’s credit rating, the margin under the Revolving Credit Facility ranges from 75 to 145 basis points, the facility fee ranges from 10 to 30 basis points, and the margin under the Term Loan ranges from 80 to 165 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 September 30, 2019 and December 31, 2018 (dollars in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2019 2018 ​ Total revolving credit facility ​ $ 1,100,000 ​ $ 1,100,000 ​ Borrowings outstanding at end of period (1) ​ — ​ — ​ Weighted average daily borrowings during the period ended ​ — ​ — ​ Maximum daily borrowings during the period ended ​ — ​ — ​ Weighted average interest rate during the period ended ​ — % — % Interest rate at end of the period ​ — % — % (1) Excludes $2.8 million and $3.3 million of letters of credit at September 30, 2019 and December 31, 2018, respectively. (e) The following is a summary of short-term bank borrowings under the unsecured commercial paper program at September 30, 2019 and December 31, 2018 (dollars in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2019 ​ 2018 Total unsecured commercial paper program $ 500,000 ​ $ 500,000 ​ Borrowings outstanding at end of period ​ 60,000 ​ 101,115 ​ Weighted average daily borrowings during the period ended ​ 163,347 ​ 344,235 ​ Maximum daily borrowings during the period ended ​ 435,000 ​ 440,000 ​ Weighted average interest rate during the period ended ​ 2.7 % 2.4 % Interest rate at end of the period ​ 2.3 % 2.9 % ​ (f) 82.5 basis points. Depending on the Company’s credit rating, the margin ranges from 75 to 145 basis points. The following is a summary of short-term bank borrowings under the Working Capital Credit Facility at September 30, 2019 and December 31, 2018 (dollars in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2019 ​ 2018 Total working capital credit facility ​ $ 75,000 ​ $ 75,000 ​ Borrowings outstanding at end of period ​ 34,447 ​ 16 ​ Weighted average daily borrowings during the period ended ​ 24,870 ​ 26,101 ​ Maximum daily borrowings during the period ended ​ 66,170 ​ 64,633 ​ Weighted average interest rate during the period ended ​ 3.2 % 2.9 % Interest rate at end of the period ​ 2.8 % 3.3 % ​ (g) (h) (i) (j) . (k) (l) The aggregate maturities, including amortizing principal payments on secured and unsecured debt, of total debt for the next ten calendar years subsequent to September 30, 2019 are as follows (dollars in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Fixed Total Variable Total Total Total Year ​ Secured Debt ​ Secured Debt ​ Secured Debt ​ Unsecured Debt ​ Debt 2019 ​ $ 974 ​ $ — ​ $ 974 ​ $ 60,000 ​ $ 60,974 2020 ​ ​ 108,077 ​ ​ — ​ ​ 108,077 ​ ​ — ​ ​ 108,077 2021 ​ 1,117 ​ — ​ 1,117 ​ 34,447 ​ 35,564 2022 ​ 1,157 ​ — ​ 1,157 ​ 400,000 ​ 401,157 2023 ​ 41,245 ​ — ​ 41,245 ​ 350,000 ​ 391,245 2024 ​ — ​ — ​ — ​ 315,644 ​ 315,644 2025 ​ 127,600 ​ — ​ 127,600 ​ 300,000 ​ 427,600 2026 ​ 50,000 ​ — ​ 50,000 ​ 300,000 ​ 350,000 2027 ​ — ​ — ​ — ​ 300,000 ​ 300,000 2028 ​ 80,000 ​ — ​ 80,000 ​ 300,000 ​ 380,000 Thereafter ​ 162,500 ​ 27,000 ​ 189,500 ​ 1,000,000 ​ 1,189,500 Subtotal ​ 572,670 ​ 27,000 ​ 599,670 ​ 3,360,091 ​ 3,959,761 Non-cash (a) ​ 1,020 ​ (66) ​ 954 ​ (24,818) ​ (23,864) Total ​ $ 573,690 ​ $ 26,934 ​ $ 600,624 ​ $ 3,335,273 ​ $ 3,935,897 (a) Includes the unamortized balance of fair market value adjustments, premiums/discounts and deferred financing costs . The Company amortized $1.1 million and $ 1.1 million, respectively, during the three months ended September 30, 2019 and 2018, and $3.1 million and $3.2 million, respectively, during the nine months ended September 30, 2019 and 2018, of deferred financing costs into Interest expense. We were in compliance with the covenants of our debt instruments at September 30, 2019. In October 2019, the Company issued $100.0 million of 3.20% senior unsecured medium-term notes due 2030 and $300.0 million of 3.10% senior unsecured medium-term notes due 2034. Interest is payable semi-annually in arrears on January 15 and July 15 for the 2030 notes, and May 1 and November 1 for the 2034 notes. The 2030 notes were priced at 103.32% of the principal amount at issuance, and the 2034 notes were priced at 99.56% of the principal amount at issuance. In combination with the issuance, the Company entered into treasury lock agreements to hedge against interest rate risk on all of this debt. The all-in weighted average interest rate, inclusive of the impact of the treasury locks, was 3.24% for the 2030 notes and 3.13% for the 2034 notes. The Company will use the net proceeds for the repayment of all $400.0 million aggregate principal amount (plus the make-whole amount of approximately $21.5 million and accrued and unpaid interest) of its 4.63% senior unsecured medium-term notes due January 2022. The 2034 notes were issued as “green” bonds and, as a result, the Company intends to allocate the net proceeds from the sale of the 2034 notes to fund eligible green projects, including previously incurred development costs related to properties that have received at least a LEED Silver certification. The 2030 notes are a further issuance of, and form a single series with, the $300.0 million aggregate principal amount of the Company’s 3.20% notes due 2030 that were issued on July 2, 2019. As of the completion of the offering, the aggregate principal amount of outstanding 2030 notes was $400.0 million.
United Dominion Realty L.P.
Entity information
DEBT, NET	6. 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 September 30, 2019 and December 31, 2018 ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Principal Outstanding ​ As of September 30, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ Average ​ ​ ​ ​ September 30, ​ December 31, ​ Average ​ Years to ​ Communities ​ ​ 2019 ​ 2018 ​ Interest Rate ​ Maturity ​ Encumbered Fixed Rate Debt ​ ​ Mortgage notes payable ​ $ 72,500 ​ $ — 3.10 % 10.3 1 Deferred financing costs ​ (370) ​ — Total fixed rate secured debt, net ​ 72,130 ​ — 3.10 % 10.3 1 Secured Debt ​ ​ Tax-exempt secured note payable ​ $ 27,000 ​ $ 27,000 2.07 % 12.5 1 Deferred financing costs ​ (66) ​ (71) Total Secured Debt, Net ​ $ 99,064 ​ $ 26,929 2.85 % 10.9 2 ​ 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 Mortgage notes payable Variable Rate Debt Tax-exempt secured note payable. Guarantor on Unsecured Debt The Operating Partnership is the guarantor on the General Partner’s unsecured revolving credit facility with an aggregate borrowing capacity of $1.1 billion, an unsecured commercial paper program with an aggregate borrowing capacity of $500 million, $400 million of medium-term notes due January 2022, a $350 million term loan due September 2023, $300 million of medium-term notes due July 2024, $300 million of medium-term notes due October 2025, $300 million of medium-term notes due September 2026, $300 million of medium-term notes due July 2027, $300 million of medium-term notes due January 2028, $300 million of medium-term notes due January 2029, $300 million of medium-term notes due January 2030, and $400 million of medium-term notes due August 2031. As of September 30, 2019 and December 31, 2018, the General Partner did not have an outstanding balance under the unsecured revolving credit facility and had $60.0 million and $101.1 million, respectively, outstanding under its unsecured commercial paper program. In October 2019, the General Partner issued $100.0 million of 3.20% senior unsecured medium-term notes due 2030 and $300.0 million of 3.10% senior unsecured medium-term notes due 2034. The General Partner will use the net proceeds for the repayment of its $400.0 million aggregate principal amount (plus the make-whole amount of approximately $21.5 million and accrued and unpaid interest) of its 4.63% senior unsecured medium-term notes due January 2022. The 2034 notes were issued as “green” bonds and, as a result, the General Partner intends to allocate the net proceeds from the sale of the 2034 notes to fund eligible green projects, including previously incurred development costs related to properties that have received at least a LEED Silver certification. The 2030 notes are a further issuance of, and form a single series with the $300.0 million aggregate principal amounts of the General Partner’s 3.20% notes due 2030 that were issued on July 2, 2019. As of the completion of the offering, the aggregate principal amount of outstanding 2030 notes was $400.0 million.

RELATED PARTY TRANSACTIONS (UNI

RELATED PARTY TRANSACTIONS (UNITED DOMINION REALTY, L.P.)	9 Months Ended
	Sep. 30, 2019
United Dominion Realty L.P.
Entity information
RELATED PARTY TRANSACTIONS	7. RELATED PARTY TRANSACTIONS Allocation of General and Administrative Expenses The General Partner shares various general and administrative costs, employees and other overhead costs with the Operating Partnership including legal assistance, acquisitions analysis, marketing, human resources, IT, accounting, rent, supplies and advertising, and allocates these costs to the Operating Partnership first on the basis of direct usage when identifiable, with the remainder allocated based on the reasonably anticipated benefits to the parties. The general and administrative expenses allocated to the Operating Partnership by UDR were $2.7 million and $3.3 million during the three months ended September 30, 2019 and 2018, respectively, and $9.7 million and $10.5 million during the nine months ended September 30, 2019 and 2018, respectively, and are included in General and administrative During the three months ended September 30, 2019 and 2018, the Operating Partnership reimbursed the General Partner $4.6 million and $3.8 million, respectively, and during the nine months ended September 30, 2019 and 2018, the Operating Partnership reimbursed the General Partner $12.7 million and $11.4 million, respectively, for shared services related to corporate level property management costs incurred by the General Partner. These shared cost reimbursements are initially recorded within the line item General and administrative Property management Shared Services The Operating Partnership self-manages its own properties and is party to an Inter-Company Employee and Cost Sharing Agreement with the General Partner. This agreement provides for reimbursements to the General Partner for the Operating Partnership’s allocable share of costs incurred by the General Partner for (a) shared services of corporate level property management employees and related support functions and costs, and (b) general and administrative costs. As discussed above, the reimbursement for shared services is classified in Property management Notes Payable to the General Partner The following table summarizes the Operating Partnership’s Notes payable due to the General Partner as of September 30, 2019 and December 31, 2018 ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate at ​ Balance Outstanding ​ September 30, ​ September 30, December 31, ​ ​ 2019 ​ 2019 ​ 2018 Note due August 2021 5.34 % ​ $ 5,500 ​ $ 5,500 Note due December 2023 5.18 % ​ 83,196 ​ 83,196 Note due April 2026 4.12 % ​ 184,638 ​ 184,638 Note due November 2028 ​ 4.69 % ​ ​ 133,205 ​ ​ 133,205 Note due December 2028 (a) ​ 3.63 % ​ ​ 217,428 ​ ​ 293,576 Total notes payable due to the General Partner ​ ​ $ 623,967 ​ $ 700,115 (a) In December 2018, the Operating Partnership converted the remaining outstanding portion of the Advances (to)/from the General Partner capital balance in connection with entering into an unsecured revolving note payable with the General Partner. There is no limit on the total commitments under this note. Interest is incurred on the unpaid principal balance at a variable interest rate equivalent to the General Partner’s weighted average interest rate on borrowings, or 3.63% as of September 30, 2019. The note matures on December 1, 2028. To the extent there is an outstanding principal balance on the revolving note payable, the General Partner, at its discretion, can demand payment at any time prior to the stated maturity date of the note, Certain limited partners of the Operating Partnership have provided guarantees or reimbursement agreements related to these notes payable. The guarantees were provided by the limited partners in conjunction with their contribution of properties to the Operating Partnership. The Operating Partnership recognized interest expense on the notes payable of $7.0 million and $3.1 million during the three months ended September 30, 2019 and 2018, respectively, and $21.4 million and $9.2 million during the nine months ended September 30, 2019 and 2018, respectively.

FAIR VALUE OF DERIVATIVES AND_4

FAIR VALUE OF DERIVATIVES AND FINANCIAL INSTRUMENTS (UNITED DOMINION REALTY, L.P.)	9 Months Ended
	Sep. 30, 2019
Entity information
FAIR VALUE OF DERIVATIVES AND FINANCIAL INSTRUMENTS	10. FAIR VALUE OF DERIVATIVES AND FINANCIAL INSTRUMENTS Fair value is based on the price that would be received to sell an asset or the exit price that would be paid to transfer a liability in an orderly transaction between market participants at the measurement date. A three-level valuation hierarchy prioritizes observable and unobservable inputs used to measure fair value. The fair value hierarchy consists of three broad levels, which are described below: ● Level 1 — Quoted prices in active markets for identical assets or liabilities that the entity has the ability to access. ● Level 2 — Observable inputs other than prices included in Level 1, such as quoted prices for similar assets and liabilities in active markets; quoted prices for identical or similar assets and liabilities in markets that are not active; or other inputs that are observable or can be corroborated with observable market data. ● Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets and liabilities. This includes certain pricing models, discounted cash flow methodologies and similar techniques that use significant unobservable inputs. The estimated fair values of the Company’s financial instruments either recorded or disclosed on a recurring basis as of September 30, 2019 and December 31, 2018, are summarized as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value at September 30, 2019, Using ​ ​ Total ​ ​ ​ Quoted ​ ​ ​ ​ ​ ​ Carrying ​ ​ ​ Prices in ​ ​ ​ ​ ​ ​ Amount in ​ ​ ​ Active ​ ​ ​ ​ ​ ​ ​ Statement of ​ ​ ​ ​ Markets ​ Significant ​ ​ ​ ​ ​ Financial ​ Fair Value ​ for Identical ​ Other ​ Significant ​ ​ Position at ​ Estimate at ​ Assets or ​ Observable ​ Unobservable ​ ​ September 30, ​ September 30, ​ Liabilities ​ Inputs ​ Inputs ​ ​ 2019 ​ 2019 ​ (Level 1) ​ (Level 2) ​ (Level 3) Description: ​ ​ ​ ​ ​ ​ Notes receivable (a) ​ $ 37,899 ​ $ 42,613 ​ $ — ​ $ — ​ $ 42,613 Derivatives - Interest rate contracts (b) ​ 730 ​ 730 ​ — ​ 730 ​ — Total assets ​ $ 38,629 ​ $ 43,343 ​ $ — ​ $ 730 ​ $ 42,613 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives - Interest rate contracts (b) ​ $ 469 ​ $ 469 ​ $ — ​ $ 469 ​ $ — Secured debt instruments - fixed rate: (c) ​ ​ ​ ​ ​ ​ Mortgage notes payable ​ ​ 575,965 ​ ​ 569,318 ​ ​ — ​ ​ — ​ ​ 569,318 Secured debt instruments - variable rate: (c) ​ ​ ​ ​ ​ ​ Tax-exempt secured notes payable ​ 27,000 ​ 27,000 ​ — ​ — ​ 27,000 Unsecured debt instruments: (c) ​ ​ ​ ​ ​ ​ Working capital credit facility ​ ​ 34,447 ​ ​ 34,447 ​ ​ — ​ ​ — ​ ​ 34,447 Commercial paper program ​ ​ 60,000 ​ ​ 60,000 ​ ​ — ​ ​ — ​ ​ 60,000 Unsecured notes ​ ​ 3,260,258 ​ ​ 3,415,618 ​ ​ — ​ ​ — ​ ​ 3,415,618 Total liabilities ​ $ 3,958,139 ​ $ 4,106,852 ​ $ — ​ $ 469 ​ $ 4,106,383 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (d) ​ $ 1,072,181 ​ $ 1,072,181 ​ $ — ​ $ 1,072,181 ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value at December 31, 2018, Using ​ ​ Total ​ ​ ​ Quoted ​ ​ ​ ​ ​ ​ Carrying ​ ​ ​ Prices in ​ ​ ​ ​ ​ ​ Amount in ​ ​ ​ Active ​ ​ ​ ​ ​ ​ Statement of ​ ​ ​ Markets ​ Significant ​ ​ ​ ​ Financial ​ Fair Value ​ for Identical ​ Other ​ Significant ​ ​ Position at ​ Estimate at ​ Assets or ​ Observable ​ Unobservable ​ ​ December 31, ​ December 31, ​ Liabilities ​ Inputs ​ Inputs ​ 2018 ​ 2018 ​ (Level 1) ​ (Level 2) ​ (Level 3) Description: ​ ​ ​ ​ ​ ​ Notes receivable (a) ​ $ 42,259 ​ $ 45,026 ​ $ — ​ $ — ​ $ 45,026 Derivatives - Interest rate contracts (b) ​ 4,757 ​ 4,757 ​ — ​ 4,757 ​ — Total assets ​ $ 47,016 ​ $ 49,783 ​ $ — ​ $ 4,757 ​ $ 45,026 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives - Interest rate contracts (b) ​ $ 356 ​ $ 356 ​ $ — ​ $ 356 ​ $ — Secured debt instruments - fixed rate: (c) ​ ​ ​ ​ ​ ​ Mortgage notes payable ​ ​ 417,989 ​ ​ 416,314 ​ ​ — ​ ​ — ​ ​ 416,314 Fannie Mae credit facility ​ 90,000 ​ 90,213 ​ — ​ — ​ 90,213 Secured debt instruments - variable rate: (c) ​ ​ ​ ​ ​ ​ Tax-exempt secured notes payable ​ 94,700 ​ 94,700 ​ — ​ — ​ 94,700 Unsecured debt instruments: (c) ​ ​ ​ ​ ​ ​ ​ Working capital credit facility ​ ​ 16 ​ ​ 16 ​ ​ — ​ ​ — ​ ​ 16 Commercial paper program ​ ​ 101,115 ​ ​ 101,115 ​ ​ — ​ ​ — ​ ​ 101,115 Unsecured notes ​ ​ 2,861,842 ​ ​ 2,829,390 ​ ​ — ​ ​ — ​ ​ 2,829,390 Total liabilities ​ $ 3,566,018 ​ $ 3,532,104 ​ $ — ​ $ 356 ​ $ 3,531,748 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (d) ​ $ 972,740 ​ $ 972,740 ​ $ — ​ $ 972,740 ​ $ — (a) See Note 2, Significant Accounting Policies . (b) See Note 11, Derivatives and Hedging Activity . (c) See Note 7, Secured and Unsecured Debt, Net . (d) See Note 9, Noncontrolling Interests. There were no transfers into or out of any of the levels of the fair value hierarchy during the nine months ended September 30, 2019. Financial Instruments Carried at Fair Value The fair values of interest rate swaps are determined using the market standard methodology of netting the discounted future fixed cash receipts (or payments) and the discounted expected variable cash payments (or receipts). The variable cash payments (or receipts) are based on an expectation of future interest rates (forward curves) derived from observable market interest rate curves. The fair values of interest rate options are determined using the market standard methodology of discounting the future expected cash receipts that would occur if variable interest rates rise above the strike rate of the caps. The variable interest rates used in the calculation of projected receipts on the cap are based on an expectation of future interest rates derived from observable market interest rate curves and volatilities. The Company incorporates credit valuation adjustments to appropriately reflect both its own nonperformance risk and the respective counterparty’s nonperformance risk in the fair value measurements. In adjusting the fair value of its derivative contracts for the effect of nonperformance risk, the Company has considered the impact of netting and any applicable credit enhancements, such as collateral postings, thresholds, mutual puts, and guarantees. Although the Company has determined that the majority of the inputs used to value its derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with its derivatives utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by itself and its counterparties. However, as of September 30, 2019 and December 31, 2018, 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 September 30, 2019 and December 31, 2018, 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, which includes notes receivable and debt instruments, are classified in Level 3 of the fair value hierarchy due to the significant unobservable inputs that are utilized in their respective valuations. 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 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 Realty L.P.
Entity information
FAIR VALUE OF DERIVATIVES AND FINANCIAL INSTRUMENTS	8. FAIR VALUE OF DERIVATIVES AND FINANCIAL INSTRUMENTS Fair value is based on the price that would be received to sell an asset or the exit price that would be paid to transfer a liability in an orderly transaction between market participants at the measurement date. A three-level valuation hierarchy prioritizes observable and unobservable inputs used to measure fair value. The fair value hierarchy consists of three broad levels, which are described below: ● Level 1 — Quoted prices in active markets for identical assets or liabilities that the entity has the ability to access. ● Level 2 — Observable inputs other than prices included in Level 1, such as quoted prices for similar assets and liabilities in active markets; quoted prices for identical or similar assets and liabilities in markets that are not active; or other inputs that are observable or can be corroborated with observable market data. ● Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets and liabilities. This includes certain pricing models, discounted cash flow methodologies and similar techniques that use significant unobservable inputs. The estimated fair values of the Operating Partnership’s financial instruments either recorded or disclosed on a recurring basis as of September 30, 2019 and December 31, 2018 are summarized as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value at September 30, 2019, Using ​ Total ​ ​ Quoted ​ ​ ​ ​ ​ ​ Carrying ​ ​ ​ ​ Prices in ​ ​ ​ ​ ​ ​ ​ ​ Amount in ​ ​ ​ ​ Active ​ ​ ​ ​ ​ ​ ​ ​ Statement of ​ ​ ​ ​ Markets ​ Significant ​ ​ ​ ​ ​ Financial ​ Fair Value ​ for Identical ​ Other ​ Significant ​ ​ Position at ​ Estimate at ​ Assets or ​ Observable ​ Unobservable ​ ​ September 30, ​ September 30, ​ Liabilities ​ Inputs ​ Inputs ​ ​ 2019 ​ 2019 ​ (Level 1) ​ (Level 2) ​ (Level 3) Description: ​ ​ ​ ​ ​ Secured debt instruments - fixed rate: (a) ​ ​ ​ ​ ​ Mortgage notes payable ​ $ 72,500 ​ $ 68,669 ​ $ — ​ $ — ​ $ 68,669 Secured debt instruments - variable rate: (a) ​ ​ ​ ​ ​ ​ Tax-exempt secured notes payable ​ ​ 27,000 ​ ​ 27,000 ​ ​ — ​ ​ — ​ ​ 27,000 Total liabilities ​ $ 99,500 ​ $ 95,669 ​ $ — ​ $ — ​ $ 95,669 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value at December 31, 2018, Using ​ ​ ​ ​ ​ Quoted ​ ​ ​ ​ ​ ​ Total ​ ​ ​ ​ Prices in ​ ​ ​ ​ ​ ​ ​ ​ Carrying ​ ​ ​ ​ Active ​ ​ ​ ​ ​ ​ ​ ​ Amount in ​ ​ ​ ​ Markets ​ ​ ​ ​ ​ ​ ​ ​ Statement of ​ ​ ​ ​ for Identical ​ Significant ​ ​ ​ ​ ​ Financial ​ Fair Value ​ Assets ​ Other ​ Significant ​ ​ Position at ​ Estimate at ​ or ​ Observable ​ Unobservable ​ ​ December 31, ​ December 31, ​ Liabilities ​ Inputs ​ Inputs ​ ​ 2018 ​ 2018 ​ (Level 1) ​ (Level 2) ​ (Level 3) Description: ​ ​ ​ ​ ​ Secured debt instruments - variable rate: (a) ​ ​ ​ ​ ​ ​ Tax-exempt secured notes payable ​ $ 27,000 ​ $ 27,000 ​ $ — ​ $ — ​ $ 27,000 Total liabilities ​ $ 27,000 ​ $ 27,000 ​ $ — ​ $ — ​ $ 27,000 (a) See Note 6, Debt, Net. ​ There were no transfers into or out of each of the levels of the fair value hierarchy during the nine months ended September 30, 2019. ​ Financial Instruments Carried at Fair Value The fair values of interest rate swaps are determined using the market standard methodology of netting the discounted future fixed cash receipts (or payments) and the discounted expected variable cash payments (or receipts). The variable cash payments (or receipts) are based on an expectation of future interest rates (forward curves) derived from observable market interest rate curves. The fair values of interest rate options are determined using the market standard methodology of discounting the future expected cash receipts that would occur if variable interest rates rise above the strike rate of the caps. The variable interest rates used in the calculation of projected receipts on the cap are based on an expectation of future interest rates derived from observable market interest rate curves and volatilities. The General Partner, on behalf of the Operating Partnership, incorporates credit valuation adjustments to appropriately reflect both its own nonperformance risk and the respective counterparty’s nonperformance risk in the fair value measurements. In adjusting the fair value of its derivative contracts for the effect of nonperformance risk, the Operating Partnership has considered the impact of netting and any applicable credit enhancements, such as collateral postings, thresholds, mutual puts, and guarantees. Although the General Partner, on behalf of the Operating Partnership, has determined that the majority of the inputs used to value its derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with its derivatives utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by itself and its counterparties. However, as of September 30, 2019 and December 31, 2018, the Operating Partnership has assessed the significance of the impact of the credit valuation adjustments on the overall valuation of its derivative positions and has determined that the credit valuation adjustments are not significant to the overall valuation of its derivatives. As a result, the Operating Partnership has determined that its derivative valuations in their entirety are classified in Level 2 of the fair value hierarchy. In conjunction with the FASB’s fair value measurement guidance, the Operating Partnership made an accounting policy election to measure the credit risk of its derivative financial instruments that are subject to master netting agreements on a net basis by counterparty portfolio. Financial Instruments Not Carried at Fair Value As of September 30, 2019, 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, which includes debt instruments, are classified in Level 3 of the fair value hierarchy due to the significant unobservable inputs that are utilized in their respective valuations. 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. The Operating Partnership did not incur any other-than-temporary impairments in the value of its investments in unconsolidated entities during the three and nine months ended September 30, 2019 and 2018.

