Related Party Transactions - Summary of Fees to Vornado (Detail) - Vornado [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Related Party Transaction [Line Items]
Fees to related party	$ 1,661	$ 2,523	$ 3,388	$ 10,840
Company Management Fees [Member]
Related Party Transaction [Line Items]
Fees to related party	700	700	1,400	1,400
Development Fees [Member]
Related Party Transaction [Line Items]
Fees to related party	4	75	32	119
Leasing Fees [Member]
Related Party Transaction [Line Items]
Fees to related party	4	833	15	7,291
Property Management Fees and Payments for Cleaning and Security Services [Member]
Related Party Transaction [Line Items]
Fees to related party	$ 953	$ 915	$ 1,941	$ 2,030