Income Taxes (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Taxes [Line Items]
Minimum Percentage of Adjusted Taxable Income to be Distributed to Shareholders as a Real Estate Investment Trust	90.00%
Prior Year Distributions Carryforward as Current Year Distribution	$ 0.3800	$ 0.2866	$ 0.2164	$ 0.1692
Income Tax Expense (Benefit)	$ 181	$ (134)	$ 2,590
Operating Partnership [Member]
Income Taxes [Line Items]
Income Tax Expense (Benefit)	$ 0	$ 500	$ 900