Related Party Transactions Excluded Properties and Businesses (Details)	Sep. 30, 2014 office_and_property
Retail Site [Member] | Manhattan [Member]
Related Party Transaction [Line Items]
Number of properties	4
Office Building [Member]
Related Party Transaction [Line Items]
Number of properties	14
Office Building [Member] | Manhattan [Member]
Related Party Transaction [Line Items]
Number of properties	9