Income Taxes (Tables)

12 Months Ended

Dec. 31, 2019

Income Tax Disclosure [Abstract]

Schedule of components of provision for income taxes [Table Text Block]

The provision for income taxes consists of the following:

	For the Years Ended December 31,
	2019			2018			2017
	(in thousands)
Current portion of income tax expense (benefit)
Federal	$	(3,826	)	$	—		$	5,698
State	1,618			1,662			3,398
Deferred portion of income tax expense (benefit)	(41,835		)	141,708			(192,066		)
Income tax expense (benefit)	$	(44,043	)	$	143,370		$	(182,970	)
Effective tax rate	19.1		%	22.0		%	53.2		%

Schedule of components of net deferred income tax liabilities [Table Text Block]

The components of the net deferred tax liabilities are as follows:

	As of December 31,
	2019			2018
	(in thousands)
Deferred tax liabilities
Oil and gas properties	$	205,028		$	218,094
Derivative assets	4,646			35,247
Other	12,361			4,812
Total deferred tax liabilities	222,035			258,153
Deferred tax assets
Credit carryover	11,270			22,554
Pension	5,971			6,427
Federal and state tax net operating loss carryovers	4,172			4,217
Stock compensation	3,503			3,263
Other liabilities	10,803			1,497
Total deferred tax assets	35,719			37,958
Valuation allowance	(3,070		)	(3,083		)
Net deferred tax assets	32,649			34,875
Total net deferred tax liabilities	$	189,386		$	223,278
Current federal income tax refundable	$	3,885		$	59
Current state income tax payable	$	1,404		$	1,331

Schedule of effective income tax rate reconciliation [Table Text Block]

Recorded income tax expense or benefit differs from the amount that would be provided by applying the statutory United States federal income tax rate to income before income taxes. These differences primarily relate to the effect of state income taxes, excess tax benefits and deficiencies from stock-based compensation awards, tax limitations on compensation of covered individuals, changes in valuation allowances, and the cumulative impact of other smaller permanent differences, and is reported as follows:

	For the Years Ended December 31,
	2019			2018		2017
	(in thousands)
Federal statutory tax expense (benefit)	$	(48,519	)	$	136,873	$	(120,335	)
Increase (decrease) in tax resulting from:
Federal tax reform changes - 2017 Tax Act	—			—		(63,675		)
State tax expense (benefit) (net of federal benefit)	260			2,771		(3,286		)
Change in valuation allowance	(13		)	105		(2,727		)
Employee share-based compensation	3,346			2,508		8,190
Other	883			1,113		(1,137		)
Income tax expense (benefit)	$	(44,043	)	$	143,370	$	(182,970	)