Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 2,369,141	$ (16,947,614)
Other comprehensive income (loss):
Increase (decrease) in net unrealized gain (loss) on available-for-sale securities, net	3,699,186	(2,246,013)
Reclassification adjustment for net gain (loss) included in net income (loss)	(148,284)	1,123,693
Reclassification adjustment for other-than-temporary impairments included in net income (loss)	0	20,994
Total other comprehensive income (loss)	3,550,902	(1,101,326)
Less: Dividends to preferred stockholders	(880,509)	(880,509)
Comprehensive income (loss) attributable to common stockholders	$ 5,039,534	$ (18,929,449)