Summary of Significant Accounting Policies (Details) (USD $)	6 Months Ended		12 Months Ended											6 Months Ended		6 Months Ended								3 Months Ended			6 Months Ended		3 Months Ended			6 Months Ended								6 Months Ended
	Jun. 30, 2012 mi	Jun. 30, 2011	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Jun. 30, 2012 Commodity Contract [Member] Not Designated as Hedging Instrument [Member] Current Assets [Member]	Dec. 31, 2011 Commodity Contract [Member] Not Designated as Hedging Instrument [Member] Current Assets [Member]	Jun. 30, 2012 Commodity Contract [Member] Not Designated as Hedging Instrument [Member] Other Assets [Member]	Dec. 31, 2011 Commodity Contract [Member] Not Designated as Hedging Instrument [Member] Other Assets [Member]	Jun. 30, 2012 Commodity Contract [Member] Not Designated as Hedging Instrument [Member] Current Liabilities [Member]	Dec. 31, 2011 Commodity Contract [Member] Not Designated as Hedging Instrument [Member] Current Liabilities [Member]	Jun. 30, 2012 Commodity Contract [Member] Not Designated as Hedging Instrument [Member] Other Liabilities [Member]	Dec. 31, 2011 Commodity Contract [Member] Not Designated as Hedging Instrument [Member] Other Liabilities [Member]	Jun. 30, 2012 Wells Fargo Bank [Member]	Dec. 31, 2011 Wells Fargo Bank [Member]	Jun. 30, 2012 Revenue [Member]	Jun. 30, 2012 Revenue [Member] Customer Concentration Risk [Member]	Jun. 30, 2012 Accounts Receivable [Member]	Jun. 30, 2012 Accounts Receivable [Member] Product Concentration Risk [Member]	Jun. 30, 2012 Minimum [Member]	Jun. 30, 2012 Minimum [Member] Customer Concentration Risk [Member]	Jun. 30, 2012 Maximum [Member]	Jun. 30, 2012 Maximum [Member] Customer Concentration Risk [Member]	Jun. 30, 2012 Producing Oil and Gas Properties [Member]	Jun. 30, 2011 Producing Oil and Gas Properties [Member]	Mar. 31, 2011 Producing Oil and Gas Properties [Member]	Jun. 30, 2012 Producing Oil and Gas Properties [Member]	Jun. 30, 2011 Producing Oil and Gas Properties [Member]	Jun. 30, 2012 Non-Producing Oil and Gas Properties [Member]	Jun. 30, 2011 Non-Producing Oil and Gas Properties [Member]	Mar. 31, 2011 Non-Producing Oil and Gas Properties [Member]	Jun. 30, 2012 Non-Producing Oil and Gas Properties [Member]	Jun. 30, 2011 Non-Producing Oil and Gas Properties [Member]	Jun. 30, 2012 South Texas Project acreage [Member]	Dec. 31, 2011 South Texas Project acreage [Member]	Jun. 30, 2012 West Texas Project acreage [Member]	Dec. 31, 2011 West Texas Project acreage [Member]	Jun. 30, 2012 Napoleonville, Louisiana acreage [Member]	Dec. 31, 2011 Napoleonville, Louisiana acreage [Member]	Jun. 30, 2012 Other acreage areas [Member]	Dec. 31, 2011 Other acreage areas [Member]
Nature of Operations and Principles of Consolidation [Abstract]
Primary area of operation (in miles)	1,000
Cash and Cash Equivalents [Abstract]
Maximum maturity period (in days)	90 days
Components of prepayments [Abstract]
Cash collateral deposits for commodity purchases	$ 5,000,000		$ 6,521,000
Insurance premiums	2,266,000		2,033,000
Commodity imbalances and futures	1,058,000		1,452,000
Rents, license and other	759,000		645,000
Prepayments, total	9,083,000		10,651,000
Property, Plant and Equipment [Line Items]
Property and equipment, useful life (in years)																				3 years		20 years
Impairment provisions	629,000	562,000																						70,000	0		71,000	0	294,000	335,000		558,000	562,000
Capitalized costs for non producing oil and gas leasehold interests specified as percentage of total costs																													4.00%			4.00%
Total Non-producing Leasehold Costs	3,886,000		3,295,000																															2,930,000	2,212,000	226,000	288,000	323,000	320,000	407,000	475,000
Capitalized Costs, Oil and Gas Producing Activities, Net [Abstract]
Balance December 31, 2011	171,803,000																																							475,000
Property additions																																								490,000
Impairments																																								(558,000)
Balance June 30, 2012	197,325,000		171,803,000																																					407,000
Proceeds from Sale of Oil and Gas Property and Equipment																										6,200,000					329,000
Pre-tax gain on Sale of Oil and Gas Property																										2,708,000					125,000
Cash Deposits and Other Assets [Abstract]
Insurance collateral deposits	3,101,000		3,331,000
State collateral deposits	141,000		168,000
Materials and supplies	697,000		668,000
Cash deposits and other	3,939,000		4,167,000
Concentration of Credit Risk [Line Items]
Concentration risk, percentage (in hundredths)																	50.00%		90.00%
Concentration risk, additional characteristic																	large crude oil refining concerns		crude oil and natural gas marketing activities
Number of customers																					2		3
Percentage of US demand supplied by company	less than one percent
Percentage of revenues from one customer which loss would not have material effect (in hundredths)																10.00%
Industry practice payment of receivables (in days)																		25 days
Letter of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity														60,000,000
Standby letters of credit issued														35,600,000	38,900,000
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.
Statement of Cash Flows [Abstract]
Interest paid	3,000	7,000
Income taxes paid	3,301,000	508,000
Proceeds from income tax refunds		2,094,000
Capital expenditures incurred but not yet paid	2,627,000	3,511,000	4,070,000	2,868,000
Earnings Per Share [Abstract]
Weighted average number of shares outstanding (in shares)			4,217,596	4,217,596	4,217,596
Contracts at gross valuation [Abstract]
Asset Derivatives						4,426,000	3,500,000	0	0	0	0	0	0
Liability Derivatives						0	0	0	0	4,036,000	2,117,000	0	0
Less Counterparty Offsets						(3,416,000)	(1,436,000)	0	0	(3,416,000)	(1,436,000)	0	0
As Reported Fair Value Contracts						$ 1,010,000	$ 2,064,000	$ 0	$ 0	$ 620,000	$ 681,000	$ 0	$ 0