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CONDENSED CONSOLIDATING FINANCIAL INFORMATION (Narrative) (Details) - Senior notes - USD ($) | Oct. 11, 2017 | Dec. 21, 2016 | Oct. 14, 2016 | Apr. 21, 2015
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6.625% senior unsecured notes due 2023 |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |
Debt instrument, amount |  |  |  | $ 350,000,000.0
6.000% senior unsecured notes due 2024 |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |
Debt instrument, amount |  |  | $ 650,000,000.0 |
6.375% senior unsecured notes due 2025 |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |
Debt instrument, amount |  | $ 600,000,000.0 |  |
6.375% senior unsecured notes due 2026 |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |
Debt instrument, amount | $ 450,000,000.0 |  |  |

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