Unaudited Quarterly Operating Results (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Information [Line Items]
Total Revenue	$ 11,925	$ 12,051	$ 6,311	$ 5,985	$ 12,841	$ 13,223	$ 7,006	$ 13,122	$ 36,272	$ 46,192
Net income (loss)	361	(26)	(1)	(1,913)	(269)	317	(728)	1,195	(1,579)	515	$ 2,912
Net (Loss) Income attributable to Common Stockholders	$ 343	$ (22)	$ 26	$ (1,902)	$ (287)	$ 324	$ (688)	$ 1,209	$ (1,555)	$ 558	$ 2,950
Net Income (loss) Per Share (in dollars per share)	$ 0.01	$ 0.00	$ 0.00	$ (0.09)	$ (0.01)	$ 0.02	$ (0.04)	$ 0.06	$ (0.07)	$ 0.03	$ 0.14
Net Income (Loss), Per Share attributable to Common Stockholders (in dollars per share)	$ 0.01	$ 0.00	$ 0.00	$ (0.09)	$ (0.01)	$ 0.02	$ (0.03)	$ 0.06	$ (0.07)	$ 0.03	$ 0.14
Reportable Segment
Quarterly Financial Information [Line Items]
Segment Profit (Loss)	$ 1,973	$ 720	$ 715	$ (811)	$ 215	$ 1,187	$ 56	$ 3,186	$ 2,597	$ 4,644