DERIVATIVES AND HEDGING ACTIV_8

DERIVATIVES AND HEDGING ACTIVITY (UNITED DOMINION REALTY, L.P.)	9 Months Ended
	Sep. 30, 2019
Entity information
DERIVATIVES AND HEDGING ACTIVITY	11. 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 changes in the fair value of derivatives designated and that qualify as cash flow hedges are recorded in Accumulated other comprehensive income/(loss), net Amounts reported in Accumulated other comprehensive income/(loss), net Interest expense As of September 30, 2019, the Company had the following outstanding interest rate derivatives that were designated as cash flow hedges of interest rate risk ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ Number of ​ Product ​ Instruments ​ Notional Interest rate swaps (a) ​ 4 ​ $ 315,000 (a) In addition to the interest rate swaps summarized above, the Company entered into an additional interest rate swap with a notional value of $315.0 million that will become effective in January 2020 upon the maturity of the interest rate swaps summarized above. Additionally, the Company had previously entered into two additional interest rate swaps with a notional value totaling $75.0 million that were subsequently terminated and settled during the nine months ended September 30, 2019 in conjunction with the July 2019 issuance of $300.0 million of senior unsecured medium-term notes as disclosed in Note 7, Secured and Unsecured, Net ​ 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 no gain or loss for both the three and nine months ended September 30, 2019 and 2018. As of September 30, 2019, the Company had the following outstanding derivatives that were not designated as hedges in qualifying hedging relationships ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ Number of ​ ​ Product ​ Instruments ​ Notional Interest rate caps ​ 1 ​ $ 19,880 ​ Tabular Disclosure of Fair Values of Derivative Instruments on the Consolidated Balance Sheet The table below presents the fair value of the Company’s derivative financial instruments as well as their classification on the Consolidated Balance Sheets as of September 30, 2019 and December 31, 2018 ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Asset Derivatives ​ Liability Derivatives ​ ​ (included in Other assets ) ​ (included in Other liabilities ) ​ ​ Fair Value at: ​ Fair Value at: ​ ​ September 30, ​ December 31, ​ September 30, ​ December 31, ​ ​ 2019 ​ 2018 ​ 2019 ​ 2018 Derivatives designated as hedging instruments: ​ ​ ​ ​ Interest rate products ​ $ 730 ​ $ 4,757 ​ $ 469 ​ $ 356 ​ Tabular Disclosure of the Effect of Derivative Instruments on the Consolidated Statements of Operations The tables below present the effect of the Company’s derivative financial instruments on the Consolidated Statements of Operations for the three and nine months ended September 30, 2019 and 2018 ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gain/(Loss) Recognized in ​ ​ ​ ​ Gain/(Loss) Reclassified ​ Interest expense ​ ​ Unrealized holding gain/(loss) ​ from Accumulated OCI into ​ (Amount Excluded from ​ ​ Recognized in OCI ​ Interest expense ​ Effectiveness Testing) Derivatives in Cash Flow Hedging Relationships 2019 2018 2019 2018 2019 2018 Three Months Ended September 30, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate products ​ $ (659) ​ $ 2,320 ​ $ 624 ​ $ 564 ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate products ​ $ (7,181) ​ $ 4,312 ​ $ 2,504 ​ $ 1,162 ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, ​ September 30, ​ ​ 2019 ​ 2018 ​ 2019 ​ 2018 Total amount of Interest expense ​ $ 42,523 ​ $ 34,401 ​ $ 110,482 ​ $ 95,942 ​ The Company did not recognize any gain/(loss) in Interest income and other income/(expense), net Credit-risk-related Contingent Features The Company has agreements with its derivative counterparties that contain a provision where 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. 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 September 30, 2019, the fair value of derivatives was in a net asset position, which includes accrued interest but excludes any adjustment for nonperformance risk related to these agreements, of $0.5 million. Tabular Disclosure of Offsetting Derivatives The Company has elected not to offset derivative positions on the consolidated financial statements. The tables below present the effect on its financial position had the Company made the election to offset its derivative positions as of September 30, 2019 and December 31, 2018 (dollars in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross Net Amounts of Gross Amounts Not Offset ​ ​ ​ ​ ​ ​ ​ ​ Amounts ​ Assets ​ in the Consolidated ​ ​ ​ ​ ​ Gross ​ Offset in the ​ Presented in the ​ Balance Sheet ​ ​ ​ ​ ​ Amounts of ​ Consolidated ​ Consolidated ​ ​ ​ ​ Cash ​ ​ ​ ​ ​ Recognized ​ Balance ​ Balance Sheets ​ Financial ​ Collateral ​ ​ ​ Offsetting of Derivative Assets ​ Assets ​ Sheets ​ (a) ​ Instruments Received Net Amount September 30, 2019 ​ $ 730 ​ $ — ​ $ 730 ​ $ (371) ​ $ — ​ $ 359 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2018 ​ $ 4,757 ​ $ — ​ $ 4,757 ​ $ — ​ $ — ​ $ 4,757 (a) Amounts reconcile to the aggregate fair value of derivative assets in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Consolidated Balance Sheets” located in this footnote. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross Net Amounts of Gross Amounts Not Offset ​ ​ ​ ​ ​ ​ ​ ​ Amounts ​ Liabilities ​ in the Consolidated ​ ​ ​ ​ ​ Gross ​ Offset in the ​ Presented in the ​ Balance Sheet ​ ​ ​ ​ ​ Amounts of ​ Consolidated ​ Consolidated ​ ​ ​ ​ Cash ​ ​ ​ ​ ​ Recognized ​ Balance ​ Balance Sheets ​ Financial ​ Collateral ​ ​ ​ Offsetting of Derivative Liabilities Liabilities Sheets (a) Instruments Posted Net Amount September 30, 2019 ​ $ 469 ​ $ — ​ $ 469 ​ $ (371) ​ $ — ​ $ 98 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2018 ​ $ 356 ​ $ — ​ $ 356 ​ $ — ​ $ — ​ $ 356 (a) Amounts reconcile to the aggregate fair value of derivative liabilities in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Consolidated Balance Sheets” located in this footnote.
United Dominion Realty L.P.
Entity information
DERIVATIVES AND HEDGING ACTIVITY	9. 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 upfront premium. A portion of the General Partner’s interest rate derivatives are owed by the Operating Partnership based on the General Partner’s underlying debt instruments owed by the Operating Partnership. (See Note 6, Debt, Net. The changes in the fair value of derivatives designated and that qualify as cash flow hedges is recorded in Accumulated other comprehensive income/(loss), net Amounts reported in Accumulated other comprehensive income/(loss), net 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 no gain or loss for each of the three and nine months ended September 30, 2019 and 2018. As of September 30, 2019, we had the following outstanding derivatives that were not designated as hedges in qualifying hedging relationships ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ Number of ​ ​ Product ​ Instruments ​ Notional Interest rate caps 1 ​ $ 19,880 ​ Tabular Disclosure of Fair Values of Derivative Instruments on the Consolidated Balance Sheets As of September 30, 2019 and December 31, 2018, the fair value of the Operating Partnership’s derivative financial instruments was zero. Tabular Disclosure of the Effect of Derivative Instruments on the Consolidated Statements of Operations During the three and nine months ended September 30, 2019 and 2018, the Operating Partnership’s derivative instruments did not impact the Consolidated Statement of Operations. Credit-risk-related Contingent Features The General Partner has agreements with its derivative counterparties that contain a provision where 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. 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.

CAPITAL STRUCTURE (UNITED DOMIN

CAPITAL STRUCTURE (UNITED DOMINION REALTY, L.P.)	9 Months Ended
	Sep. 30, 2019
United Dominion Realty L.P.
Entity information
CAPITAL STRUCTURE	10. CAPITAL STRUCTURE General Partnership Units The General Partner has complete discretion to manage and control the operations and business of the Operating Partnership, which includes but is not limited to the acquisition and disposition of real property, construction of buildings and making capital improvements, and the borrowing of funds from outside lenders or UDR and its subsidiaries to finance such activities. The General Partner can generally authorize, issue, sell, redeem or purchase any OP Unit or securities of the Operating Partnership without the approval of the limited partners. The General Partner can also approve, with regard to the issuances of OP Units, the class or one or more series of classes, with designations, preferences, participating, optional or other special rights, powers and duties including rights, powers and duties senior to limited partnership interests without approval of any limited partners except holders of Class A Limited Partnership Units. There were 110,883 General Partnership units outstanding at September 30, 2019 and December 31, 2018, all of which were held by UDR. Limited Partnership Units As of September 30, 2019 and December 31, 2018, there were 183,952,659 and 183,525,660, respectively, of limited partnership units outstanding, of which 1,873,332 were Class A Limited Partnership Units for both periods. UDR owned 176,099,189, or 95.7%, and 174,137,816, or 94.9%, of OP Units outstanding at September 30, 2019 and December 31, 2018, respectively, of which 121,661 were Class A Limited Partnership Units for both periods. The remaining 7,853,470, or 4.3%, and 9,387,844, or 5.1%, of OP Units outstanding were held by non-affiliated partners at September 30, 2019 and December 31, 2018, respectively, of which 1,751,671 were Class A Limited Partnership Units for both periods. 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 non-affiliated limited partners was $380.7 million and $371.9 million as of September 30, 2019 and December 31, 2018, respectively, based on the value of UDR’s common stock at each period end. A limited partner has no right to receive any distributions from the Operating Partnership on or after the date of redemption of its OP Units. Class A Limited Partnership Units Class A Limited Partnership Units have a cumulative, annual, non-compounded preferred return, which is equal to 8% based on a value of $16.61 per Class A Limited Partnership Unit. Holders of the Class A Limited Partnership Units exclusively possess certain voting rights. The Operating Partnership may not do the following without approval of the holders of the Class A Limited Partnership Units: (i) increase the authorized or issued amount of Class A Limited Partnership Units, (ii) reclassify any other partnership interest into Class A Limited Partnership Units, (iii) create, authorize or issue any obligations or security convertible into or the right to purchase Class A Limited Partnership Units, (iv) enter into a merger or acquisition, or (v) amend or modify the Operating Partnership Agreement in a manner that adversely affects the relative rights, preferences or privileges of the Class A Limited Partnership Units. The following table shows OP Units outstanding and OP Unit activity as of and for the nine months ended September 30, 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ UDR, Inc. ​ ​ ​ Class A ​ ​ Class A ​ ​ ​ ​ Limited ​ Limited ​ Limited ​ Limited ​ General ​ ​ ​ ​ Partners ​ Partners ​ Partner ​ Partner ​ Partner ​ Total Ending balance at December 31, 2018 ​ 1,751,671 ​ 7,636,173 ​ 174,016,155 ​ 121,661 ​ 110,883 ​ 183,636,543 Vesting of LTIP Units ​ — ​ 426,999 ​ — ​ — ​ — ​ 426,999 OP redemptions for UDR stock — (1,961,373) ​ 1,961,373 — — — Ending balance at September 30, 2019 1,751,671 6,101,799 175,977,528 121,661 110,883 184,063,542 ​ 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 certain employees and non-employee directors and vest over a period of up to four years. 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_3

COMMITMENTS AND CONTINGENCIES (UNITED DOMINION REALTY, L.P.) Commitments and Contingencies (UNITED DOMINION REALTY, L.P.)	9 Months Ended
	Sep. 30, 2019
Entity information
COMMITMENTS AND CONTINGENCIES	13. COMMITMENTS AND CONTINGENCIES Commitments Real Estate Commitments The following summarizes the Company’s real estate commitments at September 30, 2019 ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number ​ UDR's ​ UDR's Remaining ​ ​ ​ Properties ​ Investment (a) ​ Commitment ​ Wholly-owned — under development 1 ​ $ 21,845 ​ $ 75,655 Wholly-owned — redevelopment 2 ​ ​ 11,582 ​ ​ 23,918 Joint ventures: ​ ​ Unconsolidated joint ventures - development 1 ​ 14,402 ​ 21,496 (b) Preferred equity investments 2 ​ ​ 53,781 (c) ​ 27,390 (d) Other investments ​ - ​ ​ 12,926 ​ ​ 9,000 (e) Total ​ $ 114,536 ​ $ 157,459 (a) Represents UDR’s investment as of September 30, 2019. (b) Represents UDR’s proportionate share of expected remaining costs to complete the development. (c) Represents UDR’s investment in 1300 Fairmount and Modera Lake Merritt for the properties under development as of September 30, 2019. (d) Represents UDR’s remaining commitment for 1300 Fairmount and Modera Lake Merritt. (e) Represents UDR’s remaining commitment for other investment ventures. ​ Purchase Commitments ​ In 2019, the Company entered into a contract to purchase a development land parcel located in King of Prussia, Pennsylvania for a purchase price of approximately $14.8 million. The Company made a $0.8 million deposit on the purchase, which is generally non-refundable other than due to a failure of closing conditions pursuant to the terms of the purchase agreement. The acquisition is expected to close in 2020, subject to customary closing conditions. ​ 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 flows.
United Dominion Realty L.P.
Entity information
COMMITMENTS AND CONTINGENCIES	11. COMMITMENTS AND CONTINGENCIES Commitments Real Estate Commitments The following summarizes the Operating Partnership’s real estate commitments at September 30, 2019 ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number ​ ​ ​ Operating Partnership's ​ ​ Properties ​ Investment ​ Remaining Commitment Real estate communities - redevelopment 1 ​ $ 6,254 ​ $ 18,746 ​ 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 flows.

