Federal Income Taxes (Details Narrative) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Preferred Dividends Paid, net	$ 20,050,319	$ 16,665,934	$ 14,563,645
Preferred stock, dividend declared per share, paid	$ 0.55	$ 0.52	$ 0.51
S&F Tax [Member]
Amount of operating losses of S&F	$ 1,203,926	$ 2,066,587	$ 2,307,104
Federal state and franchise taxes included in general and administrative expenses	8,000	0	5,000
Series A Preferred Stock [Member]
Preferred Dividends Paid, net		$ 5,667,441	$ 7,556,588
Preferred stock, dividend declared per share, paid		$ 1.546875	$ 2.0625
Percentage of distributions characterized as ordinary income		0.494148	1.79472
Percentage of distributions characterized as capital gains		0.138204	0.26778
Percentage of distributions characterized as return capital		$ 0.914523
Series B Preferred Stock [Member]
Preferred Dividends Paid, net	$ 7,602,400	$ 7,602,400
Preferred stock, dividend declared per share, paid	$ 2.00	$ 2.00	$ 2.22466
Percentage of distributions characterized as ordinary income	1.288868	0.638896
Percentage of distributions characterized as capital gains		0.178688
Percentage of distributions characterized as return capital	$ 0.711132	$ 1.182416
Series C Preferred Stock [Member]
Preferred Dividends Paid, net	$ 9,703,124	$ 3,396,094
Preferred stock, dividend declared per share, paid	$ 1.68750	$ 0.590625
Percentage of distributions characterized as ordinary income	1.087484	0.188674
Percentage of distributions characterized as capital gains		0.052769
Percentage of distributions characterized as return capital	$ 0.600016	$ 0.349182
Series D Preferred Stock [Member]
Preferred Dividends Paid, net	$ 2,744,794
Preferred stock, dividend declared per share, paid	$ 1.372397
Percentage of distributions characterized as ordinary income	0.884419
Percentage of distributions characterized as return capital	$ 0.487978