Senior Unsecured Notes (Details) - USD ($) $ in Thousands				3 Months Ended			6 Months Ended
		Jun. 30, 2020	Jun. 17, 2020	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Senior Unsecured Notes [Line Items]
Repayment of 1.50% Senior Convertible Notes due 2021							$ 53,508	$ 0
Gain on Extinguishment of Debt, Non Cash Portion							292,984	0
Gain on extinguishment of debt				$ 227,281		$ 0	239,476	$ 0
Senior Unsecured Notes [Member]
Senior Unsecured Notes [Line Items]
Senior Unsecured Notes, exchanged or repurchased face amount			$ 611,900
Debt Instrument, Redemption Price, Percentage		80.00%
Senior Notes, Principal amount		$ 1,824,151		1,824,151			1,824,151		$ 2,649,296
Senior Unsecured Notes, unamortized deferred financing costs		16,315		16,315			16,315		38,998
Senior Unsecured Notes, Principal Amount, Net		$ 1,807,836		$ 1,807,836			$ 1,807,836		2,610,298
Interest Paid, Senior Unsecured Notes, Accrued and Unpaid			8,100
Senior Unsecured Notes [Member] | Accelerated unamortized deferred financing costs [Member]
Senior Unsecured Notes [Line Items]
Gain on Extinguishment of Debt, Non Cash Portion			5,000
6.125% Senior Unsecured Notes due 2022 [Member]
Senior Unsecured Notes [Line Items]
Senior Notes, interest rate, stated percentage		6.125%		6.125%			6.125%
Senior Unsecured Notes, exchanged or repurchased face amount			141,701		$ 40,700
Senior Notes, Principal amount		$ 294,346		$ 294,346			$ 294,346		476,796
Senior Unsecured Notes, unamortized deferred financing costs		1,494		1,494			1,494		2,920
Senior Unsecured Notes, Principal Amount, Net		$ 292,852		$ 292,852			$ 292,852		473,876
Senior Unsecured Notes, repurchased settlement amount					28,300
Gain on extinguishment of debt					12,200
Discount realized on extinguishment of debt					12,400
6.125% Senior Unsecured Notes due 2022 [Member] | Accelerated unamortized deferred financing costs [Member]
Senior Unsecured Notes [Line Items]
Gain on Extinguishment of Debt, Non Cash Portion					$ 235
5.0% Senior Unsecured Notes due 2024 [Member]
Senior Unsecured Notes [Line Items]
Senior Notes, interest rate, stated percentage		5.00%		5.00%			5.00%
Senior Unsecured Notes, exchanged or repurchased face amount			155,339
Senior Notes, Principal amount		$ 344,661		$ 344,661			$ 344,661		500,000
Senior Unsecured Notes, unamortized deferred financing costs		2,278		2,278			2,278		3,766
Senior Unsecured Notes, Principal Amount, Net		$ 342,383		$ 342,383			$ 342,383		496,234
5.625% Senior Unsecured Notes due 2025 [Member]
Senior Unsecured Notes [Line Items]
Senior Notes, interest rate, stated percentage		5.625%		5.625%			5.625%
Senior Unsecured Notes, exchanged or repurchased face amount			150,882
Senior Notes, Principal amount		$ 349,118		$ 349,118			$ 349,118		500,000
Senior Unsecured Notes, unamortized deferred financing costs		3,108		3,108			3,108		4,903
Senior Unsecured Notes, Principal Amount, Net		$ 346,010		$ 346,010			$ 346,010		495,097
6.75% Senior Unsecured Notes due 2026 [Member]
Senior Unsecured Notes [Line Items]
Senior Notes, interest rate, stated percentage		6.75%		6.75%			6.75%
Senior Unsecured Notes, exchanged or repurchased face amount			80,765
Senior Notes, Principal amount		$ 419,235		$ 419,235			$ 419,235		500,000
Senior Unsecured Notes, unamortized deferred financing costs		4,321		4,321			4,321		5,571
Senior Unsecured Notes, Principal Amount, Net		$ 414,914		$ 414,914			$ 414,914		494,429
6.625% Senior Unsecured Notes due 2027 [Member]
Senior Unsecured Notes [Line Items]
Senior Notes, interest rate, stated percentage		6.625%		6.625%			6.625%
Senior Unsecured Notes, exchanged or repurchased face amount			$ 83,209
Senior Notes, Principal amount		$ 416,791		$ 416,791			$ 416,791		500,000
Senior Unsecured Notes, unamortized deferred financing costs		5,114		5,114			5,114		6,601
Senior Unsecured Notes, Principal Amount, Net		$ 411,677		$ 411,677			$ 411,677		493,399
1.50% Senior Unsecured Convertible Notes Due 2021 [Member]
Senior Unsecured Notes [Line Items]
Senior Notes, interest rate, stated percentage		1.50%	1.50%	1.50%			1.50%
Senior Unsecured Notes, exchanged or repurchased face amount			$ 107,015
Repayment of 1.50% Senior Convertible Notes due 2021			53,500
Senior Notes, Principal amount	[1],[2]	$ 0		$ 0			$ 0		172,500
Senior Unsecured Notes, unamortized deferred financing costs	[2]	0		0			0		15,237	[3]
1.50% Senior Unsecured Convertible Notes due 2021, Unamortized Debt Discount									(13,900)
Senior Unsecured Notes, Principal Amount, Net	[2]	$ 0		$ 0			$ 0		$ 157,263
Interest Paid, Senior Unsecured Notes, Accrued and Unpaid			740
1.50% Senior Unsecured Convertible Notes Due 2021 [Member] | Accelerated unamortized deferred financing costs [Member]
Senior Unsecured Notes [Line Items]
Gain on Extinguishment of Debt, Non Cash Portion			593
1.50% Senior Unsecured Convertible Notes Due 2021 [Member] | Accelerated unamortized debt discount [Member]
Senior Unsecured Notes [Line Items]
Gain on Extinguishment of Debt, Non Cash Portion			6,100
Senior Unsecured Notes and 1.50% Senior Unsecured Convertible Notes due 2021
Senior Unsecured Notes [Line Items]
Senior Unsecured Notes, exchanged or repurchased face amount			$ 718,911

[1] ⁽¹⁾ The Company’s 2021 Senior Convertible Notes became secured in the second quarter of 2020 upon closing of the Exchange Offers. Please refer to Note 5 - Long-Term Debt for additional information.

[2] ⁽²⁾ As discussed above, as required by the 2021 Notes Indenture and as permitted by the Credit Agreement, as the Company issued Permitted Second Lien Debt upon the closing of the Exchange Offers, its remaining 2021 Senior Convertible Notes contemporaneously became secured.

[3] ⁽¹⁾ Unamortized deferred financing costs attributable to the 2021 Senior Convertible Notes include $13.9 million related to the unamortized debt discount as of December 31, 2019.