Schedule III - Real Estate and Accumulated Depreciation (Parenthetical) (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Reconciliation to Consolidated Balance Sheet at December 31, 2013
Income Properties: Land Buildings, and Improvements	$ 154,902,374	$ 132,202,887
Total	170,194,285
Real Estate [Member]
Reconciliation to Consolidated Balance Sheet at December 31, 2013
Land, Timber, and Subsurface Interests	15,291,911
Income Properties: Land Buildings, and Improvements	154,902,374
Land Timber Subsurface Interests and Income Properties	170,194,285
Cost Basis of Assets Classified as Held for Sale on Balance Sheet
Total	$ 170,194,285	$ 151,226,811	$ 134,561,058	$ 134,705,516