Income Taxes (Tables)

12 Months Ended

Dec. 31, 2020

Income Tax Disclosure [Abstract]

Summary of Income Tax Expense (Benefit)

Income tax expense is summarized as follows:

	Year Ended December 31,
(In thousands)	2020		2019		2018
Current
Federal	$	(31,838)	$	(29,584)	$	(95,191)
State	655		4,320		6,682
	(31,183)		(25,264)		(88,509)
Deferred
Federal	67,451		233,136		230,643
State	4,326		11,282		(1,040)
	71,777		244,418		229,603
Income tax expense	$	40,594	$	219,154	$	141,094

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

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

	Year Ended December 31,
	2020				2019				2018
(In thousands, except rates)	Amount		Rate		Amount		Rate		Amount		Rate
Computed "expected" federal income tax	$	50,636	21.00	%	$	189,047	21.00	%	$	146,609	21.00	%
State income tax, net of federal income tax benefit	4,486		1.86	%	14,773		1.64	%	11,850		1.70	%
Deferred tax adjustment related to change in overall state tax rate	1,213		0.50	%	(660)		(0.07)	%	(15,208)		(2.18)	%
Valuation allowance	(3,800)		(1.58)	%	17,676		1.96	%	8,975		1.29	%
Excess executive compensation	5,249		2.18	%	1,935		0.21	%	1,382		0.20	%
Reserve on uncertain tax positions	5,964		2.47	%	5		—	%	—		—	%
Tax credits generated	(23,216)		(9.63)	%	—		—	%	—		—	%
Tax Act	—		—	%	—		—	%	(11,367)		(1.63)	%
Other, net	62		0.04	%	(3,622)		(0.40)	%	(1,147)		(0.16)	%
Income tax expense	$	40,594	16.84	%	$	219,154	24.34	%	$	141,094	20.21	%

Schedule of Composition of Net Deferred Tax Liabilities

The composition of net deferred tax liabilities is as follows:

	December 31,
(In thousands)	2020		2019
Deferred Tax Assets
Net operating losses	$	22,177	$	22,360
Alternative minimum tax credits	—		22,120
Incentive compensation	16,427		17,776
Deferred compensation	5,753		5,463
Post-retirement benefits	7,482		7,847
Equity method investments	—		21,454
Capital loss carryforward	16,486		—
Leases	7,709		8,192
Other	3,267		1,336
Less: valuation allowance	(28,231)		(31,763)
Total	51,070		74,785
Deferred Tax Liabilities
Properties and equipment	809,919		768,692
Equity method investments	1,649		—
Leases	7,709		8,192
Derivative instruments	5,988		5
Total	825,265		776,889
Net deferred tax liabilities	$	774,195	$	702,104

Schedule of Reconciliation of Unrecognized Tax Benefits

A reconciliation of unrecognized tax benefits is as follows:

	Year Ended December 31,
(In thousands)	2020		2019		2018
Balance at beginning of year	$	520	$	16,850	$	663
Additions for tax positions of current year	499		—		—
Additions for tax positions of prior years	5,465		—		16,187
Reductions for tax positions of prior years	—		(16,330)		—
Balance at end of year	$	6,484	$	520	$	16,850