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Revenues - Disaggregation of Revenue (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021 USD ($) community	Mar. 31, 2020 USD ($)	Dec. 31, 2020 USD ($)
Disaggregation of Revenue [Line Items]
Rental and other property	$ 352,876	$ 389,750
Management and other fees from affiliates	2,249	2,617
Total revenues	$ 355,125	392,367
Occupancy threshold for classification as stabilized	90.00%
Apartment communities owned (in communities) \| community	244
Deferred revenue	$ 3,000		$ 3,100
Deferred revenue, revenue recognized	100
Deferred revenue balance from contracts with remaining performance obligations	3,000
Rental income
Disaggregation of Revenue [Line Items]
Rental and other property	347,305	383,498
Other property
Disaggregation of Revenue [Line Items]
Rental and other property	5,571	6,252
Rental and other property revenues
Disaggregation of Revenue [Line Items]
Rental and other property	352,876	389,750
Rental and other property revenues \| Same-property
Disaggregation of Revenue [Line Items]
Rental and other property	317,806	345,652
Rental and other property revenues \| Acquisitions
Disaggregation of Revenue [Line Items]
Rental and other property	13,673	12,558
Rental and other property revenues \| Development
Disaggregation of Revenue [Line Items]
Rental and other property	6,930	4,075
Rental and other property revenues \| Redevelopment
Disaggregation of Revenue [Line Items]
Rental and other property	4,590	5,401
Rental and other property revenues \| Non-residential/other, net
Disaggregation of Revenue [Line Items]
Rental and other property	$ 13,246	22,064
Apartment communities owned (in communities) \| community	3
Rental and other property revenues \| Straight line rent concession
Disaggregation of Revenue [Line Items]
Rental and other property	$ (3,369)	0
Rental and other property revenues \| Operating Segments \| Southern California
Disaggregation of Revenue [Line Items]
Rental and other property	143,012	151,895
Rental and other property revenues \| Operating Segments \| Northern California
Disaggregation of Revenue [Line Items]
Rental and other property	146,690	158,456
Rental and other property revenues \| Operating Segments \| Seattle Metro
Disaggregation of Revenue [Line Items]
Rental and other property	58,633	63,044
Rental and other property revenues \| Other real estate assets
Disaggregation of Revenue [Line Items]
Rental and other property	$ 4,541	$ 16,355