6.	Income Taxes

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


	Years Ended December 31,
	2012			2011		2010
Deferred:
Federal	$	3,359		$	3,199	$	3,917
State		(21	)		289		183

Total deferred provision for income taxes	$	3,338		$	3,488	$	4,100

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,
	2012			2011			2010
Statutory tax at 34%	$	3,306		$	3,648		$	3,931
State taxes, net of federal impact		(21	)		289			184
Permanent differences(1)		53			(289	)		53
Other differences		—			(160	)		(68	)

Total	$	3,338		$	3,488		$	4,100

(1)	Amounts primarily relate to share-based compensation expense and stock option exercises.

Deferred tax assets and liabilities are the result of temporary differences between the financial statement carrying values and tax bases of assets and liabilities. Our net deferred tax assets and liabilities are recorded as a long-term liability of $48.6 million and $46.3 million at December 31, 2012 and 2011, respectively. At December 31, 2012, $531,000 of deferred taxes expected to be realized within one year were included in current liabilities. At December 31, 2011, $504,000 of deferred taxes expected to be realized within one year were included in current assets.

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


	Years Ended December 31,
	2012			2011
Deferred tax assets:
Net operating loss carryforwards	$	27,353		$	31,052
Unrealized loss on commodity derivatives		—			504
Other		542			866

Total deferred tax assets		27,895			32,422
Deferred tax liabilities:
Difference in depreciation, depletion and capitalization methods—oil and gas properties		(76,170	)		(78,174	)
Unrealized gain on commodity derivatives		(849	)		—

Total deferred tax liabilities		(77,019	)		(78,174	)

Net deferred tax liability	$	(49,124	)	$	(45,752	)

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


Expiration Dates	Amounts		Stock Option Adjustments		Total
2023	$	1,523	$	—	$	1,523
2024		1,082		—		1,082
2025		2,594		—		2,594
2026		1,683		—		1,683
2027		1,020		—		1,020
2028		1,308		—		1,308
2029		3,299		—		3,299
2030		12,605		750		13,355
2031		18,642		2,984		21,626
2032		34,673		1,043		35,716

Total	$	78,429	$	4,777	$	83,206

As of December 31, 2012, we had net operating loss carryfowards of approximately $83.2 million, of which approximately $4.8 million was generated from the benefit of stock options. When these benefits are realized, they will be credited to additional paid-in capital.