Recent Acquisitions of Real Estate (Pro Forma Information) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Two Years Prior Acquisitions
Business Acquisition, Pro Forma Information
Revenues	$ 64,883
Net income (loss) attributable to common stockholders	$ (10,237)
Three Years Prior Acquisitions
Business Acquisition, Pro Forma Information
Revenues		$ 52,794
Net income (loss) attributable to common stockholders		$ (16,833)