Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Schedule of componenets of provision for income taxes [Table Text Block]

The provision for income taxes consists of the following:



	For the Years Ended December 31,
	2017			2016			2015
	(in thousands)
Current portion of income tax expense
Federal	$	5,698		$	2,932		$	—
State	3,398			1,539			1,571
Deferred portion of income tax benefit	(192,066		)	(448,643		)	(276,722		)
Total income tax benefit	$	(182,970	)	$	(444,172	)	$	(275,151	)
Effective tax rate	53.2		%	37.0		%	38.1		%

Schedule of components of net deferred income tax liabilities [Table Text Block]

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



	As of December 31,
	2017			2016
	(in thousands)
Deferred tax liabilities
Oil and gas properties	$	142,467		$	518,394
Other	3,412			7,733
Total deferred tax liabilities	145,879			526,127
Deferred tax assets
Derivative liabilities	29,463			31,349
Credit carryover	22,537			12,448
Pension	7,986			10,366
Federal and state tax net operating loss carryovers	3,867			151,343
Stock compensation	3,545			10,083
Other liabilities	1,470			201
Total deferred tax assets	68,868			215,790
Valuation allowance	(2,978		)	(5,335		)
Net deferred tax assets	65,890			210,455
Total net deferred tax liabilities	$	79,989		$	315,672
Current federal income tax refundable	$	37		$	644
Current state income tax payable	$	3,009		$	1,181

Schedule of effective income tax rate reconciliation [Table Text Block]

Federal income tax benefit differs from the amount that would be provided by applying the U.S. federal statutory rate to income before income taxes primarily due to the effect of state income taxes, changes in valuation allowances, R&D credits, and accumulated impacts of other smaller permanent differences, reported as follows:



	For the Years Ended December 31,
	2017			2016			2015
	(in thousands)
Federal statutory tax benefit	$	(120,335	)	$	(420,671	)	$	(253,001	)
Increase (decrease) in tax resulting from:
Federal tax reform changes - 2017 Tax Act	(63,675		)	—			—
State tax benefit (net of federal benefit)	(3,286		)	(17,549		)	(21,583		)
Change in valuation allowance	(2,727		)	(5,059		)	3,148
Employee share-based compensation	8,190			—			—
Other	(1,137		)	(893		)	(3,715		)
Income tax benefit	$	(182,970	)	$	(444,172	)	$	(275,151	)

Schedule of unrecognized tax benefits [Table Text Block]

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



	For the Years Ended December 31,
	2017		2016			2015
	(in thousands)
Beginning balance	$	446	$	2,782		$	1,582
Additions for tax positions of prior years	—		9			1,200
Settlements	—		(2,345		)	—
Ending balance	$	446	$	446		$	2,782