Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Components of Income Tax Expense (Benefit)

The components of the Company’s income tax expense (benefit) are as follows:

years ended December 31 (add 000)	2018			2017			2016
Federal income taxes:
Current	$	15,285		$	129,236		$	97,975
Deferred		69,599			(239,304	)		68,899
Total federal income taxes		84,884			(110,068	)		166,874
State income taxes:
Current		5,986			14,843			15,189
Deferred		14,134			(882	)		(1,149	)
Total state income taxes		20,120			13,961			14,040
Foreign income taxes:
Current		(1,354	)		1,175			1,064
Deferred		2,055			475			(394	)
Total foreign income taxes		701			1,650			670
Income tax expense (benefit)	$	105,705		$	(94,457	)	$	181,584

Summary of Effective Income Tax Rate

The Company’s effective income tax rate varied from the statutory United States income tax rate because of the following tax differences:

years ended December 31	2018			2017			2016
Statutory income tax rate		21.0	%		35.0	%		35.0	%
(Reduction) increase resulting from:
Impact from 2017 Tax Act		(3.3	)		(41.7	)		—
Effect of statutory depletion		(3.4	)		(5.6	)		(5.4	)
State income taxes, net of federal tax benefit		2.8			1.5			1.5
Stock based compensation		(0.5	)		(1.0	)		(0.1	)
Domestic production deduction		—			(2.2	)		(2.0	)
Other items		1.7			(1.3	)		0.9
Effective income tax rate		18.3	%	(15.3%)				29.9	%

Components of Deferred Tax Assets and Liabilities

The principal components of the Company’s deferred tax assets and liabilities are as follows:

December 31	Deferred Assets (Liabilities)
(add 000)	2018			2017
Deferred tax assets related to:
Employee benefits	$	-		$	16,059
Inventories		52,618			56,242
Valuation and other reserves		22,359			22,989
Net operating loss carryforwards		10,990			11,780
Accumulated other comprehensive loss		84,207			80,116
Other items, net		3,052			3,963
Gross deferred tax assets		173,226			191,149
Valuation allowance on deferred tax assets		(8,604	)		(10,349	)
Total net deferred tax assets		164,622			180,800
Deferred tax liabilities related to:
Property, plant and equipment		(478,329	)		(407,400	)
Partnerships and joint ventures		(204,315	)		(15,617	)
Goodwill and other intangibles		(170,538	)		(168,506	)
Employee benefits		(17,004	)		-
Total deferred tax liabilities		(870,186	)		(591,523	)
Deferred income taxes, net	$	(705,564	)	$	(410,723	)

Schedule of Unrecognized Tax Benefits Excluding Interest Correlative Effects

The following table summarizes the Company’s unrecognized tax benefits, excluding interest and correlative effects:

years ended December 31 (add 000)	2018			2017			2016
Unrecognized tax benefits at beginning of year	$	22,367		$	21,807		$	18,727
Gross increases – tax positions in prior years		944			1,396			2,401
Gross decreases – tax positions in prior years		-			(672	)		(1,924	)
Gross increases – tax positions in current year		1,802			4,961			4,650
Gross decreases – tax positions in current year		(1,013	)		(946	)		(2,047	)
Lapse of statute of limitations		—			(4,179	)		—
Unrecognized tax benefits at end of year	$	24,100		$	22,367		$	21,807
Amount that, if recognized, would favorably impact the effective tax rate	$	12,820		$	10,399		$	11,603