Segment Information (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($) segment	Jun. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
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	$ 294,041	$ 283,720	$ 583,285	$ 546,836
Management and other fees from affiliates	2,778	2,738	5,543	5,427
Corporate-level property management expenses	(11,451)	(10,176)	(22,883)	(20,348)
Depreciation and amortization	(136,718)	(134,517)	(273,065)	(268,050)
General and administrative	(13,813)	(13,127)	(29,124)	(25,369)
Expensed acquisition and investment related costs	(5)	(10)	(344)	(18)
Casualty loss	0	0	(433)	0
Gain on sale of real estate and land	0	0	59,238	0
Interest expense	(52,600)	(50,477)	(103,645)	(100,854)
Total return swap income	821	2,283	1,854	4,827
Interest and other income (loss)	12,199	(17,208)	24,649	(24,775)
Equity income (loss) from co-investments	12,237	(8,400)	23,108	12,771
Deferred tax (expense) benefit on unconsolidated co-investments	(1,733)	6,864	(833)	9,618
Net income	105,756	61,690	267,350	140,065
Net reportable operating segment - real estate assets	10,630,120		10,630,120		$ 10,814,094
Real estate under development	22,668		22,668		24,857
Co-investments	1,122,114		1,122,114		1,127,491
Cash and cash equivalents, including restricted cash	69,114	48,463	69,114	48,463	42,681	$ 58,638
Marketable securities	102,131		102,131		112,743
Notes and other receivables	150,464		150,464		103,045
Operating lease right-of-use assets	65,505		65,505		67,239
Prepaid expenses and other assets	83,157		83,157		80,755
Total assets	12,245,273		12,245,273		12,372,905
Rental and Other Property Revenues
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	413,265	397,240	822,921	776,456
Management and other fees from affiliates
Revenues from External Customers and Long-Lived Assets [Line Items]
Management and other fees from affiliates	2,778	2,738	5,543	5,427
Operating Segments | Southern California
Revenues from External Customers and Long-Lived Assets [Line Items]
Net operating income	121,923	115,176	238,865	222,978
Net reportable operating segment - real estate assets	3,855,167		3,855,167		3,892,003
Operating Segments | Southern California | Rental and Other Property Revenues
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	169,857	160,809	336,734	314,147
Operating Segments | Northern California
Revenues from External Customers and Long-Lived Assets [Line Items]
Net operating income	116,184	113,095	230,635	218,235
Net reportable operating segment - real estate assets	5,324,254		5,324,254		5,414,467
Operating Segments | Northern California | Rental and Other Property Revenues
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	166,415	160,513	330,039	313,258
Operating Segments | Seattle Metro
Revenues from External Customers and Long-Lived Assets [Line Items]
Net operating income	50,388	49,268	100,283	92,564
Net reportable operating segment - real estate assets	1,354,592		1,354,592		1,374,379
Operating Segments | Seattle Metro | Rental and Other Property Revenues
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	70,216	67,707	140,255	131,910
Other real estate assets
Revenues from External Customers and Long-Lived Assets [Line Items]
Net operating income	5,546	6,181	13,502	13,059
Net reportable operating segment - real estate assets	96,107		96,107		$ 133,245
Other real estate assets | Rental and Other Property Revenues
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	$ 6,777	$ 8,211	$ 15,893	$ 17,141