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Long-term Debt Senior Notes (Details) - USD ($) $ in Thousands |  |  |  |  |  |  | 3 Months Ended | 12 Months Ended
--- | --- | --- | --- | --- | --- | --- | --- | ---
Aug. 20, 2018 | Jul. 16, 2018 | Sep. 12, 2016 | May 21, 2015 | Nov. 17, 2014 | May 20, 2013 | Sep. 30, 2018 | Mar. 31, 2016 | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Senior Notes [Line Items] |  |  |  |  |  |  |  |  |  |  |
Principal amount, net of unamortized deferred financing costs |  |  |  |  |  |  |  |  | $ 2,453,035 | $ 2,448,439 |
Loss on extinguishment of debt |  |  |  |  |  |  |  |  | 0 | (26,740) | $ (35)
Accelerated unamortized deferred financing costs for extinguishment of debt |  |  |  |  |  |  |  |  | $ 0 | 6,334 | $ 22
6.125% Senior Notes Due 2022 [Member] |  |  |  |  |  |  |  |  |  |  |
Senior Notes [Line Items] |  |  |  |  |  |  |  |  |  |  |
Senior Notes, interest rate, stated percentage |  |  |  |  |  |  |  |  | 6.125% |  |
Principal amount |  |  |  |  | $ 600,000 |  |  |  | $ 476,796 | 476,796 |
Unamortized deferred financing costs |  |  |  |  |  |  |  |  | (2,920) | (3,921) |
Principal amount, net of unamortized deferred financing costs |  |  |  |  |  |  |  |  | $ 473,876 | 472,875 |
Senior Notes, repurchased face amount |  |  |  |  |  |  | $ 85,000 | $ 38,200 |  |  |
Senior Notes repurchased, settlement amount |  |  |  |  |  |  | 89,500 | $ 24,300 |  |  |
Net proceeds from Senior Notes issuance |  |  |  |  | 590,000 |  |  |  |  |  |
Senior Notes debt issuance costs |  |  |  |  | $ 10,000 |  |  |  |  |  |
5% Senior Notes Due 2024 [Member] |  |  |  |  |  |  |  |  |  |  |
Senior Notes [Line Items] |  |  |  |  |  |  |  |  |  |  |
Senior Notes, interest rate, stated percentage |  |  |  |  |  |  |  |  | 5.00% |  |
Principal amount |  |  |  |  |  | $ 500,000 |  |  | $ 500,000 | 500,000 |
Unamortized deferred financing costs |  |  |  |  |  |  |  |  | (3,766) | (4,688) |
Principal amount, net of unamortized deferred financing costs |  |  |  |  |  |  |  |  | $ 496,234 | 495,312 |
Net proceeds from Senior Notes issuance |  |  |  |  |  | 490,200 |  |  |  |  |
Senior Notes debt issuance costs |  |  |  |  |  | $ 9,800 |  |  |  |  |
5.625% Senior Notes Due 2025 [Member] |  |  |  |  |  |  |  |  |  |  |
Senior Notes [Line Items] |  |  |  |  |  |  |  |  |  |  |
Senior Notes, interest rate, stated percentage |  |  |  |  |  |  |  |  | 5.625% |  |
Principal amount |  |  |  | $ 500,000 |  |  |  |  | $ 500,000 | 500,000 |
Unamortized deferred financing costs |  |  |  |  |  |  |  |  | (4,903) | (5,808) |
Principal amount, net of unamortized deferred financing costs |  |  |  |  |  |  |  |  | $ 495,097 | 494,192 |
Net proceeds from Senior Notes issuance |  |  |  | 491,000 |  |  |  |  |  |  |
Senior Notes debt issuance costs |  |  |  | $ 9,000 |  |  |  |  |  |  |
6.75% Senior Notes Due 2026 [Member] |  |  |  |  |  |  |  |  |  |  |
Senior Notes [Line Items] |  |  |  |  |  |  |  |  |  |  |
Senior Notes, interest rate, stated percentage |  |  |  |  |  |  |  |  | 6.75% |  |
Principal amount |  |  | $ 500,000 |  |  |  |  |  | $ 500,000 | 500,000 |
Unamortized deferred financing costs |  |  |  |  |  |  |  |  | (5,571) | (6,407) |
Principal amount, net of unamortized deferred financing costs |  |  |  |  |  |  |  |  | $ 494,429 | 493,593 |
Net proceeds from Senior Notes issuance |  |  | 491,600 |  |  |  |  |  |  |  |
Senior Notes debt issuance costs |  |  | $ 8,400 |  |  |  |  |  |  |  |
6.625% Senior Notes Due 2027 [Member] |  |  |  |  |  |  |  |  |  |  |
Senior Notes [Line Items] |  |  |  |  |  |  |  |  |  |  |
Senior Notes, interest rate, stated percentage |  |  |  |  |  |  |  |  | 6.625% |  |
Principal amount | $ 500,000 |  |  |  |  |  |  |  | $ 500,000 | 500,000 |
Unamortized deferred financing costs |  |  |  |  |  |  |  |  | (6,601) | (7,533) |
Principal amount, net of unamortized deferred financing costs |  |  |  |  |  |  |  |  | 493,399 | 492,467 |
Net proceeds from Senior Notes issuance | 492,100 |  |  |  |  |  |  |  |  |  |
Senior Notes debt issuance costs | $ 7,900 |  |  |  |  |  |  |  |  |  |
Senior Notes [Member] |  |  |  |  |  |  |  |  |  |  |
Senior Notes [Line Items] |  |  |  |  |  |  |  |  |  |  |
Principal amount |  |  |  |  |  |  |  |  | 2,476,796 | 2,476,796 |
Unamortized deferred financing costs |  |  |  |  |  |  |  |  | (23,761) | (28,357) |
Principal amount, net of unamortized deferred financing costs |  |  |  |  |  |  |  |  | $ 2,453,035 | 2,448,439 |
6.50% Senior Notes Due 2021 [Member] |  |  |  |  |  |  |  |  |  |  |
Senior Notes [Line Items] |  |  |  |  |  |  |  |  |  |  |
Senior Notes repurchased, settlement amount |  | $ 355,900 |  |  |  |  |  |  |  |  |
6.50% Senior Notes Due 2023 [Member] |  |  |  |  |  |  |  |  |  |  |
Senior Notes [Line Items] |  |  |  |  |  |  |  |  |  |  |
Senior Notes, repurchased face amount |  |  |  |  |  |  | 395,000 |  |  |  |
Q3 2018 Senior Notes Transactions [Member] |  |  |  |  |  |  |  |  |  |  |
Senior Notes [Line Items] |  |  |  |  |  |  |  |  |  |  |
Senior Notes repurchased, settlement amount |  |  |  |  |  |  | $ 497,800 |  |  |  |
Loss on extinguishment of debt |  |  |  |  |  |  |  |  |  | (26,700) |
Premiums paid for extinguishment of debt |  |  |  |  |  |  |  |  |  | 20,400 |
Accelerated unamortized deferred financing costs for extinguishment of debt |  |  |  |  |  |  |  |  |  | $ 6,300 |

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