Segments Disclosure - Schedule of NOI for Each Reportable Segment Information (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Property-related revenues	$ 66,371	$ 666,410	$ 652,160
Property-related operating expenses	(26,011)	(250,040)	(244,754)
NOI from unconsolidated joint ventures	1,680	17,195	16,580
NOI	42,040	433,565	423,986
New York [Member]
Segment Reporting Information [Line Items]
Property-related revenues	47,460	449,794	452,842
Property-related operating expenses	(18,679)	(176,445)	(174,273)
NOI from unconsolidated joint ventures	1,680	16,874	16,210
NOI	30,461	290,223	294,779
Washington, D.C. [Member]
Segment Reporting Information [Line Items]
Property-related revenues	7,225	86,389	82,366
Property-related operating expenses	(3,307)	(32,721)	(32,482)
NOI	3,918	53,668	49,884
San Francisco [Member]
Segment Reporting Information [Line Items]
Property-related revenues	9,978	127,813	114,472
Property-related operating expenses	(3,269)	(30,889)	(29,277)
NOI	6,709	96,924	85,195
Other [Member]
Segment Reporting Information [Line Items]
Property-related revenues	1,708	2,414	2,480
Property-related operating expenses	(756)	(9,985)	(8,722)
NOI from unconsolidated joint ventures		321	370
NOI	$ 952	$ (7,250)	$ (5,872)