EARNINGS PER SHARE - Earnings per Share (Details) - USD ($)	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income (loss)	$ 2,551,010	$ 1,878,703	$ 1,551,671	$ 2,157,748	$ 1,394,170	$ 1,474,767	$ 5,981,384	$ 5,026,685
Less dividends:
Common stock	2,120,188	1,870,754	1,870,416	1,776,575	1,776,575	1,658,136	5,861,358	5,211,286
Preferred stock	3,792	$ 3,750	$ 3,750	3,792	$ 3,792	$ 480,472	11,292	488,056
Deemed dividend on preferred stock related to redemption	0			0			0	3,093,028
Dividends	2,123,980			1,780,367			5,872,650	8,792,370
Undistributed earnings (deficit)	$ 427,030			$ 377,381			$ 108,734	$ (3,765,685)
Common Stock
Less dividends:
Distributed earnings (in dollars per share)	$ 0.09			$ 0.08			$ 0.24	$ 0.22
Undistributed earnings (deficit) (in dollars per share)	0.01			0.01			0	(0.16)
Total (in dollars per share)	0.10			0.09			0.24	0.06
Unvested Share-Based Payment Awards
Less dividends:
Distributed earnings (in dollars per share)	0.09			0.08			0.24	0.22
Undistributed earnings (deficit) (in dollars per share)	0.01			0.01			0	0
Total (in dollars per share)	$ 0.10			$ 0.09			$ 0.24	$ 0.22