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CAPITAL STOCK (Details) | 1 Months Ended | 3 Months Ended | 12 Months Ended |  |  |  |
--- | --- | --- | --- | --- | --- | --- | ---
Feb. 01, 2016 shares | Mar. 31, 2018 USD ($) | Sep. 30, 2016 USD ($) | Dec. 31, 2018 USD ($) $ / shares shares | Dec. 31, 2017 USD ($) shares | Dec. 31, 2016 USD ($) shares | Nov. 26, 2018 USD ($) | Oct. 18, 2018 $ / shares | Feb. 09, 2017 $ / shares shares | Aug. 10, 2016 $ / shares shares
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Stock Repurchase Program, Authorized Amount |  |  |  |  |  |  | $ 200,000,000 |  |  |
Stock Repurchased During Period, Shares | shares |  |  |  | 5,400,000 |  |  |  |  |  |
Repurchase of common shares |  |  |  | $ (47,500,000) | $ 0 | $ 0 |  |  |  |
Stock Repurchase Program, Average Price | $ / shares |  |  |  | $ 8.78 |  |  |  |  |  |
Stock Repurchase Program, Remaining Authorized Repurchase Amount |  |  |  | $ 152,700,000 |  |  |  |  |  |
Dividends Payable |  |  |  | 15,000,000 |  |  |  |  |  |
Common Stock, New Shares, Issued | shares |  |  |  |  |  |  |  |  | 63,250,000 | 44,400,000
Shares Issued, Price Per Share | $ / shares |  |  |  |  |  |  |  |  | $ 10.75 | $ 6.75
Net proceeds from issuance of common shares |  |  |  | 0 | 661,300,000 | $ 287,400,000 |  |  |  |
Debt Extinguished |  |  |  | $ 227,400,000 | $ 1,610,700,000 |  |  |  |  |
Trading Day Window Determining Number of Common Shares Issuable on Conversion | 20 |  |  |  |  |  |  |  |  |
Common shares, issued (in shares) | shares |  |  |  | 301,886,794 | 301,886,794 |  |  |  |  |
Common Shares Issued in Debt to Equity Exchange | shares |  |  |  |  |  | 8,200,000 |  |  |  |
Gain (loss) on extinguishment/restructuring of debt |  |  |  | $ (6,800,000) | $ (165,400,000) | $ 166,300,000 |  |  |  |
Common Stock [Member] |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Dividends payable, per share | $ / shares |  |  |  |  |  |  |  | $ 0.05 |  |
Common shares, issued (in shares) | shares | 26,500,000 |  |  |  |  |  |  |  |  |
Convertible Preferred Stock, Common Shares Issued Upon Conversion | shares | 25,200,000 |  |  |  |  |  |  |  |  |
Convertible Preferred Stock, Common Shares Issued Upon Conversion in Lieu of Dividend | shares | 1,300,000 |  |  |  |  |  |  |  |  |
Exchange of Debt for Equity [Member] |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Gain (loss) on extinguishment/restructuring of debt |  |  |  |  |  | 11,300,000 |  |  |  |
$500 Million 3.95% 2018 Senior Notes [Member] |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Debt Instrument, Face Amount Exchanged |  |  |  |  |  | $ 17,600,000 |  |  |  |
Debt Instrument, Interest Rate, Stated Percentage |  |  |  |  |  | 3.95% |  |  |  |
Gain (loss) on extinguishment/restructuring of debt |  |  | $ 19,900,000 |  |  | $ 1,800,000 |  |  |  |
$500 Million 3.95% 2018 Senior Notes [Member] | Exchange of Debt for Equity [Member] |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Debt Instrument, Face Amount Exchanged |  |  |  |  |  | 10,000,000 |  |  |  |
$218.5 Million 8.00% 2020 1.5 Lien Notes |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Debt Extinguished |  |  |  |  | $ 218,500,000 |  |  |  |  |
Debt Instrument, Face Amount Exchanged |  |  |  |  |  | $ 512,200,000 |  |  |  |
