Summary of Significant Accounting Policies (Details Textual) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Accounts Receivable (Textual) [Abstract]
Allowance for doubtful accounts receivable, current	$ 100,000		$ 100,000
Trade Accounts Receivable, Gross	59,500,000		56,900,000
Accounts receivable related to joint interest owners	1,200,000		1,600,000
Severance Tax Receivable	12,100,000		11,600,000
Other Receivables	300,000		800,000
Summary of Significant Accounting Policies (Textual) [Abstract]
Total capitalized internal costs	7,100,000	9,100,000
Total capitalized interest cost on unproved properties	1,300,000	1,900,000
Discount rate for estimated future net revenues from proved properties	10.00%
Net gain (loss) on derivative activities	(5,100,000)	(300,000)
Unrealized Gain (Loss) on Derivatives	(3,400,000)
Derivative Asset, Fair Value, Gross Asset	300,000
Derivative Liability, Fair Value, Gross Liability	3,800,000
Derivative, Fair Value, Net	(3,500,000)
Receivables from settled derivatives	100,000
Liabilities, Fair Value Disclosure	700,000
Percentage of working interest in wells	100.00%
Total amount of supervision fees charged to wells	2,800,000	2,800,000
Inventories carried at cost	3,300,000		3,500,000
Adjustments to Additional Paid in Capital, Income Tax Deficiency from Share-based Compensation	1,700,000
Outstanding checks included in trade accounts payable	10,900,000		26,100,000
Restricted cash and cash equivalents included in other long term assets	1,000,000		1,000,000
Asset Retirement Obligation - current portion	14,586,000		15,859,000
Senior Notes Due Two Thousand Seven Teen [Member]
Debt Issuance Costs (Textual) [Abstract]
Debt Instrument, Interest Rate, Stated Percentage	7.125%
Balance of issuance costs for credit facility	1,700,000
Senior Notes Due Two Thousand Twenty [Member]
Debt Issuance Costs (Textual) [Abstract]
Debt Instrument, Interest Rate, Stated Percentage	8.875%
Balance of issuance costs for credit facility	3,400,000
Senior Notes Due 2022 [Member]
Debt Issuance Costs (Textual) [Abstract]
Debt Instrument, Interest Rate, Stated Percentage	7.875%
Balance of issuance costs for credit facility	6,400,000
Line of Credit [Member]
Debt Issuance Costs (Textual) [Abstract]
Balance of issuance costs for credit facility	$ 3,100,000
Minimum [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Property, Plant and Equipment, Useful Life	2 years
Maximum [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Property, Plant and Equipment, Useful Life	20 years