Reportable Segments - NOI from Our Rental Real Estate for Each Segment Specific to Continuing Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Segment Reporting Information [Line Items]
Rental income	$ 695,099	$ 623,206	$ 2,035,477	$ 1,818,867
Operating income	414,011	521,554	873,683	1,033,958
Total Assets	20,265,405		20,265,405		$ 21,169,241
Same Store
Segment Reporting Information [Line Items]
Rental income	650,712	581,818	1,882,181	1,694,503
Operating expenses	205,032	198,139	600,987	583,471
Operating income	445,680	383,679	1,281,194	1,111,032
Total Assets	17,022,377		17,022,377
Capital Expenditures			125,641
Non-same store/other
Segment Reporting Information [Line Items]
Rental income	44,387	41,388	153,296	124,364
Operating expenses	19,377	15,231	67,189	55,570
Operating income	25,010	26,157	86,107	68,794
Total Assets	3,243,028		3,243,028
Capital Expenditures			16,066
Same Store, Non-same Store and Other
Segment Reporting Information [Line Items]
Rental income	695,099	623,206	2,035,477	1,818,867
Operating expenses	224,409	213,370	668,176	639,041
Operating income	470,690	409,836	1,367,301	1,179,826
Total Assets	20,265,405		20,265,405
Capital Expenditures			141,707
Los Angeles | Same Store
Segment Reporting Information [Line Items]
Rental income	119,269	110,180	351,896	316,206
Operating expenses	34,783	33,568	103,121	99,837
Operating income	84,486	76,612	248,775	216,369
Total Assets	2,604,866		2,604,866
Capital Expenditures			21,459
Orange County | Same Store
Segment Reporting Information [Line Items]
Rental income	31,252	28,263	91,271	80,773
Operating expenses	6,875	6,455	19,681	18,865
Operating income	24,377	21,808	71,590	61,908
Total Assets	358,574		358,574
Capital Expenditures			4,170
San Diego | Same Store
Segment Reporting Information [Line Items]
Rental income	22,129	20,283	64,540	58,210
Operating expenses	5,018	4,717	14,574	13,892
Operating income	17,111	15,566	49,966	44,318
Total Assets	227,344		227,344
Capital Expenditures			4,206
Subtotal - Southern California | Same Store
Segment Reporting Information [Line Items]
Rental income	172,650	158,726	507,707	455,189
Operating expenses	46,676	44,740	137,376	132,594
Operating income	125,974	113,986	370,331	322,595
Total Assets	3,190,784		3,190,784
Capital Expenditures			29,835
San Francisco | Same Store
Segment Reporting Information [Line Items]
Rental income	106,382	96,451	312,401	285,212
Operating expenses	31,984	30,173	93,572	89,559
Operating income	74,398	66,278	218,829	195,653
Total Assets	3,090,195		3,090,195
Capital Expenditures			21,988
Washington D.C. | Same Store
Segment Reporting Information [Line Items]
Rental income	106,098	98,643	306,161	290,255
Operating expenses	35,686	34,238	102,564	97,407
Operating income	70,412	64,405	203,597	192,848
Total Assets	3,057,549		3,057,549
Capital Expenditures			22,596
New York | Same Store
Segment Reporting Information [Line Items]
Rental income	112,595	93,454	318,756	270,776
Operating expenses	46,194	45,282	139,121	136,859
Operating income	66,401	48,172	179,635	133,917
Total Assets	3,424,747		3,424,747
Capital Expenditures			17,365
Seattle | Same Store
Segment Reporting Information [Line Items]
Rental income	72,756	63,936	210,011	190,386
Operating expenses	20,385	20,658	59,222	61,092
Operating income	52,371	43,278	150,789	129,294
Total Assets	2,089,219		2,089,219
Capital Expenditures			16,569
Boston | Same Store
Segment Reporting Information [Line Items]
Rental income	66,981	58,863	194,640	173,953
Operating expenses	20,122	19,401	60,003	57,478
Operating income	46,859	39,462	134,637	116,475
Total Assets	1,692,529		1,692,529
Capital Expenditures			16,349
Denver | Same Store
Segment Reporting Information [Line Items]
Rental income	11,102	9,812	32,505	28,732
Operating expenses	3,191	2,950	9,129	8,482
Operating income	7,911	6,862	23,376	20,250
Total Assets	477,354		477,354
Capital Expenditures			939
All Other Markets | Same Store
Segment Reporting Information [Line Items]
Rental income	2,148	1,933
Operating expenses	794	697
Operating income	1,354	1,236
Non-same store | Non-same store/other
Segment Reporting Information [Line Items]
Rental income	42,707	15,702	131,693	31,305
Operating expenses	17,068	7,736	54,236	15,256
Operating income	25,639	7,966	77,457	16,049
Total Assets	2,517,480		2,517,480
Capital Expenditures			15,524
Other | Non-same store/other
Segment Reporting Information [Line Items]
Rental income	1,680	25,686	21,603	93,059
Operating expenses	2,309	7,495	12,953	40,314
Operating income	(629)	$ 18,191	8,650	$ 52,745
Total Assets	$ 725,548		725,548
Capital Expenditures			$ 542