Income Taxes (Tables)

12 Months Ended

Dec. 31, 2015

Schedule of componenets of provision for income taxes

The provision for income taxes consists of the following:



	For the Years Ended December 31,
	2015			2014			2013
	(in thousands)
Current portion of income tax expense
Federal	$	—		$	—		$	—
State	1,571			868			2,121
Deferred portion of income tax expense (benefit)	(276,722		)	397,780			105,555
Total income tax expense (benefit)	$	(275,151	)	$	398,648		$	107,676
Effective tax rate	38.1		%	37.4		%	38.6		%

Schedule of Deferred Tax Assets and Liabilities [Table Text Block]

The components of the net deferred income tax liabilities are as follows:



	As of December 31,
	2015			2014
	(in thousands)
Deferred tax liabilities:
Oil and gas properties	$	854,029		$	1,029,424
Derivative asset	179,543			220,437
Other	1,233			4,475
Total deferred tax liabilities	1,034,805			1,254,336
Deferred tax assets:
Federal and state tax net operating loss carryovers	244,942			184,447
Stock compensation	14,529			16,763
Other liabilities	27,449			25,715
Total deferred tax assets	286,920			226,925
Valuation allowance	(10,394		)	(7,246		)
Net deferred tax assets	276,526			219,679
Total net deferred tax liabilities ⁽¹⁾	$	758,279		$	1,034,657
Current federal income tax refundable	$	5,378		$	4,734
Current state income tax refundable	$	65		$	—
Current state income tax payable	$	—		$	25

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⁽¹⁾	All deferred tax liabilities and assets as of December 31, 2015, are classified as noncurrent on the accompanying balance sheets upon the Company’s adoption of ASU 2015-17 on a prospective basis. Prior year amounts have not been restated. Please refer to the caption Recently Issued Accounting Standards in Note 1 - Summary of Significant Accounting Policies for additional discussion.

Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]

Federal income tax expense differs from the amount that would be provided by applying the statutory United States federal income tax rate to income before income taxes primarily due to the effect of state income taxes, changes in valuation allowances, R&D credits, and other permanent differences, as follows:



	For the Years Ended December 31,
	2015			2014		2013
	(in thousands)
Federal statutory tax expense (benefit)	$	(253,001	)	$	372,644	$	97,514
Increase (decrease) in tax resulting from:
State tax expense (benefit) (net of federal benefit)	(21,583		)	21,350		9,400
Change in valuation allowance	3,148			2,245		(314		)
Research and development credit	(1,971		)	—		—
Other	(1,744		)	2,409		1,076
Income tax expense (benefit)	$	(275,151	)	$	398,648	$	107,676

Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block]

The total amount recorded for unrecognized tax benefits is presented below:



	For the Years Ended December 31,
	2015		2014			2013
	(in thousands)
Beginning balance	$	1,582	$	2,358		$	2,278
Additions for tax positions of prior years	1,200		140			80
Settlements	—		(916		)	—
Ending balance	$	2,782	$	1,582		$	2,358