Summary of Significant Accounting Policies (Details)	12 Months Ended
	Dec. 31, 2015 USD ($) bbl Contract shares	Dec. 31, 2014 USD ($) bbl Contract shares	Dec. 31, 2013 USD ($) shares
Allowance for Doubtful Accounts [Abstract]
Percentage of crude oil and natural gas sales in accounts receivable	90.00%
Number of days, cash is received from transaction date	20 days
Inventory [Abstract]
Inventory valuation loss	$ 5,357,000	$ 14,247,000
Components of prepayments and other [Abstract]
Cash collateral deposits for commodity purchases	167,000	7,872,000
Insurance premiums	1,609,000	2,316,000
Rents, license and other	813,000	752,000
Prepayments, total	2,589,000	10,940,000
Fair value measurements for producing and non-producing oil and gas properties that were subject to fair value impairment [Abstract]
Leasehold additions	2,385,000	7,943,000	$ 13,223,000
Impairment valuation loss	(12,082,000)	(8,009,000)	(2,630,000)
Sale of used trucks and equipment [Abstract]
Sales of used trucks and equipment	535,000	1,028,000	683,000
Total Non-producing Leasehold Costs	231,000	959,000
Pre-tax gain on sale of oil and gas properties	0	2,528,000	0
Cash Deposits and Other Assets [Abstract]
Insurance collateral deposits	6,531,000	4,536,000
State collateral deposits	140,000	155,000
Materials and supplies	292,000	307,000
Cash deposits and other	6,963,000	4,998,000
Revenue Recognition [Abstract]
Revenue gross-up	480,111,000	1,212,034,000	1,602,626,000
Statement of Cash Flows [Abstract]
Interest paid	13,000	2,000	24,000
Federal and state tax paid	6,197,000	8,169,000	9,949,000
State tax refund	0	18,000	4,000
Property and equipment additions	$ 1,707,000	$ 1,137,000	$ 1,507,000
Earnings Per Share [Abstract]
Weighted average number of shares outstanding (in shares) | shares	4,217,596	4,217,596	4,217,596
Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	3 years
Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	20 years
Producing Oil and Gas Properties [Member]
Fair value measurements for producing and non-producing oil and gas properties that were subject to fair value impairment [Abstract]
Impairment valuation loss	$ 10,324,000	$ 4,001,000	$ 1,373,000
Sale of used trucks and equipment [Abstract]
Proceeds from sale of oil and gas properties		1,731,000
Pre-tax gain on sale of oil and gas properties		1,149,000
Producing Oil and Gas Properties Impaired in 2014 [Member]
Fair value measurements for producing and non-producing oil and gas properties that were subject to fair value impairment [Abstract]
Net book value at January 1	18,744,000
Leasehold additions	2,117,000
Depletion taken	(4,454,000)
Impairment valuation loss	(10,324,000)
Net book value at December 31	6,083,000	18,744,000
Producing Oil and Gas Properties Impaired in 2013 [Member]
Fair value measurements for producing and non-producing oil and gas properties that were subject to fair value impairment [Abstract]
Net book value at January 1	4,856,000	10,180,000
Leasehold additions		469,000
Depletion taken		(1,792,000)
Impairment valuation loss		(4,001,000)
Net book value at December 31		4,856,000	10,180,000
Non-Producing Oil and Gas Properties [Member]
Fair value measurements for producing and non-producing oil and gas properties that were subject to fair value impairment [Abstract]
Impairment valuation loss	$ 1,758,000	4,008,000	$ 1,257,000
Sale of used trucks and equipment [Abstract]
Capitalized costs for non-producing oil and gas leasehold interests specified as percentage of total costs	3.00%
South Texas Project acreage [Member]
Sale of used trucks and equipment [Abstract]
Total Non-producing Leasehold Costs	$ 0	357,000
South Texas Project [Member]
Sale of used trucks and equipment [Abstract]
Proceeds from sale of oil and gas properties		1,509,000
Pre-tax gain on sale of oil and gas properties		632,000
