Summary of Significant Accounting Policies - Additional Information (Detail) a in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) a	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Significant Accounting Policies [Line Items]
Capitalized Exploratory Well Costs	$ 0	$ 8,575,000
Capitalized Exploratory Well Cost, Charged to Expense	8,454,000
Capital Expenditures Incurred but Not yet Paid	7,033,000	19,405,000
Restricted cash and cash equivalents	$ 200,000	217,000
Contractual Period Of Sale Contracts	5 years
Non-Oil And Gas Properties [Member]
Significant Accounting Policies [Line Items]
Depreciation expense of property and equipment	$ 1,067,000	903,000	$ 1,028,000
Minimum [Member]
Significant Accounting Policies [Line Items]
Reimbursement range on water, sewer and other infrastructure-related assets	70.00%
Maximum [Member]
Significant Accounting Policies [Line Items]
Reimbursement range on water, sewer and other infrastructure-related assets	90.00%
Capitalize reforestation costs	2 years
Computer Software, Intangible Asset [Member]
Significant Accounting Policies [Line Items]
Carrying value of capitalized software	$ 237,000	1,188,000
Capitalized software amortization	$ 996,000	1,067,000	1,593,000
Computer Software, Intangible Asset [Member] | Minimum [Member]
Significant Accounting Policies [Line Items]
Useful life range	3 years
Computer Software, Intangible Asset [Member] | Maximum [Member]
Significant Accounting Policies [Line Items]
Useful life range	5 years
Georgia [Member]
Significant Accounting Policies [Line Items]
Timber owned directly or through ventures | a	89
Depletion	$ 250,000	$ 371,000	$ 609,000