Investments in Non-controlled Entities Schedule of Equity Method Investments (Details)	0 Months Ended
	Oct. 06, 2013 entity
Schedule of Equity Method Investments [Line Items]
Number of entities acquired	4
Empire State Building, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Ownership percentage	23.75%
1333 Broadway Associates [Member]
Schedule of Equity Method Investments [Line Items]
Ownership percentage	50.00%
1350 Broadway Associates [Member]
Schedule of Equity Method Investments [Line Items]
Ownership percentage	50.00%
501 Seventh Avenue Associates [Member]
Schedule of Equity Method Investments [Line Items]
Ownership percentage	20.469%