Income Taxes (Tables)

12 Months Ended

Dec. 31, 2019

Income Tax Disclosure [Abstract]

Summary of Income Tax Expense (Benefit)

Income tax expense (benefit) is summarized as follows:

	Year Ended December 31,
(In thousands)	2019			2018			2017
Current
Federal	$	(29,584	)	$	(95,191	)	$	(9,531	)
State	4,320			6,682			1,816
	(25,264		)	(88,509		)	(7,715		)
Deferred
Federal	233,136			230,643			(313,938		)
State	11,282			(1,040		)	(7,175		)
	244,418			229,603			(321,113		)
Income tax expense (benefit)	$	219,154		$	141,094		$	(328,828	)

Schedule of Reconciliation of Income Tax Expense (Benefit) Computed by Applying Statutory Federal Income Tax Rate

Income tax expense (benefit) was different than the amounts computed by applying the statutory federal income tax rate as follows:

	Year Ended December 31,
	2019					2018					2017
(In thousands, except rates)	Amount			Rate		Amount			Rate		Amount			Rate
Computed "expected" federal income tax	$	189,047		21.00	%	$	146,609		21.00	%	$	(79,952	)	35.00	%
State income tax, net of federal income tax benefit	14,773			1.64	%	11,850			1.70	%	(4,239		)	1.86	%
Deferred tax adjustment related to change in overall state tax rate	(660		)	(0.07	)%	(15,208		)	(2.18	)%	(48		)	0.02	%
Valuation allowance	17,676			1.96	%	8,975			1.29	%	(505		)	0.22	%
Provision to return adjustments	(1,966		)	(0.22	)%	(1,773		)	(0.25	)%	(3,242		)	1.42	%
Excess stock compensation	(918		)	(0.10	)%	327			0.05	%	2,965			(1.30	)%
Tax Act	—			—	%	(11,367		)	(1.63	)%	(242,875		)	106.32	%
Other, net	1,202			0.13	%	1,681			0.24	%	(932		)	0.41	%
Income tax expense (benefit)	$	219,154		24.34	%	$	141,094		20.21	%	$	(328,828	)	143.95	%

Schedule of Composition of Net Deferred Tax Liabilities

The composition of net deferred tax liabilities is as follows:

	December 31,
(In thousands)	2019			2018
Deferred Tax Assets
Net operating losses	$	22,360		$	56,769
Alternative minimum tax credits	22,120			114,149
Foreign tax credits	—			3,473
Other business credits	—			3,380
Incentive compensation	17,776			17,378
Deferred compensation	5,463			5,690
Post-retirement benefits	7,847			6,799
Equity method investments	21,454			20,746
Capital loss carryforward	—			8,877
Other	1,336			2,957
Less: valuation allowance	(31,763		)	(14,943		)
Total	66,593			225,275
Deferred Tax Liabilities
Properties and equipment	768,692			670,704
Derivative instruments	5			13,168
Total	768,697			683,872
Net deferred tax liabilities	$	702,104		$	458,597

Schedule of Reconciliation of Unrecognized Tax Benefits

A reconciliation of unrecognized tax benefits is as follows:

	Year Ended December 31,
(In thousands)	2019			2018		2017
Balance at beginning of year	$	16,850		$	663	$	663
Additions for tax positions of prior years	—			16,187		—
Reductions for tax positions of prior years	(16,330		)	—		—
Balance at end of year	$	520		$	16,850	$	663