Debt Instrument, Interest Rate, Stated Percentage |  |  |  |  | 8.00% | 8.00% |  |  |  |
Gain (loss) on extinguishment/restructuring of debt |  |  |  |  | $ 45,100,000 | $ 174,300,000 |  |  |  |
$218.5 Million 8.00% 2020 1.5 Lien Notes | Exchange of Debt for Equity [Member] |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Debt Instrument, Face Amount Exchanged |  |  |  |  |  | 20,100,000 |  |  |  |
$544.2 Million 7.75% 2020 Second Lien Notes |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Debt Extinguished |  |  |  |  | $ 430,100,000 |  |  |  |  |
Debt Instrument, Face Amount Exchanged |  |  |  |  |  | 114,100,000 |  |  |  |
Debt Instrument, Interest Rate, Stated Percentage |  |  |  |  | 7.75% |  |  |  |  |
Gain (loss) on extinguishment/restructuring of debt |  |  |  |  | $ (104,500,000) | 6,900,000 |  |  |  |
$700 Million 4.875% 2021 Senior Notes |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Debt Extinguished |  |  |  | $ 14,400,000 | $ 171,000,000 |  |  |  |  |
Debt Instrument, Face Amount Exchanged |  |  |  |  |  | $ 76,300,000 |  |  |  |
Debt Instrument, Interest Rate, Stated Percentage |  |  |  | 4.875% | 4.875% | 4.875% |  |  |  |
Gain (loss) on extinguishment/restructuring of debt |  |  |  | $ 100,000 | $ (2,800,000) | $ 33,300,000 |  |  |  |
$700 Million 4.875% 2021 Senior Notes | Exchange of Debt for Equity [Member] |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Debt Instrument, Face Amount Exchanged |  |  |  |  |  | 26,800,000 |  |  |  |
$1.075 Billion 5.75% 2025 Senior Notes [Member] |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Proceeds from Issuance of Debt |  | $ 500,000,000 |  |  |  |  |  |  |  |
Debt Instrument, Interest Rate, Stated Percentage |  |  |  | 5.75% |  |  |  |  |  |
Secured Debt [Member] |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Debt Extinguished |  |  |  | $ 648,600,000 |  |  |  |  |  |
Unsecured Debt [Member] |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Debt Extinguished |  |  |  | 422,200,000 |  |  |  |  |  |
$540 Million 8.25% 2020 First Lien Notes |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Debt Extinguished |  | $ 35,600,000 |  |  | $ 540,000,000 |  |  |  |  |
Debt Instrument, Interest Rate, Stated Percentage |  |  |  |  | 8.25% |  |  |  |  |
Gain (loss) on extinguishment/restructuring of debt |  |  |  |  | $ (93,500,000) |  |  |  |  |
$400 Million 5.90% 2020 Senior Notes |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Debt Extinguished |  |  |  | $ 88,900,000 | $ 136,700,000 |  |  |  |  |
Debt Instrument, Face Amount Exchanged |  |  |  |  |  | 65,100,000 |  |  |  |
Debt Instrument, Interest Rate, Stated Percentage |  |  |  | 5.90% | 5.90% |  |  |  |  |
Gain (loss) on extinguishment/restructuring of debt |  |  |  | $ (3,300,000) | $ (7,800,000) | 28,300,000 |  |  |  |
$500 Million 4.80% 2020 Senior Notes |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Debt Extinguished |  |  |  | $ 122,400,000 | $ 114,400,000 |  |  |  |  |
Debt Instrument, Face Amount Exchanged |  |  |  |  |  | $ 44,700,000 |  |  |  |
Debt Instrument, Interest Rate, Stated Percentage |  |  |  | 4.80% | 4.80% | 4.80% |  |  |  |
Gain (loss) on extinguishment/restructuring of debt |  |  |  | $ (3,700,000) | $ (1,900,000) | $ 19,500,000 |  |  |  |

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