Revenues - Disaggregation of Revenue (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022 USD ($) community	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($) community	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)
Disaggregation of Revenue [Line Items]
Rental and other property	$ 406,862	$ 360,620	$ 1,183,318	$ 1,062,253
Management and other fees from affiliates	2,886	2,237	8,313	6,707
Revenues	$ 409,748	362,857	$ 1,191,631	1,068,960
Occupancy threshold for classification as stabilized	90.00%		90.00%
Apartment communities owned (in communities) | community	253		253
Deferred revenue	$ 1,900		$ 1,900		$ 2,400
Deferred revenue, revenue recognized			500
Deferred revenue balance from contracts with remaining performance obligations	1,900		1,900
Rental income
Disaggregation of Revenue [Line Items]
Rental and other property	401,467	355,591	1,166,670	1,046,218
Other property
Disaggregation of Revenue [Line Items]
Rental and other property	5,395	5,029	16,648	16,035
Rental and other property revenues
Disaggregation of Revenue [Line Items]
Rental and other property	406,862	360,620	1,183,318	1,062,253
Rental and other property revenues | Same-property
Disaggregation of Revenue [Line Items]
Rental and other property	380,562	341,744	1,110,166	1,007,402
Rental and other property revenues | Acquisitions
Disaggregation of Revenue [Line Items]
Rental and other property	2,570	1,004	6,070	1,323
Rental and other property revenues | Development
Disaggregation of Revenue [Line Items]
Rental and other property	11,327	8,055	31,938	22,485
Rental and other property revenues | Redevelopment
Disaggregation of Revenue [Line Items]
Rental and other property	1,422	1,533	4,348	4,671
Rental and other property revenues | Non-residential/other, net
Disaggregation of Revenue [Line Items]
Rental and other property	$ 12,413	11,320	$ 38,079	35,722
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	$ (1,432)	(3,036)	$ (7,283)	(9,350)
Rental and other property revenues | Operating Segments | Southern California
Disaggregation of Revenue [Line Items]
Rental and other property	168,883	150,807	490,363	434,926
Rental and other property revenues | Operating Segments | Northern California
Disaggregation of Revenue [Line Items]
Rental and other property	163,157	145,807	476,245	435,883
Rental and other property revenues | Operating Segments | Seattle Metro
Disaggregation of Revenue [Line Items]
Rental and other property	69,054	60,280	200,964	178,180
Rental and other property revenues | Other real estate assets
Disaggregation of Revenue [Line Items]
Rental and other property	$ 5,768	$ 3,726	$ 15,746	$ 13,264