Income Taxes (Tables)

12 Months Ended

Dec. 31, 2016

Income Tax Disclosure [Abstract]

Summary of income tax benefit

Income tax benefit is summarized as follows:

	Year Ended December 31,
(In thousands)	2016			2015			2014
Current
Federal	$	(9,920	)	$	983		$	44,887
State	(1,848		)	(1,397		)	(4,387		)
	(11,768		)	(414		)	40,500
Deferred
Federal	(218,357		)	(72,869		)	(32,375		)
State	(12,350		)	(99		)	(80,192		)
	(230,707		)	(72,968		)	(112,567		)
Income tax benefit	$	(242,475	)	$	(73,382	)	$	(72,067	)

Schedule of reconciliation of actual provision for income taxes and provision for income taxes computed by applying the statutory federal income tax rate

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

	Year Ended December 31,
	2016					2015					2014
(In thousands, except rates)	Amount			Rate		Amount			Rate		Amount			Rate
Computed "expected" federal income tax	$	(230,860	)	35.00	%	$	(65,546	)	35.00	%	$	11,341		35.00	%
State income tax, net of federal income tax benefit	(10,888		)	1.65	%	(3,152		)	1.68	%	903			2.79	%
Deferred tax adjustment related to change in overall state tax rate	(663		)	0.10	%	2,822			(1.51	)%	(86,956		)	(268.36	)%
Valuation allowance	221			(0.03	)%	187			(0.10	)%	3,977			12.27	%
Uncertain tax positions	—			—	%	—			—	%	(1,974		)	(6.09	)%
Provision to return adjustments	(121		)	0.02	%	(6,326		)	3.38	%	(791		)	(2.44	)%
Other, net	(164		)	0.02	%	(1,367		)	0.73	%	1,433			4.42	%
Income tax benefit	$	(242,475	)	36.76	%	$	(73,382	)	39.18	%	$	(72,067	)	(222.41	)%

Schedule of deferred tax liabilities and deferred tax assets

The composition of net deferred tax liabilities is as follows:

	December 31,
(In thousands)	2016			2015
Deferred Tax Assets
Net operating losses	$	352,001		$	223,402
Alternative minimum tax credits	218,773			228,693
Foreign tax credits	3,816			3,837
Derivative instruments	13,771			—
Incentive compensation	22,852			22,509
Deferred compensation	8,217			7,869
Post-retirement benefits	13,865			13,556
Other	2,743			2,905
Less: valuation allowance	(5,186		)	(4,965		)
Total	630,852			497,806
Deferred Tax Liabilities
Properties and equipment	1,207,545			1,303,840
Equity method investments	2,754			1,202
Total	1,210,299			1,305,042
Net deferred tax liabilities	$	579,447		$	807,236

Schedule of reconciliation of the beginning and ending amounts of unrecognized tax benefits

A reconciliation of unrecognized tax benefits is as follows:

	Year Ended December 31,
(In thousands)	2016		2015		2014
Balance at beginning of year	$	663	$	663	$	3,700
Additions based on tax provisions related to the current year	—		—		—
Additions for tax positions of prior years	—		—		—
Reductions for tax positions of prior years	—		—		(3,037		)
Settlements	—		—		—
Balance at end of year	$	663	$	663	$	663