Segment Information (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($) segment	Jun. 30, 2023 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of reportable segments | segment			3
Number of operating segments | segment			3
Net operating income	$ 313,749	$ 294,041	$ 612,098	$ 583,285
Management and other fees from affiliates	2,573	2,778	5,286	5,543
Corporate-level property management expenses	(12,123)	(11,451)	(23,854)	(22,883)
Depreciation and amortization	(145,613)	(136,718)	(285,346)	(273,065)
General and administrative	(21,136)	(13,813)	(38,307)	(29,124)
Expensed acquisition and investment related costs	0	(5)	(68)	(344)
Casualty loss	0	0	0	(433)
Gain on sale of real estate and land	0	0	0	59,238
Interest expense	(59,120)	(52,600)	(115,053)	(103,645)
Total return swap income	629	821	1,425	1,854
Interest and other income	9,568	12,199	66,843	24,649
Equity income from co-investments	9,652	12,237	22,018	23,108
Tax benefit (expense) on unconsolidated co-investments	807	(1,733)	758	(833)
Gain on remeasurement of co-investment	0	0	138,326	0
Net income	98,986	105,756	384,126	267,350
Net reportable operating segment - real estate assets	10,922,498		10,922,498		$ 10,470,292
Real estate under development	24,515		24,515		23,724
Co-investments	1,041,328		1,041,328		1,061,733
Cash and cash equivalents, including restricted cash	64,151	69,114	64,151	69,114	400,334	$ 42,681
Marketable securities	84,291		84,291		87,795
Notes and other receivables	233,776		233,776		174,621
Operating lease right-of-use assets	53,373		53,373		63,757
Prepaid expenses and other assets	85,528		85,528		79,171
Total assets	12,509,460		12,509,460		12,361,427
Rental and Other Property Revenues
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	439,782	413,265	863,997	822,921
Management and other fees from affiliates
Revenues from External Customers and Long-Lived Assets [Line Items]
Management and other fees from affiliates	2,573	2,778	5,286	5,543
Operating Segments | Southern California
Revenues from External Customers and Long-Lived Assets [Line Items]
Net operating income	133,340	121,923	257,673	238,865
Net reportable operating segment - real estate assets	4,173,397		4,173,397		3,802,648
Operating Segments | Southern California | Rental and Other Property Revenues
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	186,604	169,857	362,606	336,734
Operating Segments | Northern California
Revenues from External Customers and Long-Lived Assets [Line Items]
Net operating income	120,916	116,228	236,595	230,783
Net reportable operating segment - real estate assets	5,294,272		5,294,272		5,242,343
Operating Segments | Northern California | Rental and Other Property Revenues
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	172,615	166,459	341,454	330,187
Operating Segments | Seattle Metro
Revenues from External Customers and Long-Lived Assets [Line Items]
Net operating income	51,990	50,388	102,906	100,283
Net reportable operating segment - real estate assets	1,363,449		1,363,449		1,333,030
Operating Segments | Seattle Metro | Rental and Other Property Revenues
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	73,782	70,217	145,695	140,255
Other real estate assets
Revenues from External Customers and Long-Lived Assets [Line Items]
Net operating income	7,503	5,502	14,924	13,354
Net reportable operating segment - real estate assets	91,380		91,380		$ 92,271
Other real estate assets | Rental and Other Property Revenues
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	$ 6,781	$ 6,732	$ 14,242	$ 15,745