Commitments and Contingencies Major Customers and Other Concentrations (Details) (USD $)	12 Months Ended
	Dec. 31, 2014 tenant office_and_property	Dec. 31, 2013 tenant office_and_property
Concentration Risk [Line Items]
Cash, FDIC Insured Amount	250,000
Customer Concentration Risk [Member] | Sales Revenue, Services, Net [Member]
Concentration Risk [Line Items]
Number of tenants	3	3
Concentration risk percentage	10.00%	10.00%
Number of properties	3	3
Customer Concentration Risk [Member] | Sales Revenue, Services, Net [Member] | Empire State Building Co. [Member]
Concentration Risk [Line Items]
Concentration risk percentage	33.86%
Customer Concentration Risk [Member] | Sales Revenue, Services, Net [Member] | One Grand Central Place [Member]
Concentration Risk [Line Items]
Concentration risk percentage	13.47%	20.99%
Customer Concentration Risk [Member] | Sales Revenue, Services, Net [Member] | First Stamford Place [Member]
Concentration Risk [Line Items]
Concentration risk percentage	6.95%	11.62%
Customer Concentration Risk [Member] | Sales Revenue, Services, Net [Member] | Major Tenant Three [Member]
Concentration Risk [Line Items]
Concentration risk percentage	14.62%	11.41%
Customer Concentration Risk [Member] | Sales Revenue, Services, Net [Member] | Customer 1 [Member]
Concentration Risk [Line Items]
Concentration risk percentage	8.17%	6.01%
Customer Concentration Risk [Member] | Sales Revenue, Services, Net [Member] | Customer 2 [Member]
Concentration Risk [Line Items]
Concentration risk percentage	4.17%	2.72%
Customer Concentration Risk [Member] | Sales Revenue, Services, Net [Member] | Customer 3 [Member]
Concentration Risk [Line Items]
Concentration risk percentage	2.28%	2.68%