Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Components of Income Tax Expense (Benefit)

Components of income tax expense (benefit) were as follows (in thousands):

	Year Ended December 31,
	2018		2017			2016
Current	$	35	$	(12,786	)	$	(71,768	)
Deferred		500		217			28,392
Total income tax expense (benefit)	$	535	$	(12,569	)	$	(43,376	)

Reconciliation of Income Taxes Computed to Income Tax Expense (Benefit)

The reconciliation of income taxes computed at the U.S. federal statutory tax rate to our income tax expense (benefit) is as follows (in thousands, except percentages):

	Year Ended December 31,
	2018					2017						2016
Income tax expense (benefit) at the federal    statutory rate	$	52,366		21.0	%	$	23,490			35.0	%	$	(102,339	)	35.0	%
Compensation adjustments		457		0.2			664			1.0			4,920		(1.7	)
State income taxes		560		0.2			63			0.1			(755	)	0.2
Debt restructuring cost		—		—			18			—			1,463		(0.5	)
Impact of U.S. tax reform		487		0.2			105,933			157.8			—		—
Gain on exchange of debt		—		—			(24,981	)		(37.2	)		—		—
Valuation allowance		(53,980	)	(21.7	)		(118,643	)		(176.8	)		52,915		(18.1	)
Other		645		0.3			887			1.4			420		(0.1	)
Total income tax expense (benefit)	$	535		0.2	%	$	(12,569	)	(18.7		%)	$	(43,376	)	14.8	%

Significant Components of Deferred Tax Assets and Liabilities

Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes.  Significant components of our deferred tax assets and liabilities were as follows (in thousands):

	December 31,
	2018			2017
Deferred tax liabilities:
Derivatives	$	11,139		$	—
Investment in non-consolidated entity		6,875			—
Other		812			695
Total deferred tax liabilities		18,826			695
Deferred tax assets:
Property and equipment		3,934			18,234
Asset retirement obligations		65,811			63,755
Federal net operating losses		10,039			18,988
State net operating losses		7,133			7,126
Interest expense carryover		41,814			—
Exchange transaction		—			55,807
Share-based compensation		583			1,335
Valuation allowance		(117,764	)		(171,547	)
Other		7,091			6,805
Total deferred tax assets		18,641			503
Net deferred tax liabilities	$	(185	)	$	(192	)

Net Operating Loss, Interest and Tax Credit Carryovers

The table below presents the details of our net operating loss and tax credit carryovers as of December 31, 2018 (in thousands):

	Amount		Expiration Year
Federal net operating loss	$	47,804	N/A
State net operating losses		117,835	2025-2036
Interest limitation carryover		197,049	N/A

Balances in Uncertain Tax Positions

Balances in the uncertain tax positions are as follows (in thousands):

	December 31,
	2018		2017
Balance, beginning and end of period	$	9,482	$	9,482