(5) Income Taxes

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

	2014		2013		2012
Current income tax expense	$	5,282	$	3,240	$	3,547
Deferred income tax expense		1,273		1,793		2,131

Income tax expense	$	6,555	$	5,033	$	5,678

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

	2014						2013						2012
	Amount			Percent of Pretax Income			Amount			Percent of Pretax Income			Amount			Percent of Pretax Income
Income taxes computed at the federal statutory rate	$	9,073			35.0	%	$	6,942			35.0	%	$	7,735			35.0	%
(Reduction) increase in taxes resulting from:
Statutory depletion in excess of cost depletion		(2,139	)		(8.2	)		(1,965	)		(9.9	)		(2,048	)		(9.3	)
Manufacturing deduction		(574	)		(2.2	)		(299	)		(1.5	)		(335	)		(1.5	)
State income taxes, net of federal income tax benefit		104			0.4			132			0.7			331			1.5
Other		91			0.3			223			1.1			(5	)		(0.0	)

Income tax expense	$	6,555			25.3	%	$	5,033			25.4	%	$	5,678			25.7	%

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, 2014		December 31, 2013
Deferred tax liabilities
Lime and limestone property, plant and equipment	$	20,089	$	20,614
Natural gas interests drilling costs and equipment		3,387		3,680
Other		292		344

		23,768		24,638
Deferred tax assets
Alternative minimum tax credit carry forwards		3,887		5,866
Minimum pension liability		346		299
Fair value liability of interest rate hedges		240		557
Other		470		635

		4,943		7,357

Net deferred tax liabilities	$	18,825	$	17,281

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

Prepaid expenses and other current assets

881

203

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

Prepaid expenses and other current assets		$	434		$	518
Deferred tax liabilities, net		$	19,259		$	17,799

The Company had no federal net operating loss carry forwards at December 31, 2014. At December 31, 2014, 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, 2011 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, 2011 and subsequent years. The Company treats interest and penalties on income tax liabilities as income tax expense.