Unaudited Quarterly Operating Results (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Selected Quarterly Financial Information [Abstract]
Total Revenue	$ 12,841	$ 13,223	$ 7,006	$ 13,122	$ 15,884	$ 12,187	$ 7,159	$ 16,826	$ 46,192	$ 52,056
Net income (loss)	(269)	317	(728)	1,195	1,745	(811)	377	1,601	515	2,912	$ 5,762
Net Income (loss) Per Share	$ (287)	$ 324	$ (688)	$ 1,209	$ 1,715	$ (788)	$ 406	$ 1,617	$ 558	$ 2,950	$ 5,655
Net Income (loss) Per Share	$ (0.01)	$ 0.02	$ (0.04)	$ 0.06	$ 0.08	$ (0.04)	$ 0.02	$ 0.08	$ 0.03	$ 0.14	$ 0.27
Net Income(Loss), Per Share attributable to Common Stockholders (in dollars per share)	$ (0.01)	$ 0.02	$ (0.03)	$ 0.06	$ 0.08	$ (0.04)	$ 0.02	$ 0.08	$ 0.03	$ 0.14	$ 0.27
Reportable Segment
Selected Quarterly Financial Information [Abstract]
Segment Profit (Loss)	$ 215	$ 1,187	$ 56	$ 3,186	$ 4,221	$ (614)	$ 1,362	$ 4,643	$ 4,644	$ 9,612