REPORTABLE SEGMENTS (UNITED DOM

REPORTABLE SEGMENTS (UNITED DOMINION REALTY, L.P.)	9 Months Ended
	Sep. 30, 2019
Entity information
REPORTABLE SEGMENTS	14. 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 2.875% 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 Non-Mature Communities/Other ● Same-Store Communities represent those communities acquired, developed, and stabilized prior to July 1, 2018 (for quarter-to-date comparison) or January 1, 2018 (for year-to-date comparison) and held as of September 30, 2019. A comparison of operating results from the prior year is meaningful as these communities were owned and had stabilized occupancy and operating expenses as of the beginning of the prior period, there is no plan to conduct substantial redevelopment activities, and the community is not held for disposition within the current year. A community is considered to have stabilized occupancy once it achieves 90% occupancy for at least three consecutive months. ● Non-Mature Communities/Other represent those communities that do not meet the criteria to be included in Same-Store Communities , including, but not limited to, recently acquired, developed and redeveloped communities, and the non-apartment components of mixed use properties. Management evaluates the performance of each of our apartment communities on a Same-Store Community Non-Mature Community/Other Revenue is measured based on consideration specified in contracts with customers. The Company recognizes revenue when it satisfies a performance obligation by providing the services specified in a contract to the customer. All revenues are from external customers and no single tenant or related group of tenants contributed 10% or more of UDR’s total revenues during the three and nine months ended September 30, 2019 and 2018. ​ The following is a description of the principal streams from which the Company generates its revenue: Lease Revenue ​ Lease revenue related to leases is recognized on an accrual basis when due from residents or tenants in accordance with ASC 842, Leases ​ Lease revenue also includes all pass-through revenue from retail and residential leases and common area maintenance reimbursements from retail leases. These services represent non-lease components in a contract as the Company transfers a service to the lessee other than the right to use the underlying asset. The Company has elected the practical expedient under the leasing standard to not separate lease and non-lease components from its resident and retail lease contracts as the timing and pattern of revenue recognition for the non-lease component and related lease component are the same and the combined single lease component would be classified as an operating lease. ​ Other Revenue ​ ​ Joint venture management and other fees ​ The Joint venture management and other fees Joint venture management and other fees ​ The following table details rental income and NOI for UDR’s reportable segments for the three and nine months ended September 30, 2019 and 2018, and reconciles NOI to Net income/(loss) attributable to UDR, Inc. (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, (a) ​ September 30, (b) ​ 2019 2018 2019 2018 Reportable apartment home segment lease revenue ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Same-Store Communities ​ ​ ​ ​ ​ West Region ​ $ 99,316 ​ $ 95,447 ​ $ 293,294 ​ $ 281,722 Mid-Atlantic Region ​ 52,826 ​ 51,291 ​ 157,179 ​ 152,867 Southeast Region ​ 28,540 ​ 27,773 ​ 84,551 ​ 81,554 Northeast Region ​ 30,196 ​ 29,491 ​ 89,650 ​ 87,776 Southwest Region ​ 15,451 ​ 15,060 ​ 40,705 ​ 39,586 Non-Mature Communities/Other ​ 40,975 ​ 24,237 ​ 106,499 ​ 66,906 Total segment and consolidated rental income ​ $ 267,304 ​ $ 243,299 ​ $ 771,878 ​ $ 710,411 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Reportable apartment home segment other revenue ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Same-Store Communities ​ ​ ​ ​ ​ West Region ​ $ 7,869 ​ $ 7,168 ​ $ 23,488 ​ $ 21,567 Mid-Atlantic Region ​ 4,376 ​ 4,032 ​ 12,958 ​ 11,944 Southeast Region ​ 3,438 ​ 3,211 ​ 10,423 ​ 9,918 Northeast Region ​ 1,321 ​ 1,226 ​ 3,753 ​ 3,422 Southwest Region ​ 1,527 ​ 1,525 ​ 4,100 ​ 3,986 Non-Mature Communities/Other ​ 3,173 ​ 2,795 ​ 8,793 ​ 9,125 Total segment and consolidated rental income ​ $ 21,704 ​ $ 19,957 ​ $ 63,515 ​ $ 59,962 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total reportable apartment home segment rental income ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Same-Store Communities ​ ​ ​ ​ ​ West Region ​ $ 107,185 ​ $ 102,615 ​ $ 316,782 ​ $ 303,289 Mid-Atlantic Region ​ 57,202 ​ 55,323 ​ 170,137 ​ 164,811 Southeast Region ​ 31,978 ​ 30,984 ​ 94,974 ​ 91,472 Northeast Region ​ 31,517 ​ 30,717 ​ 93,403 ​ 91,198 Southwest Region ​ 16,978 ​ 16,585 ​ 44,805 ​ 43,572 Non-Mature Communities/Other ​ 44,148 ​ 27,032 ​ 115,292 ​ 76,031 Total segment and consolidated rental income ​ $ 289,008 ​ $ 263,256 ​ $ 835,393 ​ $ 770,373 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Reportable apartment home segment NOI ​ ​ ​ ​ Same-Store Communities ​ ​ ​ ​ West Region ​ $ 81,170 ​ $ 77,321 ​ $ 240,442 ​ $ 229,129 Mid-Atlantic Region ​ 39,850 ​ 38,220 ​ 119,075 ​ 114,465 Southeast Region ​ 22,133 ​ 21,597 ​ 66,301 ​ 63,806 Northeast Region ​ 20,560 ​ 20,640 ​ 63,012 ​ 62,710 Southwest Region ​ 10,449 ​ 9,899 ​ 26,995 ​ 25,760 Non-Mature Communities/Other ​ 29,487 ​ 17,137 ​ 77,242 ​ 48,833 Total segment and consolidated NOI ​ 203,649 ​ 184,814 ​ 593,067 ​ 544,703 Reconciling items: ​ ​ ​ ​ Joint venture management and other fees ​ 6,386 ​ 2,888 ​ 11,982 ​ 8,819 Property management ​ (8,309) ​ (7,240) ​ (24,018) ​ (21,185) Other operating expenses ​ (2,751) ​ (3,314) ​ (11,132) ​ (8,148) Real estate depreciation and amortization ​ (127,391) ​ (107,881) ​ (357,793) ​ (322,537) General and administrative ​ (12,197) ​ (11,896) ​ (37,002) ​ (36,028) Casualty-related (charges)/recoveries, net ​ 1,088 ​ (678) ​ 842 ​ (2,364) Other depreciation and amortization ​ (1,619) ​ (1,682) ​ (4,953) ​ (5,057) Gain/(loss) on sale of real estate owned ​ ​ — ​ ​ — ​ ​ 5,282 ​ ​ 70,300 Income/(loss) from unconsolidated entities ​ 12,713 ​ (1,382) ​ 19,387 ​ (5,091) Interest expense ​ (42,523) ​ (34,401) ​ (110,482) ​ (95,942) Interest income and other income/(expense), net ​ 1,875 ​ 1,188 ​ 12,998 ​ 5,075 Tax (provision)/benefit, net ​ (1,499) ​ (158) ​ (3,836) ​ (618) Net (income)/loss attributable to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership ​ (2,162) ​ (1,616) ​ (6,871) ​ (10,819) Net (income)/loss attributable to noncontrolling interests ​ (56) ​ (32) ​ (145) ​ (141) Net income/(loss) attributable to UDR, Inc. ​ $ 27,204 ​ $ 18,610 ​ $ 87,326 ​ $ 120,967 (a) Same-Store Community population consisted of 38,177 apartment homes. (b) Same-Store Community population consisted of 37,959 apartment homes. ​ The following table details the assets of UDR’s reportable segments as of September 30, 2019 and December 31, 2018 (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2019 ​ 2018 Reportable apartment home segment assets: ​ ​ Same-Store Communities (a): ​ ​ West Region ​ $ 3,797,149 ​ $ 3,763,366 Mid-Atlantic Region ​ 2,338,963 ​ 2,317,369 Southeast Region ​ 799,739 ​ 779,310 Northeast Region ​ 1,498,500 ​ 1,491,994 Southwest Region ​ 595,982 ​ 589,188 Non-Mature Communities/Other ​ 2,534,062 ​ 1,254,932 Total segment assets ​ 11,564,395 ​ 10,196,159 Accumulated depreciation ​ (4,000,608) ​ (3,654,160) Total segment assets — net book value ​ 7,563,787 ​ 6,541,999 Reconciling items: ​ ​ Cash and cash equivalents ​ 1,895 ​ 185,216 Restricted cash ​ 21,646 ​ 23,675 Notes receivable, net ​ 37,899 ​ 42,259 Investment in and advances to unconsolidated joint ventures, net ​ 791,180 ​ 780,869 Operating lease right-of-use assets ​ ​ 135,889 ​ ​ — Other assets ​ 145,301 ​ 137,710 Total consolidated assets ​ $ 8,697,597 ​ $ 7,711,728 (a) Same-Store Community population consisted of 38,177 apartment homes. ​ 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., Richmond and Baltimore iii. Southeast Region — Orlando, Nashville, Tampa and Other Florida iv. Northeast Region — New York and Boston v. Southwest Region — Dallas, Austin and Denver
United Dominion Realty L.P.
Entity information
REPORTABLE SEGMENTS	12. REPORTABLE SEGMENTS GAAP guidance requires that segment disclosures present the measure(s) used by the Chief Operating Decision Maker to decide how to allocate resources and for purposes of assessing such segments’ performance. The Operating Partnership has the same Chief Operating Decision Maker as that of its parent, the General Partner. The Chief Operating Decision Maker consists of several members of UDR’s executive management team who use several generally accepted industry financial measures to assess the performance of the business for our reportable operating segments. The Operating Partnership owns and operates multifamily apartment communities throughout the United States that generate rental and other property related income through the leasing of apartment homes to a diverse base of tenants. The primary financial measures of the Operating Partnership’s apartment communities are rental income and net operating income (“NOI”), and are included in the Chief Operating Decision Maker’s assessment of the Operating Partnership’s performance on a consolidated basis. Rental income represents gross market rent less adjustments for concessions, vacancy loss and bad debt. NOI is defined as total revenues less direct property operating expenses. Rental expenses include real estate taxes, insurance, personnel, utilities, repairs and maintenance, administrative and marketing. Excluded from NOI are property management costs, which are the Operating Partnership’s allocable share of costs incurred by the General Partner for shared services of corporate level property management employees and related support functions and costs. The Chief Operating Decision Maker of the General Partner utilizes NOI as the key measure of segment profit or loss. The Operating Partnership’s two reportable segments are Same-Store Communities Non-Mature Communities/Other: ● Same-Store Communities represent those communities acquired, developed, and stabilized prior to July 1, 2018 (for the quarter-to-date comparison) or January 1, 2018 (for the year-to-date) and held as of September 30, 2019. A comparison of operating results from the prior year is meaningful as these communities were owned and had stabilized occupancy and operating expenses as of the beginning of the prior period, there is no plan to conduct substantial redevelopment activities, and the community is not held for disposition within the current year. A community is considered to have stabilized occupancy once it achieves 90% occupancy for at least three consecutive months. ● Non-Mature Communities/Other represent those communities that do not meet the criteria to be included in Same-Store Communities , including, but not limited to, recently acquired, developed and redeveloped communities, and the non-apartment components of mixed use properties. Management of the General Partner evaluates the performance of each of the Operating Partnership’s apartment communities on a Same-Store Community Non-Mature Community/Other All revenues are from external customers and no single tenant or related group of tenants contributed 10% or more of the Operating Partnership’s total revenues during the three and nine months ended September 30, 2019 and 2018. The following is a description of the principal streams from which the Operating Partnership generates its revenue: Lease Revenue ​ Lease revenue related to leases is recognized on an accrual basis when due from residents or tenants in accordance with ASC 842, Leases ​ Lease revenue also includes all pass-through revenue from retail and residential leases and common area maintenance reimbursements from retail leases. These services represent non-lease components in a contract as the Operating Partnership transfers a service to the lessee other than the right to use the underlying asset. The Operating Partnership has elected the practical expedient under the leasing standard to not separate lease and non-lease components from its resident and retail lease contracts as the timing and pattern of revenue recognition for the non-lease component and related lease component are the same and the combined single lease component would be classified as an operating lease. ​ Other Revenue ​ ​ The following table details rental income and NOI for the Operating Partnership’s reportable segments for the three and nine months ended September 30, 2019 and 2018, and reconciles NOI to Net income/(loss) attributable to OP unitholders (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, (a) ​ September 30, (b) ​ ​ 2019 2018 2019 2018 ​ Reportable apartment home segment lease revenue ​ ​ ​ ​ ​ Same-Store Communities ​ ​ ​ ​ ​ West Region ​ $ 62,760 ​ $ 60,569 ​ $ 185,840 ​ $ 178,401 ​ Mid-Atlantic Region ​ 14,900 ​ 14,645 ​ 44,592 ​ 43,814 ​ Southeast Region ​ 12,808 ​ 12,604 ​ 37,957 ​ 36,782 ​ Northeast Region ​ 8,098 ​ 7,936 ​ 24,036 ​ 23,541 ​ Southwest Region ​ ​ 1,901 ​ ​ 1,865 ​ ​ — ​ ​ — ​ Non-Mature Communities/Other ​ 7,468 ​ 8,694 ​ 27,295 ​ 30,830 ​ Total segment and consolidated rental income ​ $ 107,935 ​ $ 106,313 ​ $ 319,720 ​ $ 313,368 ​ Reportable apartment home segment other revenue ​ ​ ​ ​ ​ Same-Store Communities ​ ​ ​ ​ ​ West Region ​ $ 2,063 ​ $ 1,750 ​ $ 5,908 ​ $ 5,484 ​ Mid-Atlantic Region ​ 551 ​ 441 ​ 1,515 ​ 1,359 ​ Southeast Region ​ 799 ​ 658 ​ 2,301 ​ 2,099 ​ Northeast Region ​ 187 ​ 178 ​ 521 ​ 496 ​ Southwest Region ​ ​ 87 ​ ​ 58 ​ ​ — ​ ​ — ​ Non-Mature Communities/Other ​ 78 ​ 141 ​ 419 ​ 591 ​ Total segment and consolidated rental income ​ $ 3,765 ​ $ 3,226 ​ $ 10,664 ​ $ 10,029 ​ Total reportable apartment home segment rental income ​ ​ ​ ​ ​ Same-Store Communities ​ ​ ​ ​ ​ West Region ​ $ 64,823 ​ $ 62,319 ​ $ 191,748 ​ $ 183,885 ​ Mid-Atlantic Region ​ 15,451 ​ 15,086 ​ 46,107 ​ 45,173 ​ Southeast Region ​ 13,607 ​ 13,262 ​ 40,258 ​ 38,881 ​ Northeast Region ​ 8,285 ​ 8,114 ​ 24,557 ​ 24,037 ​ Southwest Region ​ ​ 1,988 ​ ​ 1,923 ​ ​ — ​ ​ — ​ Non-Mature Communities/Other ​ 7,546 ​ 8,835 ​ 27,714 ​ 31,421 ​ Total segment and consolidated rental income ​ $ 111,700 ​ $ 109,539 ​ $ 330,384 ​ $ 323,397 ​ Reportable apartment home segment NOI ​ ​ ​ ​ ​ Same-Store Communities ​ ​ ​ ​ ​ West Region ​ $ 49,528 ​ $ 47,692 ​ $ 146,673 ​ $ 140,603 ​ Mid-Atlantic Region ​ 10,611 ​ 10,178 ​ 31,691 ​ 30,953 ​ Southeast Region ​ 9,371 ​ 9,336 ​ 27,984 ​ 26,979 ​ Northeast Region ​ 5,736 ​ 6,001 ​ 18,201 ​ 18,260 ​ Southwest Region ​ ​ 1,405 ​ ​ 1,253 ​ ​ — ​ ​ — ​ Non-Mature Communities/Other ​ 4,181 ​ 5,688 ​ 17,102 ​ 21,177 ​ Total segment and consolidated NOI ​ 80,832 ​ 80,148 ​ 241,651 ​ 237,972 ​ Reconciling items: ​ ​ ​ ​ ​ Property management ​ (3,211) ​ (3,012) ​ (9,498) ​ (8,893) ​ Other operating expenses ​ (2,301) ​ (2,347) ​ (7,123) ​ (6,098) ​ Real estate depreciation and amortization ​ (35,155) ​ (35,043) ​ (104,730) ​ (108,906) ​ General and administrative ​ (4,066) ​ (4,143) ​ (12,878) ​ (12,997) ​ Casualty-related (charges)/recoveries, net ​ 1,088 ​ 10 ​ 1,169 ​ (906) ​ Gain/(loss) on sale of real estate owned ​ — ​ — ​ — ​ 70,300 ​ Income/(loss) from unconsolidated entities ​ (2,383) ​ (2,378) ​ (6,917) ​ (10,102) ​ Interest expense ​ (7,521) ​ (5,100) ​ (22,247) ​ (15,209) ​ Net (income)/loss attributable to noncontrolling interests ​ (448) ​ (440) ​ (1,252) ​ (1,278) ​ Net income/(loss) attributable to OP unitholders ​ $ 26,835 ​ $ 27,695 ​ $ 78,175 ​ $ 143,883 ​ (a) Same-Store Community population consisted of 15,941 apartment homes. (b) Same-Store Community population consisted of 15,723 apartment homes. ​ The following table details the assets of the Operating Partnership’s reportable segments as of September 30, 2019 and December 31, 2018 (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2019 ​ 2018 Reportable apartment home segment assets ​ ​ Same-Store Communities (a): ​ ​ West Region ​ $ 2,003,088 ​ $ 1,981,007 Mid-Atlantic Region ​ 667,755 ​ 663,083 Southeast Region ​ 349,767 ​ 340,722 Northeast Region ​ 408,244 ​ 406,149 Southwest Region ​ ​ 144,028 ​ ​ 141,882 Non-Mature Communities/Other ​ 288,872 ​ 279,142 Total segment assets ​ 3,861,754 ​ 3,811,985 Accumulated depreciation ​ (1,762,168) ​ (1,658,161) Total segment assets - net book value ​ 2,099,586 ​ 2,153,824 Reconciling items: ​ ​ Cash and cash equivalents ​ 40 ​ 125 Restricted cash ​ 14,637 ​ 13,563 Investment in unconsolidated entities ​ 82,269 ​ 103,026 Operating lease right-of-use assets ​ ​ 135,766 ​ ​ — Other assets ​ 23,321 ​ 34,052 Total consolidated assets ​ $ 2,355,619 ​ $ 2,304,590 (a) Same-Store Community population consisted of 15,941 apartment homes. ​ Markets included in the above geographic segments are as follows: i. West Region — Orange County, San Francisco, Seattle, Los Angeles, Monterey Peninsula, Other Southern California and Portland ii. Mid-Atlantic Region — Metropolitan, D.C. and Baltimore iii. Southeast Region — Nashville, Tampa and Other Florida iv. Northeast Region — New York and Boston v. Southwest Region — Denver