Number of oil and gas producing properties sold			0.5
Napoleonville Louisiana acreage [Member]
Sale of used trucks and equipment [Abstract]
Total Non-producing Leasehold Costs	49,000	48,000
Other acreage [Member]
Fair value measurements for producing and non-producing oil and gas properties that were subject to fair value impairment [Abstract]
Net book value at January 1	959,000	4,906,000
Leasehold additions	106,000	865,000
Advanced royalty payment	529,000	0
In-process wells suspended	395,000	73,000
Property sale	0	(877,000)
Impairment valuation loss	(1,758,000)	(4,008,000)
Net book value at December 31	231,000	959,000	$ 4,906,000
Wyoming and other acreage [Member]
Sale of used trucks and equipment [Abstract]
Total Non-producing Leasehold Costs	$ 182,000	554,000
Other Oil and Gas Property [Member]
Sale of used trucks and equipment [Abstract]
Proceeds from sale of oil and gas properties		822,000
Pre-tax gain on sale of oil and gas properties		747,000
Onshore Leasehold [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	3 years
Wells Fargo Bank [Member]
Letter of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity	$ 60,000,000
Standby letters of credit	$ 1,000,000	$ 15,300,000
Current ratio	1.1
Commodity Contract [Member]
Fair Value Forward Hydrocarbon Commodity Contracts at gross valuation [Abstract]
Number of contracts held | Contract	1	3
Commodity Contract [Member] | Not Designated as Hedging Instrument [Member] | Current Assets [Member]
Fair Value Forward Hydrocarbon Commodity Contracts at gross valuation [Abstract]
Asset Derivatives	$ 0	$ 1,332,000
Liability Derivatives	0	0
Less Counterparty Offsets	0	(396,000)
As Reported Fair Value Contracts	0	936,000
Commodity Contract [Member] | Not Designated as Hedging Instrument [Member] | Other Assets [Member]
Fair Value Forward Hydrocarbon Commodity Contracts at gross valuation [Abstract]
Asset Derivatives	0	0
Liability Derivatives	0	0
Less Counterparty Offsets	0	0
As Reported Fair Value Contracts	0	0
Commodity Contract [Member] | Not Designated as Hedging Instrument [Member] | Current Liabilities [Member]
Fair Value Forward Hydrocarbon Commodity Contracts at gross valuation [Abstract]
Asset Derivatives	0	0
Liability Derivatives	195,000	1,339,000
Less Counterparty Offsets	0	(396,000)
As Reported Fair Value Contracts	195,000	943,000
Commodity Contract [Member] | Not Designated as Hedging Instrument [Member] | Other Liabilities [Member]
Fair Value Forward Hydrocarbon Commodity Contracts at gross valuation [Abstract]
Asset Derivatives	0	0
Liability Derivatives	0	0
Less Counterparty Offsets	0	0
As Reported Fair Value Contracts	$ 0	$ 0
Commodity Contract [Member] | January 2016 [Member]
Fair Value Forward Hydrocarbon Commodity Contracts at gross valuation [Abstract]
Volume committed per day under commodity purchase and sale contract (in barrels) | bbl		65
Commodity Contract [Member] | February 2016 [Member]
Fair Value Forward Hydrocarbon Commodity Contracts at gross valuation [Abstract]
Volume committed per day under commodity purchase and sale contract (in barrels) | bbl	65
Commodity Contract [Member] | March 2016 [Member]
Fair Value Forward Hydrocarbon Commodity Contracts at gross valuation [Abstract]
Volume committed per day under commodity purchase and sale contract (in barrels) | bbl	65
Commodity Contract [Member] | Jan 2015 and Feb 2015 [Member]
Fair Value Forward Hydrocarbon Commodity Contracts at gross valuation [Abstract]
Volume committed per day under commodity purchase and sale contract (in barrels) | bbl	294
Commodity Contract [Member] | Mar 2015 through Dec 2015 [Member]
Fair Value Forward Hydrocarbon Commodity Contracts at gross valuation [Abstract]
Volume committed per day under commodity purchase and sale contract (in barrels) | bbl	129