STOCKHOLDERS' EQUITY - Shares Roll forward (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Stockholders' equity
Repurchase of common shares	(3,300)
Common Stock
Stockholders' equity
Shares issued, beginning of period	330,859	329,015	328,993
Issuance/(forfeiture) of common and restricted shares, net	291	48	174
Repurchase of common shares	(3,260)		(623)
Conversion of Series E Cumulative Convertible shares		93
Shares issued, end of period	328,273	330,859	329,015
8.00% Series E Cumulative Convertible Preferred Stock
Stockholders' equity
Shares issued, beginning of period	2,601	2,686	2,686
Conversion of Series E Cumulative Convertible shares		(85)
Shares issued, end of period	2,601	2,601	2,686
Series F
Stockholders' equity
Shares issued, beginning of period	10,424	11,868	12,101
Forfeiture of Series F shares	(318)	(1,444)	(233)
Shares issued, end of period	10,106	10,424	11,868
United Dominion Reality L.P. | Common Stock
Stockholders' equity
Adjustment for conversion of non-controlling interest of unitholders	41	170	148
UDR Lighthouse DownREIT L.P. | Common Stock
Stockholders' equity
Adjustment for conversion of non-controlling interest of unitholders	342	1,533	323
UDR Lighthouse DownREIT L.P. and United Dominion Reality L.P. [Member] | Common Stock
Stockholders' equity
Adjustment for conversion of non-controlling interest of unitholders	400
UDR Lighthouse DownREIT L.P. and United Dominion Reality L.P. [Member] | Series F
Stockholders' equity
Forfeiture of Series F shares	300
UDR Lighthouse DownREIT L.P. and United Dominion Reality L.P. [Member] | Series F | Maximum
Stockholders' equity
Forfeiture of Series F shares	(300)	(1,400)