Income Taxes (Tables)

12 Months Ended

Dec. 31, 2019

Income Taxes

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

	2019		2018		2017
Current income tax (benefit) expense	$	(4)	$	1,863	$	5,407
Deferred income tax expense (benefit)		4,848		20		(7,612)
Income tax expense (benefit)	$	4,844	$	1,883	$	(2,205)

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

	2019				2018				2017
			Percent of				Percent of				Percent of
			Pretax				Pretax				Pretax
	Amount		Income		Amount		Income		Amount		Income
Income taxes computed at the federal statutory rate	$	6,489	21.0	%	$	4,529	21.0	%	$	8,730	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		(1,200)	(3.9)			(1,199)	(5.6)			(2,004)	(8.0)
Research and development tax credits		(1,155)	(3.7)			(1,775)	(8.2)			(1,433)	(5.7)
Manufacturing deduction		—	—			—	—			(674)	(2.7)
State income taxes, net of federal income tax benefit		155	0.5			178	0.8			235	0.9
Other		555	1.8			150	0.7			388	1.6
Income tax expense (benefit)	$	4,844	15.7	%	$	1,883	8.7	%	$	(2,205)	(8.8)	%

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

	December 31,		December 31,
	2019		2018
Deferred tax liabilities
Lime and limestone property, plant and equipment	$	16,928	$	11,219
Operating lease right-of-use assets		735		—
Natural gas interests drilling costs and equipment		1,040		1,475
		18,703		12,694
Deferred tax assets
Fair value liability of foreign exchange hedges		—		3
Operating lease liabilities		728		—
Other		757		326
		1,485		329
Deferred tax liabilities, net	$	17,218	$	12,365

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

Prepaid expenses and other current assets	$	416	$	—
Accrued expenses	$	—	$	54