SIGNIFICANT ACCOUNTING POLICI_6

SIGNIFICANT ACCOUNTING POLICIES (UNITED DOMINION REALTY, L.P.) (Policies)	9 Months Ended
	Sep. 30, 2019
Entity information
Recent Accounting Pronouncements	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 Codification Improvements to Topic 326, Financial Instruments—Credit Losses, ​ In February 2016, the FASB issued ASU 2016-02, Leases ​ The Company elected the following package of practical expedients provided by the standard: (i) an entity need not reassess whether any expired or existing contract is a lease or contains a lease, (ii) an entity need not reassess the lease classification of any expired or existing leases, and (iii) an entity need not reassess initial direct costs for any existing leases. The Company also elected the short-term lease exception provided for in the standard and therefore only recognizes right-of-use assets and lease liabilities for leases with a term greater than one year. ​ The Company recognized right-of-use assets of $94.3 million and lease liabilities of $88.3 million as of January 1, 2019 upon adoption of the standard. The right-of-use assets included $6.0 million of prepaid rent and intangible assets that was included within Other assets ​ The lease liabilities represent the present value of the remaining minimum lease payments as of January 1, 2019 and primarily relate to ground leases for communities where we are the lessee. The right-of-use assets represent our right to use an underlying asset for the lease term, which are calculated utilizing the lease liabilities plus any prepaid lease payments and intangible assets for ground leases acquired in the purchase of real estate. Our right-of-use assets and related lease liabilities recognized as of January 1, 2019 may change as a result of updates to the projected future minimum lease payments. Certain of our ground lease agreements where we are the lessee have future minimum lease payments that reset in the future based upon a percentage of the fair market value of the land at the time of the reset. The Company will continue to recognize lease expense for these leases in a manner similar to previous accounting based on our election of the package of practical expedients. However, in the event we modify existing ground leases and/or enter into new ground leases subsequent to the adoption of the standard, such leases would likely be classified as finance leases under the standard and require expense recognition based on the effective interest method. Under the standard, initial direct costs for both lessees and lessors would include only those costs that are incremental to the arrangement and would not have been incurred if the lease had not been obtained. As a result, subsequent to the adoption of the standard, we are now expensing non-incremental leasing costs as incurred. ​ In July 2018, the FASB issued ASU 2018-11, Leases – Targeted Improvements Leases
Principles of Consolidation	Principles of Consolidation The Company accounts for subsidiary partnerships, joint ventures and other similar entities in which it holds an ownership interest in accordance with the consolidation guidance. The Company first evaluates whether each entity is a variable interest entity (“VIE”). Under the VIE model, the Company consolidates an entity when it has control to direct the activities of the VIE and the obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE. Under the voting model, the Company consolidates an entity when it controls the entity through ownership of a majority voting interest.
Real Estate Sales Gain Recognition	Real Estate Sales Gain Recognition ​ For sale transactions resulting in a transfer of a controlling financial interest of a property, the Company generally derecognizes the related assets and liabilities from its Consolidated Balance Sheets and records the gain or loss in the period in which the transfer of control occurs. If control of the property has not transferred to the counterparty, the criteria for derecognition are not met and the Company will continue to recognize the related assets and liabilities on its Consolidated Balance Sheets. ​ Sale transactions to entities in which the Company sells a controlling financial interest in a property but retains a noncontrolling interest are accounted for as partial sales. Partial sales resulting in a change in control are accounted for at fair value and a full gain or loss is recognized. Therefore, the Company will record a gain or loss on the partial interest sold, and the initial measurement of our retained interest will be accounted for at fair value. ​ Sales of real estate to joint ventures or other noncontrolled investees are also accounted for at fair value and the Company will record a full gain or loss in the period the property is contributed. ​ To the extent that the Company acquires a controlling financial interest in a property that it previously accounted for as an equity method investment, the Company will not remeasure its previously held interest if the acquisition is treated as an asset acquisition. The Company will include the carrying amount of its previously held equity method interest along with the consideration paid and transaction costs incurred in determining the amounts to allocate to the related assets and liabilities acquired on its Consolidated Balance Sheets. When treated as an asset acquisition, the Company will not recognize a gain or loss on consolidation of a property.
Comprehensive Income/(Loss)	Comprehensive Income/(Loss) Comprehensive income/(loss), which is defined as the change in equity during each period from transactions and other events and circumstances from nonowner sources, including all changes in equity during a period except for those resulting from investments by or distributions to stockholders, is displayed in the accompanying Consolidated Statements of Comprehensive Income/(Loss). For the three and nine months ended September 30, 2019 and 2018, the Company’s other comprehensive income/(loss) consisted of the gain/(loss) 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 Derivatives and Hedging Activity,
Income Taxes	Income Taxes Due to the structure of the Company as a REIT and the nature of the operations for the operating properties, no provision for federal income taxes has been provided for at UDR. Historically, the Company has generally incurred only state and local excise and franchise taxes. UDR has elected for certain consolidated subsidiaries to be treated as taxable REIT subsidiaries (“TRS”). Income taxes for our TRS are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities from a change in tax rate is recognized in earnings in the period of the enactment date. The Company’s deferred tax assets are generally the result of differing depreciable lives on capitalized assets and timing of expense recognition for certain accrued liabilities. As of September 30, 2019 and December 31, 2018, UDR’s net deferred tax asset/(liability) was $(1.3) million and less than $(0.1) million, respectively. GAAP defines a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. GAAP also provides guidance on derecognition, classification, interest and penalties, accounting for interim periods, disclosure and transition. The Company recognizes its tax positions and evaluates them using a two-step process. First, UDR determines whether a tax position is more likely than not (greater than 50 percent probability) to be sustained upon examination, including resolution of any related appeals or litigation processes, based on the technical merits of the position. Second, the Company will determine the amount of benefit to recognize and record the amount that is more likely than not to be realized upon ultimate settlement. UDR had no material unrecognized tax benefit, accrued interest or penalties at September 30, 2019. UDR and its subsidiaries are subject to federal income tax as well as income tax of various state and local jurisdictions. The tax years 2016 through 2018 remain open to examination by tax jurisdictions to which we are subject. When applicable, UDR recognizes interest and/or penalties related to uncertain tax positions in Tax (provision)/benefit, net
United Dominion Realty L.P.
Entity information
Recent Accounting Pronouncements	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 Codification Improvements to Topic 326, Financial Instruments—Credit Losses, I n February 2016, the FASB issued ASU 2016-02, Leases . The standard amended the existing lease accounting guidance and required lessees to recognize a lease liability and a right-of-use asset for all leases on their balance sheets. Lessees of operating leases continued to recognize lease expense in a manner similar to previous accounting. For lessors, accounting for leases under the new guidance was substantially the same as in prior periods, but eliminated current real estate-specific provisions and changed the treatment of initial direct costs. The standard was effective for the Operating Partnership on January 1, 2019. ​ The Operating Partnership elected the following package of practical expedients provided by the standard: (i) an entity need not reassess whether any expired or existing contract is a lease or contains a lease, (ii) an entity need not reassess the lease classification of any expired or existing leases, and (iii) an entity need not reassess initial direct costs for any existing leases. The Operating Partnership also elected the short-term lease exception provided for in the standard and therefore only recognizes right-of-use assets and lease liabilities for leases with a term greater than one year. ​ The Operating Partnership recognized right-of-use assets of $94.2 million and lease liabilities of $88.2 million as of January 1, 2019 upon adoption of the standard. The right-of-use assets included $6.0 million of prepaid rent and intangible assets that was included within Other assets ​ The lease liabilities represent the present value of the remaining minimum lease payments as of January 1, 2019 related to ground leases for communities where we are the lessee. The right-of-use assets represent our right to use an underlying asset for the lease term, which are calculated utilizing the lease liabilities plus any prepaid lease payments and intangible assets for ground leases acquired in the purchase of real estate. Our right-of-use assets and related lease liabilities recognized as of January 1, 2019 may change as a result of updates to the projected future minimum lease payments. Certain of our ground lease agreements where we are the lessee have future minimum lease payments that reset in the future based upon a percentage of the fair market value of the land at the time of the reset. The Operating Partnership will continue to recognize lease expense for these leases in a manner similar to previous accounting based on our election of the package of practical expedients. However, in the event we modify existing ground leases and/or enter into new ground leases subsequent to the adoption of the standard, such leases would likely be classified as finance leases under the standard and require expense recognition based on the effective interest method. Under the standard, initial direct costs for both lessees and lessors would include only those costs that are incremental to the arrangement and would not have been incurred if the lease had not been obtained. As a result, subsequent to the adoption of the standard, we are now expensing non-incremental leasing costs as incurred. ​ In July 2018, the FASB issued ASU 2018-11, Leases – Targeted Improvements Leases option that permitted entities to not recast the comparative periods presented when transitioning to the standard, which the Operating Partnership also elected.
Principles of Consolidation	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 consolidation guidance. The Operating Partnership first evaluates whether each entity is a variable interest entity (“VIE”). Under the VIE model, the Operating Partnership consolidates an entity when it has control to direct the activities of the VIE and the obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE. Under the voting model, the Operating Partnership consolidates an entity when it controls the entity through ownership of a majority voting interest.
Income/(Loss) Per Operating Partnership Unit	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.
Real Estate Sales Gain Recognition	Real Estate Sales Gain Recognition ​ For sale transactions resulting in a transfer of a controlling financial interest of a property, the Operating Partnership generally derecognizes the related assets and liabilities from its Consolidated Balance Sheets and records the gain or loss in the period in which the transfer of control occurs. If control of the property has not transferred to the counterparty, the criteria for derecognition are not met and the Operating Partnership will continue to recognize the related assets and liabilities on its Consolidated Balance Sheets. ​ Sale transactions to entities in which the Operating Partnership sells a controlling financial interest in a property but retains a noncontrolling interest are accounted for as partial sales. Partial sales resulting in a change in control are accounted for at fair value and a full gain or loss is recognized. Therefore, the Operating Partnership will record a gain or loss on the partial interest sold, and the initial measurement of our retained interest will be accounted for at fair value. ​ Sales of real estate to joint ventures or other noncontrolled investees are also accounted for at fair value and the Operating Partnership will record a full gain or loss in the period the property is contributed. ​ To the extent that the Operating Partnership acquires a controlling financial interest in a property that it previously accounted for as an equity method investment, the Operating Partnership will not remeasure its previously held interest if the acquisition is treated as an asset acquisition. The Operating Partnership will include the carrying amount of its previously held equity method interest along with the consideration paid and transaction costs incurred in determining the amounts to allocate to the related assets and liabilities acquired on its Consolidated Balance Sheets. When treated as an asset acquisition, the Operating Partnership will not recognize a gain or loss on consolidation of a property.
Comprehensive Income/(Loss)	Comprehensive Income/(Loss) Comprehensive income/(loss), which is defined as the change in equity during each period from transactions and other events and circumstances from nonowner sources, including all changes in equity during a period except for those resulting from investments by or distributions to unitholders, is displayed in the accompanying Consolidated Statements of Comprehensive Income/(Loss). For the three and nine months ended September 30, 2019 and 2018, the Operating Partnership’s other comprehensive income/(loss) consisted of the gain/(loss) 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 Derivatives and Hedging Activity,
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 (2016 through 2018) 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 (UNITED DOM_2

REAL ESTATE OWNED (UNITED DOMINION REALTY, L.P.) (Tables)	9 Months Ended
	Sep. 30, 2019
Entity information
Summary of carrying amounts for real estate owned (at cost)	​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2019 ​ 2018 Land ​ $ 2,020,617 ​ $ 1,849,799 Depreciable property — held and used: ​ ​ Land improvements ​ 220,654 ​ 213,224 Building, improvements, and furniture, fixtures and equipment ​ 9,260,709 ​ 8,133,136 Real estate intangible assets ​ ​ 40,570 ​ ​ — Under development: ​ ​ Land and land improvements ​ 13,853 ​ — Building, improvements, and furniture, fixtures and equipment ​ 7,992 ​ — Real estate owned ​ 11,564,395 ​ 10,196,159 Accumulated depreciation ​ (4,000,608) ​ (3,654,160) Real estate owned, net ​ $ 7,563,787 ​ $ 6,541,999
United Dominion Realty L.P.
Entity information
Summary of carrying amounts for real estate owned (at cost)	​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2019 ​ 2018 Land ​ $ 711,256 ​ $ 711,256 Depreciable property — held and used: ​ ​ ​ ​ Land improvements ​ ​ 95,096 ​ ​ 92,000 Buildings, improvements, and furniture, fixtures and equipment ​ 3,055,402 ​ 3,008,729 Real estate owned ​ 3,861,754 ​ 3,811,985 Accumulated depreciation ​ (1,762,168) ​ (1,658,161) Real estate owned, net ​ $ 2,099,586 ​ $ 2,153,824

UNCONSOLIDATED ENTITIES (UNIT_2

UNCONSOLIDATED ENTITIES (UNITED DOMINION REALTY, L.P.) Unconsolidated Entities (UNITED DOMINION REALTY, L.P.) (Tables)	9 Months Ended
	Sep. 30, 2019
Unconsolidated entities
Combined summary of balance sheets relating to unconsolidated joint ventures and partnerships	Combined summary balance sheets relating to the unconsolidated joint ventures and partnerships (not just our proportionate share) are presented below as of September 30, 2019 and December 31, 2018 ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ 2019 2018 Total real estate, net $ 3,101,213 $ 3,311,034 Cash and cash equivalents ​ 56,829 ​ 49,867 Other assets ​ ​ 165,767 ​ 124,428 Total assets $ 3,323,809 $ 3,485,329 ​ ​ ​ ​ ​ ​ ​ Third party debt, net ​ $ 1,909,223 ​ $ 2,125,350 Accounts payable and accrued liabilities ​ ​ 73,803 ​ ​ 71,272 Total liabilities ​ 1,983,026 ​ 2,196,622 Total equity $ 1,340,783 $ 1,288,707
Schedule of combined financial information relating to unconsolidated joint ventures and partnerships operations (not just proportionate share)	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 nine months ended September 30, 2019 and 2018 ( dollars in thousands : ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, ​ September 30, ​ 2019 2018 2019 2018 Total revenues $ 75,378 $ 76,203 $ 233,836 $ 215,140 Property operating expenses ​ 27,505 ​ 30,096 ​ 87,073 ​ 85,435 Real estate depreciation and amortization ​ 26,027 ​ 29,545 ​ 83,661 ​ 85,063 Operating income/(loss) ​ 21,846 ​ ​ 16,562 ​ 63,102 ​ ​ 44,642 Interest expense ​ (20,779) ​ (22,919) ​ (64,309) ​ (63,990) Gain/(loss) on sale of property (a) ​ ​ 97,201 ​ ​ — ​ ​ 115,558 ​ ​ — Net unrealized gain/(loss) on held investments ​ ​ 25,669 ​ ​ — ​ ​ 27,191 ​ ​ — Other income/(loss) ​ ​ 82 ​ ​ 40 ​ ​ 194 ​ ​ 141 Net income/(loss) $ 124,019 $ (6,317) $ 141,736 $ (19,207) ​ ​ ​ (a) Represent the gains on the sale of three operating communities at the UDR/KFH joint venture level, as described in note (c) to the table above summarizing the Company’s investment in and advances to unconsolidated joint ventures and partnerships, net.
United Dominion Realty L.P.
Unconsolidated entities
Combined summary of balance sheets relating to unconsolidated joint ventures and partnerships	Combined summary balance sheets relating to all of the DownREIT Partnership (not just our proportionate share) are presented below as of September 30, 2019 and December 31, 2018 ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ 2019 2018 Total real estate, net $ 1,119,828 $ 1,167,720 Cash and cash equivalents ​ 22 ​ 39 Note receivable from the General Partner ​ 221,789 ​ 221,022 Other assets ​ 5,259 ​ 5,561 Total assets $ 1,346,898 $ 1,394,342 ​ ​ ​ ​ ​ ​ ​ Secured debt, net ​ $ 428,457 ​ $ 431,735 Other liabilities ​ 25,880 ​ 26,597 Total liabilities ​ 454,337 ​ 458,332 Total capital ​ $ 892,561 ​ $ 936,010 ​
Schedule of combined financial information relating to unconsolidated joint ventures and partnerships operations (not just proportionate share)	Combined summary financial information relating to all of the DownREIT Partnership (not just our proportionate share) is presented below for the three and nine months ended September 30, 2019 and 2018 ( dollars in thousands : ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, ​ September 30, ​ ​ 2019 2018 2019 2018 Rental income $ 32,434 $ 35,069 ​ $ 96,065 $ 103,842 Property operating expenses ​ (13,087) ​ (14,303) ​ (38,934) ​ (43,180) Real estate depreciation and amortization ​ (20,620) ​ (22,097) ​ (61,424) ​ (65,704) Operating income/(loss) ​ (1,273) ​ (1,331) ​ (4,293) ​ (5,042) Interest expense ​ (4,162) ​ (3,343) ​ (11,979) ​ (10,553) Interest income on note receivable from the General Partner ​ 2,054 ​ 1,196 ​ 6,060 ​ 3,587 Net income/(loss) $ (3,381) $ (3,478) ​ $ (10,212) $ (12,008)

LEASES (UNITED DOMINION REALT_2

LEASES (UNITED DOMINION REALTY, L.P.) (Tables)	9 Months Ended
	Sep. 30, 2019
Lease
Lessee - Future minimum lease payments and total operating lease liabilities	Future minimum lease payments and total operating lease liabilities from our ground leases and office space as of September 30, 2019 are as follows (dollars in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ground Leases ​ Office Space ​ Total 2019 ​ $ 1,953 ​ $ 19 ​ $ 1,972 2020 ​ ​ 7,813 ​ ​ 76 ​ ​ 7,889 2021 ​ ​ 7,813 ​ ​ 32 ​ ​ 7,845 2022 ​ ​ 7,813 ​ ​ - ​ ​ 7,813 2023 ​ ​ 7,813 ​ ​ - ​ ​ 7,813 Thereafter ​ ​ 370,467 ​ ​ - ​ ​ 370,467 Total future minimum lease payments (undiscounted) ​ ​ 403,672 ​ ​ 127 ​ ​ 403,799 Difference between future undiscounted cash flows and discounted cash flows ​ ​ (273,659) ​ ​ (5) ​ ​ (273,664) Total operating lease liabilities (discounted) ​ $ 130,013 ​ $ 122 ​ $ 130,135
Lessee - components of operating lease expenses	The components of operating lease expenses from our ground leases and office space were as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, 2019 ​ September 30, 2019 Ground lease expense: ​ ​ ​ ​ ​ ​ Contractual lease rent expense ​ $ 1,954 ​ $ 6,232 Variable ground lease expense (a) ​ ​ 187 ​ ​ 469 Total ground lease expense (b) ​ ​ 2,141 ​ ​ 6,701 Contractual office space expense (b) ​ ​ 19 ​ ​ 57 Total operating lease expense (c) ​ $ 2,160 ​ $ 6,758 (a) Variable ground lease expense includes adjustments such as changes in the consumer price index and payments based on a percentage of income of the lessee. (b) Ground lease expense is reported within the line item Other operating expenses and office space expense is recorded in General and administrative on the Consolidated Statements of Operations. (c) For the nine months ended September 30, 2019, Operating lease right-of-use assets and Operating lease liabilities amortized by $0.6 million and $0.3 million, respectively. The Company recorded $0.1 million and $0.3 million of total operating lease expense during the three and nine months ended September 30, 2019, respectively, due to the net impact of the amortization.
Lessor - Future minimum lease payments	Future minimum lease payments from our retail and commercial leases as of September 30, 2019 are as follows (dollars in thousands): ​ ​ ​ ​ ​ ​ Retail and Commercial Leases 2019 ​ $ 4,958 2020 ​ ​ 20,565 2021 ​ ​ 19,788 2022 ​ ​ 18,094 2023 ​ ​ 16,843 Thereafter ​ ​ 92,719 Total future minimum lease payments (a) ​ $ 172,967 (a) We have excluded our apartment home leases from this table as our apartment home leases generally have initial terms of 12 months of less.
United Dominion Realty L.P.
Lease
Lessee - Future minimum lease payments and total operating lease liabilities	Future minimum lease payments and total operating lease liabilities from our ground leases as of September 30, 2019 are as follows (dollars in thousands): ​ ​ ​ ​ ​ ​ Ground Leases 2019 ​ $ 1,953 2020 ​ ​ 7,813 2021 ​ ​ 7,813 2022 ​ ​ 7,813 2023 ​ ​ 7,813 Thereafter ​ ​ 370,467 Total future minimum lease payments (undiscounted) ​ ​ 403,672 Difference between future undiscounted cash flows and discounted cash flows ​ ​ (273,659) Total operating lease liabilities (discounted) ​ $ 130,013
Lessee - components of operating lease expenses	The components of operating lease expenses from our ground leases were as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, 2019 ​ September 30, 2019 Ground lease expense: ​ ​ ​ ​ ​ ​ Contractual lease rent expense ​ $ 1,954 ​ $ 6,232 Variable ground lease expense (a) ​ ​ 187 ​ ​ 469 Total operating lease expense (b)(c) ​ $ 2,141 ​ $ 6,701 (a) Variable ground lease expense includes adjustments such as changes in the consumer price index and payments based on a percentage of income of the lessee. (b) Ground lease expense is reported within the line item Other operating expenses on the Consolidated Statements of Operations. (c) For the nine months ended September 30, 2019, Operating lease right-of-use assets and Operating lease liabilities amortized by $0.6 million and $0.3 million, respectively. The Operating Partnership recorded $0.1 million and $0.3 million of total operating lease expense during the three and nine months ended September 30, 2019, respectively, due to the net impact of the amortization.
Lessor - Future minimum lease payments	Future minimum lease payments from our retail and commercial leases as of September 30, 2019 are as follows (dollars in thousands): ​ ​ ​ ​ ​ ​ Retail and Commercial Leases 2019 ​ $ 1,810 2020 ​ ​ 7,778 2021 ​ ​ 7,442 2022 ​ ​ 6,841 2023 ​ ​ 6,517 Thereafter ​ ​ 19,874 Total future minimum lease payments (a) ​ $ 50,262 (a) We have excluded our apartment home leases from this table as our apartment home leases generally have initial terms of 12 months of less.

