(5) Income Taxes

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


	2016		2015		2014
Current income tax expense	$	5,087	$	4,822	$	5,282
Deferred income tax expense (benefit)		777		(227)		1,273
Income tax expense	$	5,864	$	4,595	$	6,555

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


	2016				2015				2014
			Percent of				Percent of				Percent of
			Pretax				Pretax				Pretax
	Amount		Income		Amount		Income		Amount		Income
Income taxes computed at the federal statutory rate	$	8,266	35.0	%	$	6,118	35.0	%	$	9,073	35.0	%
(Reduction) increase in taxes resulting from:
Statutory depletion in excess of cost depletion		(1,854)	(7.9)			(1,708)	(9.8)			(2,139)	(8.2)
Manufacturing deduction		(666)	(2.8)			(548)	(3.1)			(574)	(2.2)
State income taxes, net of federal income tax benefit		202	0.9			309	1.8			104	0.4
Other		(84)	(0.4)			424	2.4			91	0.3
Income tax expense	$	5,864	24.8	%	$	4,595	26.3	%	$	6,555	25.3	%

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,		December 31,
	2016		2015
Deferred tax liabilities
Lime and limestone property, plant and equipment	$	17,907	$	18,833
Natural gas interests drilling costs and equipment		2,811		3,101
		20,718		21,934
Deferred tax assets
Alternative minimum tax credit carry forwards		296		2,259
Fair value liability of foreign exchange hedges		129		—
Other		461		491
		886		2,750
Deferred tax liabilities, net	$	19,832	$	19,184

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


Prepaid expenses and other current assets		$	75		$	286

The Company had no federal net operating loss carry forwards at December 31, 2016. Deferred tax assets are considered fully recognizable because of the Company’s recent income history and expectations of income in the future. The Company’s federal income tax returns for the year ended December 31, 2013 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, 2013 and subsequent years. The Company treats interest and penalties on income tax liabilities as income tax expense.