Reportable Segments - NOI from Our Rental Real Estate for Each Segment Specific to Continuing Operations (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Segment Reporting Information [Line Items]
Rental income	$ 717,309	$ 687,030	$ 1,422,397	$ 1,340,378
Operating income	218,461	309,934	516,049	459,672
Total Assets	20,145,729		20,145,729		$ 20,218,262
Same Store
Segment Reporting Information [Line Items]
Rental income	697,444	661,374	1,375,078	1,281,947
Operating expenses	219,034	207,578	444,251	417,686
Operating income	478,410	453,796	930,827	864,261
Total Assets	18,091,614		18,091,614
Capital Expenditures			118,496
Non-same store/other
Segment Reporting Information [Line Items]
Rental income	19,865	25,656	47,319	58,431
Operating expenses	8,817	10,627	27,848	26,081
Operating income	11,048	15,029	19,471	32,350
Total Assets	2,054,115		2,054,115
Capital Expenditures			16,751
Same Store, Non-same Store and Other
Segment Reporting Information [Line Items]
Rental income	717,309	687,030	1,422,397	1,340,378
Operating expenses	227,851	218,205	472,099	443,767
Operating income	489,458	468,825	950,298	896,611
Total Assets	20,145,729		20,145,729
Capital Expenditures			135,247
Los Angeles | Same Store
Segment Reporting Information [Line Items]
Rental income	118,562	118,840	234,243	227,809
Operating expenses	35,795	33,060	73,597	67,243
Operating income	82,767	85,780	160,646	160,566
Total Assets	2,522,130		2,522,130
Capital Expenditures			23,582
Orange County | Same Store
Segment Reporting Information [Line Items]
Rental income	32,316	31,252	63,904	60,018
Operating expenses	7,186	6,482	14,372	13,013
Operating income	25,130	24,770	49,532	47,005
Total Assets	349,363		349,363
Capital Expenditures			4,230
San Diego | Same Store
Segment Reporting Information [Line Items]
Rental income	24,691	23,067	45,452	42,410
Operating expenses	5,747	5,220	10,348	9,605
Operating income	18,944	17,847	35,104	32,805
Total Assets	229,569		229,569
Capital Expenditures			7,907
Subtotal - Southern California | Same Store
Segment Reporting Information [Line Items]
Rental income	175,569	173,159	343,599	330,237
Operating expenses	48,728	44,762	98,317	89,861
Operating income	126,841	128,397	245,282	240,376
Total Assets	3,101,062		3,101,062
Capital Expenditures			35,719
San Francisco | Same Store
Segment Reporting Information [Line Items]
Rental income	108,641	105,403	216,121	206,019
Operating expenses	32,062	30,081	66,067	61,753
Operating income	76,579	75,322	150,054	144,266
Total Assets	3,023,790		3,023,790
Capital Expenditures			19,750
Washington D.C. | Same Store
Segment Reporting Information [Line Items]
Rental income	109,660	103,268	217,282	203,973
Operating expenses	34,807	34,311	71,075	68,523
Operating income	74,853	68,957	146,207	135,450
Total Assets	3,039,410		3,039,410
Capital Expenditures			23,142
New York | Same Store
Segment Reporting Information [Line Items]
Rental income	119,785	106,332	237,830	206,162
Operating expenses	48,088	46,067	97,859	93,941
Operating income	71,697	60,265	139,971	112,221
Total Assets	3,375,622		3,375,622
Capital Expenditures			10,072
Seattle | Same Store
Segment Reporting Information [Line Items]
Rental income	74,729	71,577	149,291	140,114
Operating expenses	21,246	20,269	41,726	40,195
Operating income	53,483	51,308	107,565	99,919
Total Assets	2,141,765		2,141,765
Capital Expenditures			14,237
Boston | Same Store
Segment Reporting Information [Line Items]
Rental income	72,469	67,117	143,127	131,779
Operating expenses	20,747	20,016	43,383	41,074
Operating income	51,722	47,101	99,744	90,705
Total Assets	1,773,166		1,773,166
Capital Expenditures			11,998
Denver | Same Store
Segment Reporting Information [Line Items]
Rental income	17,873	16,833	35,469	33,065
Operating expenses	5,010	4,697	10,500	9,331
Operating income	12,863	12,136	24,969	23,734
Total Assets	840,581		840,581
Capital Expenditures			1,773
Other Expansion Markets | Same Store
Segment Reporting Information [Line Items]
Rental income	18,718	17,685	32,359	30,598
Operating expenses	8,346	7,375	15,324	13,008
Operating income	10,372	10,310	17,035	17,590
Total Assets	796,218		796,218
Capital Expenditures			1,805
Non-same store | Non-same store/other
Segment Reporting Information [Line Items]
Rental income	19,664	14,848	44,677	33,690
Operating expenses	7,219	6,064	17,236	15,357
Operating income	12,445	8,784	27,441	18,333
Total Assets	1,321,994		1,321,994
Capital Expenditures			16,682
Other | Non-same store/other
Segment Reporting Information [Line Items]
Rental income	201	10,808	2,642	24,741
Operating expenses	1,598	4,563	10,612	10,724
Operating income	(1,397)	$ 6,245	(7,970)	$ 14,017
Total Assets	$ 732,121		732,121
Capital Expenditures			$ 69