DEBT, NET (UNITED DOMINION RE_2

DEBT, NET (UNITED DOMINION REALTY, L.P.) (Tables)	9 Months Ended
	Sep. 30, 2019
Entity information
Schedule of debt instruments	The following is a summary of our secured and unsecured debt at September 30, 2019 and December 31, 2018 ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Principal Outstanding ​ As of September 30, 2019 ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ Weighted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Average ​ Average ​ Number of ​ ​ September 30, ​ December 31, ​ Interest ​ Years to ​ Communities ​ 2019 2018 Rate Maturity Encumbered Secured Debt: ​ ​ ​ ​ ​ ​ ​ Fixed Rate Debt ​ ​ Mortgage notes payable (a) ​ $ 575,965 ​ $ 417,989 3.55 % 6.6 9 Fannie Mae credit facilities (b) ​ — ​ 90,000 — % — — Deferred financing costs ​ (2,275) ​ (1,343) Total fixed rate secured debt, net ​ 573,690 ​ 506,646 3.55 % 6.6 9 Variable Rate Debt ​ ​ Tax-exempt secured notes payable (c) ​ 27,000 ​ 94,700 2.07 % 12.5 1 Deferred financing costs ​ (66) ​ (119) Total variable rate secured debt, net ​ 26,934 ​ 94,581 2.07 % 12.5 1 Total Secured Debt, net ​ 600,624 ​ 601,227 3.49 % 6.8 10 Unsecured Debt: ​ ​ Variable Rate Debt ​ ​ Borrowings outstanding under unsecured credit facility due January 2023 (d) (l) ​ — ​ — — % 3.3 Borrowings outstanding under unsecured commercial paper program due October 2019 (e) (l) ​ ​ 60,000 ​ ​ 101,115 ​ 2.28 % 0.1 ​ ​ Borrowings outstanding under unsecured working capital credit facility due January 2021 ​ 34,447 ​ 16 2.84 % 1.3 Term Loan due September 2023 (d) (l) ​ 35,000 ​ 35,000 3.01 % 4.0 Fixed Rate Debt ​ ​ 3.70% Medium-Term Notes due October 2020 (net of discounts of $0 and $14, respectively) (k) (l) ​ — ​ 299,986 — % — 4.63% Medium-Term Notes due January 2022 (net of discounts of $818 and $1,087, respectively) (l) ​ 399,182 ​ 398,913 4.63 % 2.3 1.93% Term Loan due September 2023 (d) (l) ​ ​ 315,000 ​ 315,000 1.93 % 4.0 ​ ​ 3.75% Medium-Term Notes due July 2024 (net of discounts of $495 and $574, respectively) (g) (l) ​ 299,505 ​ 299,426 3.75 % 4.8 8.50% Debentures due September 2024 ​ 15,644 ​ 15,644 8.50 % 5.0 4.00% Medium-Term Notes due October 2025 (net of discounts of $413 and $465, respectively) (h) (l) ​ 299,587 ​ 299,535 4.00 % 6.0 2.95% Medium-Term Notes due September 2026 (l) ​ 300,000 ​ 300,000 2.95 % 6.9 3.50% Medium-Term Notes due July 2027 (net of discounts of $547 and $600, respectively) (l) ​ ​ 299,453 ​ ​ 299,400 ​ 3.50 % 7.8 ​ ​ 3.50% Medium-Term Notes due January 2028 (net of discounts of $983 and $1,072, respectively) (l) ​ ​ 299,017 ​ ​ 298,928 ​ 3.50 % 8.3 ​ ​ 4.40% Medium-Term Notes due January 2029 (net of discounts of $6 and $6, respectively) (i) (l) ​ ​ 299,994 ​ ​ 299,994 ​ 4.40 % 9.3 ​ ​ 3.20% Medium-Term Notes due January 2030 (net of discounts of $990 and $0, respectively) (j) (l) ​ ​ 299,010 ​ ​ — ​ 3.20 % 10.3 ​ ​ 3.00% Medium-Term Notes due August 2031 (net of discounts of $1,148 and $0, respectively) (k) (l) ​ ​ 398,852 ​ ​ — ​ 3.00 % 11.9 ​ ​ Other ​ 14 ​ 16 Deferred financing costs ​ (19,432) ​ (16,413) Total Unsecured Debt, net ​ 3,335,273 ​ 2,946,560 3.54 % 6.9 Total Debt, net ​ $ 3,935,897 ​ $ 3,547,787 3.63 % 6.9
Secured credit facilities	Further information related to the Fannie Mae credit facility is as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2019 ​ 2018 Borrowings outstanding ​ $ — ​ $ 90,000 ​ Weighted average borrowings during the period ended ​ 80,000 ​ 253,813 ​ Maximum daily borrowings during the period ended ​ 90,000 ​ 314,869 ​ Weighted average interest rate during the period ended ​ 4.0 % 4.7 % Weighted average interest rate at the end of the period ​ — % 4.0 % ​ (c) (d) six-month extension options, subject to certain conditions. The Term Loan has a scheduled maturity date of September 30, 2023.
Schedule of aggregate maturities, including amortizing principal payments of secured and unsecured debt	The aggregate maturities, including amortizing principal payments on secured and unsecured debt, of total debt for the next ten calendar years subsequent to September 30, 2019 are as follows (dollars in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Fixed Total Variable Total Total Total Year ​ Secured Debt ​ Secured Debt ​ Secured Debt ​ Unsecured Debt ​ Debt 2019 ​ $ 974 ​ $ — ​ $ 974 ​ $ 60,000 ​ $ 60,974 2020 ​ ​ 108,077 ​ ​ — ​ ​ 108,077 ​ ​ — ​ ​ 108,077 2021 ​ 1,117 ​ — ​ 1,117 ​ 34,447 ​ 35,564 2022 ​ 1,157 ​ — ​ 1,157 ​ 400,000 ​ 401,157 2023 ​ 41,245 ​ — ​ 41,245 ​ 350,000 ​ 391,245 2024 ​ — ​ — ​ — ​ 315,644 ​ 315,644 2025 ​ 127,600 ​ — ​ 127,600 ​ 300,000 ​ 427,600 2026 ​ 50,000 ​ — ​ 50,000 ​ 300,000 ​ 350,000 2027 ​ — ​ — ​ — ​ 300,000 ​ 300,000 2028 ​ 80,000 ​ — ​ 80,000 ​ 300,000 ​ 380,000 Thereafter ​ 162,500 ​ 27,000 ​ 189,500 ​ 1,000,000 ​ 1,189,500 Subtotal ​ 572,670 ​ 27,000 ​ 599,670 ​ 3,360,091 ​ 3,959,761 Non-cash (a) ​ 1,020 ​ (66) ​ 954 ​ (24,818) ​ (23,864) Total ​ $ 573,690 ​ $ 26,934 ​ $ 600,624 ​ $ 3,335,273 ​ $ 3,935,897 (a) Includes the unamortized balance of fair market value adjustments, premiums/discounts and deferred financing costs . The Company amortized $1.1 million and $ 1.1 million, respectively, during the three months ended September 30, 2019 and 2018, and $3.1 million and $3.2 million, respectively, during the nine months ended September 30, 2019 and 2018, of deferred financing costs into Interest expense.
United Dominion Realty L.P.
Entity information
Schedule of debt instruments	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Principal Outstanding ​ As of September 30, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ Average ​ ​ ​ ​ September 30, ​ December 31, ​ Average ​ Years to ​ Communities ​ ​ 2019 ​ 2018 ​ Interest Rate ​ Maturity ​ Encumbered Fixed Rate Debt ​ ​ Mortgage notes payable ​ $ 72,500 ​ $ — 3.10 % 10.3 1 Deferred financing costs ​ (370) ​ — Total fixed rate secured debt, net ​ 72,130 ​ — 3.10 % 10.3 1 Secured Debt ​ ​ Tax-exempt secured note payable ​ $ 27,000 ​ $ 27,000 2.07 % 12.5 1 Deferred financing costs ​ (66) ​ (71) Total Secured Debt, Net ​ $ 99,064 ​ $ 26,929 2.85 % 10.9 2

RELATED PARTY TRANSACTIONS (U_2

RELATED PARTY TRANSACTIONS (UNITED DOMINION REALTY, L.P.) (Tables)	9 Months Ended
	Sep. 30, 2019
United Dominion Realty L.P.
Related Party Transaction [Line Items]
Schedule of Notes payable due to General Partner	The following table summarizes the Operating Partnership’s Notes payable due to the General Partner as of September 30, 2019 and December 31, 2018 ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate at ​ Balance Outstanding ​ September 30, ​ September 30, December 31, ​ ​ 2019 ​ 2019 ​ 2018 Note due August 2021 5.34 % ​ $ 5,500 ​ $ 5,500 Note due December 2023 5.18 % ​ 83,196 ​ 83,196 Note due April 2026 4.12 % ​ 184,638 ​ 184,638 Note due November 2028 ​ 4.69 % ​ ​ 133,205 ​ ​ 133,205 Note due December 2028 (a) ​ 3.63 % ​ ​ 217,428 ​ ​ 293,576 Total notes payable due to the General Partner ​ ​ $ 623,967 ​ $ 700,115 (a) In December 2018, the Operating Partnership converted the remaining outstanding portion of the Advances (to)/from the General Partner capital balance in connection with entering into an unsecured revolving note payable with the General Partner. There is no limit on the total commitments under this note. Interest is incurred on the unpaid principal balance at a variable interest rate equivalent to the General Partner’s weighted average interest rate on borrowings, or 3.63% as of September 30, 2019. The note matures on December 1, 2028. To the extent there is an outstanding principal balance on the revolving note payable, the General Partner, at its discretion, can demand payment at any time prior to the stated maturity date of the note,

FAIR VALUE OF DERIVATIVES AND_5

FAIR VALUE OF DERIVATIVES AND FINANCIAL INSTRUMENTS (UNITED DOMINION REALTY, L.P.) (Tables)	9 Months Ended
	Sep. 30, 2019
Entity information
Schedule of estimated fair values	The estimated fair values of the Company’s financial instruments either recorded or disclosed on a recurring basis as of September 30, 2019 and December 31, 2018, are summarized as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value at September 30, 2019, Using ​ ​ Total ​ ​ ​ Quoted ​ ​ ​ ​ ​ ​ Carrying ​ ​ ​ Prices in ​ ​ ​ ​ ​ ​ Amount in ​ ​ ​ Active ​ ​ ​ ​ ​ ​ ​ Statement of ​ ​ ​ ​ Markets ​ Significant ​ ​ ​ ​ ​ Financial ​ Fair Value ​ for Identical ​ Other ​ Significant ​ ​ Position at ​ Estimate at ​ Assets or ​ Observable ​ Unobservable ​ ​ September 30, ​ September 30, ​ Liabilities ​ Inputs ​ Inputs ​ ​ 2019 ​ 2019 ​ (Level 1) ​ (Level 2) ​ (Level 3) Description: ​ ​ ​ ​ ​ ​ Notes receivable (a) ​ $ 37,899 ​ $ 42,613 ​ $ — ​ $ — ​ $ 42,613 Derivatives - Interest rate contracts (b) ​ 730 ​ 730 ​ — ​ 730 ​ — Total assets ​ $ 38,629 ​ $ 43,343 ​ $ — ​ $ 730 ​ $ 42,613 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives - Interest rate contracts (b) ​ $ 469 ​ $ 469 ​ $ — ​ $ 469 ​ $ — Secured debt instruments - fixed rate: (c) ​ ​ ​ ​ ​ ​ Mortgage notes payable ​ ​ 575,965 ​ ​ 569,318 ​ ​ — ​ ​ — ​ ​ 569,318 Secured debt instruments - variable rate: (c) ​ ​ ​ ​ ​ ​ Tax-exempt secured notes payable ​ 27,000 ​ 27,000 ​ — ​ — ​ 27,000 Unsecured debt instruments: (c) ​ ​ ​ ​ ​ ​ Working capital credit facility ​ ​ 34,447 ​ ​ 34,447 ​ ​ — ​ ​ — ​ ​ 34,447 Commercial paper program ​ ​ 60,000 ​ ​ 60,000 ​ ​ — ​ ​ — ​ ​ 60,000 Unsecured notes ​ ​ 3,260,258 ​ ​ 3,415,618 ​ ​ — ​ ​ — ​ ​ 3,415,618 Total liabilities ​ $ 3,958,139 ​ $ 4,106,852 ​ $ — ​ $ 469 ​ $ 4,106,383 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (d) ​ $ 1,072,181 ​ $ 1,072,181 ​ $ — ​ $ 1,072,181 ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value at December 31, 2018, Using ​ ​ Total ​ ​ ​ Quoted ​ ​ ​ ​ ​ ​ Carrying ​ ​ ​ Prices in ​ ​ ​ ​ ​ ​ Amount in ​ ​ ​ Active ​ ​ ​ ​ ​ ​ Statement of ​ ​ ​ Markets ​ Significant ​ ​ ​ ​ Financial ​ Fair Value ​ for Identical ​ Other ​ Significant ​ ​ Position at ​ Estimate at ​ Assets or ​ Observable ​ Unobservable ​ ​ December 31, ​ December 31, ​ Liabilities ​ Inputs ​ Inputs ​ 2018 ​ 2018 ​ (Level 1) ​ (Level 2) ​ (Level 3) Description: ​ ​ ​ ​ ​ ​ Notes receivable (a) ​ $ 42,259 ​ $ 45,026 ​ $ — ​ $ — ​ $ 45,026 Derivatives - Interest rate contracts (b) ​ 4,757 ​ 4,757 ​ — ​ 4,757 ​ — Total assets ​ $ 47,016 ​ $ 49,783 ​ $ — ​ $ 4,757 ​ $ 45,026 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives - Interest rate contracts (b) ​ $ 356 ​ $ 356 ​ $ — ​ $ 356 ​ $ — Secured debt instruments - fixed rate: (c) ​ ​ ​ ​ ​ ​ Mortgage notes payable ​ ​ 417,989 ​ ​ 416,314 ​ ​ — ​ ​ — ​ ​ 416,314 Fannie Mae credit facility ​ 90,000 ​ 90,213 ​ — ​ — ​ 90,213 Secured debt instruments - variable rate: (c) ​ ​ ​ ​ ​ ​ Tax-exempt secured notes payable ​ 94,700 ​ 94,700 ​ — ​ — ​ 94,700 Unsecured debt instruments: (c) ​ ​ ​ ​ ​ ​ ​ Working capital credit facility ​ ​ 16 ​ ​ 16 ​ ​ — ​ ​ — ​ ​ 16 Commercial paper program ​ ​ 101,115 ​ ​ 101,115 ​ ​ — ​ ​ — ​ ​ 101,115 Unsecured notes ​ ​ 2,861,842 ​ ​ 2,829,390 ​ ​ — ​ ​ — ​ ​ 2,829,390 Total liabilities ​ $ 3,566,018 ​ $ 3,532,104 ​ $ — ​ $ 356 ​ $ 3,531,748 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership (d) ​ $ 972,740 ​ $ 972,740 ​ $ — ​ $ 972,740 ​ $ — (a) See Note 2, Significant Accounting Policies . (b) See Note 11, Derivatives and Hedging Activity . (c) See Note 7, Secured and Unsecured Debt, Net . (d) See Note 9, Noncontrolling Interests.
United Dominion Realty L.P.
Entity information
Schedule of estimated fair values	The estimated fair values of the Operating Partnership’s financial instruments either recorded or disclosed on a recurring basis as of September 30, 2019 and December 31, 2018 are summarized as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value at September 30, 2019, Using ​ Total ​ ​ Quoted ​ ​ ​ ​ ​ ​ Carrying ​ ​ ​ ​ Prices in ​ ​ ​ ​ ​ ​ ​ ​ Amount in ​ ​ ​ ​ Active ​ ​ ​ ​ ​ ​ ​ ​ Statement of ​ ​ ​ ​ Markets ​ Significant ​ ​ ​ ​ ​ Financial ​ Fair Value ​ for Identical ​ Other ​ Significant ​ ​ Position at ​ Estimate at ​ Assets or ​ Observable ​ Unobservable ​ ​ September 30, ​ September 30, ​ Liabilities ​ Inputs ​ Inputs ​ ​ 2019 ​ 2019 ​ (Level 1) ​ (Level 2) ​ (Level 3) Description: ​ ​ ​ ​ ​ Secured debt instruments - fixed rate: (a) ​ ​ ​ ​ ​ Mortgage notes payable ​ $ 72,500 ​ $ 68,669 ​ $ — ​ $ — ​ $ 68,669 Secured debt instruments - variable rate: (a) ​ ​ ​ ​ ​ ​ Tax-exempt secured notes payable ​ ​ 27,000 ​ ​ 27,000 ​ ​ — ​ ​ — ​ ​ 27,000 Total liabilities ​ $ 99,500 ​ $ 95,669 ​ $ — ​ $ — ​ $ 95,669 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value at December 31, 2018, Using ​ ​ ​ ​ ​ Quoted ​ ​ ​ ​ ​ ​ Total ​ ​ ​ ​ Prices in ​ ​ ​ ​ ​ ​ ​ ​ Carrying ​ ​ ​ ​ Active ​ ​ ​ ​ ​ ​ ​ ​ Amount in ​ ​ ​ ​ Markets ​ ​ ​ ​ ​ ​ ​ ​ Statement of ​ ​ ​ ​ for Identical ​ Significant ​ ​ ​ ​ ​ Financial ​ Fair Value ​ Assets ​ Other ​ Significant ​ ​ Position at ​ Estimate at ​ or ​ Observable ​ Unobservable ​ ​ December 31, ​ December 31, ​ Liabilities ​ Inputs ​ Inputs ​ ​ 2018 ​ 2018 ​ (Level 1) ​ (Level 2) ​ (Level 3) Description: ​ ​ ​ ​ ​ Secured debt instruments - variable rate: (a) ​ ​ ​ ​ ​ ​ Tax-exempt secured notes payable ​ $ 27,000 ​ $ 27,000 ​ $ — ​ $ — ​ $ 27,000 Total liabilities ​ $ 27,000 ​ $ 27,000 ​ $ — ​ $ — ​ $ 27,000 (a) See Note 6, Debt, Net. ​

DERIVATIVES AND HEDGING ACTIV_9

DERIVATIVES AND HEDGING ACTIVITY (UNITED DOMINION REALTY, L.P.) (Tables)	9 Months Ended
	Sep. 30, 2019
Entity information
Schedule of outstanding interest rate derivatives	As of September 30, 2019, the Company had the following outstanding interest rate derivatives that were designated as cash flow hedges of interest rate risk ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ Number of ​ Product ​ Instruments ​ Notional Interest rate swaps (a) ​ 4 ​ $ 315,000 (a) In addition to the interest rate swaps summarized above, the Company entered into an additional interest rate swap with a notional value of $315.0 million that will become effective in January 2020 upon the maturity of the interest rate swaps summarized above. Additionally, the Company had previously entered into two additional interest rate swaps with a notional value totaling $75.0 million that were subsequently terminated and settled during the nine months ended September 30, 2019 in conjunction with the July 2019 issuance of $300.0 million of senior unsecured medium-term notes as disclosed in Note 7, Secured and Unsecured, Net ​ 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 no gain or loss for both the three and nine months ended September 30, 2019 and 2018. As of September 30, 2019, the Company had the following outstanding derivatives that were not designated as hedges in qualifying hedging relationships ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ Number of ​ ​ Product ​ Instruments ​ Notional Interest rate caps ​ 1 ​ $ 19,880
Fair value of Company's derivative financial instruments and their classification on Consolidated Balance Sheets	The table below presents the fair value of the Company’s derivative financial instruments as well as their classification on the Consolidated Balance Sheets as of September 30, 2019 and December 31, 2018 ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Asset Derivatives ​ Liability Derivatives ​ ​ (included in Other assets ) ​ (included in Other liabilities ) ​ ​ Fair Value at: ​ Fair Value at: ​ ​ September 30, ​ December 31, ​ September 30, ​ December 31, ​ ​ 2019 ​ 2018 ​ 2019 ​ 2018 Derivatives designated as hedging instruments: ​ ​ ​ ​ Interest rate products ​ $ 730 ​ $ 4,757 ​ $ 469 ​ $ 356
Effect of Company's derivative financial instruments on Consolidated Statements of Operations	The tables below present the effect of the Company’s derivative financial instruments on the Consolidated Statements of Operations for the three and nine months ended September 30, 2019 and 2018 ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gain/(Loss) Recognized in ​ ​ ​ ​ Gain/(Loss) Reclassified ​ Interest expense ​ ​ Unrealized holding gain/(loss) ​ from Accumulated OCI into ​ (Amount Excluded from ​ ​ Recognized in OCI ​ Interest expense ​ Effectiveness Testing) Derivatives in Cash Flow Hedging Relationships 2019 2018 2019 2018 2019 2018 Three Months Ended September 30, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate products ​ $ (659) ​ $ 2,320 ​ $ 624 ​ $ 564 ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate products ​ $ (7,181) ​ $ 4,312 ​ $ 2,504 ​ $ 1,162 ​ $ — ​ $ —
Effect of Company's derivatives not designated as hedging instruments on the Consolidated Statements of Operations	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, ​ September 30, ​ ​ 2019 ​ 2018 ​ 2019 ​ 2018 Total amount of Interest expense ​ $ 42,523 ​ $ 34,401 ​ $ 110,482 ​ $ 95,942 ​
Offsetting of Derivative Assets	The Company has elected not to offset derivative positions on the consolidated financial statements. The tables below present the effect on its financial position had the Company made the election to offset its derivative positions as of September 30, 2019 and December 31, 2018 (dollars in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross Net Amounts of Gross Amounts Not Offset ​ ​ ​ ​ ​ ​ ​ ​ Amounts ​ Assets ​ in the Consolidated ​ ​ ​ ​ ​ Gross ​ Offset in the ​ Presented in the ​ Balance Sheet ​ ​ ​ ​ ​ Amounts of ​ Consolidated ​ Consolidated ​ ​ ​ ​ Cash ​ ​ ​ ​ ​ Recognized ​ Balance ​ Balance Sheets ​ Financial ​ Collateral ​ ​ ​ Offsetting of Derivative Assets ​ Assets ​ Sheets ​ (a) ​ Instruments Received Net Amount September 30, 2019 ​ $ 730 ​ $ — ​ $ 730 ​ $ (371) ​ $ — ​ $ 359 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2018 ​ $ 4,757 ​ $ — ​ $ 4,757 ​ $ — ​ $ — ​ $ 4,757 (a) Amounts reconcile to the aggregate fair value of derivative assets in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Consolidated Balance Sheets” located in this footnote.
Offsetting of Derivative Liabilities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross Net Amounts of Gross Amounts Not Offset ​ ​ ​ ​ ​ ​ ​ ​ Amounts ​ Liabilities ​ in the Consolidated ​ ​ ​ ​ ​ Gross ​ Offset in the ​ Presented in the ​ Balance Sheet ​ ​ ​ ​ ​ Amounts of ​ Consolidated ​ Consolidated ​ ​ ​ ​ Cash ​ ​ ​ ​ ​ Recognized ​ Balance ​ Balance Sheets ​ Financial ​ Collateral ​ ​ ​ Offsetting of Derivative Liabilities Liabilities Sheets (a) Instruments Posted Net Amount September 30, 2019 ​ $ 469 ​ $ — ​ $ 469 ​ $ (371) ​ $ — ​ $ 98 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2018 ​ $ 356 ​ $ — ​ $ 356 ​ $ — ​ $ — ​ $ 356 (a) Amounts reconcile to the aggregate fair value of derivative liabilities in the “Tabular Disclosure of Fair Values of Derivative Instruments on the Consolidated Balance Sheets” located in this footnote.
United Dominion Realty L.P.
Entity information
Schedule of outstanding interest rate derivatives	As of September 30, 2019, we had the following outstanding derivatives that were not designated as hedges in qualifying hedging relationships ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ Number of ​ ​ Product ​ Instruments ​ Notional Interest rate caps 1 ​ $ 19,880 ​

