Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($)	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 1,474,767	$ 11,315,000
Other comprehensive income (loss):
Increase (decrease) in unrealized gain (loss) on available-for-sale securities, net	0	(12,154,936)
Reclassification adjustment for net gain (loss) included in net income (loss)	0	1,289,589
Total other comprehensive income (loss)	0	(10,865,347)
Less: Dividends to preferred stockholders	(480,472)	(880,509)
Less: Deemed dividend on preferred stock related to redemption	(3,093,028)
Comprehensive income (loss) attributable to common stockholders	$ (2,098,733)	$ (430,856)