Segments - Schedule of NOI for Each Reportable Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Property-related revenues	$ 168,455	$ 184,370	$ 349,773	$ 370,163
Property-related operating expenses	(65,712)	(67,572)	(134,177)	(135,953)
NOI from unconsolidated joint ventures	10,376	4,185	23,768	9,596
NOI	113,119	120,983	239,364	243,806
New York [Member]
Segment Reporting Information [Line Items]
Property-related revenues	110,679	118,741	232,256	239,837
Property-related operating expenses	(47,213)	(46,504)	(96,242)	(94,607)
NOI from unconsolidated joint ventures	2,680	2,886	5,624	7,543
NOI	66,146	75,123	141,638	152,773
San Francisco [Member]
Segment Reporting Information [Line Items]
Property-related revenues	54,827	58,431	111,494	115,615
Property-related operating expenses	(16,054)	(17,479)	(32,973)	(33,825)
NOI from unconsolidated joint ventures	9,165	1,213	19,547	1,913
NOI	47,938	42,165	98,068	83,703
Other [Member]
Segment Reporting Information [Line Items]
Property-related revenues	2,949	7,198	6,023	14,711
Property-related operating expenses	(2,445)	(3,589)	(4,962)	(7,521)
NOI from unconsolidated joint ventures	(1,469)	86	(1,403)	140
NOI	$ (965)	$ 3,695	$ (342)	$ 7,330