CAPITAL STRUCTURE (UNITED DOM_2

CAPITAL STRUCTURE (UNITED DOMINION REALTY, L.P.) Capital Structure (UNITED DOMINION REALTY, L.P.) (Tables)	9 Months Ended
	Sep. 30, 2019
United Dominion Realty L.P.
Entity information
Schedule of Limited Partners' Capital Account by Class [Table Text Block]	The following table shows OP Units outstanding and OP Unit activity as of and for the nine months ended September 30, 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ UDR, Inc. ​ ​ ​ Class A ​ ​ Class A ​ ​ ​ ​ Limited ​ Limited ​ Limited ​ Limited ​ General ​ ​ ​ ​ Partners ​ Partners ​ Partner ​ Partner ​ Partner ​ Total Ending balance at December 31, 2018 ​ 1,751,671 ​ 7,636,173 ​ 174,016,155 ​ 121,661 ​ 110,883 ​ 183,636,543 Vesting of LTIP Units ​ — ​ 426,999 ​ — ​ — ​ — ​ 426,999 OP redemptions for UDR stock — (1,961,373) ​ 1,961,373 — — — Ending balance at September 30, 2019 1,751,671 6,101,799 175,977,528 121,661 110,883 184,063,542

COMMITMENTS AND CONTINGENCIES_4

COMMITMENTS AND CONTINGENCIES (UNITED DOMINION REALTY, L.P.) (Tables)	9 Months Ended
	Sep. 30, 2019
Loss Contingencies [Line Items]
Summary of real estate commitments	The following summarizes the Company’s real estate commitments at September 30, 2019 ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number ​ UDR's ​ UDR's Remaining ​ ​ ​ Properties ​ Investment (a) ​ Commitment ​ Wholly-owned — under development 1 ​ $ 21,845 ​ $ 75,655 Wholly-owned — redevelopment 2 ​ ​ 11,582 ​ ​ 23,918 Joint ventures: ​ ​ Unconsolidated joint ventures - development 1 ​ 14,402 ​ 21,496 (b) Preferred equity investments 2 ​ ​ 53,781 (c) ​ 27,390 (d) Other investments ​ - ​ ​ 12,926 ​ ​ 9,000 (e) Total ​ $ 114,536 ​ $ 157,459 (a) Represents UDR’s investment as of September 30, 2019. (b) Represents UDR’s proportionate share of expected remaining costs to complete the development. (c) Represents UDR’s investment in 1300 Fairmount and Modera Lake Merritt for the properties under development as of September 30, 2019. (d) Represents UDR’s remaining commitment for 1300 Fairmount and Modera Lake Merritt. (e) Represents UDR’s remaining commitment for other investment ventures. ​
United Dominion Realty L.P.
Loss Contingencies [Line Items]
Summary of real estate commitments	The following summarizes the Operating Partnership’s real estate commitments at September 30, 2019 ( dollars in thousands ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number ​ ​ ​ Operating Partnership's ​ ​ Properties ​ Investment ​ Remaining Commitment Real estate communities - redevelopment 1 ​ $ 6,254 ​ $ 18,746 ​

REPORTABLE SEGMENTS (UNITED D_2

REPORTABLE SEGMENTS (UNITED DOMINION REALTY, L.P.) (Tables)	9 Months Ended
	Sep. 30, 2019
Entity information
Summary of rental income and NOI for the Operating Partnerships reportable segments and reconciliation of NOI to Net income/(loss)	The following table details rental income and NOI for UDR’s reportable segments for the three and nine months ended September 30, 2019 and 2018, and reconciles NOI to Net income/(loss) attributable to UDR, Inc. (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, (a) ​ September 30, (b) ​ 2019 2018 2019 2018 Reportable apartment home segment lease revenue ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Same-Store Communities ​ ​ ​ ​ ​ West Region ​ $ 99,316 ​ $ 95,447 ​ $ 293,294 ​ $ 281,722 Mid-Atlantic Region ​ 52,826 ​ 51,291 ​ 157,179 ​ 152,867 Southeast Region ​ 28,540 ​ 27,773 ​ 84,551 ​ 81,554 Northeast Region ​ 30,196 ​ 29,491 ​ 89,650 ​ 87,776 Southwest Region ​ 15,451 ​ 15,060 ​ 40,705 ​ 39,586 Non-Mature Communities/Other ​ 40,975 ​ 24,237 ​ 106,499 ​ 66,906 Total segment and consolidated rental income ​ $ 267,304 ​ $ 243,299 ​ $ 771,878 ​ $ 710,411 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Reportable apartment home segment other revenue ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Same-Store Communities ​ ​ ​ ​ ​ West Region ​ $ 7,869 ​ $ 7,168 ​ $ 23,488 ​ $ 21,567 Mid-Atlantic Region ​ 4,376 ​ 4,032 ​ 12,958 ​ 11,944 Southeast Region ​ 3,438 ​ 3,211 ​ 10,423 ​ 9,918 Northeast Region ​ 1,321 ​ 1,226 ​ 3,753 ​ 3,422 Southwest Region ​ 1,527 ​ 1,525 ​ 4,100 ​ 3,986 Non-Mature Communities/Other ​ 3,173 ​ 2,795 ​ 8,793 ​ 9,125 Total segment and consolidated rental income ​ $ 21,704 ​ $ 19,957 ​ $ 63,515 ​ $ 59,962 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total reportable apartment home segment rental income ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Same-Store Communities ​ ​ ​ ​ ​ West Region ​ $ 107,185 ​ $ 102,615 ​ $ 316,782 ​ $ 303,289 Mid-Atlantic Region ​ 57,202 ​ 55,323 ​ 170,137 ​ 164,811 Southeast Region ​ 31,978 ​ 30,984 ​ 94,974 ​ 91,472 Northeast Region ​ 31,517 ​ 30,717 ​ 93,403 ​ 91,198 Southwest Region ​ 16,978 ​ 16,585 ​ 44,805 ​ 43,572 Non-Mature Communities/Other ​ 44,148 ​ 27,032 ​ 115,292 ​ 76,031 Total segment and consolidated rental income ​ $ 289,008 ​ $ 263,256 ​ $ 835,393 ​ $ 770,373 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Reportable apartment home segment NOI ​ ​ ​ ​ Same-Store Communities ​ ​ ​ ​ West Region ​ $ 81,170 ​ $ 77,321 ​ $ 240,442 ​ $ 229,129 Mid-Atlantic Region ​ 39,850 ​ 38,220 ​ 119,075 ​ 114,465 Southeast Region ​ 22,133 ​ 21,597 ​ 66,301 ​ 63,806 Northeast Region ​ 20,560 ​ 20,640 ​ 63,012 ​ 62,710 Southwest Region ​ 10,449 ​ 9,899 ​ 26,995 ​ 25,760 Non-Mature Communities/Other ​ 29,487 ​ 17,137 ​ 77,242 ​ 48,833 Total segment and consolidated NOI ​ 203,649 ​ 184,814 ​ 593,067 ​ 544,703 Reconciling items: ​ ​ ​ ​ Joint venture management and other fees ​ 6,386 ​ 2,888 ​ 11,982 ​ 8,819 Property management ​ (8,309) ​ (7,240) ​ (24,018) ​ (21,185) Other operating expenses ​ (2,751) ​ (3,314) ​ (11,132) ​ (8,148) Real estate depreciation and amortization ​ (127,391) ​ (107,881) ​ (357,793) ​ (322,537) General and administrative ​ (12,197) ​ (11,896) ​ (37,002) ​ (36,028) Casualty-related (charges)/recoveries, net ​ 1,088 ​ (678) ​ 842 ​ (2,364) Other depreciation and amortization ​ (1,619) ​ (1,682) ​ (4,953) ​ (5,057) Gain/(loss) on sale of real estate owned ​ ​ — ​ ​ — ​ ​ 5,282 ​ ​ 70,300 Income/(loss) from unconsolidated entities ​ 12,713 ​ (1,382) ​ 19,387 ​ (5,091) Interest expense ​ (42,523) ​ (34,401) ​ (110,482) ​ (95,942) Interest income and other income/(expense), net ​ 1,875 ​ 1,188 ​ 12,998 ​ 5,075 Tax (provision)/benefit, net ​ (1,499) ​ (158) ​ (3,836) ​ (618) Net (income)/loss attributable to redeemable noncontrolling interests in the Operating Partnership and DownREIT Partnership ​ (2,162) ​ (1,616) ​ (6,871) ​ (10,819) Net (income)/loss attributable to noncontrolling interests ​ (56) ​ (32) ​ (145) ​ (141) Net income/(loss) attributable to UDR, Inc. ​ $ 27,204 ​ $ 18,610 ​ $ 87,326 ​ $ 120,967 (a) Same-Store Community population consisted of 38,177 apartment homes. (b) Same-Store Community population consisted of 37,959 apartment homes. ​
Details of assets of the Operating Partnership's reportable segments	The following table details the assets of UDR’s reportable segments as of September 30, 2019 and December 31, 2018 (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2019 ​ 2018 Reportable apartment home segment assets: ​ ​ Same-Store Communities (a): ​ ​ West Region ​ $ 3,797,149 ​ $ 3,763,366 Mid-Atlantic Region ​ 2,338,963 ​ 2,317,369 Southeast Region ​ 799,739 ​ 779,310 Northeast Region ​ 1,498,500 ​ 1,491,994 Southwest Region ​ 595,982 ​ 589,188 Non-Mature Communities/Other ​ 2,534,062 ​ 1,254,932 Total segment assets ​ 11,564,395 ​ 10,196,159 Accumulated depreciation ​ (4,000,608) ​ (3,654,160) Total segment assets — net book value ​ 7,563,787 ​ 6,541,999 Reconciling items: ​ ​ Cash and cash equivalents ​ 1,895 ​ 185,216 Restricted cash ​ 21,646 ​ 23,675 Notes receivable, net ​ 37,899 ​ 42,259 Investment in and advances to unconsolidated joint ventures, net ​ 791,180 ​ 780,869 Operating lease right-of-use assets ​ ​ 135,889 ​ ​ — Other assets ​ 145,301 ​ 137,710 Total consolidated assets ​ $ 8,697,597 ​ $ 7,711,728 (a) Same-Store Community population consisted of 38,177 apartment homes. ​
United Dominion Realty L.P.
Entity information
Summary of rental income and NOI for the Operating Partnerships reportable segments and reconciliation of NOI to Net income/(loss)	The following table details rental income and NOI for the Operating Partnership’s reportable segments for the three and nine months ended September 30, 2019 and 2018, and reconciles NOI to Net income/(loss) attributable to OP unitholders (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, (a) ​ September 30, (b) ​ ​ 2019 2018 2019 2018 ​ Reportable apartment home segment lease revenue ​ ​ ​ ​ ​ Same-Store Communities ​ ​ ​ ​ ​ West Region ​ $ 62,760 ​ $ 60,569 ​ $ 185,840 ​ $ 178,401 ​ Mid-Atlantic Region ​ 14,900 ​ 14,645 ​ 44,592 ​ 43,814 ​ Southeast Region ​ 12,808 ​ 12,604 ​ 37,957 ​ 36,782 ​ Northeast Region ​ 8,098 ​ 7,936 ​ 24,036 ​ 23,541 ​ Southwest Region ​ ​ 1,901 ​ ​ 1,865 ​ ​ — ​ ​ — ​ Non-Mature Communities/Other ​ 7,468 ​ 8,694 ​ 27,295 ​ 30,830 ​ Total segment and consolidated rental income ​ $ 107,935 ​ $ 106,313 ​ $ 319,720 ​ $ 313,368 ​ Reportable apartment home segment other revenue ​ ​ ​ ​ ​ Same-Store Communities ​ ​ ​ ​ ​ West Region ​ $ 2,063 ​ $ 1,750 ​ $ 5,908 ​ $ 5,484 ​ Mid-Atlantic Region ​ 551 ​ 441 ​ 1,515 ​ 1,359 ​ Southeast Region ​ 799 ​ 658 ​ 2,301 ​ 2,099 ​ Northeast Region ​ 187 ​ 178 ​ 521 ​ 496 ​ Southwest Region ​ ​ 87 ​ ​ 58 ​ ​ — ​ ​ — ​ Non-Mature Communities/Other ​ 78 ​ 141 ​ 419 ​ 591 ​ Total segment and consolidated rental income ​ $ 3,765 ​ $ 3,226 ​ $ 10,664 ​ $ 10,029 ​ Total reportable apartment home segment rental income ​ ​ ​ ​ ​ Same-Store Communities ​ ​ ​ ​ ​ West Region ​ $ 64,823 ​ $ 62,319 ​ $ 191,748 ​ $ 183,885 ​ Mid-Atlantic Region ​ 15,451 ​ 15,086 ​ 46,107 ​ 45,173 ​ Southeast Region ​ 13,607 ​ 13,262 ​ 40,258 ​ 38,881 ​ Northeast Region ​ 8,285 ​ 8,114 ​ 24,557 ​ 24,037 ​ Southwest Region ​ ​ 1,988 ​ ​ 1,923 ​ ​ — ​ ​ — ​ Non-Mature Communities/Other ​ 7,546 ​ 8,835 ​ 27,714 ​ 31,421 ​ Total segment and consolidated rental income ​ $ 111,700 ​ $ 109,539 ​ $ 330,384 ​ $ 323,397 ​ Reportable apartment home segment NOI ​ ​ ​ ​ ​ Same-Store Communities ​ ​ ​ ​ ​ West Region ​ $ 49,528 ​ $ 47,692 ​ $ 146,673 ​ $ 140,603 ​ Mid-Atlantic Region ​ 10,611 ​ 10,178 ​ 31,691 ​ 30,953 ​ Southeast Region ​ 9,371 ​ 9,336 ​ 27,984 ​ 26,979 ​ Northeast Region ​ 5,736 ​ 6,001 ​ 18,201 ​ 18,260 ​ Southwest Region ​ ​ 1,405 ​ ​ 1,253 ​ ​ — ​ ​ — ​ Non-Mature Communities/Other ​ 4,181 ​ 5,688 ​ 17,102 ​ 21,177 ​ Total segment and consolidated NOI ​ 80,832 ​ 80,148 ​ 241,651 ​ 237,972 ​ Reconciling items: ​ ​ ​ ​ ​ Property management ​ (3,211) ​ (3,012) ​ (9,498) ​ (8,893) ​ Other operating expenses ​ (2,301) ​ (2,347) ​ (7,123) ​ (6,098) ​ Real estate depreciation and amortization ​ (35,155) ​ (35,043) ​ (104,730) ​ (108,906) ​ General and administrative ​ (4,066) ​ (4,143) ​ (12,878) ​ (12,997) ​ Casualty-related (charges)/recoveries, net ​ 1,088 ​ 10 ​ 1,169 ​ (906) ​ Gain/(loss) on sale of real estate owned ​ — ​ — ​ — ​ 70,300 ​ Income/(loss) from unconsolidated entities ​ (2,383) ​ (2,378) ​ (6,917) ​ (10,102) ​ Interest expense ​ (7,521) ​ (5,100) ​ (22,247) ​ (15,209) ​ Net (income)/loss attributable to noncontrolling interests ​ (448) ​ (440) ​ (1,252) ​ (1,278) ​ Net income/(loss) attributable to OP unitholders ​ $ 26,835 ​ $ 27,695 ​ $ 78,175 ​ $ 143,883 ​ (a) Same-Store Community population consisted of 15,941 apartment homes. (b) Same-Store Community population consisted of 15,723 apartment homes. ​
Details of assets of the Operating Partnership's reportable segments	The following table details the assets of the Operating Partnership’s reportable segments as of September 30, 2019 and December 31, 2018 (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2019 ​ 2018 Reportable apartment home segment assets ​ ​ Same-Store Communities (a): ​ ​ West Region ​ $ 2,003,088 ​ $ 1,981,007 Mid-Atlantic Region ​ 667,755 ​ 663,083 Southeast Region ​ 349,767 ​ 340,722 Northeast Region ​ 408,244 ​ 406,149 Southwest Region ​ ​ 144,028 ​ ​ 141,882 Non-Mature Communities/Other ​ 288,872 ​ 279,142 Total segment assets ​ 3,861,754 ​ 3,811,985 Accumulated depreciation ​ (1,762,168) ​ (1,658,161) Total segment assets - net book value ​ 2,099,586 ​ 2,153,824 Reconciling items: ​ ​ Cash and cash equivalents ​ 40 ​ 125 Restricted cash ​ 14,637 ​ 13,563 Investment in unconsolidated entities ​ 82,269 ​ 103,026 Operating lease right-of-use assets ​ ​ 135,766 ​ ​ — Other assets ​ 23,321 ​ 34,052 Total consolidated assets ​ $ 2,355,619 ​ $ 2,304,590 (a) Same-Store Community population consisted of 15,941 apartment homes. ​

