Investment in Unconsolidated Venture (Details) ft² in Millions		1 Months Ended	12 Months Ended
	May 20, 2016 USD ($) ft²	Dec. 31, 2016 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Business Acquisition [Line Items]
Noncontrolling interest, ownership percentage by noncontrolling owners	0.2867%	1.00%	1.00%
Purchase price			$ 4,297,842	$ 0
Dividends from unconsolidated venture			64,070	$ 0
RXR Realty
Business Acquisition [Line Items]
Purchase price	$ 1,650,000,000
Class-A Office Building | RXR Realty | Acquisition Financing
Business Acquisition [Line Items]
Amount financed	1,100,000,000
Additional future funding capacity	$ 100,000,000
Financing term	7 years
Class-A Office Building | RXR Realty | Acquisition Financing | Weighted Average
Business Acquisition [Line Items]
Fixed interest rate per annum	4.30%
1285 Avenue of the Americas Venture | Class-A Office Building | Co-Sponsor
Business Acquisition [Line Items]
Square feet of office building acquired | ft²	1.8
Purchase price	$ 1,900,000	$ 2,400,000
Carrying value		$ 5,200,000	5,200,000
Equity in earnings (losses) of unconsolidated venture			939,303
Dividends from unconsolidated venture			64,070
Income (loss) from equity method investment			$ 875,233