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, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Segment Reporting Information [Line Items]
Rental income	$ 734,163	$ 717,309	$ 1,464,981	$ 1,422,397
Operating expenses	232,069	227,851	475,626	472,099
NOI	502,094	489,458	989,355	950,298
Total Assets	19,779,568		19,779,568		$ 20,034,564
Capital Expenditures			153,304
Same Store
Segment Reporting Information [Line Items]
Rental income	718,169	697,784	1,432,565	1,383,857
Operating expenses	224,525	218,681	455,437	446,721
NOI	493,644	479,103	977,128	937,136
Total Assets	18,199,960		18,199,960
Capital Expenditures			139,687
Non-same store/other
Segment Reporting Information [Line Items]
Rental income	15,994	19,525	32,416	38,540
Operating expenses	7,544	9,170	20,189	25,378
NOI	8,450	10,355	12,227	13,162
Total Assets	1,579,608		1,579,608
Capital Expenditures			13,617
Los Angeles | Same Store
Segment Reporting Information [Line Items]
Rental income	120,119	116,295	239,386	229,783
Operating expenses	35,778	35,264	73,603	72,575
NOI	84,341	81,031	165,783	157,208
Total Assets	2,455,957		2,455,957
Capital Expenditures			24,700
Orange County | Same Store
Segment Reporting Information [Line Items]
Rental income	31,171	30,045	62,272	59,417
Operating expenses	6,937	6,703	13,865	13,396
NOI	24,234	23,342	48,407	46,021
Total Assets	335,826		335,826
Capital Expenditures			8,702
San Diego | Same Store
Segment Reporting Information [Line Items]
Rental income	25,991	24,691	51,815	48,925
Operating expenses	5,780	5,736	11,659	11,550
NOI	20,211	18,955	40,156	37,375
Total Assets	336,372		336,372
Capital Expenditures			8,283
Subtotal - Southern California | Same Store
Segment Reporting Information [Line Items]
Rental income	177,281	171,031	353,473	338,125
Operating expenses	48,495	47,703	99,127	97,521
NOI	128,786	123,328	254,346	240,604
Total Assets	3,128,155		3,128,155
Capital Expenditures			41,685
Washington D.C. | Same Store
Segment Reporting Information [Line Items]
Rental income	116,465	111,220	231,584	220,318
Operating expenses	36,342	35,472	72,407	72,109
NOI	80,123	75,748	159,177	148,209
Total Assets	3,029,979		3,029,979
Capital Expenditures			22,162
San Francisco | Same Store
Segment Reporting Information [Line Items]
Rental income	108,731	107,288	217,043	213,502
Operating expenses	31,263	31,893	65,700	65,735
NOI	77,468	75,395	151,343	147,767
Total Assets	3,018,760		3,018,760
Capital Expenditures			28,267
New York | Same Store
Segment Reporting Information [Line Items]
Rental income	122,172	119,785	246,136	237,830
Operating expenses	50,045	47,649	101,320	97,137
NOI	72,127	72,136	144,816	140,693
Total Assets	3,240,380		3,240,380
Capital Expenditures			12,363
Boston | Same Store
Segment Reporting Information [Line Items]
Rental income	82,081	78,851	162,532	155,729
Operating expenses	22,988	22,034	46,726	46,197
NOI	59,093	56,817	115,806	109,532
Total Assets	2,051,119		2,051,119
Capital Expenditures			12,924
Seattle | Same Store
Segment Reporting Information [Line Items]
Rental income	74,792	73,018	148,624	145,796
Operating expenses	22,013	20,951	43,291	41,172
NOI	52,779	52,067	105,333	104,624
Total Assets	2,043,317		2,043,317
Capital Expenditures			16,325
Denver | Same Store
Segment Reporting Information [Line Items]
Rental income	18,002	17,873	35,810	35,469
Operating expenses	5,221	5,211	10,667	10,685
NOI	12,781	12,662	25,143	24,784
Total Assets	807,719		807,719
Capital Expenditures			2,156
Other Expansion Markets | Same Store
Segment Reporting Information [Line Items]
Rental income	18,645	18,718	37,363	37,088
Operating expenses	8,158	7,768	16,199	16,165
NOI	10,487	10,950	21,164	20,923
Total Assets	880,531		880,531
Capital Expenditures			3,805
Non-same store | Non-same store/other
Segment Reporting Information [Line Items]
Rental income	14,599	7,497	27,547	12,400
Operating expenses	6,297	3,744	12,418	6,509
NOI	8,302	3,753	15,129	5,891
Total Assets	756,305		756,305
Capital Expenditures			13,153
Other | Non-same store/other
Segment Reporting Information [Line Items]
Rental income	1,395	12,028	4,869	26,140
Operating expenses	1,247	5,426	7,771	18,869
NOI	148	$ 6,602	(2,902)	$ 7,271
Total Assets	$ 823,303		823,303
Capital Expenditures			$ 464