Consolidated Statements of Cash Flows (Parenthetical)	12 Months Ended
	Dec. 31, 2015 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2015 a
Interest paid	$ 4,700,000	$ 1,600,000
Interest Paid, Capitalized	0	8,000
Income Taxes Paid	1,200,000	1,600,000
Convertible notes face amount	173,700,000
Acquisition of interest in property	5,700,000
Non Cash Accrual increase in Land and Development Costs and Accrued and Other Liabilities	1,700,000
Net realized gain loss on investments	$ 163,000	0
Percentage of Interest received in the subsurface rights	50.00%
Area of a real estate property			160
Reduction in the value of accrued stock based Compensation	$ 314,000
Non-cash conveyance of certain real property for legal settlement		$ 703,000
Lee and Hendry County Florida [Member]
Acquisition of interest in property	$ 68,000
Area of a real estate property | a			1,400
4.50% Convertible Senior Notes due 2020 [Member]
Debt Instrument Maturity Year	2020
Equity component of the convertible notes issued	$ 2,100,000
Decrease in long-term debt	3,400,000
Increase in deferred income taxes	1,300,000
Convertible notes face amount	$ 75,000,000