Summary of Significant Accounting Policies (Details Textual) (USD $)	3 Months Ended								3 Months Ended								3 Months Ended				3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	May 01, 2013	Dec. 31, 2012	Mar. 31, 2013 Senior Notes Due Two Thousand Seven Teen [Member]	Mar. 31, 2013 Senior Notes Due Two Thousand Twenty [Member]	Mar. 31, 2013 Senior Notes Due 2022 [Member]	Mar. 31, 2013 Line of Credit [Member]	Jun. 30, 2013 Maximum [Member]	Jun. 30, 2013 Minimum [Member]	Mar. 31, 2013 Trade Accounts Receivable [Member]	Dec. 31, 2012 Trade Accounts Receivable [Member]	Mar. 31, 2013 Joint Interest Owners [Member]	Dec. 31, 2012 Joint Interest Owners [Member]	Mar. 31, 2013 Other Accounts Receivable [Member]	Dec. 31, 2012 Other Accounts Receivable [Member]	Mar. 31, 2013 Maximum [Member]	Mar. 31, 2013 Minimum [Member]	Jun. 30, 2013 Natural Gas [Member] MMBTU	Mar. 31, 2013 Natural Gas [Member]	Jun. 30, 2013 Oil [Member] Boe	Mar. 31, 2013 Oil [Member]
Accounts Receivable (Textual) [Abstract]
Allowance for doubtful accounts receivable, current	$ 100,000			$ 100,000
Trade Accounts Receivable, Gross											54,900,000	53,900,000
Accounts receivable related to joint interest owners													3,900,000	3,600,000
Other Receivables															14,400,000	9,800,000
Summary of Significant Accounting Policies (Textual) [Abstract]
Significant Acquisitions and Disposals, Acquisition Costs or Sale Proceeds			5,800,000
Reduction of asset retirement obligation due to sale of properties			11,300,000
Total capitalized internal costs	9,100,000	8,300,000
Total capitalized interest cost on unproved properties	1,900,000	2,000,000
Property, Plant and Equipment, Useful Life																	20 years	2 years
Discount rate for estimated future net revenues from proved properties	10.00%
Net gain (loss) related to derivative activities, recognized	(300,000)	(400,000)
Fair value of derivative instruments	400,000																			100,000		300,000
Receivables from settled derivatives	200,000
Production from Price Floors																			2,550,000		225,000
Price Floor Strike Price									4.07	3.65
Price Floor Strike Price	93.60
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	2,500,000			5,600,000
Outstanding checks included in trade accounts payable	11,300,000			13,300,000
Maturity Period of Cash and cash Equivalents	3 months
Restricted cash and cash equivalents included in other long term assets	1,000,000			1,000,000
Asset Retirement Obligation - current portion	8,779,000			7,134,000
Debt Issuance Costs (Textual) [Abstract]
Balance of issuance costs for credit facility					2,100,000	3,900,000	6,900,000	4,000,000
Debt Instrument, Interest Rate, Stated Percentage					7.125%	8.875%	7.875%
Reduction of credit facility unamortized issuance costs				$ 700,000