Discontinued Operations (Details Textuals) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		0 Months Ended	12 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Apr. 07, 2014 Princeton Pike Corporate Center [Member]	Feb. 25, 2014 Princeton Pike Corporate Center [Member]	Sep. 30, 2013 Discontinued Operations [Member]	Sep. 30, 2013 Discontinued Operations [Member]	Dec. 31, 2013 Discontinued Operations [Member] Properties
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net gain on disposition of discontinued operations	$ (3)	$ (16)	$ 900	$ 3,029	$ 900	$ 5,300	$ (16)	$ 3,029
Number of properties sold									14