Investments in Unconsolidated Joint Ventures - Additional Information (Details) ft² in Millions	Jan. 24, 2017 USD ($) ft²	Mar. 31, 2017 ft²	Dec. 31, 2016 ft²
Schedule Of Equity Method Investments [Line Items]
Area of office and retail properties | ft²		12.5
712 Fifth Avenue [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method ownership percentage		50.00%	50.00%
60 Wall Street [Member]
Schedule Of Equity Method Investments [Line Items]
Property ownership, percentage	5.20%
Area of office and retail properties | ft²	1.6		1.6
Acquisition amount | $	$ 1,040,000,000
Mortgage financing amount | $	$ 575,000,000
Equity method ownership percentage		5.20%	5.20%