Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Summary of net deferred tax position

The Company’s net deferred tax position as of December 31, 2017 and 2016 is as follows (in thousands).

	December 31,
	2017			2016
Deferred tax assets
Unrealized loss on derivatives	$	3,200		$	8,734
Net operating loss carryforwards	118,134			137,757
Alternative minimum tax carryforward	—			8,633
Percentage depletion carryover	1,582			2,595
Property and equipment	—			44,391
Basis increase related to the San Mateo transaction	18,382			—
Total deferred tax assets	141,298			202,110
Valuation allowance on deferred tax assets	(89,482		)	(190,255		)
Total deferred tax assets, net of valuation allowance	51,816			11,855
Deferred tax liabilities
Property and equipment	(40,568		)	—
Other	(11,248		)	(11,855		)
Total deferred tax liabilities	(51,816		)	(11,855		)
Net deferred tax liabilities	$	—		$	—

Income tax expense reconciled to the tax computed at the statutory federal rate

The current income tax (benefit) provision for the years ended December 31, 2017, 2016 and 2015 was comprised of the following (in thousands).

	Year Ended December 31,
	2017			2016			2015
Current income tax provision
State income tax	$	21		$	108		$	371
Federal alternative minimum tax	(8,178		)	(1,144		)	2,588
Net current income tax (benefit) provision	$	(8,157	)	$	(1,036	)	$	2,959

Reconciliations of the tax expense (benefit) computed at the statutory federal rate to the Company’s total income tax benefit for the years ended December 31, 2017, 2016 and 2015 is as follows (in thousands).

	Year Ended December 31,
	2017			2016			2015
Federal tax expense (benefit) at statutory rate (1)	$	45,447		$	(34,333	)	$	(289,412	)
State income tax	368			539			(13,215		)
Permanent differences (2)	(4,740		)	(499		)	698
Federal alternative minimum tax	—			1,144			(2,588		)
AMT credit refundable (net of sequestration)	8,178			—			—
Tax Cuts and Jobs Act rate change	51,525			—			—
Change in federal valuation allowance	(101,917		)	33,688			145,777
Change in state valuation allowance	1,139			(539		)	8,413
Net deferred income tax benefit	—			—			(150,327		)
Net current income tax (benefit) provision	(8,157		)	(1,036		)	2,959
Total income tax benefit	$	(8,157	)	$	(1,036	)	$	(147,368	)

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(1) The statutory federal tax rate was 35% for the years ended December 31, 2017, 2016 and 2015.

(2) Amount is primarily attributable to stock-based compensation.