Related Party Transactions - Summary of Fees to Vornado (Detail) - Vornado - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Related Party Transaction [Line Items]
Fees to related party	$ 2,075	$ 3,361	$ 6,247	$ 9,980
Company management fees
Related Party Transaction [Line Items]
Fees to related party	700	700	2,100	2,100
Development fees
Related Party Transaction [Line Items]
Fees to related party	188	0	456	29
Leasing fees
Related Party Transaction [Line Items]
Fees to related party	113	1,422	172	4,168
Property management, cleaning, engineering and security fees
Related Party Transaction [Line Items]
Fees to related party	$ 1,074	$ 1,239	$ 3,519	$ 3,683