Land and Subsurface Interests - Additional Information (Detail)				3 Months Ended
	Apr. 13, 2016 USD ($) a $ / shares	Mar. 30, 2016 USD ($) a $ / a	Feb. 12, 2016 USD ($) a $ / a	Mar. 31, 2016 USD ($) ft² a Country	Mar. 31, 2015 USD ($) Transaction	Apr. 22, 2016 a	Feb. 18, 2016 a	Dec. 31, 2015 USD ($) a
Real Estate Properties [Line Items]
Area of a real estate property				1,700,000			0.37	160
Revenue from land sold		$ 2,000,000		$ 2,200,000
Revenue per acre | $ / a		455,000
Gain (Loss) from sale of land					$ 5,440
Percentage of infrastructure work completed				66.00%
Other Assets				$ 8,518,819				$ 6,034,824
Number of land transactions | Transaction					0
Subsurface interest area of land | a				500,000
Subsurface Interest in number of countries | Country				20
Amended oil exploration lease term				The terms of the lease state the Company will receive royalty payments if production occurs, and may receive additional annual rental payments if the lease is continued in years six through eight.
Lease income recognized from oil exploration lease				$ 303,000	$ 460,000
Area on which royalties received | a				800
Oil royalty income recognized				$ 5,000	21,000
Payments for release of surface entry rights				$ 0	$ 2,000
Subsequent Event [Member]
Real Estate Properties [Line Items]
Area of a real estate property | a	600					21
Revenue from land sold	$ 9,000,000
Land Venture Partners, LLC [Member] | Subsequent Event [Member]
Real Estate Properties [Line Items]
Sale of subsurface interest area of land | a	500,000
Sale price of subsurface interest area of land	$ 24,000,000
Gain (loss) on sale of subsurface interest area of land after tax	$ 22,600,000
Gain (loss) on sale of subsurface interest area of land per share after tax | $ / shares	$ 2.40
Town Center Sales Agreements
Real Estate Properties [Line Items]
Area of real estate property not covered under contract | a				235
Amount of contractual obligation				$ 4,500,000
Other Assets				2,800,000				$ 1,300,000
Town Center Sales Agreements | Minimum [Member]
Real Estate Properties [Line Items]
Cost of the contract				12,500,000
Town Center Sales Agreements | Maximum [Member]
Real Estate Properties [Line Items]
Cost of the contract				$ 13,000,000
NADG - First Parcel
Real Estate Properties [Line Items]
Area of a real estate property | a				81.55
Revenue from land sold				$ 20,200,000
Daytona Beach, Florida [Member]
Real Estate Properties [Line Items]
Area of a real estate property | a				6				6
Revenue from land sold			$ 190,000
Revenue per acre | $ / a			62,000
Land [Member]
Real Estate Properties [Line Items]
Area of a real estate property | a		4.40		7.46
Gain (Loss) from sale of land		$ 1,250,000
Remaining gain (loss) from sale of land		$ 683,000
Land [Member] | Daytona Beach, Florida [Member]
Real Estate Properties [Line Items]
Area of a real estate property | a			3.06
Gain (Loss) from sale of land			$ 145,000