Segment Information (Details)	3 Months Ended	12 Months Ended
	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($) segment	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
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		$ 1,431,418,000	$ 1,486,150,000	$ 1,450,628,000
Total net operating income		986,159,000	1,045,750,000	1,054,101,000
Management and other fees from affiliates	$ 330,000,000.0	9,138,000	9,598,000	9,527,000
Corporate-level property management expenses		(36,188,000)	(34,573,000)	(34,067,000)
Depreciation and amortization		(520,066,000)	(525,497,000)	(483,750,000)
General and administrative		(51,838,000)	(65,388,000)	(54,262,000)
Expensed acquisition and investment related costs		(203,000)	(1,591,000)	(168,000)
Impairment loss		0	(1,825,000)	(7,105,000)
Gain (loss) on sale of real estate and land		142,993,000	64,967,000	(3,164,000)
Interest expense		(203,125,000)	(220,633,000)	(217,339,000)
Total return swap income		10,774,000	10,733,000	8,446,000
Interest and other income		98,744,000	40,999,000	46,298,000
Equity income from co-investments		111,721,000	66,512,000	112,136,000
Deferred tax expense on unrealized gain on unconsolidated co-investment		(15,668,000)	(1,531,000)	(1,457,000)
(Loss) gain on early retirement of debt, net		(19,010,000)	(22,883,000)	3,717,000
Gain on remeasurement of co-investment		2,260,000	234,694,000	31,535,000
Net income		515,691,000	599,332,000	464,448,000
Assets:
Net reportable operating segments - real estate assets		10,983,073,000	10,927,786,000
Real estate under development		111,562,000	386,047,000
Co-investments		1,177,802,000	1,018,010,000
Real estate held for sale		0	57,938,000
Cash and cash equivalents, including restricted cash		58,638,000	84,041,000
Marketable securities		191,829,000	147,768,000
Notes receivable		341,033,000	195,104,000
Operating lease right-of-use assets		68,972,000	72,143,000
Prepaid expenses and other assets		64,964,000	47,340,000
Total assets		12,997,873,000	12,936,177,000
Rental and other property
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property revenues		1,431,418,000	1,486,150,000	1,450,628,000
Management and other fees from affiliates
Revenues from External Customers and Long-Lived Assets [Line Items]
Management and other fees from affiliates		9,138,000	9,598,000	9,527,000
Operating segments | Southern California
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net operating income		408,207,000	391,095,000	423,177,000
Assets:
Net reportable operating segments - real estate assets		4,018,839,000	3,981,650,000
Operating segments | Southern California | Rental and other property
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property revenues		588,381,000	566,553,000	593,253,000
Operating segments | Northern California
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net operating income		401,862,000	431,124,000	412,706,000
Assets:
Net reportable operating segments - real estate assets		5,460,701,000	5,405,102,000
Operating segments | Northern California | Rental and other property
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property revenues		584,034,000	604,348,000	557,139,000
Operating segments | Seattle Metro
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net operating income		160,954,000	166,847,000	172,601,000
Assets:
Net reportable operating segments - real estate assets		1,407,033,000	1,403,678,000
Operating segments | Seattle Metro | Rental and other property
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property revenues		239,839,000	243,900,000	243,060,000
Other real estate assets
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net operating income		15,136,000	56,684,000	45,617,000
Assets:
Net reportable operating segments - real estate assets		96,500,000	137,356,000
Other real estate assets | Rental and other property
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property revenues		$ 19,164,000	$ 71,349,000	$ 57,176,000