Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Income Taxes

Schedule of income tax (benefit) expense (in thousands)

	2018		2017		2016
Current income tax expense	$	1,863	$	5,407	$	5,087
Deferred income tax expense (benefit)		20		(7,612)		777
Income tax expense (benefit)	$	1,883	$	(2,205)	$	5,864

Schedule of reconciliation of income taxes computed at the federal statutory rate to income tax expense (in thousands)

	2018				2017				2016
			Percent of				Percent of				Percent of
			Pretax				Pretax				Pretax
	Amount		Income		Amount		Income		Amount		Income
Income taxes computed at the federal statutory rate	$	4,529	21.0	%	$	8,730	35.0	%	$	8,266	35.0	%
(Reduction) increase in taxes resulting from:
Benefit of reduced federal income tax rates		—	—			(7,447)	(29.9)			—	—
Statutory depletion in excess of cost depletion		(1,199)	(5.6)			(2,004)	(8.0)			(1,854)	(7.9)
Research and development tax credit		(1,775)	(8.2)			(1,433)	(5.7)			(167)	(0.7)
Manufacturing deduction		—	—			(674)	(2.7)			(666)	(2.8)
State income taxes, net of federal income tax benefit		178	0.8			235	0.9			202	0.9
Other		150	0.7			388	1.6			83	0.3
Income tax expense (benefit)	$	1,883	8.7	%	$	(2,205)	(8.8)	%	$	5,864	24.8	%

Summary of the Company's deferred tax liabilities and assets (in thousands)

	December 31,		December 31,
	2018		2017
Deferred tax liabilities
Lime and limestone property, plant and equipment	$	11,219	$	11,023
Fair value liability of foreign exchange hedges		—		26
Natural gas interests drilling costs and equipment		1,475		1,622
		12,694		12,671
Deferred tax assets
Fair value liability of foreign exchange hedges		3		—
Other		326		297
		329		297
Deferred tax liabilities, net	$	12,365	$	12,374

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

Prepaid expenses and other current assets	$	—	$	1,394
Accrued expenses	$	54	$	—