Segment Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) segment	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Segment Reporting [Abstract]
Number of reportable operating segments defined by geographical regions | segment	3
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property revenues	$ 1,658,264	$ 1,595,675	$ 1,431,418
Total net operating income	1,172,785	1,128,406	986,182
Management and other fees from affiliates	11,131	11,139	9,138
Corporate-level property management expenses	(45,872)	(40,704)	(36,211)
Depreciation and amortization	(548,438)	(539,319)	(520,066)
General and administrative	(63,474)	(56,577)	(51,838)
Expensed acquisition and investment related costs	(595)	(2,132)	(203)
Casualty loss	(433)	0	0
Gain on sale of real estate and land	59,238	94,416	142,993
Interest expense	(212,905)	(204,798)	(203,125)
Total return swap income	3,148	7,907	10,774
Interest and other income (loss)	46,259	(19,040)	98,744
Equity income from co-investments	10,561	26,030	111,721
Tax (expense) benefit on unconsolidated co-investments	(697)	10,236	(15,668)
Loss on early retirement of debt, net	0	(2)	(19,010)
Gain on remeasurement of co-investment	0	17,423	2,260
Net income	430,708	432,985	515,691
Assets:
Net reportable operating segments - real estate assets	10,470,292	10,814,094
Real estate under development	23,724	24,857
Co-investments	1,061,733	1,127,491
Cash and cash equivalents, including restricted cash	400,334	42,681
Marketable securities	87,795	112,743
Notes and other receivables	174,621	103,045
Operating lease right-of-use assets	63,757	67,239
Prepaid expenses and other assets	79,171	80,755
Total assets	12,361,427	12,372,905
Rental and other property
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property revenues	1,658,264	1,595,675	1,431,418
Management and other fees from affiliates
Revenues from External Customers and Long-Lived Assets [Line Items]
Management and other fees from affiliates	11,131	11,139	9,138
Operating segments | Southern California
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net operating income	483,013	459,762	398,576
Assets:
Net reportable operating segments - real estate assets	3,802,648	3,892,003
Operating segments | Southern California | Rental and other property
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property revenues	682,116	646,252	574,129
Operating segments | Northern California
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net operating income	464,949	445,933	401,870
Assets:
Net reportable operating segments - real estate assets	5,242,343	5,414,467
Operating segments | Northern California | Rental and other property
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property revenues	666,836	639,306	584,034
Operating segments | Seattle Metro
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net operating income	201,228	191,476	160,959
Assets:
Net reportable operating segments - real estate assets	1,333,030	1,374,379
Operating segments | Seattle Metro | Rental and other property
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property revenues	282,092	271,248	239,839
Other real estate assets
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net operating income	23,595	31,235	24,777
Assets:
Net reportable operating segments - real estate assets	92,271	133,245
Other real estate assets | Rental and other property
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property revenues	$ 27,220	$ 38,869	$ 33,416