Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 1,394,170	$ (21,490,063)	$ 2,868,937	$ (10,175,063)
Other comprehensive income (loss):
Increase (decrease) in unrealized gain (loss) on available-for-sale securities, net	0	12,154,936	0	0
Reclassification adjustment for net gain (loss) included in net income (loss)	0	11,328,205	0	12,617,794
Total other comprehensive income (loss)	0	23,483,141	0	12,617,794
Less: Dividends to preferred stockholders	(3,792)	(870,726)	(484,264)	(1,751,235)
Less: Deemed dividend on preferred stock related to redemption	0	0	(3,093,028)	0
Comprehensive income (loss) attributable to common stockholders	$ 1,390,378	$ 1,122,352	$ (708,355)	$ 691,496