LAND AND SUBSURFACE INTERESTS - Real Estate Operations Revenues (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenues
Total Revenues	$ 18,428,697	$ 12,380,602	$ 57,113,481	$ 73,931,669
Real Estate Operations
Revenues
Subsurface Revenue	377,000	2,374,000	1,403,000	2,827,000
Total Revenues	8,012,509	2,926,406	24,476,153	45,658,221
Land
Revenues
Revenue from contract with customer, including assessed tax	6,971,000		21,821,000	39,564,000
Land | Real Estate Operations
Revenues
Revenue from contract with customer, including assessed tax	6,971,000		21,821,000	39,564,000
Revenue from Reimbursement of Infrastructure Costs
Revenues
Revenue from contract with customer, including assessed tax				1,276,000
Revenue from Reimbursement of Infrastructure Costs | Real Estate Operations
Revenues
Revenue from contract with customer, including assessed tax				1,276,000
Impact Fee and Mitigation Credit Sales
Revenues
Revenue from contract with customer, including assessed tax	665,000	548,000	1,251,000	1,987,000
Impact Fee and Mitigation Credit Sales | Real Estate Operations
Revenues
Revenue from contract with customer, including assessed tax	$ 665,000	548,000	1,251,000	1,987,000
Fill Dirt and Other Revenue
Revenues
Revenue from contract with customer, including assessed tax		4,000	1,000	4,000
Fill Dirt and Other Revenue | Real Estate Operations
Revenues
Revenue from contract with customer, including assessed tax		$ 4,000	$ 1,000	$ 4,000