Segment Information - Schedule of Reconciliation of Assets from Segment to Consolidated (Details) - USD ($) $ in Thousands	Sep. 30, 2026	Dec. 31, 2025	Sep. 30, 2025	Dec. 31, 2024
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Line Items]
Net reportable operating segments - real estate assets	$ 11,570,641	$ 11,904,582
Real estate under development	210,654	157,122
Co-investments	612,871	630,550
Cash and cash equivalents, including restricted cash	80,298	85,586	$ 75,243	$ 75,846
Marketable securities	102,665	98,070
Notes and other receivables	94,064	141,591
Operating lease right-of-use assets	31,231	50,833
Prepaid expenses and other assets	113,830	90,675
Total assets	12,816,254	13,159,009
Operating Segments | Southern California
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Line Items]
Net reportable operating segments - real estate assets	4,048,757	4,176,549
Operating Segments | Northern California
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Line Items]
Net reportable operating segments - real estate assets	5,981,917	6,136,977
Operating Segments | Seattle Metro
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Line Items]
Net reportable operating segments - real estate assets	1,356,710	1,392,105
Other real estate assets
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Line Items]
Net reportable operating segments - real estate assets	$ 183,257	$ 198,951