Selected Quarterly Financial Data (Unaudited) (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Summary of Selected Quarterly Financial Information
Total Income	$ 18,879,238	$ 18,554,782	$ 18,148,732	$ 15,849,181	$ 16,426,921	$ 16,253,966	$ 16,097,925	$ 13,426,295	$ 71,431,933	$ 62,205,107	$ 46,827,764
Total Expenses	16,152,398	16,777,494	16,489,825	15,101,441	16,636,587	14,935,457	14,196,653	12,240,957	64,521,158	58,009,654	44,214,508
Other Income (Expense)	(1,173,827)	(1,121,174)	(228,377)	(156,907)	(524,561)	(600,121)	(229,785)	2,977,034	(2,680,285)	1,622,567	3,902,282
Net Income	1,563,618	629,271	1,476,725	568,189	(733,004)	800,877	1,619,439	4,149,511	4,237,803	5,836,823	6,474,057
Net Income (Loss) Attributable to Common Shareholders	$ (325,529)	$ (1,259,876)	$ (412,422)	$ (1,320,958)	$ (2,622,151)	$ (1,088,270)	$ (269,708)	$ 2,260,364	$ (3,318,785)	$ (1,719,765)	$ 1,749,339
Net Income (Loss) Attributable to Common Shareholders per Share -
Basic	$ (0.01)	$ (0.06)	$ (0.02)	$ (0.06)	$ (0.14)	$ (0.06)	$ (0.02)	$ 0.13	$ (0.15)	$ (0.09)	$ 0.11
Diluted	$ (0.01)	$ (0.06)	$ (0.02)	$ (0.06)	$ (0.14)	$ (0.06)	$ (0.02)	$ 0.13	$ (0.15)	$ (0.09)	$ 0.11