Related Party Transactions Repayment of Loans to Property Owning Entities (Details) (500 Mamaroneck Avenue [Member], USD $) In Millions, unless otherwise specified	0 Months Ended
	Oct. 08, 2013
Investor [Member]
Related Party Transaction [Line Items]
Repayment of notes from related parties	$ 3.6
Anthony E. and Peter L. Malkin [Member]
Related Party Transaction [Line Items]
Repayment of notes from related parties	1.2
Anthony E. and Peter L. Malkin Interests Held [Member]
Related Party Transaction [Line Items]
Notes payable to related party assumed	$ 3.8