Income Taxes (Tables)

Our provision for income taxes comprised the following (in thousands):

	Years Ended December 31,
	2017			2016			2015
Current:
Federal	$	(66	)	$	—		$	(265	)
State		—			—			—
Total current provision for income taxes	$	(66	)	$	—		$	(265	)
Deferred:
Federal	$	75,341		$	(24,957	)	$	(91,716	)
State		1,146			539			(1,424	)
Total deferred provision for income taxes	$	76,487		$	(24,418	)	$	(93,140	)

Total income tax expense differed from the amounts computed by applying the U.S. Federal statutory tax rates to pre-tax income (in thousands):

	Years Ended December 31,
	2017			2016			2015
Statutory tax at 35%	$	(12,578	)	$	(26,831	)	$	(93,628	)
State taxes, net of federal impact		528			578			(1,463	)
Share-based compensation tax shortfall		1,279			1,826			1,939
Permanent differences		11			11			26
Other differences		30			(2	)		(1,035	)
Change in federal tax rate		(51,939	)		—			—
Write-off of deferred tax assets		139,090			—			756
Total	$	76,421		$	(24,418	)	$	(93,405	)

Significant components of net deferred tax assets and liabilities are (in thousands):

	Years Ended December 31,
	2017			2016
Deferred tax assets:
Net operating loss carryforwards	$	39,991		$	155,018
Derivative liabilities		471			1,732
Other		533			892
Total deferred tax assets		40,995			157,642
Deferred tax liabilities:
Difference in depreciation, depletion and capitalization methods — oil and gas properties		(122,335	)		(162,501	)
Derivative assets		(302	)		—
Total deferred tax liabilities		(122,637	)		(162,501	)
Valuation allowance		(460	)		(756	)
Net deferred tax liability	$	(82,102	)	$	(5,615	)