Income Taxes (Tables)

12 Months Ended

Dec. 31, 2014

Income Tax Disclosure [Abstract]

Reconciliation Between Statutory Federal Income Tax Rate and Effective Income Tax

Our income tax expense was $396.5 million for the year ended December 31, 2014 compared to $33.9 million in 2013 and $12.1 million in 2012. Reconciliation between the statutory federal income tax rate and our effective income tax rate is as follows:

	Year Ended December 31,
	2014		2013			2012
Federal statutory tax rate	35.0	%		35.0	%		35.0	%
State	3.1			(2.3	)		0.7
State apportionment rate change	(0.2	)		(14.9	)		¾
Non-deductible executive compensation	0.2			0.7			1.4
Valuation allowances	0.2			3.5			8.8
Other	0.2			0.6			2.2
Consolidated effective tax rate	38.5	%		22.6	%		48.1	%

Income Tax Expense (Benefit) Attributable to Income Before Income Taxes

Income tax expense (benefit) attributable to income before income taxes consists of the following (in thousands):

		2014						2013									2012
		Current	Deferred		Total		Current			Deferred			Total			Current			Deferred		Total
U.S. federal	$	¾	$	361,152	$	361,152	$	¾		$	58,527		$	58,527		$	—		$	11,873	$	11,873
U.S. state and local		1		35,350		35,351		(143	)		(24,527	)		(24,670	)		(1,778	)		1,959		181
Total	$	1	$	396,502	$	396,503	$	(143	)	$	34,000		$	33,857		$	(1,778	)	$	13,832	$	12,054

Significant Components of Deferred Tax Assets and Liabilities

Significant components of deferred tax assets and liabilities are as follows:

	December 31,
	2014			2013
	(in thousands)
Deferred tax assets:
Current
Deferred compensation	$	9,286		$	9,128
Current portion of asset retirement obligation		5,745			1,854
Cumulative mark-to-market loss		584			15,193
Net operating loss carryforward		—			23,079
Other		9,921			7,936
Total current		25,536			57,190
Non-current
Net operating loss carryforward		176,812			57,266
Deferred compensation		64,656			91,094
Equity compensation		25,833			22,800
AMT credits and other credits		4,447			4,122
Non-current portion of asset retirement obligation		104,063			86,126
Cumulative mark-to-market loss		65			¾
Other		987			1,116
Valuation allowance		(16,599	)		(14,781	)
Total non-current		360,264			247,743
Deferred tax liabilities:
Current
Net gain in AOCI related to hedge derivatives		—			(3,987	)
Other		(2,350	)		(1,789	)
Cumulative mark-to-market gain		(138,773	)		¾
Total current		(141,123	)		(5,776	)
Non-current
Depreciation, depletion and investments		(1,342,039	)		(1,010,757	)
Cumulative mark-to-market gain		(15,410	)		(6,424	)
Other		(310	)		(2,542	)
Total non-current		(1,357,759	)		(1,019,723	)
Net deferred tax liability	$	(1,113,082	)	$	(720,566	)