Segment Reporting - Total Revenue, NOI, and Real Estate by Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting
Total revenue	$ 2,767,909	$ 2,593,446	$ 2,294,850
NOI	1,886,748	1,741,854	1,456,875
Gross real estate	26,930,462	25,590,474	24,140,139
Same Store
Segment Reporting
Real estate capitalized additions	188,507	209,607	158,991
Operating segment | Same Store
Segment Reporting
Total revenue	2,542,634	2,394,292	1,995,716
NOI	1,755,112	1,655,706	1,356,363
Gross real estate	22,387,464	22,197,772	19,741,013
Operating segment | Same Store | New England
Segment Reporting
Total revenue	366,777	341,769	295,505
NOI	244,700	226,987	189,571
Gross real estate	2,925,841	2,893,843	2,771,067
Operating segment | Same Store | Metro NY/NJ
Segment Reporting
Total revenue	529,684	495,107	407,621
NOI	362,599	342,511	279,078
Gross real estate	4,417,603	4,401,146	4,025,983
Operating segment | Same Store | Mid-Atlantic
Segment Reporting
Total revenue	369,027	348,096	302,652
NOI	255,741	238,970	203,502
Gross real estate	3,439,654	3,396,654	3,068,575
Operating segment | Same Store | Southeast Florida
Segment Reporting
Total revenue	76,301	69,685	31,703
NOI	50,315	44,696	19,689
Gross real estate	801,617	798,437	395,999
Operating segment | Same Store | Denver, CO
Segment Reporting
Total revenue	28,209	26,848	23,742
NOI	20,020	19,652	16,451
Gross real estate	322,419	321,685	320,435
Operating segment | Same Store | Pacific Northwest
Segment Reporting
Total revenue	171,740	165,186	126,513
NOI	121,783	117,211	85,980
Gross real estate	1,546,038	1,534,208	1,288,975
Operating segment | Same Store | Northern California
Segment Reporting
Total revenue	425,165	405,184	366,215
NOI	303,526	288,772	258,756
Gross real estate	3,789,965	3,765,490	3,605,284
Operating segment | Same Store | Southern California
Segment Reporting
Total revenue	551,743	520,483	441,765
NOI	380,262	361,809	303,336
Gross real estate	4,816,245	4,762,736	4,264,695
Operating segment | Same Store | Other Expansion Regions
Segment Reporting
Total revenue	23,988	21,934
NOI	16,166	15,098
Gross real estate	328,082	323,573
Operating segment | Other Stabilized Communities
Segment Reporting
Total revenue	134,804	93,305	121,659
NOI	92,808	67,462	75,422
Gross real estate	1,799,035	1,515,963	2,413,391
Operating segment | Development / Redevelopment
Segment Reporting
Total revenue	61,552	29,734	42,885
NOI	38,828	18,686	25,090
Gross real estate	2,408,450	1,574,649	1,580,653
Operating segment | Disposals
Segment Reporting
Gross real estate		280,889	760,990
Segment Reconciling Items
Segment Reporting
Gross real estate	199,062	179,204	147,546
Non-allocated
Segment Reporting
Total revenue	7,722	6,333	3,084
Gross real estate	136,451	122,886	257,536
Continuing Operations
Segment Reporting
Total revenue	2,746,712	2,523,664	2,163,344
Continuing Operations | Operating segment | Same Store
Segment Reporting
Total revenue	2,542,634	2,394,292	1,995,716
Continuing Operations | Operating segment | Other Stabilized Communities
Segment Reporting
Total revenue	134,804	93,305	121,659
Continuing Operations | Non-allocated
Segment Reporting
Total revenue	$ 7,722	$ 6,333	$ 3,084