Revenues - Disaggregation of Revenue (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021 USD ($) community	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) community	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Disaggregation of Revenue [Line Items]
Rental and other property	$ 360,620	$ 368,464	$ 1,062,253	$ 1,126,363
Management and other fees from affiliates	2,237	2,347	6,707	7,312
Revenues	$ 362,857	370,811	$ 1,068,960	1,133,675
Occupancy threshold for classification as stabilized	90.00%		90.00%
Apartment communities owned (in communities) | community	246		246
Deferred revenue	$ 2,600		$ 2,600		$ 3,100
Deferred revenue, revenue recognized			500
Deferred revenue balance from contracts with remaining performance obligations	2,600		2,600
Rental income
Disaggregation of Revenue [Line Items]
Rental and other property	355,591	362,073	1,046,218	1,108,658
Other property
Disaggregation of Revenue [Line Items]
Rental and other property	5,029	6,391	16,035	17,705
Rental and other property revenues
Disaggregation of Revenue [Line Items]
Rental and other property	360,620	368,464	1,062,253	1,126,363
Rental and other property revenues | Same-property
Disaggregation of Revenue [Line Items]
Rental and other property	325,153	316,639	957,908	986,945
Rental and other property revenues | Acquisitions
Disaggregation of Revenue [Line Items]
Rental and other property	14,789	14,237	42,410	40,491
Rental and other property revenues | Development
Disaggregation of Revenue [Line Items]
Rental and other property	8,055	5,461	22,485	13,956
Rental and other property revenues | Redevelopment
Disaggregation of Revenue [Line Items]
Rental and other property	4,340	4,277	13,079	14,774
Rental and other property revenues | Non-residential/other, net
Disaggregation of Revenue [Line Items]
Rental and other property	$ 11,319	13,119	$ 35,721	52,491
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	$ (3,036)	14,731	$ (9,350)	17,706
Rental and other property revenues | Operating Segments | Southern California
Disaggregation of Revenue [Line Items]
Rental and other property	150,807	136,651	434,926	426,987
Rental and other property revenues | Operating Segments | Northern California
Disaggregation of Revenue [Line Items]
Rental and other property	145,807	147,081	435,883	457,655
Rental and other property revenues | Operating Segments | Seattle Metro
Disaggregation of Revenue [Line Items]
Rental and other property	60,280	60,617	178,180	184,310
Rental and other property revenues | Other real estate assets
Disaggregation of Revenue [Line Items]
Rental and other property	$ 3,726	$ 24,115	$ 13,264	$ 57,411