Long-Term Debt (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019
Debt Instrument [Line Items]
Long-term debt	$ 2,900,000	$ 2,900,000	$ 2,900,000
Debt issuance costs and debt discount	(49,159)	(53,249)	(44,806)
Long-term debt	2,850,841	2,846,751	2,855,194
2010 Senior Notes due October 2020 \| Senior Notes
Debt Instrument [Line Items]
Long-term debt	0	0	250,000
2010 Senior Notes due October 2040 \| Senior Notes
Debt Instrument [Line Items]
Long-term debt	250,000	250,000	250,000
2011 Senior Notes due November 2041 \| Senior Notes
Debt Instrument [Line Items]
Long-term debt	300,000	300,000	300,000
2013 Senior Notes due March 2023 \| Senior Notes
Debt Instrument [Line Items]
Long-term debt	250,000	250,000	250,000
2016 Senior Notes due August 2021 \| Senior Notes
Debt Instrument [Line Items]
Long-term debt	0	0	350,000
2017/2018 Senior Notes due December 2025 \| Senior Notes
Debt Instrument [Line Items]
Long-term debt	1,500,000	1,500,000	1,500,000
2019 Senior Notes due December 2027 \| Senior Notes
Debt Instrument [Line Items]
Long-term debt	$ 600,000	$ 600,000	$ 0

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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