Unaudited Quarterly Operating Results (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Information [Line Items]
Total Revenue	$ 9,279	$ 13,968	$ 4,926	$ 10,541	$ 20,525	$ 9,951	$ 9,275	$ 11,011	$ 38,714	$ 50,762
Net Income (Loss)	(121)	384	(326)	(684)	9,709	37	709	124	(747)	10,579	$ 4,235
Net Income (Loss) attributable to Common Stockholders	$ (123)	$ 398	$ (333)	$ (682)	$ 9,707	$ 47	$ 707	$ 119	$ (740)	$ 10,580	$ 4,255
Net Income (Loss) Per Share (in dollars per share)	$ 0	$ 0.02	$ (0.01)	$ (0.03)	$ 0.37	$ 0	$ 0.03	$ 0	$ (0.03)	$ 0.41	$ 0.16
Net Income (Loss), Per Share attributable to Common Stockholders (in dollars per share)	$ 0	$ 0.02	$ (0.01)	$ (0.03)	$ 0.37	$ 0	$ 0.03	$ 0	$ (0.03)	$ 0.40	$ 0.16
Reportable Segment
Quarterly Financial Information [Line Items]
Segment Profit (Loss)	$ 908	$ 1,294	$ (289)	$ 770	$ 6,301	$ (708)	$ 895	$ 1,442	$ 2,683	$ 7,930