8. Income Taxes

The components of the provision (benefit) for income taxes for the years ended December 31, 2017 and 2016 are as follows:


	Year Ended December 31,
(Thousands of dollars)	2017			2016
Current:
Federal	$	4,522		$	1,789
State		262			164

Total current		4,784			1,953
Deferred:
Federal		(13,226	)		117
State		689			30

Total deferred		(12,537	)		147

Total income tax provision (benefit)	$	(7,753	)	$	2,100


	At December 31,
(Thousands of dollars)	2017		2016
Deferred Tax Assets:
Accrued liabilities	$	349	$	550
Allowance for doubtful accounts		22		152
Derivative Contracts		684		1,273
Alternative minimum tax credits		9,919		6,612
Net operating loss carry-forwards		528		586
Percentage depletion carry-forwards		727		3,025

Total deferred tax assets		12,229		12,198
Deferred Tax Liabilities:
Basis differences relating to managed partnerships		3,193		6,211
Depletion and depreciation		33,998		43,487

Total deferred tax liabilities		37,191		49,698

Net deferred tax liabilities	$	24,962	$	37,500

The total provision for income taxes for the years ended December 31, 2017 and 2016 varies from the federal statutory tax rate as a result of the following:


	Year Ended December 31,
(Thousands of dollars)	2017			2016
Expected tax expense	$	11,643		$	1,885
Revaluation of deferred tax attributes		(20,204	)		—
State income tax, net of federal benefit		717			194
Percentage depletion		(89	)		(84	)
IRS settlement		—			75
Other, net		180			30

Total income tax provision (benefit)	$	(7,753	)	$	2,100

Deferred income taxes reflect the impact of temporary differences between the amount of assets and liabilities recognized for financial reporting purposes and such amounts recognized for tax purposes.

On December 22, 2017, the U.S. enacted into law the Tax Cuts and Jobs Act (“2017 Tax Act”). For the year ended December 31, 2017, the Company recorded a tax benefit of $20.204 million directly related to the effect of the 2017 Tax Act, based on the remeasurement of deferred tax assets and liabilities at the lower corporate tax rate.

The Company has $9.918 million in alternative minimum tax (“AMT”) credits at December 31, 2017. Under the 2017 Tax Act, the Company may fully offset any regular tax liability in future years. In addition, a portion of the minimum tax credit which exceeds the regular tax liability is refundable in future years. The refundable portion is 50% of any excess credit in the years 2018 through 2020 and 100% in 2021. The Company will therefore expect to receive credits against regular tax and refunds of previously paid taxes in the amount of $9.918 million over the next four years.

The Company is entitled to percentage depletion on certain of its wells, which is calculated without reference to the basis of the property. To the extent that such depletion exceeds a property’s basis, it creates a permanent difference, which lowers the Company’s effective rate.

The Company is allowed a credit against the Texas Franchise Tax based on net operating losses incurred in prior periods. The credits allowed are $89 thousand in the years 2018 through 2026. Any credits not utilized in a given year due to the allowable credit exceeding the tax liability may be carried forward. No credit may be carried forward past 2026. The value of the credit is calculated net of the federal income tax effect.

In 2016, the Company paid $75 thousand in settlement of an audit of its 2014 federal income tax return.

The Company has not recorded any provision for uncertain tax positions. The Company files income tax returns in the U.S. federal jurisdiction and various state and local jurisdictions. The 2004, 2005, 2006, 2009 and 2014 federal income tax returns have been audited by the Internal Revenue Service. The 2015 through 2017 returns are currently open for examination by the IRS. Returns for unexamined earlier years may be examined and adjustments made to the amount of percentage depletion and AMT credit carryforwards flowing from those years into an open tax year, although in general no assessment of income tax may be made for those years on which the statute has closed. State returns for the years 2014 through 2017 remain open for examination by the relevant taxing authorities.