Summary of Significant Accounting Policies (Details Textual) $ in Thousands	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2015 USD ($) shares	Mar. 31, 2015 USD ($)	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($) shares	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($) $ / MMBTU $ / bbl	Dec. 31, 2014 USD ($)	Jun. 30, 2014 $ / MMBTU $ / BBL
Derivative [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount | shares	2,452,421			2,500,000
Summary of Significant Accounting Policies (Additional Textual) [Abstract]
Debt Issuance Cost							$ 1,800
Long-term Line of Credit	$ 0			$ 0		$ 0
Senior unsecured notes	390,667			390,667		$ 390,667	$ 0
Capitalized general and administrative costs	1,900		$ 1,600	3,500	$ 2,800
Capitalized interest expense	1,300		700	$ 2,300	1,400
Present value discounted percent of future net revenues of proved oil and natural gas reserves				10.00%
Net capitalized costs less related deferred income taxes exceeded the full-cost ceiling		$ 42,800		$ 146,300
Impairment of Oil and Gas Properties	229,026	67,100	$ 0	296,153	$ 0
Deferred income tax credit	82,700	$ 24,300		107,000
Oil
Summary of Significant Accounting Policies (Additional Textual) [Abstract]
Average oil and natural gas prices						68.17		96.75
Natural Gas
Summary of Significant Accounting Policies (Additional Textual) [Abstract]
Average oil and natural gas prices | $ / MMBTU						3.39		4.104
Revolving Credit Facility
Summary of Significant Accounting Policies (Additional Textual) [Abstract]
Deferred Finance Costs Disclosures	1,400			1,400		$ 1,400
Senior Unsecured Notes
Summary of Significant Accounting Policies (Additional Textual) [Abstract]
Deferred Finance Costs Disclosures	$ 9,300			$ 9,300		$ 9,300
Restricted Stock Units (RSUs)
Derivative [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount | shares	72,283			100,000
Preferred Stock
Derivative [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount | shares	0			1,500,000
Restricted Stock
Derivative [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount | shares	688,902			700,000