Related Party Transactions - Summary of Fees to Vornado (Detail) - Vornado - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Related Party Transaction [Line Items]
Fees to related party	$ 4,019	$ 1,641	$ 6,619	$ 3,374
Company management fees
Related Party Transaction [Line Items]
Fees to related party	700	700	1,400	1,400
Development fees
Related Party Transaction [Line Items]
Fees to related party	5	2	29	9
Leasing fees
Related Party Transaction [Line Items]
Fees to related party	2,017	0	2,746	0
Property management, cleaning, engineering and security fees
Related Party Transaction [Line Items]
Fees to related party	$ 1,297	$ 939	$ 2,444	$ 1,965