Real Estate Transactions (Assets and Liabilities Held-for-sale) (Details) - 100 North Point Center $ in Thousands	Dec. 31, 2015 USD ($)
Real estate assets and related assets held for sale
Operating Properties, net of accumulated depreciation of $7,072	$ 6,421
Notes and accounts receivable	210
Deferred rents receivable	496
Other assets, net of accumulated amortization of $128	119
Total assets of discontinued operation	7,246
Liabilities of real estate assets held for sale
Accounts payable and accrued expenses	140
Deferred Income	200
Other liabilities	1,007
Total liabilities of discontinued operation	1,347
Accumulated depreciation	7,072
Accumulated amortization	$ 128