Long-Term Debt (Tables)

6 Months Ended

Jun. 30, 2017

Debt Disclosure [Abstract]

Schedule of Line of Credit 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 July 26, 2017, June 30, 2017, and December 31, 2016:

	As of July 26, 2017		As of June 30, 2017		As of December 31, 2016
	(in thousands)
Credit facility balance (1)	$	—	$	—	$	—
Letters of credit (2)	200		200		200
Available borrowing capacity	924,800		924,800		1,164,800
Total aggregate lender commitment amount	$	925,000	$	925,000	$	1,165,000

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⁽¹⁾  Unamortized deferred financing costs attributable to the credit facility are presented as a component of other noncurrent assets on the accompanying balance sheets and totaled $3.9 million and $5.9 million as of June 30, 2017, and December 31, 2016, respectively.

⁽²⁾  Letters of credit outstanding reduce the amount available under the credit facility on a dollar-for-dollar basis.

Schedule of Long-term Debt Instruments [Table Text Block]

The Senior Notes, net of unamortized deferred financing costs line on the accompanying balance sheets as of June 30, 2017, and December 31, 2016, consisted of the following:

	As of June 30, 2017						As of December 31, 2016
	Principal Amount		Unamortized Deferred Financing Costs		Senior Notes, Net of Unamortized Deferred Financing Costs		Principal Amount		Unamortized Deferred Financing Costs		Senior Notes, Net of Unamortized Deferred Financing Costs
	(in thousands)
6.50% Senior Notes due 2021 (1) (2)	$	344,611	$	3,003	$	341,608	$	346,955	$	3,372	$	343,583
6.125% Senior Notes due 2022 (2)	561,796		6,390		555,406		561,796		6,979		554,817
6.50% Senior Notes due 2023 (2)	394,985		4,071		390,914		394,985		4,436		390,549
5.0% Senior Notes due 2024	500,000		6,072		493,928		500,000		6,533		493,467
5.625% Senior Notes due 2025	500,000		7,166		492,834		500,000		7,619		492,381
6.75% Senior Notes due 2026	500,000		7,660		492,340		500,000		8,078		491,922
Total	$	2,801,392	$	34,362	$	2,767,030	$	2,803,736	$	37,017	$	2,766,719

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⁽¹⁾  During the first quarter of 2017, the Company repurchased a total of $2.3 million in aggregate principal amount of 6.50% Senior Notes due 2021 in open market transactions at a slight premium. The Company canceled all of these repurchased Senior Notes upon cash settlement.

⁽²⁾  During the first quarter of 2016, the Company repurchased a total of $46.3 million in aggregate principal amount of certain of its Senior Notes in open market transactions for a settlement amount of $29.9 million, excluding interest. The Company recorded a net gain on extinguishment of debt of approximately $15.7 million for the six months ended June 30, 2016. This amount includes a gain of approximately $16.4 million associated with the discount realized upon repurchase, which was partially offset by approximately $0.7 million related to the acceleration of unamortized deferred financing costs. The Company canceled all of these repurchased Senior Notes upon cash settlement.

Convertible Debt [Table Text Block]

The net carrying amount of the liability component of the Senior Convertible Notes, as reflected on the accompanying balance sheets as of June 30, 2017, and December 31, 2016, consisted of the following:

	As of June 30, 2017			As of December 31, 2016
	(in thousands)
Principal amount of Senior Convertible Notes	$	172,500		$	172,500
Unamortized debt discount	(33,913		)	(37,513		)
Unamortized deferred financing costs	(3,669		)	(4,131		)
Net carrying amount	$	134,918		$	130,856