CONSOLIDATED STATEMENTS OF CASH FLOWS (UNITED DOMINION REALTY, L.P.) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Operating Activities
Net income/(loss)	$ 199,579	$ 221,542	$ 132,655
Adjustments to reconcile net income/(loss) to net cash provided by/(used in) operating activities:
Depreciation and amortization	507,923	435,679	436,462
(Gain)/loss on sale of real estate owned	(5,282)	(136,197)	(43,404)
(Income)/loss from unconsolidated entities	(137,873)	5,055	(31,257)
Other	39,958	4,998	20,467
Changes in operating assets and liabilities:
(Increase)/decrease in operating assets	(10,956)	(13,880)	(9,008)
Increase/(decrease) in operating liabilities	7,846	24,987	(4,278)
Net cash provided by/(used in) operating activities	630,704	560,676	518,915
Investing Activities
Acquisition of real estate assets	(1,370,770)		(96,791)
Proceeds from sales of real estate investments, net	38,000	247,031	71,235
Capital expenditures and other major improvements - real estate assets	(167,188)	(112,359)	(124,728)
Distributions received from unconsolidated entities	72,441	42,683	116,329
Net cash provided by/(used in) investing activities	(1,686,687)	(113,548)	(407,406)
Financing Activities
Proceeds from the issuance of secured debt	162,500	80,000
Payments on secured debt	(162,253)	(279,243)	(326,346)
Other	(41,725)	(41,485)	(21,361)
Net cash provided by/(used in) financing activities	880,383	(260,067)	(111,785)
Net increase/(decrease) in cash, cash equivalents, and restricted cash	(175,600)	187,061	(276)
Cash, cash equivalents, and restricted cash, beginning of year	208,891	21,830	22,106
Cash, cash equivalents, and restricted cash, end of year	33,291	208,891	21,830
Supplemental Information:
Interest paid during the period, net of amounts capitalized	169,558	132,466	126,348
Non-cash transactions:
Development costs and capital expenditures incurred but not yet paid	16,635	10,304	43,930
Recognition of operating lease right-of-use assets	94,349
Recognition of operating lease liabilities	88,336
Right-of-use assets obtained in exchange for operating lease liabilities remeasurements	111,055
Dividends declared but not yet paid	109,382	97,666	91,455
United Dominion Realty L.P.
Operating Activities
Net income/(loss)	103,995	231,485	107,855
Adjustments to reconcile net income/(loss) to net cash provided by/(used in) operating activities:
Depreciation and amortization	139,975	143,481	152,473
(Gain)/loss on sale of real estate owned		(75,507)	(41,272)
(Income)/loss from unconsolidated entities	8,313	(43,496)	19,256
Other	3,534	1,771	5,642
Changes in operating assets and liabilities:
(Increase)/decrease in operating assets	1,084	(3,260)	(3,992)
Increase/(decrease) in operating liabilities	(1,808)	1,194	(4,705)
Net cash provided by/(used in) operating activities	255,093	255,668	235,257
Investing Activities
Acquisition of real estate assets			(137,332)
Proceeds from sales of real estate investments, net		98,533	67,985
Capital expenditures and other major improvements - real estate assets	(62,397)	(44,227)	(53,346)
Distributions received from unconsolidated entities	18,491	17,377	16,704
Net cash provided by/(used in) investing activities	(43,906)	71,683	(105,989)
Financing Activities
Advances (to)/from the General Partner, net		(348,381)	163,196
Proceeds from the issuance of secured debt	72,500
Payments on secured debt		(133,205)	(275,345)
Issuance/(repayment) of notes payable to the General Partner	(272,913)	169,577
Distributions paid to partnership unitholders	(10,064)	(12,705)	(11,694)
Other	(376)	(1,821)	(5,003)
Net cash provided by/(used in) financing activities	(210,853)	(326,535)	(128,846)
Net increase/(decrease) in cash, cash equivalents, and restricted cash	334	816	422
Cash, cash equivalents, and restricted cash, beginning of year	13,688	12,872	12,450
Cash, cash equivalents, and restricted cash, end of year	14,022	13,688	12,872
Supplemental Information:
Interest paid during the period, net of amounts capitalized	38,400	17,173	24,331
Non-cash transactions:
Development costs and capital expenditures incurred but not yet paid	2,913	2,056	2,032
Recognition of operating lease right-of-use assets	94,174
Recognition of operating lease liabilities	88,161
Right-of-use assets obtained in exchange for operating lease liabilities remeasurements	112,498
LTIP Unit grants	27,066	15,839	7,763
Dividends declared but not yet paid	$ 63,364	59,461	$ 57,025
Conversion of Advances (to)/from the General Partner to notes payable		$ 257,204