Long-Term Debt (Tables)

12 Months Ended

Dec. 31, 2019

Debt Disclosure [Abstract]

Borrowing Base Utilization Grid, Credit Facility [Table Text Block]

The borrowing base utilization grid as set forth in the Credit Agreement is as follows:

Borrowing Base Utilization Percentage	<25%		≥25% <50%		≥50% <75%		≥75% <90%		≥90%
Eurodollar Loans (1)	1.500	%	1.750	%	2.000	%	2.250	%	2.500	%
ABR Loans or Swingline Loans	0.500	%	0.750	%	1.000	%	1.250	%	1.500	%
Commitment Fee Rate	0.375	%	0.375	%	0.500	%	0.500	%	0.500	%

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⁽¹⁾ 

The Company’s Credit Agreement specifies that in the event that LIBOR is no longer a widely used benchmark rate, or that it shall no longer be used for determining interest rates for loans in the United States, a replacement interest rate that fairly reflects the cost to the lenders of funding loans shall be established by the Administrative Agent, as defined in the Credit Agreement, in consultation with the borrower.

Schedule of Credit Agreement Facilities [Table Text Block]

The following table presents the outstanding balance, total amount of letters of credit outstanding, and available borrowing capacity under the Credit Agreement as of February 6, 2020, December 31, 2019, and December 31, 2018:

	As of February 6, 2020		As of December 31, 2019		As of December 31, 2018
	(in thousands)
Revolving credit facility (1)	$	113,500	$	122,500	$	—
Letters of credit (2)	—		—		200
Available borrowing capacity	1,086,500		1,077,500		999,800
Total aggregate lender commitment amount	$	1,200,000	$	1,200,000	$	1,000,000

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⁽¹⁾  Unamortized deferred financing costs attributable to the revolving credit facility are presented as a component of the other noncurrent assets line item on the accompanying balance sheets and totaled $5.9 million and $6.4 million as of December 31, 2019, and 2018, respectively. These costs are being amortized over the term of the credit facility on a straight-line basis.

⁽²⁾ 

Letters of credit outstanding reduce the amount available under the credit facility on a dollar-for-dollar basis. The letter of credit outstanding as of December 31, 2018, was released effective January 8, 2019.

Schedule of Senior Notes [Table Text Block]

The Senior Notes, net of unamortized deferred financing costs line item on the accompanying balance sheets as of December 31, 2019, and 2018, consisted of the following:

	As of December 31,
	2019						2018
	Principal Amount		Unamortized Deferred Financing Costs		Principal Amount, Net of Unamortized Deferred Financing Costs		Principal Amount		Unamortized Deferred Financing Costs		Principal Amount, Net of Unamortized Deferred Financing Costs
	(in thousands)
6.125% Senior Notes due 2022	$	476,796	$	2,920	$	473,876	$	476,796	$	3,921	$	472,875
5.0% Senior Notes due 2024	500,000		3,766		496,234		500,000		4,688		495,312
5.625% Senior Notes due 2025	500,000		4,903		495,097		500,000		5,808		494,192
6.75% Senior Notes due 2026	500,000		5,571		494,429		500,000		6,407		493,593
6.625% Senior Notes due 2027	500,000		6,601		493,399		500,000		7,533		492,467
Total	$	2,476,796	$	23,761	$	2,453,035	$	2,476,796	$	28,357	$	2,448,439

Schedule of Senior Convertible Notes [Table Text Block]

The Senior Convertible Notes, net of unamortized discount and deferred financing costs line on the accompanying balance sheets consisted of the following as of December 31, 2019 and 2018:

	As of December 31,
	2019			2018
	(in thousands)
Principal amount of Senior Convertible Notes	$	172,500		$	172,500
Unamortized debt discount	(13,861		)	(22,313		)
Unamortized deferred financing costs	(1,376		)	(2,293		)
Senior Convertible Notes, net of unamortized discount and deferred financing costs	$	157,263		$	147,894