CONSOLIDATION AND BASIS OF PR_2

CONSOLIDATION AND BASIS OF PRESENTATION - GP Units (UNITED DOMINION REALTY, L.P.) (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2019communityitemshares	Sep. 30, 2018	Sep. 30, 2019communityitemshares	Sep. 30, 2018	Dec. 31, 2018shares
Basis of presentation
Number of real estate properties | community	138		138
Number of apartments owned (in apartments homes) | item	43,683		43,683
Operating Partnership outstanding units	184,063,542		184,063,542
Operating Partnership units outstanding related to limited partner	184,063,542		184,063,542		183,636,543
United Dominion Realty L.P.
Basis of presentation
Rental revenues percent of General Partner's consolidated rental revenues			40.00%	42.00%
General Partners' ownership (as a percent)	95.70%		95.70%
Operating Partnership units outstanding related to limited partner	176,210,072		176,210,072
United Dominion Realty L.P.
Basis of presentation
Rental revenues percent of General Partner's consolidated rental revenues	39.00%	42.00%
Number of real estate properties | community	52		52
Number of markets operating within (in markets) | item	15		15
Number of apartments owned (in apartments homes) | item	16,434		16,434
Operating Partnership outstanding units	184,063,542		184,063,542		183,636,543
OP units outstanding related to general partner	110,883		110,883		110,883
Operating Partnership units outstanding related to limited partner	183,952,659		183,952,659		183,525,660
UDR, Inc.
Basis of presentation
General Partners' ownership (as a percent)	55.90%		55.90%
Operating Partnership outstanding units	18,104,895		18,104,895
Operating Partnership units outstanding related to limited partner	176,099,189		176,099,189		174,137,816
Percentage of units outstanding in Partnership	95.70%		95.70%		94.90%
UDR, Inc. | United Dominion Realty L.P.
Basis of presentation
General Partners' ownership (as a percent)	95.70%		95.70%
Operating Partnership outstanding units					174,248,699
OP units outstanding related to general partner	176,210,072		176,210,072
Percentage of units outstanding in Partnership					94.90%
Non-affiliated Partners
Basis of presentation
Operating Partnership outstanding units	14,262,485		14,262,485
Operating Partnership units outstanding related to limited partner	7,853,470		7,853,470
Percentage of units outstanding in Partnership	4.30%		4.30%
Non-affiliated Partners | United Dominion Realty L.P.
Basis of presentation
Operating Partnership outstanding units					9,387,844
Operating Partnership units outstanding related to limited partner	7,853,470		7,853,470
Percentage of units outstanding in Partnership	4.30%		4.30%		5.10%
Class A Limited Partner | United Dominion Realty L.P.
Basis of presentation
Operating Partnership units outstanding related to limited partner	1,873,332		1,873,332		1,873,332
Class A Limited Partner | UDR, Inc.
Basis of presentation
Operating Partnership units outstanding related to limited partner	121,661		121,661		121,661
Limited Partner
Basis of presentation
Operating Partnership units outstanding related to limited partner	6,101,799		6,101,799		7,636,173
Limited Partner | UDR, Inc.
Basis of presentation
Operating Partnership units outstanding related to limited partner	175,977,528		175,977,528		174,016,155
General Partner | UDR, Inc.
Basis of presentation
Operating Partnership units outstanding related to limited partner	110,883		110,883		110,883
Non-affiliated Partners | United Dominion Realty L.P.
Basis of presentation
Operating Partnership units outstanding related to limited partner	7,853,470		7,853,470		9,387,844
Percentage of units outstanding in Partnership	4.30%		4.30%		5.10%
Non-affiliated Partners | Class A Limited Partner
Basis of presentation
Operating Partnership units outstanding related to limited partner	1,751,671		1,751,671		1,751,671

SIGNIFICANT ACCOUNTING POLICI_7

SIGNIFICANT ACCOUNTING POLICIES (UNITED DOMINION REALTY, L.P.) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Accounting policies
Lease classification per practical expedient	true
Operating lease right-of-use assets	$ 135,889
Operating lease liabilities	130,135
Increase in operating lease right-to-use assets	42,143
Increase in operating lease liabilities	42,100
United Dominion Realty L.P.
Accounting policies
Operating lease right-of-use assets	135,766
Operating lease liabilities	130,013
Increase in operating lease right-to-use assets	42,143
Increase in operating lease liabilities	42,100
Unrecognized Tax Benefits	$ 0
ASU 2016-02 | Adjustment
Accounting policies
Operating lease right-of-use assets		$ 94,300
Operating lease liabilities		88,300
Prepaid rent and intangible assets			$ 6,000
ASU 2016-02 | Adjustment | United Dominion Realty L.P.
Accounting policies
Operating lease right-of-use assets		94,200
Operating lease liabilities		$ 88,200
Prepaid rent and intangible assets			$ 6,000

REAL ESTATE OWNED (UNITED DOM_3

REAL ESTATE OWNED (UNITED DOMINION REALTY, L.P.) - Summary (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Real estate owned
Land	$ 2,020,617	$ 1,849,799
Depreciable property - held and used:
Land improvements	220,654	213,224
Building, improvements, and furniture, fixtures and equipment	9,260,709	8,133,136
Real estate owned	11,564,395	10,196,159
Accumulated depreciation	(4,000,608)	(3,654,160)
Total real estate owned, net of accumulated depreciation	7,563,787	6,541,999
United Dominion Realty L.P.
Real estate owned
Land	711,256	711,256
Depreciable property - held and used:
Land improvements	95,096	92,000
Building, improvements, and furniture, fixtures and equipment	3,055,402	3,008,729
Real estate owned	3,861,754	3,811,985
Accumulated depreciation	(1,762,168)	(1,658,161)
Total real estate owned, net of accumulated depreciation	$ 2,099,586	$ 2,153,824

REAL ESTATE OWNED (UNITED DOM_4

REAL ESTATE OWNED (UNITED DOMINION REALTY, L.P.) - Acquisitions and Dispositions (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019USD ($)communityitemstate	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)communityitemstate	Sep. 30, 2018USD ($)
Real Estate Owned Disclosure
Number of communities owned (in communities) | community	138		138
Number of states in which there are owned and consolidated communities | state	13		13
Development costs excluding direct costs and capitalized interest	$ 1.9	$ 1.6	$ 6.9	$ 6.6
Number of apartments owned (in apartments homes) | item	43,683		43,683
Interest capitalized during period	$ 1.4	1.6	$ 3.8	9.8
United Dominion Realty L.P.
Real Estate Owned Disclosure
Number of communities owned (in communities) | community	52		52
Number of states in which there are owned and consolidated communities | state	9		9
Development costs excluding direct costs and capitalized interest	$ 0.3	0	$ 0.6
Number of apartments owned (in apartments homes) | item	16,434		16,434
Interest capitalized during period			$ 0.1
United Dominion Realty L.P. | Maximum
Real Estate Owned Disclosure
Development costs excluding direct costs and capitalized interest				0.1
Interest capitalized during period	$ 0.1	$ 0.1		$ 0.1

UNCONSOLIDATED ENTITIES (UNIT_3

UNCONSOLIDATED ENTITIES (UNITED DOMINION REALTY, L.P.) - Summary Financial Information (Details) - UDR Lighthouse DownREIT L.P. - United Dominion Realty L.P. - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Total real estate, net	$ 1,119,828		$ 1,119,828		$ 1,167,720
Cash and cash equivalents	22		22		39
Note receivable from the General Partner	221,789		221,789		221,022
Other assets	5,259		5,259		5,561
Total assets	1,346,898		1,346,898		1,394,342
Secured debt, net	428,457		428,457		431,735
Other liabilities	25,880		25,880		26,597
Liabilities	454,337		454,337		458,332
Total capital	892,561		892,561		$ 936,010
Rental income	32,434	$ 35,069	96,065	$ 103,842
Property operating expenses	(13,087)	(14,303)	(38,934)	(43,180)
Real estate depreciation and amortization	(20,620)	(22,097)	(61,424)	(65,704)
Operating income/(loss)	(1,273)	(1,331)	(4,293)	(5,042)
Interest expense	(4,162)	(3,343)	(11,979)	(10,553)
Interest income on note receivable from the General Partner	2,054	1,196	6,060	3,587
Net income /(loss)	$ (3,381)	$ (3,478)	$ (10,212)	$ (12,008)

UNCONSOLIDATED ENTITIES (UNIT_4

UNCONSOLIDATED ENTITIES (UNITED DOMINION REALTY, L.P.) - Additional Information (Details) $ in Thousands	Sep. 30, 2019USD ($)communityitem	Dec. 31, 2018USD ($)
Unconsolidated entities
Number of real estate properties | community	138
Number of apartment homes owned and consolidated | item	43,683
Equity Method Investments | $	$ 791,180	$ 780,869
United Dominion Realty L.P.
Unconsolidated entities
Number of real estate properties | community	52
Number of apartment homes owned and consolidated | item	16,434
Equity Method Investments | $	$ 82,269	103,026
United Dominion Realty L.P. | UDR Lighthouse DownREIT L.P.
Unconsolidated entities
Number of real estate properties | community	12
Number of apartment homes owned and consolidated | item	5,657
Equity Method Investments | $	$ 82,300	$ 103,000

LEASES (UNITED DOMINION REALT_3

LEASES (UNITED DOMINION REALTY, L.P.) - Lessee Future Minimum Payments - (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2019USD ($)community
Lessee operating leases
Number of communities subject to ground leases | community	6
Operating leases existence of option to extend	true
Lease classification per practical expedient	true
Operating lease right-of-use assets	$ 135,889
Increase in operating lease right-to-use assets	42,143
Increase in operating lease liabilities	$ 42,100
Weighted average remaining lease term	55 years 2 months 12 days
Weighted average discount rate	5.10%
Future minimum lease payments
2019	$ 1,972
2020	7,889
2021	7,845
2022	7,813
2023	7,813
Thereafter	370,467
Total future minimum lease payments (undiscounted)	403,799
Difference between future undiscounted cash flows and discounted cash flows	(273,664)
Operating lease liabilities	130,135
Ground Leases
Future minimum lease payments
2019	1,953
2020	7,813
2021	7,813
2022	7,813
2023	7,813
Thereafter	370,467
Total future minimum lease payments (undiscounted)	403,672
Difference between future undiscounted cash flows and discounted cash flows	(273,659)
Operating lease liabilities	$ 130,013
United Dominion Realty L.P.
Lessee operating leases
Number of communities subject to ground leases | community	6
Operating leases existence of option to extend	true
Operating lease right-of-use assets	$ 135,766
Increase in operating lease right-to-use assets	42,143
Increase in operating lease liabilities	$ 42,100
Weighted average remaining lease term	55 years 3 months 18 days
Weighted average discount rate	5.10%
Future minimum lease payments
Operating lease liabilities	$ 130,013
United Dominion Realty L.P. | Ground Leases
Future minimum lease payments
2019	1,953
2020	7,813
2021	7,813
2022	7,813
2023	7,813
Thereafter	370,467
Total future minimum lease payments (undiscounted)	403,672
Difference between future undiscounted cash flows and discounted cash flows	(273,659)
Operating lease liabilities	$ 130,013

LEASES (UNITED DOMINION REALT_4

LEASES (UNITED DOMINION REALTY, L.P.) - Lessee Expenses (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Lessee operating leases
Contractual lease expense	$ 100	$ 300
Variable lease expense	100	300
Total lease expense	2,160	6,758
Operating lease right-of-use asset amortization		600
Operating lease liabilities amortization		300
Ground Leases
Lessee operating leases
Contractual lease expense	1,954	6,232
Variable lease expense	187	469
United Dominion Realty L.P.
Lessee operating leases
Contractual lease expense	100	300
Operating lease right-of-use asset amortization		600
Operating lease liabilities amortization		300
United Dominion Realty L.P. | Ground Leases
Lessee operating leases
Contractual lease expense	1,954	6,232
Variable lease expense	187	469
Total lease expense	$ 2,141	$ 6,701

LEASES (UNITED DOMINION REALT_5

LEASES (UNITED DOMINION REALTY, L.P.) - Lessor (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Sep. 30, 2019	Sep. 30, 2019
Lessor leases
Lease classification per practical expedient			true
Future minimum lease payments
Variable lease expense		$ 100	$ 300
Apartment Homes
Lessor leases
Percentage of lease revenue			98.10%
Apartment Homes | Maximum
Lessor leases
Lease terms		12 months	12 months
Retail and Commercial Spaces
Lessor leases
Percentage of lease revenue			1.90%
Future minimum lease payments
2019		$ 4,958	$ 4,958
2020		20,565	20,565
2021		19,788	19,788
2022		18,094	18,094
2023		16,843	16,843
Thereafter		92,719	92,719
Total future minimum payments		$ 172,967	$ 172,967
Retail and Commercial Spaces | Minimum
Lessor leases
Lease terms		5 years	5 years
Retail and Commercial Spaces | Maximum
Lessor leases
Lease terms		15 years	15 years
United Dominion Realty L.P. | Minimum
Lessor leases
Lease terms	5 years
United Dominion Realty L.P. | Maximum
Lessor leases
Lease terms	15 years
United Dominion Realty L.P. | Apartment Homes
Lessor leases
Percentage of lease revenue			98.40%
United Dominion Realty L.P. | Apartment Homes | Maximum
Lessor leases
Lease terms		12 months	12 months
United Dominion Realty L.P. | Retail and Commercial Spaces
Lessor leases
Percentage of lease revenue	1.60%
Lease classification per practical expedient			true
Future minimum lease payments
2019		$ 1,810	$ 1,810
2020		7,778	7,778
2021		7,442	7,442
2022		6,841	6,841
2023		6,517	6,517
Thereafter		19,874	19,874
Total future minimum payments		50,262	50,262
Variable lease expense			$ 100
United Dominion Realty L.P. | Retail and Commercial Spaces | Maximum
Future minimum lease payments
Variable lease expense		$ 100

DEBT, NET (UNITED DOMINION RE_3

DEBT, NET (UNITED DOMINION REALTY, L.P.) - Summary (Details) $ in Thousands	1 Months Ended	9 Months Ended
	Oct. 30, 2019	Sep. 30, 2019USD ($)community	Dec. 31, 2018USD ($)
Fixed and variable rate debt
Weighted Average Interest Rate	4.63%	3.63%
Weighted Average
Fixed and variable rate debt
Years to maturity		6 years 10 months 24 days
Fixed Rate Debt | Mortgages Notes Payable
Fixed and variable rate debt
Principal outstanding		$ 575,965	$ 417,989
Weighted Average Interest Rate		3.55%
Communities Encumbered (in communities) | community		9
Fixed Rate Debt | Mortgages Notes Payable | Weighted Average
Fixed and variable rate debt
Years to maturity		6 years 7 months 6 days
Fixed Rate Debt | Fannie Mae credit facilities
Fixed and variable rate debt
Principal outstanding			90,000
Variable Rate Debt | Tax-exempt secured notes payable
Fixed and variable rate debt
Principal outstanding		$ 27,000	94,700
Weighted Average Interest Rate		2.07%
Communities Encumbered (in communities) | community		1
Variable Rate Debt | Tax-exempt secured notes payable | Weighted Average
Fixed and variable rate debt
Years to maturity		12 years 6 months
United Dominion Realty L.P.
Fixed and variable rate debt
Principal outstanding		$ 99,064	26,929
Weighted Average Interest Rate		2.85%
Communities Encumbered (in communities) | community		2
United Dominion Realty L.P. | Weighted Average
Fixed and variable rate debt
Years to maturity		10 years 10 months 24 days
United Dominion Realty L.P. | Mortgages Notes Payable
Fixed and variable rate debt
Principal outstanding		$ 72,500
Interest rate		3.10%
United Dominion Realty L.P. | Fixed Rate Debt
Fixed and variable rate debt
Principal outstanding		$ 72,130
Weighted Average Interest Rate		3.10%
Communities Encumbered (in communities) | community		1
United Dominion Realty L.P. | Fixed Rate Debt | Weighted Average
Fixed and variable rate debt
Years to maturity		10 years 3 months 18 days
United Dominion Realty L.P. | Fixed Rate Debt | Mortgages Notes Payable
Fixed and variable rate debt
Principal outstanding		$ 72,500
Weighted Average Interest Rate		3.10%
Communities Encumbered (in communities) | community		1
Deferred finance costs, net		$ (370)
United Dominion Realty L.P. | Fixed Rate Debt | Mortgages Notes Payable | Weighted Average
Fixed and variable rate debt
Years to maturity		10 years 3 months 18 days
United Dominion Realty L.P. | Variable Rate Debt
Fixed and variable rate debt
Deferred finance costs, net		$ (66)	(71)
United Dominion Realty L.P. | Variable Rate Debt | Tax-exempt secured notes payable
Fixed and variable rate debt
Principal outstanding		$ 27,000	$ 27,000
Weighted Average Interest Rate		2.07%
Communities Encumbered (in communities) | community		1
United Dominion Realty L.P. | Variable Rate Debt | Tax-exempt secured notes payable | Weighted Average
Fixed and variable rate debt
Years to maturity		12 years 6 months

DEBT, NET (UNITED DOMINION RE_4

DEBT, NET (UNITED DOMINION REALTY, L.P.) - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended
	Oct. 30, 2019	Aug. 31, 2019	Sep. 30, 2019	Jul. 31, 2019	Jul. 02, 2019	Dec. 31, 2018
Fixed and variable rate debt
Long-term commercial paper			$ 500,000
Borrowings outstanding			2,800			$ 3,300
Commercial Paper
Fixed and variable rate debt
Commercial paper program			$ 60,000			$ 101,115
Interest rate at the end of the period			2.30%			2.90%
3.70% Term Notes Due October 2020
Fixed and variable rate debt
Interest rate		3.70%
Make-whole amount		$ 5,400
4.63% Medium-Term Notes due January 2022
Fixed and variable rate debt
Medium-term notes	$ 400,000
Interest rate	4.63%
Make-whole amount	$ 21,500
3.20% Medium-Term Notes due January 2030
Fixed and variable rate debt
Guarantor borrowing capacity			$ 300,000
Medium-term notes	$ 100,000			$ 300,000	$ 300,000
Interest rate	3.20%			3.20%	3.20%
Borrowings outstanding	$ 400,000
Medium-Term Notes Due August 2031
Fixed and variable rate debt
Guarantor borrowing capacity			400,000
3.10% senior unsecured notes due 2034
Fixed and variable rate debt
Medium-term notes	$ 300,000
Interest rate	3.10%
United Dominion Realty L.P. | Financial Guarantee
Fixed and variable rate debt
Guarantor borrowing capacity			1,100,000
United Dominion Realty L.P. | Unsecured Commercial Bank Credit Facility
Fixed and variable rate debt
Long-term commercial paper			$ 500,000
United Dominion Realty L.P. | Mortgages Notes Payable
Fixed and variable rate debt
Interest rate			3.10%
United Dominion Realty L.P. | Mortgages Notes Payable | Variable Rate Debt | Operating Partnership
Fixed and variable rate debt
Interest rate at the end of the period			2.07%
United Dominion Realty L.P. | Unsecured Commercial Paper
Fixed and variable rate debt
Borrowings outstanding			$ 60,000			$ 101,100
United Dominion Realty L.P. | 3.70% Term Notes Due October 2020
Fixed and variable rate debt
Guarantor borrowing capacity			300,000
United Dominion Realty L.P. | 4.63% Medium-Term Notes due January 2022
Fixed and variable rate debt
Guarantor borrowing capacity			400,000
United Dominion Realty L.P. | Term Loan due September 2023
Fixed and variable rate debt
Guarantor borrowing capacity			350,000
United Dominion Realty L.P. | 3.75% Medium-Term Notes Due July 2024
Fixed and variable rate debt
Guarantor borrowing capacity			300,000
United Dominion Realty L.P. | 4.00% Medium-Term Note due October 2025
Fixed and variable rate debt
Guarantor borrowing capacity			300,000
United Dominion Realty L.P. | 2.95% Medium-Term Note due September 2026
Fixed and variable rate debt
Guarantor borrowing capacity			300,000
United Dominion Realty L.P. | 3.50 Medium-Term Note due July 2027
Fixed and variable rate debt
Guarantor borrowing capacity			300,000
United Dominion Realty L.P. | Medium-Term note due January 2029
Fixed and variable rate debt
Guarantor borrowing capacity			$ 300,000

RELATED PARTY TRANSACTIONS (U_3

RELATED PARTY TRANSACTIONS (UNITED DOMINION REALTY, L.P.) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Related party transactions
Related party management fees	$ 4,600	$ 3,800	$ 12,700	$ 11,400
United Dominion Realty L.P.
Related party transactions
Debt Instrument, Interest Rate Period End	3.63%		3.63%
Notes payable due to the General Partner	$ 623,967		$ 623,967		$ 700,115
Interest expense, related party	6,983	3,053	21,358	9,159
United Dominion Realty L.P. | UDR, Inc.
Related party transactions
General and administrative expenses allocated to the Operating Partnership by UDR	$ 2,700	$ 3,300	$ 9,700	$ 10,500
Note due August 2021 | United Dominion Realty L.P.
Related party transactions
Debt Instrument, Interest Rate Period End	5.34%		5.34%
Notes payable due to the General Partner	$ 5,500		$ 5,500		5,500
Note due December 2023 | United Dominion Realty L.P.
Related party transactions
Debt Instrument, Interest Rate Period End	5.18%		5.18%
Notes payable due to the General Partner	$ 83,196		$ 83,196		83,196
Note due April 2026 | United Dominion Realty L.P.
Related party transactions
Debt Instrument, Interest Rate Period End	4.12%		4.12%
Notes payable due to the General Partner	$ 184,638		$ 184,638		184,638
Note due November 2028 | United Dominion Realty L.P.
Related party transactions
Debt Instrument, Interest Rate Period End	4.69%		4.69%
Notes payable due to the General Partner	$ 133,205		$ 133,205		133,205
Note due December 2028 | United Dominion Realty L.P.
Related party transactions
Debt Instrument, Interest Rate Period End	3.63%		3.63%
Notes payable due to the General Partner	$ 217,428		$ 217,428		$ 293,576

