Segment Reporting - Total Revenue, NOI, and Real Estate by Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Segment Reporting
Total revenue	$ 2,593,446	$ 2,294,850	$ 2,301,261
NOI	1,765,786	1,478,468	1,472,421
Gross real estate	25,903,895	24,418,587	22,961,785
Same Store
Segment Reporting
Real estate capitalized additions	209,607	158,991	126,548
Operating segment | Same Store
Segment Reporting
Total revenue	2,250,368	2,027,538	2,026,462
NOI	1,561,672	1,377,956	1,408,949
Gross real estate	20,228,469	20,019,461	19,485,214
Operating segment | Same Store | New England
Segment Reporting
Total revenue	344,384	305,627	294,955
NOI	228,316	196,075	193,754
Gross real estate	2,881,980	2,845,834	2,678,628
Operating segment | Same Store | Metro NY/NJ
Segment Reporting
Total revenue	466,512	415,936	399,686
NOI	324,901	284,819	277,666
Gross real estate	4,115,989	4,089,024	3,895,554
Operating segment | Same Store | Mid-Atlantic
Segment Reporting
Total revenue	333,400	310,274	336,264
NOI	227,031	208,505	233,307
Gross real estate	3,203,802	3,174,279	3,479,627
Operating segment | Same Store | Southeast Florida
Segment Reporting
Total revenue	38,265	31,703	29,151
NOI	25,003	19,689	15,730
Gross real estate	398,823	395,999	393,926
Operating segment | Same Store | Denver, CO
Segment Reporting
Total revenue	26,848	23,742	21,293
NOI	19,652	16,451	13,796
Gross real estate	321,685	320,435	319,562
Operating segment | Same Store | Pacific Northwest
Segment Reporting
Total revenue	145,255	126,513	110,976
NOI	102,838	85,980	77,324
Gross real estate	1,297,627	1,288,975	1,052,903
Operating segment | Same Store | Northern California
Segment Reporting
Total revenue	403,611	371,978	400,934
NOI	288,468	263,101	298,176
Gross real estate	3,687,929	3,640,220	3,438,290
Operating segment | Same Store | Southern California
Segment Reporting
Total revenue	492,093	441,765	433,203
NOI	345,463	303,336	299,196
Gross real estate	4,320,634	4,264,695	4,226,724
Operating segment | Other Stabilized Communities
Segment Reporting
Total revenue	210,341	121,659	79,431
NOI	141,593	75,422	52,614
Gross real estate	2,973,170	2,413,391	1,081,327
Operating segment | Development / Redevelopment
Segment Reporting
Total revenue	91,030	42,885	28,298
NOI	62,521	25,090	10,858
Gross real estate	2,367,634	1,580,653	1,917,913
Operating segment | Disposals
Segment Reporting
Gross real estate		482,542	955,497
Segment Reconciling Items
Segment Reporting
Gross real estate	179,204	147,546	110,142
Non-allocated
Segment Reporting
Total revenue	6,333	3,084	1,978
Gross real estate	155,418	257,536	367,189
Continuing Operations
Segment Reporting
Total revenue	2,558,072	2,195,166	2,136,169
Continuing Operations | Operating segment | Same Store
Segment Reporting
Total revenue	2,250,368	2,027,538	2,026,462
Continuing Operations | Operating segment | Other Stabilized Communities
Segment Reporting
Total revenue	210,341	121,659	79,431
Continuing Operations | Non-allocated
Segment Reporting
Total revenue	$ 6,333	$ 3,084	$ 1,978