Note 4 - Income Taxes

Income tax (benefit) expense for the three months ended March 31, 2015, and 2014, differs from the amount that would be provided by applying the statutory United States federal income tax rate to income before income taxes primarily due to the effect of state income taxes, changes in valuation allowances, percentage depletion, research and development (“R&D”) credits, and other permanent differences. The quarterly rate can also be impacted by the proportional effects of forecasted net income as of each period end presented.

The provision for income taxes consists of the following:



	For the Three Months Ended March 31,
	2015			2014
	(in thousands)
Current portion of income tax expense:
Federal	$	—		$	—
State	274			489
Deferred portion of income tax (benefit) expense	(33,727		)	38,374
Total income tax (benefit) expense	$	(33,453	)	$	38,863
	38.7		%	37.2		%

A change in the Company’s effective tax rate between reported periods will generally reflect differences in its estimated highest marginal state tax rate due to changes in the composition of income from Company activities among various state tax jurisdictions. Cumulative effects of state rate changes are reflected in the period legislation is enacted.

The Company is generally no longer subject to United States federal or state income tax examinations by tax authorities for years before 2007. During the first quarter of 2015, as a result of its R&D credit settlement with the IRS Appeals Office in late 2014, the Company recorded an additional $2.0 million net R&D credit from a claim filed on an amended return. No R&D credit was recorded in 2014.