6.	Income Taxes

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


	Years Ended December 31,
	2015			2014			2013
Current:
Federal	$	(265	)	$	(25	)	$	429
State		—			—			—

Total current provision for income taxes	$	(265	)	$	(25	)	$	429

Deferred:
Federal	$	(91,716	)	$	32,754		$	41,175
State		(1,424	)		963			903

Total deferred provision for income taxes	$	(93,140	)	$	33,717		$	42,078

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,
	2015			2014			2013
Statutory tax at 35%	$	(93,628	)	$	31,452		$	40,167
State taxes, net of federal impact		(1,463	)		989			709
Share-based compensation tax shortfall		1,939			1,670			—
Permanent differences		26			37			34
Other differences		(1,035	)		(456	)		1,597
Valuation allowance		756			—			—

Total	$	(93,405	)	$	33,692		$	42,507

In 2015 and 2014, the Company recorded a tax shortfall related to share-based compensation of $1.9 million and $1.7 million, respectively. This shortfall is for grants in which the realized tax deduction was less than the expense booked for these grants due to a decline in share price from the time of grant. Although we had excess tax benefits related to share-based compensation in prior years, this benefit was not recorded as the excess tax benefits were not realized due to our net operating loss carryforwards.

Deferred tax assets and liabilities are the result of temporary differences between the financial statement carrying values and tax basis of assets and liabilities. Our net deferred tax assets and liabilities are recorded as a long-term liability of $31.8 million and $110.7 million at December 31, 2015 and 2014, respectively. At December 31, 2014, $14.2 million of deferred taxes expected to be realized within one year were included in current liabilities.

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


	Years Ended December 31,
	2015			2014
Deferred tax assets:
Net operating loss carryforwards	$	88,230		$	46,730
Other		1,672			1,305

Total deferred tax assets		89,902			48,035
Deferred tax liabilities:
Difference in depreciation, depletion and capitalization methods — oil and gas properties		(118,534	)		(158,647	)
Unrealized gain on commodity derivatives		(2,391	)		(14,307	)

Total deferred tax liabilities		(120,925	)		(172,954	)
Valuation allowance		(756	)		—

Net deferred tax liability	$	(31,779	)	$	(124,919	)

Net operating loss carryforwards for tax purposes have the following expiration dates (in thousands):


Expiration Dates	Amounts		Stock Adjustments		Total
2030	$	4,083	$	750	$	4,833
2031		18,642		1,012		19,654
2032		51,931		2,724		54,655
2033		616		503		1,119
2034		56,511		—		56,511
2035		120,298		—		120,298

Total	$	252,081	$	4,989	$	257,070

As of December 31, 2015, we had net operating loss carryforwards of approximately $257.1 million, of which approximately $5 million was generated from the benefit of stock options. When these benefits are realized, they will be credited to additional paid-in capital.