Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Provision for Income Taxes

The items comprising the Company's benefit for income taxes are as follows for the periods presented:

	Year ended December 31,
In thousands	2017			2016			2015
Current income tax (provision) benefit:
United States federal (1)	$	7,781		$	22,941		$	—
Various states	—			(2		)	(24		)
Total current income tax (provision) benefit	7,781			22,939			(24		)
Deferred income tax (provision) benefit:
United States federal - taxation on operations	(81,054		)	182,422			140,578
United States federal - effect of US tax reform	713,655			—			—
Various states	(7,002		)	27,414			40,863
Total deferred income tax benefit	625,599			209,836			181,441
Benefit for income taxes	$	633,380		$	232,775		$	181,417

Schedule of Provision for Income Taxes with Income Tax at Federal Statutory Rate

	Year ended December 31,
	2017					2016					2015
In thousands, except rates	Amount			Rate		Amount			Rate		Amount			Rate
Expected income tax (provision) benefit based on US statutory tax rate of 35%	$	(54,623	)	35.0	%	$	221,359		35.0	%	$	187,280		35.0	%
State income taxes, net of federal benefit	(4,682		)	3.0	%	18,829			3.0	%	16,219			3.0	%
Effect of US tax reform legislation	713,655			(457.3	%)	—			—	%	—			—	%
Tax deficiency from stock-based compensation (1)	(3,932		)	2.5	%	—			—	%	—			—	%
Canadian valuation allowance (2)	(404		)	0.3	%	(1,044		)	(0.2	%)	(13,503		)	(2.5	%)
Effect of differing statutory tax rate in Canada	(194		)	0.1	%	(481		)	(0.1	%)	(5,239		)	(1.0	%)
Non-deductible compensation	(13,813		)	8.9	%	(3,471		)	(0.5	%)	(1,488		)	(0.3	%)
Other, net	(2,627		)	1.7	%	(2,417		)	(0.4	%)	(1,852		)	(0.3	%)
Benefit for income taxes	$	633,380		(405.8	%)	$	232,775		36.8	%	$	181,417		33.9	%

Components of Deferred Tax Assets and Liabilities

The components of the Company’s deferred tax assets and deferred tax liabilities as of December 31, 2017 and 2016 are reflected in the table below.

	December 31,
In thousands	2017			2016
Deferred tax assets
United States net operating loss carryforwards	$	604,423		$	478,975
Canadian net operating loss carryforwards	19,341			18,936
Alternative minimum tax carryforwards	7,781			16,663
Equity compensation	12,962			32,924
Non-cash losses on derivatives	—			21,064
Other	21,885			11,466
Total deferred tax assets	666,392			580,028
Canadian valuation allowance	(19,341		)	(18,936		)
Total deferred tax assets, net of valuation allowance	647,051			561,092
Deferred tax liabilities
Property and equipment	(1,903,451		)	(2,448,450		)
Other	(3,158		)	(2,947		)
Total deferred tax liabilities	(1,906,609		)	(2,451,397		)
Deferred income tax liabilities, net	$	(1,259,558	)	$	(1,890,305	)