Schedule III - Real Estate and Accumulated Depreciation (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Balance at January 1	$ 68,589,778	$ 67,383,413	$ 64,076,469
Current year depreciation expense	5,726,319	6,005,270	5,759,599
Disposition of real estate	(15,459,409)	(4,798,905)	(2,452,655)
Balance at December 31	$ 58,856,688	$ 68,589,778	$ 67,383,413