Reportable Segments - NOI from Our Rental Real Estate for Each Segment Specific to Continuing Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Segment Reporting Information [Line Items]
Rental income	$ 730,818	$ 705,088
Operating expenses	243,557	244,248
NOI	487,261	460,840
Total Assets	19,894,797		$ 20,034,564
Capital Expenditures	73,520
Same Store
Segment Reporting Information [Line Items]
Rental income	716,665	688,303
Operating expenses	231,905	228,961
NOI	484,760	459,342
Total Assets	18,404,886
Capital Expenditures	66,071
Non-same store/other
Segment Reporting Information [Line Items]
Rental income	14,153	16,785
Operating expenses	11,652	15,287
NOI	2,501	1,498
Total Assets	1,489,911
Capital Expenditures	7,449
Los Angeles | Same Store
Segment Reporting Information [Line Items]
Rental income	119,267	113,489
Operating expenses	37,825	37,311
NOI	81,442	76,178
Total Assets	2,473,271
Capital Expenditures	11,267
Orange County | Same Store
Segment Reporting Information [Line Items]
Rental income	31,101	29,372
Operating expenses	6,927	6,694
NOI	24,174	22,678
Total Assets	335,110
Capital Expenditures	2,569
San Diego | Same Store
Segment Reporting Information [Line Items]
Rental income	25,824	24,234
Operating expenses	5,880	5,814
NOI	19,944	18,420
Total Assets	336,081
Capital Expenditures	3,167
Subtotal - Southern California | Same Store
Segment Reporting Information [Line Items]
Rental income	176,192	167,095
Operating expenses	50,632	49,819
NOI	125,560	117,276
Total Assets	3,144,462
Capital Expenditures	17,003
Washington D.C. | Same Store
Segment Reporting Information [Line Items]
Rental income	116,387	110,255
Operating expenses	36,528	37,153
NOI	79,859	73,102
Total Assets	3,098,097
Capital Expenditures	12,202
San Francisco | Same Store
Segment Reporting Information [Line Items]
Rental income	109,313	107,286
Operating expenses	34,967	34,246
NOI	74,346	73,040
Total Assets	3,043,672
Capital Expenditures	13,622
New York | Same Store
Segment Reporting Information [Line Items]
Rental income	123,964	118,045
Operating expenses	51,275	49,488
NOI	72,689	68,557
Total Assets	3,284,640
Capital Expenditures	6,085
Boston | Same Store
Segment Reporting Information [Line Items]
Rental income	80,451	76,878
Operating expenses	23,738	24,163
NOI	56,713	52,715
Total Assets	2,068,351
Capital Expenditures	6,026
Seattle | Same Store
Segment Reporting Information [Line Items]
Rental income	73,832	72,778
Operating expenses	21,277	20,221
NOI	52,555	52,557
Total Assets	2,061,322
Capital Expenditures	8,590
Denver | Same Store
Segment Reporting Information [Line Items]
Rental income	17,808	17,596
Operating expenses	5,447	5,474
NOI	12,361	12,122
Total Assets	816,012
Capital Expenditures	1,007
Other Expansion Markets | Same Store
Segment Reporting Information [Line Items]
Rental income	18,718	18,370
Operating expenses	8,041	8,397
NOI	10,677	9,973
Total Assets	888,330
Capital Expenditures	1,536
Non-same store | Non-same store/other
Segment Reporting Information [Line Items]
Rental income	12,948	4,903
Operating expenses	6,092	2,860
NOI	6,856	2,043
Total Assets	665,260
Capital Expenditures	7,381
Other | Non-same store/other
Segment Reporting Information [Line Items]
Rental income	1,205	11,882
Operating expenses	5,560	12,427
NOI	(4,355)	$ (545)
Total Assets	824,651
Capital Expenditures	$ 68