(5) Income Taxes

Income tax expense for the years ended December 31 is as follows:

	2013		2012		2011

Current income tax expense	$	3,240	$	3,547	$	4,398
Deferred income tax expense		1,793		2,131		3,560


Income tax expense	$	5,033	$	5,678	$	7,958

A reconciliation of income taxes computed at the federal statutory rate to income tax expense for the years ended December 31 is as follows:

	2013						2012						2011

	Amount			Percent of Pretax Income			Amount			Percent of Pretax Income			Amount			Percent of Pretax Income
Income taxes computed at the federal statutory rate	$	6,942			35.0	%	$	7,735			35.0	%	$	10,550			35.0	%
(Reduction) increase in taxes resulting from:
Statutory depletion in excess of cost depletion		(1,965	)		(9.9	)		(2,048	)		(9.3	)		(2,366	)		(7.9	)
Manufacturing deduction		(299	)		(1.5	)		(335	)		(1.5	)		(308	)		(1.0	)
State income taxes, net of federal income tax benefit		132			0.7			331			1.5			24			0.1
Other		223			1.1			(5	)		(0.0	)		58			0.2


Income tax expense	$	5,033			25.4	%	$	5,678			25.7	%	$	7,958			26.4	%

Generally, US GAAP requires deferred tax assets to be reduced by a valuation allowance if, based on the weight of available evidence, it is "more likely than not" that some portion or all of the deferred tax assets will not be realized. US GAAP requires an assessment of all available evidence, both positive and negative, to determine the amount of any required valuation allowance.

Components of the Company's deferred tax liabilities and assets are as follows:

	December 31, 2013		December 31, 2012

Deferred tax liabilities
Lime and limestone property, plant and equipment	$	20,614	$	19,306
Natural gas interests drilling costs and equipment		3,680		3,952
Other		344		344


		24,638		23,602
Deferred tax assets
Alternative minimum tax credit carry forwards		5,866		6,489
Minimum pension liability		299		412
Fair value liability of interest rate hedges		557		956
Other		635		769


		7,357		8,626


Net deferred tax liabilities	$	17,281	$	14,976

Current income taxes are classified on the Company's Consolidated Balance Sheets as follows:


Accrued expenses	$	0	$	307
Prepaid expenses and other current assets	$	203	$	0

Deferred income taxes are classified on the Company's Consolidated Balance Sheets as follows:


Prepaid expenses and other current assets	$	518	$	678
Deferred tax liabilities, net	$	17,799	$	15,654

The Company had no federal net operating loss carry forwards at December 31, 2013. At December 31, 2013, the Company had determined that, because of its recent income history and expectations of income in the future, its deferred tax assets were fully realizable. The Company's federal income tax returns for the year ended December 31, 2010 and subsequent years remain subject to examination. The Company's income tax returns in certain state income tax jurisdictions remain subject to examination for various periods for the year ended December 31, 2010 and subsequent years. The Company treats interest and penalties on income tax liabilities as income taxes.