Reportable Segments - NOI from Our Rental Real Estate for Each Segment Specific to Continuing Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Segment Reporting Information [Line Items]
Rental income	$ 653,348	$ 597,602
Operating income	149,738	135,560
Total Assets	20,830,237		$ 21,169,241
Same Store
Segment Reporting Information [Line Items]
Rental income	618,357	573,752
Operating expenses	209,991	204,890
Operating income	408,366	368,862
Total Assets	17,873,646
Capital Expenditures	33,000
Non-same store/other
Segment Reporting Information [Line Items]
Rental income	34,991	23,850
Operating expenses	15,571	15,634
Operating income	19,420	8,216
Total Assets	2,956,591
Capital Expenditures	2,285
Same Store, Non-same Store and Other
Segment Reporting Information [Line Items]
Rental income	653,348	597,602
Operating expenses	225,562	220,524
Operating income	427,786	377,078
Total Assets	20,830,237
Capital Expenditures	35,285
Los Angeles | Same Store
Segment Reporting Information [Line Items]
Rental income	115,353	106,418
Operating expenses	36,775	35,693
Operating income	78,578	70,725
Total Assets	2,773,359
Capital Expenditures	6,880
Orange County | Same Store
Segment Reporting Information [Line Items]
Rental income	28,767	25,841
Operating expenses	6,425	6,314
Operating income	22,342	19,527
Total Assets	367,316
Capital Expenditures	919
San Diego | Same Store
Segment Reporting Information [Line Items]
Rental income	20,940	18,740
Operating expenses	4,929	4,633
Operating income	16,011	14,107
Total Assets	230,718
Capital Expenditures	849
Subtotal - Southern California | Same Store
Segment Reporting Information [Line Items]
Rental income	165,060	150,999
Operating expenses	48,129	46,640
Operating income	116,931	104,359
Total Assets	3,371,393
Capital Expenditures	8,648
San Francisco | Same Store
Segment Reporting Information [Line Items]
Rental income	102,440	96,728
Operating expenses	32,119	30,985
Operating income	70,321	65,743
Total Assets	3,165,308
Capital Expenditures	5,330
Washington D.C. | Same Store
Segment Reporting Information [Line Items]
Rental income	100,472	97,487
Operating expenses	33,901	32,607
Operating income	66,571	64,880
Total Assets	3,149,802
Capital Expenditures	5,681
New York | Same Store
Segment Reporting Information [Line Items]
Rental income	110,086	98,034
Operating expenses	53,071	51,854
Operating income	57,015	46,180
Total Assets	3,851,201
Capital Expenditures	6,232
Seattle | Same Store
Segment Reporting Information [Line Items]
Rental income	67,127	63,848
Operating expenses	19,325	20,436
Operating income	47,802	43,412
Total Assets	2,123,848
Capital Expenditures	2,867
Boston | Same Store
Segment Reporting Information [Line Items]
Rental income	62,594	57,312
Operating expenses	20,438	19,547
Operating income	42,156	37,765
Total Assets	1,724,548
Capital Expenditures	4,034
Denver | Same Store
Segment Reporting Information [Line Items]
Rental income	10,578	9,344
Operating expenses	3,008	2,821
Operating income	7,570	6,523
Total Assets	487,546
Capital Expenditures	208
Non-same store | Non-same store/other
Segment Reporting Information [Line Items]
Rental income	34,694	1
Operating expenses	14,182	58
Operating income	20,512	(57)
Total Assets	2,413,693
Capital Expenditures	2,274
Other | Non-same store/other
Segment Reporting Information [Line Items]
Rental income	297	23,849
Operating expenses	1,389	15,576
Operating income	(1,092)	$ 8,273
Total Assets	542,898
Capital Expenditures	$ 11