FAIR VALUE OF DERIVATIVES AND_6

FAIR VALUE OF DERIVATIVES AND FINANCIAL INSTRUMENTS (UNITED DOMINION REALTY, L.P.) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Debt instruments - fair value
Transfer between the levels	$ 0
Fair Value, Measurements, Recurring | Carrying Amount
Debt instruments - fair value
Total liabilities	3,958,139	$ 3,566,018
Fair Value, Measurements, Recurring | Fair Value
Debt instruments - fair value
Total liabilities	4,106,852	3,532,104
Level 2 | Fair Value, Measurements, Recurring | Fair Value
Debt instruments - fair value
Total liabilities	469	356
Level 3 | Fair Value, Measurements, Recurring | Fair Value
Debt instruments - fair value
Total liabilities	4,106,383	3,531,748
United Dominion Realty L.P. | Fair Value, Measurements, Recurring | Carrying Amount
Debt instruments - fair value
Total liabilities	99,500	27,000
United Dominion Realty L.P. | Fair Value, Measurements, Recurring | Fair Value
Debt instruments - fair value
Total liabilities	95,669	27,000
United Dominion Realty L.P. | Level 3 | Fair Value, Measurements, Recurring | Fair Value
Debt instruments - fair value
Total liabilities	95,669	27,000
Fixed Rate Debt | United Dominion Realty L.P. | Mortgages Notes Payable | Fair Value, Measurements, Recurring | Carrying Amount
Debt instruments - fair value
Fair value	72,500
Fixed Rate Debt | United Dominion Realty L.P. | Mortgages Notes Payable | Fair Value, Measurements, Recurring | Fair Value
Debt instruments - fair value
Fair value	68,669
Fixed Rate Debt | United Dominion Realty L.P. | Level 3 | Mortgages Notes Payable | Fair Value, Measurements, Recurring | Fair Value
Debt instruments - fair value
Fair value	68,669
Variable Rate Debt | United Dominion Realty L.P. | Tax-exempt secured notes payable | Fair Value, Measurements, Recurring | Carrying Amount
Debt instruments - fair value
Fair value	27,000	27,000
Variable Rate Debt | United Dominion Realty L.P. | Tax-exempt secured notes payable | Fair Value, Measurements, Recurring | Fair Value
Debt instruments - fair value
Fair value	27,000	27,000
Variable Rate Debt | United Dominion Realty L.P. | Level 3 | Tax-exempt secured notes payable | Fair Value, Measurements, Recurring | Fair Value
Debt instruments - fair value
Fair value	$ 27,000	$ 27,000

DERIVATIVES AND HEDGING ACTI_10

DERIVATIVES AND HEDGING ACTIVITY (UNITED DOMINION REALTY, L.P.) (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019USD ($)instrument	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)instrument	Sep. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Derivatives
Estimated additional accumulated other comprehensive Income/(Loss) transferred to interest expense	$ 9,800		$ 9,800
Payment required to pay for contract termination	$ 500		$ 500
Interest rate caps | Not Designated as Hedging Instrument
Outstanding interest rate derivatives not designated as hedging instrument
Number instruments | instrument	1		1
Notional	$ 19,880		$ 19,880
United Dominion Realty L.P.
Derivatives
Derivatives	0		0		$ 0
Estimated additional accumulated other comprehensive Income/(Loss) transferred to interest expense	0		0
United Dominion Realty L.P. | Interest rate contracts
Derivatives
Gain/(Loss) recognized in Interest Income and Other Income/(Expense), net	$ 0	$ 0	$ 0	$ 0
United Dominion Realty L.P. | Interest rate caps | Not Designated as Hedging Instrument
Outstanding interest rate derivatives not designated as hedging instrument
Number instruments | instrument	1		1
Notional	$ 19,880		$ 19,880
Other income/(expense) | Interest rate contracts
Derivatives
Gain/(Loss) recognized in Interest Income and Other Income/(Expense), net	0	0	0	0
Other income/(expense) | United Dominion Realty L.P. | Interest rate contracts
Derivatives
Gain/(Loss) recognized in Interest Income and Other Income/(Expense), net	$ 0	$ 0	0	$ 0
Interest expense | United Dominion Realty L.P. | Cash Flow Hedging
Derivatives
Gain/(Loss) recognized in Interest Income and Other Income/(Expense), net			$ 0

CAPITAL STRUCTURE (UNITED DOM_3

CAPITAL STRUCTURE (UNITED DOMINION REALTY, L.P.) - Units Rollforward (Details)	9 Months Ended
	Sep. 30, 2019shares
Capital structure
Balance	183,636,543
Vesting of LTIP Units	426,999
Balance	184,063,542
UDR, Inc.
Capital structure
Balance	174,137,816
Balance	176,099,189
Non-affiliated Partners
Capital structure
Balance	7,853,470
Class A Limited Partner | UDR, Inc.
Capital structure
Balance	121,661
Balance	121,661
Non-affiliated Partners | Class A Limited Partner
Capital structure
Balance	1,751,671
Balance	1,751,671
Limited Partner
Capital structure
Balance	7,636,173
Vesting of LTIP Units	426,999
OP redemptions for UDR stock	1,961,373
Balance	6,101,799
Limited Partner | UDR, Inc.
Capital structure
Balance	174,016,155
OP redemptions for UDR stock	(1,961,373)
Balance	175,977,528
Class A Limited Partner | UDR, Inc.
Capital structure
Balance	121,661
Balance	121,661
General Partner | UDR, Inc.
Capital structure
Balance	110,883
Balance	110,883

CAPITAL STRUCTURE (UNITED DOM_4

CAPITAL STRUCTURE (UNITED DOMINION REALTY, L.P.) - Ownership Interests (Details) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2019USD ($)class$ / sharesshares	Dec. 31, 2018USD ($)shares
Capital structure
Limited partnership units owned	184,063,542	183,636,543
Redeemable noncontrolling interests in the Operating Partnership | $	$ 1,072,181	$ 972,740
Number of classes of LTIP Units | class	2
United Dominion Realty L.P.
Capital structure
Limited partnership units owned	176,210,072
United Dominion Realty L.P.
Capital structure
General Partnership units outstanding	110,883	110,883
Limited partnership units owned	183,952,659	183,525,660
Required period to be outstanding before unit is redeemable (in years)	1 year
Redeemable noncontrolling interests in the Operating Partnership | $	$ 380,700	$ 371,900
UDR, Inc.
Capital structure
Limited partnership units owned	176,099,189	174,137,816
Percentage of units	95.70%	94.90%
UDR, Inc. | United Dominion Realty L.P.
Capital structure
General Partnership units outstanding	176,210,072
Percentage of units		94.90%
Non-affiliated Partners
Capital structure
Limited partnership units owned	7,853,470
Percentage of units	4.30%
Non-affiliated Partners | United Dominion Realty L.P.
Capital structure
Limited partnership units owned	7,853,470
Percentage of units	4.30%	5.10%
Class A Limited Partner
Capital structure
Cumulative, annual, non-compounded preferred return on Class A Partnership units	8.00%
Value of Class A Partnership units (in dollars per share) | $ / shares	$ 16.61
Class A Limited Partner | United Dominion Realty L.P.
Capital structure
Limited partnership units owned	1,873,332	1,873,332
Class A Limited Partner | UDR, Inc.
Capital structure
Limited partnership units owned	121,661	121,661
Non-affiliated Partners | United Dominion Realty L.P.
Capital structure
Limited partnership units owned	7,853,470	9,387,844
Percentage of units	4.30%	5.10%
Non-affiliated Partners | Class A Limited Partner
Capital structure
Limited partnership units owned	1,751,671	1,751,671
LTIP Units One
Capital structure
Vesting period	4 years
Minimum | LTIP Units
Capital structure
Vesting period	1 year
Period of time LTIP units have been outstanding	2 years
Minimum | Employee Director | LTIP Units Two
Capital structure
Vesting period	1 year
Maximum | LTIP Units
Capital structure
Vesting period	3 years
Maximum | Employee Director | LTIP Units Two
Capital structure
Vesting period	3 years

COMMITMENTS AND CONTINGENCIES_5

COMMITMENTS AND CONTINGENCIES (UNITED DOMINION REALTY, L.P.) Commitments and Contingencies (Details) $ in Thousands	Sep. 30, 2019USD ($)community
Commitments
Number of communities owned (in communities) | community	138
Cost Incurred to Date	$ 114,536
UDR's Remaining Commitment	$ 157,459
United Dominion Realty L.P.
Commitments
Number of communities owned (in communities) | community	52
Real estate communities - redevelopment | United Dominion Realty L.P.
Commitments
Number of communities owned (in communities) | community	1
Cost Incurred to Date	$ 6,254
UDR's Remaining Commitment	$ 18,746
Wholly owned - under development
Commitments
Number of communities owned (in communities) | community	1
Cost Incurred to Date	$ 21,845
UDR's Remaining Commitment	$ 75,655

REPORTABLE SEGMENTS (UNITED D_3

REPORTABLE SEGMENTS (UNITED DOMINION REALTY, L.P.) (Details). $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019USD ($)item	Sep. 30, 2018USD ($)item	Sep. 30, 2019USD ($)	Sep. 30, 2019USD ($)item	Sep. 30, 2019USD ($)home	Sep. 30, 2019USD ($)segment	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)item	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Segments
Equity Method Investments	$ 791,180		$ 791,180	$ 791,180	$ 791,180	$ 791,180	$ 791,180		$ 780,869
Same store communities	38,177	38,177		37,959	38,177			37,959
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Rental income	$ 289,008	$ 263,256					835,393	$ 770,373
Reconciling items:
Property management	(8,309)	(7,240)					(24,018)	(21,185)
Other operating expenses	(2,751)	(3,314)					(11,132)	(8,148)
Real estate depreciation and amortization	(127,391)	(107,881)					(357,793)	(322,537)
General and administrative	(12,197)	(11,896)					(37,002)	(36,028)
Casualty-related (charges)/recoveries, net	1,088	(678)					842	(2,364)
Gain/(loss) on sale of real estate owned							5,282	70,300
Income/(loss) from unconsolidated entities	12,713	(1,382)					19,387	(5,091)
Interest expense	(42,523)	(34,401)					(110,482)	(95,942)
Net (income)/loss attributable to noncontrolling interests	(56)	(32)					(145)	(141)
Net income/(loss) attributable to OP unitholders	27,204	18,610					87,326	120,967
Reportable apartment home segment assets:
Total segment assets	11,564,395		11,564,395	$ 11,564,395	$ 11,564,395	11,564,395	11,564,395		10,196,159
Accumulated depreciation	(4,000,608)		(4,000,608)	(4,000,608)	(4,000,608)	(4,000,608)	(4,000,608)		(3,654,160)
Total real estate owned, net of accumulated depreciation	7,563,787		7,563,787	7,563,787	7,563,787	7,563,787	7,563,787		6,541,999
Total segment asset - net book value	7,563,787		7,563,787	7,563,787	7,563,787	7,563,787	7,563,787		6,541,999
Reconciling items:
Cash and cash equivalents	1,895	1,084	1,895	1,895	1,895	1,895	1,895	1,084	185,216	$ 2,038
Restricted cash	21,646	26,996	21,646	21,646	21,646	21,646	21,646	26,996	23,675	19,792
Investment in unconsolidated entities	791,180		791,180	791,180	791,180	791,180	791,180		780,869
Operating lease right-of-use assets	135,889		135,889	135,889	135,889	135,889	135,889
Other assets	145,301		145,301	145,301	145,301	145,301	145,301		137,710
Total assets	8,697,597		$ 8,697,597	8,697,597	8,697,597	$ 8,697,597	8,697,597		7,711,728
Reportable Segments
Number of reportable segments | segment						2
Condition for Community considered to have stabilized occupancy			90%
Time to maintain percent occupancy to be considered a community			3 months
Practical expedient, single lease component			true
Same Store Communities West Region
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Lease revenue	99,316	95,447					293,294	281,722
Other revenue	7,869	7,168					23,488	21,567
Rental income	107,185	102,615					316,782	303,289
Reportable apartment home segment NOI	81,170	77,321					240,442	229,129
Reportable apartment home segment assets:
Total segment assets	3,797,149		$ 3,797,149	3,797,149	3,797,149	$ 3,797,149	3,797,149		3,763,366
Same Store Communities Mid-Atlantic Region
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Lease revenue	52,826	51,291					157,179	152,867
Other revenue	4,376	4,032					12,958	11,944
Rental income	57,202	55,323					170,137	164,811
Reportable apartment home segment NOI	39,850	38,220					119,075	114,465
Reportable apartment home segment assets:
Total segment assets	2,338,963		2,338,963	2,338,963	2,338,963	2,338,963	2,338,963		2,317,369
Same Store Communities Southeast Region
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Lease revenue	28,540	27,773					84,551	81,554
Other revenue	3,438	3,211					10,423	9,918
Rental income	31,978	30,984					94,974	91,472
Reportable apartment home segment NOI	22,133	21,597					66,301	63,806
Reportable apartment home segment assets:
Total segment assets	799,739		799,739	799,739	799,739	799,739	799,739		779,310
Same Store Communities Northeast Region
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Lease revenue	30,196	29,491					89,650	87,776
Other revenue	1,321	1,226					3,753	3,422
Rental income	31,517	30,717					93,403	91,198
Reportable apartment home segment NOI	20,560	20,640					63,012	62,710
Reportable apartment home segment assets:
Total segment assets	1,498,500		1,498,500	1,498,500	1,498,500	1,498,500	1,498,500		1,491,994
Same Store Communities Southwest Region
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Lease revenue	15,451	15,060					40,705	39,586
Other revenue	1,527	1,525					4,100	3,986
Rental income	16,978	16,585					44,805	43,572
Reportable apartment home segment NOI	10,449	9,899					26,995	25,760
Reportable apartment home segment assets:
Total segment assets	595,982		595,982	595,982	595,982	595,982	595,982		589,188
Non-Mature communities/Other
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Lease revenue	40,975	24,237					106,499	66,906
Other revenue	3,173	2,795					8,793	9,125
Rental income	44,148	27,032					115,292	76,031
Reportable apartment home segment NOI	29,487	17,137					77,242	48,833
Reportable apartment home segment assets:
Total segment assets	2,534,062		2,534,062	2,534,062	2,534,062	2,534,062	2,534,062		1,254,932
Total Communities
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Lease revenue	267,304	243,299					771,878	710,411
Other revenue	21,704	19,957					63,515	59,962
Rental income	289,008	263,256					835,393	770,373
Reportable apartment home segment NOI	203,649	184,814					593,067	544,703
United Dominion Realty L.P.
Segments
Equity Method Investments	$ 82,269		82,269	$ 82,269	$ 82,269	82,269	82,269		103,026
Same store communities	15,941			15,723	15,941
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Rental income	$ 111,700	109,539					330,384	323,397
Reconciling items:
Property management	(3,211)	(3,012)					(9,498)	(8,893)
Other operating expenses	(2,301)	(2,347)					(7,123)	(6,098)
Real estate depreciation and amortization	(35,155)	(35,043)					(104,730)	(108,906)
General and administrative	(4,066)	(4,143)					(12,878)	(12,997)
Casualty-related (charges)/recoveries, net	1,088	10					1,169	(906)
Gain/(loss) on sale of real estate owned								70,300
Income/(loss) from unconsolidated entities	(2,383)	(2,378)					(6,917)	(10,102)
Interest expense	(7,521)	(5,100)					(22,247)	(15,209)
Net (income)/loss attributable to noncontrolling interests	(448)	(440)					(1,252)	(1,278)
Net income/(loss) attributable to OP unitholders	26,835	27,695					78,175	143,883
Reportable apartment home segment assets:
Total segment assets	3,861,754		3,861,754	$ 3,861,754	$ 3,861,754	3,861,754	3,861,754		3,811,985
Accumulated depreciation	(1,762,168)		(1,762,168)	(1,762,168)	(1,762,168)	(1,762,168)	(1,762,168)		(1,658,161)
Total real estate owned, net of accumulated depreciation	2,099,586		2,099,586	2,099,586	2,099,586	2,099,586	2,099,586		2,153,824
Total segment asset - net book value	2,099,586		2,099,586	2,099,586	2,099,586	2,099,586	2,099,586		2,153,824
Reconciling items:
Cash and cash equivalents	40	83	40	40	40	40	40	83	125	293
Restricted cash	14,637	13,515	14,637	14,637	14,637	14,637	14,637	13,515	13,563	$ 12,579
Investment in unconsolidated entities	82,269		82,269	82,269	82,269	82,269	82,269		103,026
Operating lease right-of-use assets	135,766		135,766	135,766	135,766	135,766	135,766
Other assets	23,321		23,321	23,321	23,321	23,321	23,321		34,052
Total assets	2,355,619		$ 2,355,619	2,355,619	2,355,619	$ 2,355,619	2,355,619		2,304,590
Reportable Segments
Number of reportable segments | segment						2
Condition for Community considered to have stabilized occupancy			90%
Time to maintain percent occupancy to be considered a community			3 months
Practical expedient, single lease component			true
United Dominion Realty L.P. | Same Store Communities West Region
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Lease revenue	62,760	60,569					185,840	178,401
Other revenue	2,063	1,750					5,908	5,484
Rental income	64,823	62,319					191,748	183,885
Reportable apartment home segment NOI	49,528	47,692					146,673	140,603
Reportable apartment home segment assets:
Total segment assets	2,003,088		$ 2,003,088	2,003,088	2,003,088	$ 2,003,088	2,003,088		1,981,007
United Dominion Realty L.P. | Same Store Communities Mid-Atlantic Region
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Lease revenue	14,900	14,645					44,592	43,814
Other revenue	551	441					1,515	1,359
Rental income	15,451	15,086					46,107	45,173
Reportable apartment home segment NOI	10,611	10,178					31,691	30,953
Reportable apartment home segment assets:
Total segment assets	667,755		667,755	667,755	667,755	667,755	667,755		663,083
United Dominion Realty L.P. | Same Store Communities Southeast Region
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Lease revenue	12,808	12,604					37,957	36,782
Other revenue	799	658					2,301	2,099
Rental income	13,607	13,262					40,258	38,881
Reportable apartment home segment NOI	9,371	9,336					27,984	26,979
Reportable apartment home segment assets:
Total segment assets	349,767		349,767	349,767	349,767	349,767	349,767		340,722
United Dominion Realty L.P. | Same Store Communities Northeast Region
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Lease revenue	8,098	7,936					24,036	23,541
Other revenue	187	178					521	496
Rental income	8,285	8,114					24,557	24,037
Reportable apartment home segment NOI	5,736	6,001					18,201	18,260
Reportable apartment home segment assets:
Total segment assets	408,244		408,244	408,244	408,244	408,244	408,244		406,149
United Dominion Realty L.P. | Same Store Communities Southwest Region
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Lease revenue	1,901	1,865
Other revenue	87	58
Rental income	1,988	1,923
Reportable apartment home segment NOI	1,405	1,253
Reportable apartment home segment assets:
Total segment assets	144,028		144,028	144,028	144,028	144,028	144,028		141,882
United Dominion Realty L.P. | Non-Mature communities/Other
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Lease revenue	7,468	8,694					27,295	30,830
Other revenue	78	141					419	591
Rental income	7,546	8,835					27,714	31,421
Reportable apartment home segment NOI	4,181	5,688					17,102	21,177
Reportable apartment home segment assets:
Total segment assets	288,872		$ 288,872	$ 288,872	$ 288,872	$ 288,872	288,872		$ 279,142
United Dominion Realty L.P. | Total Communities
Summary of rental income and NOI for UDRs reportable segments and reconciliation of NOI to loss from continuing operations
Lease revenue	107,935	106,313					319,720	313,368
Other revenue	3,765	3,226					10,664	10,029
Rental income	111,700	109,539					330,384	323,397
Reportable apartment home segment NOI	$ 80,832	$ 80,148					$ 241,651	$ 237,972