Segments - Schedule of NOI for Each Reportable Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Property-related revenues	$ 171,263	$ 191,158	$ 521,036	$ 561,321
Property-related operating expenses	(69,349)	(71,648)	(203,526)	(207,601)
NOI from unconsolidated joint ventures	12,935	4,973	36,703	14,569
NOI	114,849	124,483	354,213	368,289
New York [Member]
Segment Reporting Information [Line Items]
Property-related revenues	106,287	122,365	338,543	362,202
Property-related operating expenses	(49,072)	(49,825)	(145,314)	(144,432)
NOI from unconsolidated joint ventures	3,116	2,776	8,740	10,319
NOI	60,331	75,316	201,969	228,089
San Francisco [Member]
Segment Reporting Information [Line Items]
Property-related revenues	62,086	61,999	173,580	177,614
Property-related operating expenses	(17,825)	(18,068)	(50,798)	(51,893)
NOI from unconsolidated joint ventures	10,019	2,106	29,566	4,019
NOI	54,280	46,037	152,348	129,740
Other [Member]
Segment Reporting Information [Line Items]
Property-related revenues	2,890	6,794	8,913	21,505
Property-related operating expenses	(2,452)	(3,755)	(7,414)	(11,276)
NOI from unconsolidated joint ventures	(200)	91	(1,603)	231
NOI	$ 238	$ 3,130	$ (104)	$ 10,460