Summary of Significant Accounting Policies (Details) (USD $)	12 Months Ended
	Dec. 31, 2013 Contract mi	Dec. 31, 2012 Contract	Dec. 31, 2011
Nature of Operations [Abstract]
Primary area of operation (in miles)	1,000
Allowance for Doubtful Accounts [Abstract]
Percentage of crude oil and natural gas sales in accounts receivable (in hundredths)	90.00%
Number of days, cash is received from transaction date	20 days
Components of prepayments and other [Abstract]
Cash collateral deposits for commodity purchases	$ 13,705,000	$ 5,000,000
Insurance premiums	2,490,000	1,872,000
Rents, license and other	584,000	840,000
Prepayments, total	16,779,000	7,712,000
Property, Plant and Equipment [Line Items]
Exploratory drilling costs	0
Fair value measurements for producing oil and gas properties that were subject to fair value impairment [Abstract]
Property additions	13,223,000	23,335,000	24,890,000
Impairment valuation loss	(2,630,000)	(5,555,000)	(14,749,000)
Total Non-producing Leasehold Costs	4,906,000	4,095,000
Pre-tax gain on sale of oil and gas properties	0	2,203,000	2,923,000
Pre-tax gain on sale of equipment	372,000	2,482,000	1,246,000
Cash Deposits and Other Assets [Abstract]
Insurance collateral deposits	3,718,000	3,413,000
State collateral deposits	160,000	170,000
Materials and supplies	609,000	616,000
Cash deposits and other	4,487,000	4,199,000
Revenue Recognition [Abstract]
Increase in the entity's reported revenue	1,602,626,000	1,381,352,000	1,812,561,000
Statement of Cash Flows [Abstract]
Interest paid	24,000	10,000	8,000
Income taxes paid	9,949,000	12,650,000	5,597,000
Proceeds from income tax refunds	4,000	10,000	2,743,000
Non-cash investing activities for property and equipment	1,507,000	2,419,000	4,070,000
Earnings Per Share [Abstract]
Weighted average number of shares outstanding (in shares)	4,217,596	4,217,596	4,217,596
Fair Value Forward Hydrocarbon Commodity Contracts at gross valuation [Abstract]
Number of contracts held	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	449,000	354,000
Liability Derivatives	0	0
Less Counterparty Offsets	(54,000)	(270,000)
As Reported Fair Value Contracts	395,000	84,000
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	54,000	381,000
Less Counterparty Offsets	(54,000)	(270,000)
As Reported Fair Value Contracts	0	111,000
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] | Jan 2014 to Feb 2014 [Member]
Fair Value Forward Hydrocarbon Commodity Contracts at gross valuation [Abstract]
Volume committed per day under commodity purchase and sale contract (in barrels)	175
Commodity Contract [Member] | Jan 2013 [Member]
Fair Value Forward Hydrocarbon Commodity Contracts at gross valuation [Abstract]
Volume committed per day under commodity purchase and sale contract (in barrels)		900
Commodity Contract [Member] | Feb 2013 to June 2013 [Member]
Fair Value Forward Hydrocarbon Commodity Contracts at gross valuation [Abstract]
Volume committed per day under commodity purchase and sale contract (in barrels)		200
Commodity Put Option [Member]
Fair Value Forward Hydrocarbon Commodity Contracts at gross valuation [Abstract]
Number of contracts held	1
Volume of crude oil committed under commodity put option (in barrels)	100,000
Wells Fargo Bank [Member]
Letter of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity	60,000,000
Standby letters of credit issued	14,600,000	21,900,000
Covenant terms	Such restrictions included the maintenance of a combined 1.1 to 1.0 current ratio and the maintenance of positive net earnings excluding inventory valuation changes, as defined, among other restrictions. The Company is currently in compliance with all such financial covenants.
Current ratio	1.1
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 oil and gas properties that were subject to fair value impairment [Abstract]
Impairment valuation loss	1,373,000	4,699,000	7,105,000
Proceeds from sale of oil and gas properties		3,049,000	6,200,000
Pre-tax gain on sale of oil and gas properties		1,728,000	2,708,000
Producing Oil and Gas Properties Impaired in 2013 [Member]
Fair value measurements for producing oil and gas properties that were subject to fair value impairment [Abstract]
Net book value at January 1	13,180,000
Property additions	5,661,000
Depletion taken	(3,727,000)
Impairment valuation loss	(1,373,000)
Net book at December 31	13,741,000
Producing Oil and Gas Properties Impaired in 2012 [Member]
Fair value measurements for producing oil and gas properties that were subject to fair value impairment [Abstract]
Net book value at January 1		11,073,000
Property additions		13,083,000
Depletion taken		(6,371,000)
Impairment valuation loss		(4,699,000)
Net book at December 31		13,086,000
Non-Producing Oil and Gas Properties [Member]
Fair value measurements for producing oil and gas properties that were subject to fair value impairment [Abstract]
Impairment valuation loss	1,257,000	856,000	7,644,000
Capitalized costs for non producing oil and gas leasehold interests specified as percentage of total costs (in hundredths)	5.00%
Proceeds from sale of oil and gas properties		578,000	329,000
Pre-tax gain on sale of oil and gas properties		475,000	125,000
South Texas Project acreage [Member]
Fair value measurements for producing oil and gas properties that were subject to fair value impairment [Abstract]
Total Non-producing Leasehold Costs	4,217,000	3,263,000
West Texas Project [Member]
Fair value measurements for producing oil and gas properties that were subject to fair value impairment [Abstract]
Total Non-producing Leasehold Costs	116,000	180,000
Napoleonville, Louisiana acreage [Member]
Fair value measurements for producing oil and gas properties that were subject to fair value impairment [Abstract]
Total Non-producing Leasehold Costs	162,000	323,000
Other acreage areas [Member]
Fair value measurements for producing oil and gas properties that were subject to fair value impairment [Abstract]
Net book value at January 1	329,000	475,000
Property additions	304,000	810,000
Property sale	0	(100,000)
Impairment valuation loss	(222,000)	(856,000)
Net book at December 31	411,000	329,000
Total Non-producing Leasehold Costs	$ 411,000	$ 329,000
Onshore leasehold [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	3 years