Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Components of income before income taxes

The components of income before income taxes from continuing operations for each of the years ended December 31 were as follows:

	2018			2017			2016
	(In thousands)
United States	$	317,655		$	350,064		$	326,252
Foreign	(784		)	(37		)	(24		)
Income before income taxes from continuing operations	$	316,871		$	350,027		$	326,228

Income tax expense

Income tax expense (benefit) from continuing operations for the years ended December 31 was as follows:

	2018			2017			2016
	(In thousands)
Current:
Federal	$	(15,901	)	$	74,272		$	81,989
State	3,651			16,192			13,190
Foreign	—			—			2
	(12,250		)	90,464			95,181
Deferred:
Income taxes:
Federal	50,755			(24,497		)	(2,102		)
State	7,206			(864		)	1,184
Investment tax credit - net	1,774			(62		)	(1,131		)
	59,735			(25,423		)	(2,049		)
Total income tax expense	$	47,485		$	65,041		$	93,132

Deferred tax assets and deferred tax liabilities

Components of deferred tax assets and deferred tax liabilities at December 31 were as follows:

	2018		2017
	(In thousands)
Deferred tax assets:
Postretirement	$	51,930	$	55,736
Compensation-related	29,885		16,298
Alternative minimum tax credit carryforward	13,404		37,683
Federal renewable energy credit	8,015		19,367
Customer advances	7,734		8,712
Asset retirement obligations	7,083		6,380
Legal and environmental contingencies	6,729		7,363
Other	37,347		35,738
Total deferred tax assets	162,127		187,277
Deferred tax liabilities:
Depreciation and basis differences on property, plant and equipment	476,832		429,577
Postretirement	44,432		43,505
Intangible asset amortization	17,752		16,979
Other	39,712		32,591
Total deferred tax liabilities	578,728		522,652
Valuation allowance	13,484		11,896
Net deferred income tax liability	$	430,085	$	347,271

Schedule of change in net deferred income tax liability reconciliation

The following table reconciles the change in the net deferred income tax liability from December 31, 2017, to December 31, 2018, to deferred income tax expense:

	2018
(In thousands)
Change in net deferred income tax liability from the preceding table	$	82,814
Deferred taxes associated with other comprehensive income	(2,679		)
Deferred taxes associated with TCJA enactment for regulated activities	(13,776		)
Deferred taxes associated with acquisitions	(5,565		)
Other	(1,059		)
Deferred income tax expense for the period	$	59,735

Reconciliation of income tax expense (benefit) at statutory federal rate versus actual rate

Total income tax expense differs from the amount computed by applying the statutory federal income tax rate to income before taxes. The reasons for this difference were as follows:

Years ended December 31,	2018					2017					2016
	Amount			%		Amount			%		Amount			%
	(Dollars in thousands)
Computed tax at federal statutory rate	$	66,543		21.0		$	122,509		35.0		$	114,179		35.0
Increases (reductions) resulting from:
State income taxes, net of federal income tax	12,190			3.8		10,724			3.1		9,027			2.8
Federal renewable energy credit	(11,759		)	(3.7	)	(13,958		)	(4.0	)	(13,544		)	(4.2	)
Tax compliance and uncertain tax positions	(2,725		)	(.9	)	(643		)	(.2	)	(3,028		)	(.9	)
Domestic production deduction	—			—		(6,849		)	(2.0	)	(6,251		)	(1.9	)
Excess deferred income tax amortization	(9,319		)	(2.9	)	(397		)	—		(828		)	(.2	)
TCJA revaluation	(5,947		)	(1.9	)	(47,242		)	(13.5	)	—			—
TCJA revaluation related to accumulated other comprehensive loss balance	(42		)	—		7,735			2.2		—			—
Other	(1,456		)	(.4	)	(6,838		)	(2.0	)	(6,423		)	(2.1	)
Total income tax expense	$	47,485		15.0		$	65,041		18.6		$	93,132		28.5

Reconciliation of unrecognized tax benefits (excluding interest)

A reconciliation of unrecognized tax benefits (excluding interest) for the years ended December 31 was as follows:

	2018		2017		2016
	(In thousands)
Balance at beginning of year	$	—	$	—	$	—
Additions based on tax positions related to current year	120		—		—
Additions for tax positions of prior years	262		—		—
Balance at end of year	$	382	$	—	$	—