Investments In and Advances To Unconsolidated Affiliates (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2016 USD ($) property	Mar. 31, 2015 USD ($)
Income Statements:
Rental and other revenues	$ 10,772	$ 12,231
Expenses:
Rental property and other expenses	4,715	5,667
Depreciation and amortization	2,747	3,115
Interest expense	1,377	2,149
Total expenses	8,839	10,931
Income before disposition of property	1,933	1,300
Gains/(losses) on disposition of property	902	2,127
Net income	$ 2,835	$ 3,427
Percentage of equity interest in joint ventures, maximum (in hundredths)	50.00%
Concourse Center Associates, LLC Joint Venture [Member]
Expenses:
Gains/(losses) on disposition of property	$ (100)
Number of buildings sold | property	2
Proceeds received from disposition of property	$ 11,000
Our share of gains on disposition of property	400
Repayment of debt	6,600
4600 Madison Associates, LLC Joint Venture [Member]
Expenses:
Gains/(losses) on disposition of property	1,000
Proceeds received from disposition of property	3,400
Our share of gains on disposition of property	100
Repayment of debt	$ 3,400
Fixed current interest rate (in hundredths)	6.85%