Revenues - Disaggregation of Revenue (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023 USD ($) community	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($) community	Jun. 30, 2022 USD ($)
Disaggregation of Revenue [Line Items]
Rental and other property	$ 413,265	$ 397,240	$ 822,921	$ 776,456
Management and other fees from affiliates	2,778	2,738	5,543	5,427
Revenues	$ 416,043	399,978	$ 828,464	781,883
Apartment communities owned (in communities) | community	252		252
Rental income
Disaggregation of Revenue [Line Items]
Rental and other property	$ 407,786	391,778	$ 812,421	765,203
Other property
Disaggregation of Revenue [Line Items]
Rental and other property	5,479	5,462	10,500	11,253
Rental and other property revenues
Disaggregation of Revenue [Line Items]
Rental and other property	413,265	397,240	822,921	776,456
Rental and other property revenues | Same-property
Disaggregation of Revenue [Line Items]
Rental and other property	$ 394,204	378,874	$ 783,099	740,289
Occupancy threshold for classification as stabilized	90.00%		90.00%
Rental and other property revenues | Acquisitions
Disaggregation of Revenue [Line Items]
Rental and other property	$ 1,332	0	$ 2,353	0
Rental and other property revenues | Development
Disaggregation of Revenue [Line Items]
Rental and other property	5,710	5,371	11,210	9,598
Rental and other property revenues | Redevelopment
Disaggregation of Revenue [Line Items]
Rental and other property	1,595	1,491	3,132	2,926
Rental and other property revenues | Non-residential/other, net
Disaggregation of Revenue [Line Items]
Rental and other property	$ 11,099	14,597	$ 23,226	29,620
Apartment communities owned (in communities) | community	2		2
Rental and other property revenues | Straight line rent concession
Disaggregation of Revenue [Line Items]
Rental and other property	$ (675)	(3,093)	$ (99)	(5,977)
Rental and other property revenues | Operating Segments | Southern California
Disaggregation of Revenue [Line Items]
Rental and other property	169,857	160,809	336,734	314,147
Rental and other property revenues | Operating Segments | Northern California
Disaggregation of Revenue [Line Items]
Rental and other property	166,415	160,513	330,039	313,258
Rental and other property revenues | Operating Segments | Seattle Metro
Disaggregation of Revenue [Line Items]
Rental and other property	70,216	67,707	140,255	131,910
Rental and other property revenues | Other real estate assets
Disaggregation of Revenue [Line Items]
Rental and other property	$ 6,777	$ 8,211	$ 15,893	$ 17,141