Summary of Significant Accounting Policies (Details Textual) (USD $)	1 Months Ended	3 Months Ended			12 Months Ended
	Jan. 31, 2007	Mar. 31, 2012 Y Boe	Mar. 31, 2011		Dec. 31, 2011
Summary of Significant Accounting Policies (Textual) [Abstract]
Total capitalized internal costs		$ 8,300,000	$ 7,200,000
Total capitalized interest cost on unproved properties		2,000,000	1,900,000
Estimated useful lives of the property, minimum		2
Estimated useful lives of the property, maximum		20
Discount rate for estimated future net revenues from proved properties		10.00%
Material natural gas imbalances		0			0
Allowance for doubtful accounts receivable, current		100,000			100,000
Accounts receivable		61,199,000			64,392,000
Net gain (loss) related to derivative activities, recognized		(400,000)	(200,000)
Fair value of derivative instruments		800,000			100,000
Decrease in retained earnings for uncertain tax positions	1,000,000
Percentage of working interest interest in wells					100.00%
Total amount of supervision fees charged to wells		2,800,000	3,500,000	[1]
Inventories carried at cost		3,200,000			3,600,000
Outstanding checks included in trade accounts payable		22,100,000			18,700,000
Maturity time period for cash and cash equivalents		3 months or less
Restricted cash and cash equivalents included in other long term assets		1,000,000			1,300,000
Accumulated other comprehensive income (loss) net of tax		300,000
Asset retirement obligation classified as a current liability in accounts payable and accrued liabilities		9,303,000			9,279,000
Oil Production covered by oil price floors		270,500
Derivative gains recorded in accumulated other comprehensive gain, net of income tax		135,000	12,000
Senior notes due 2017 [Member]
Debt Issuance Costs (Textual) [Abstract]
Senior notes, issued		250,000,000
Stated Rate of Senior notes		7.125%
Maturity date of senior notes		Jun. 01, 2017
Balance of issuance costs for credit facility		2,500,000
Net accumulated amortization of debt issuance cost		1,700,000
Senior notes due 2020 [Member]
Debt Issuance Costs (Textual) [Abstract]
Senior notes, issued		225,000,000
Stated Rate of Senior notes		8.875%
Effective yield to maturity		9.125%
Maturity date of senior notes		Jan. 15, 2020
Balance of issuance costs for credit facility		4,300,000
Net accumulated amortization of debt issuance cost		800,000
Senior Notes Due 2022 [Member]
Debt Issuance Costs (Textual) [Abstract]
Senior notes, issued		250,000,000
Stated Rate of Senior notes		7.875%
Effective yield to maturity		8.00%
Maturity date of senior notes		Mar. 01, 2022
Balance of issuance costs for credit facility		4,600,000
Net accumulated amortization of debt issuance cost		100,000
Line of Credit [Member]
Debt Issuance Costs (Textual) [Abstract]
Balance of issuance costs for credit facility		3,300,000
Net accumulated amortization of debt issuance cost		4,200,000
Maximum [Member]
Accounts, Notes, Loans and Financing Receivable (Textual) [Abstract]
Strike price of one oil price floor, maximum		105.00
Minimum [Member]
Accounts, Notes, Loans and Financing Receivable (Textual) [Abstract]
Strike price of one oil price floor, minimum		100.00
Joint Interest Owners [Member]
Accounts, Notes, Loans and Financing Receivable (Textual) [Abstract]
Accounts receivable related to joint interest owners		6,700,000			4,200,000
Other Receivables [Member]
Accounts, Notes, Loans and Financing Receivable (Textual) [Abstract]
Other Receivables		4,600,000			5,600,000
Account Receivable [Member]
Accounts, Notes, Loans and Financing Receivable (Textual) [Abstract]
Accounts receivable related to oil and gas sales		$ 49,900,000			$ 54,700,000

[1] (1) $.01 par value.