Investment in Unconsolidated Joint Ventures (Terminus Office Holdings LLC) (Details) - Terminus Office Holdings [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) Property	Feb. 28, 2013 USD ($)
Schedule of Equity Method Investments [Line Items]
Ownership Percentage of Partner in Joint Venture		50.00%
Debt Instrument, Face Amount		$ 82,000
Equity Method Investments Summarized Financial Information Cash	$ 5,200
Secured Mortgage Note Payable [Member]
Schedule of Equity Method Investments [Line Items]
Debt Instrument, Face Amount	$ 211,200
Mortgage Loans on Real Estate, Final Maturity Date	Jan. 01, 2023
Long-term Debt, Weighted Average Interest Rate	4.69%
Office Building [Member]
Schedule of Equity Method Investments [Line Items]
Number of Real Estate Properties Owned by Equity Investee | Property	2
Institutional investors advised by J.P. Morgan Asset Management [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage of Partner in Joint Venture	50.00%