Long-Term Debt - Schedule of Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020
Debt Instrument [Line Items]
Long-term debt	$ 2,600,000	$ 2,900,000	$ 2,900,000
Debt issuance costs and debt discount	(30,165)	(45,336)	(47,249)
Long-term debt, net	2,569,835	2,854,664	2,852,751
Senior Notes | 2010 Senior Notes due October 2040
Debt Instrument [Line Items]
Long-term debt	250,000	250,000	250,000
Senior Notes | 2011 Senior Notes due November 2041
Debt Instrument [Line Items]
Long-term debt	300,000	300,000	300,000
Senior Notes | 2013 Senior Notes due March 2023
Debt Instrument [Line Items]
Long-term debt	250,000	250,000	250,000
Senior Notes | 2017/2018 Senior Notes due December 2025
Debt Instrument [Line Items]
Long-term debt	0	1,500,000	1,500,000
Senior Notes | 2019 Senior Notes due December 2027
Debt Instrument [Line Items]
Long-term debt	600,000	600,000	600,000
Senior Notes | 2021 Senior Notes due April 2026
Debt Instrument [Line Items]
Long-term debt	600,000	0	0
Senior Notes | 2021 Senior Notes due April 2029
Debt Instrument [Line Items]
Long-term debt	$ 600,000	$ 0	$ 0